Blood Physiology

A) Red blood cells

The hemoglobin is an excellent acid-base buffer, so the red blood cells are responsible for most of the acid-base buffering power of the blood.

D) 3%

A) 7.8 micrometers

C) 90 to 95 cubic micrometers

B) Both statements are true.

D) Only the second statement is true.

RBCs have the ability to concentrate hemoglobin in the cell fluid up to about 34 grams in each 100 milliliters of cells.

D) 15 grams of hemoglobin per 100 milliliters

The whole blood of women contains 14 grams of hemoglobin per 100 milliliters.

C) 1.34

Therefore, in a normal man a maximum of about 20 mL of oxygen can be carried in combination with hemoglobin in each 100 mL of blood, and in a normal woman 19 mL of oxygen can be carried.

C) Only the first statement is true.

During the middle trimester of gestation, the liver is the main organ for production of RBCs, but reasonable numbers are also produced in the spleen and lymph nodes. 

During the last month or so of gestation and after birth, RBCs are produced exclusively in the bone marrow.

C) 20

Beyond this age, most RBCs continue to be produced in the marrow of the membranous bones, such as the vertebrae, sternum, ribs, and ilia. Even in these bones, the marrow becomes less productive as age increases.

B) Interleukin-3

C) Diapedesis

Diapedesis refers to squeezing through the pores of the capillary membrane.

D) 1 to 2 days

B) Only the first statement is true.

Because of the short life of the reticulocytes, their concentration among all the RBCs is normally slightly less than 1 percent.

B) Tissue oxygenation

Conditions that decrease the quantity of oxygen transported to the tissues ordinarily increase the rate of RBC production.

A) Erythropoietin

B) 90%

The remainder is formed mainly in the liver.

A) Only the first statement is true.

This is because the 10% of the normal erythropoietin formed in the liver is sufficient to cause only one-third to one-half the RBC formation needed by the body.

A) Both of these

When an individual is placed in an atmosphere of low oxygen, erythropoietin begins to be formed within minutes to hours, and it reaches maximum production within 24 hours. Yet almost no new RBCs appear in the circulating blood until about 5 days later.

C) Both

Both of these vitamins are essential for the synthesis of DNA because each, in a different way, is required for the formation of thymidine triphosphate, one of the essential building blocks of DNA.

A) None of these

These poorly formed erythrocytes are capable of carrying oxygen normally, but their fragility causes them to have a short life, usually one-half to one-third the normal.

D) Only the second statement is true.

The intrinsic factor, which is produced by the parietal (oxyntic) cells of the stomach, binds tightly with the vitamin B12.

B) Pinocytosis

C) Only the first statement is true.

Therefore, 3 to 4 years of defective B12 absorption are usually required to cause maturation failure anemia.

B) 4

A) Hemoglobin A

Hemoglobin A is a combination of two alpha chains and two beta chains.

C) 4

Because each hemoglobin chain has a heme prosthetic group containing an atom of iron, and because there are four hemoglobin chains in each hemoglobin molecule, one finds four iron atoms in each hemoglobin molecule.

A) 8

Each of the four iron atoms can bind loosely with one molecule (or two atoms) of oxygen, making a total of four molecules of oxygen (or eight atoms) that can be transported by each hemoglobin molecule.

B) The amino acid valine is substituted for glutamic acid at one point in each of the two beta chains.

C) Hemoglobin S

These crystals make it almost impossible for the cells to pass through many small capillaries, and the spiked ends of the crystals are likely to rupture the cell membranes, leading to sickle cell anemia.

D) Only the first statement is true.

The oxygen does not combine with the two positive bonds of the iron in the hemoglobin molecule. Instead, it binds loosely with one of the coordination bonds of the iron atom.

A) 65%

About 4% is in the myoglobin, 1% is in the form of various heme compounds that promote intracellular oxidation, 0.1% is combined with protein transferrin in the blood plasma, and 15% to 30% is stored in the reticuloendothelial system and liver parenchymal cells for later use.

D) Liver hepatocytes

Excess iron in the blood is deposited especially in the liver hepatocytes and less in the reticuloendothelial cells of the bone marrow.

C) Ferritin

B) Hemosiderin

Hemosiderin collects in cells in the form of large clusters that can be observed microscopically as large particles.

B) Only the first statement is true.

There, iron is liberated and is stored mainly in the ferritin pool to be used as needed for the formation of new hemoglobin.

A) 0.6

Additional quantities of iron are lost when bleeding occurs. For a woman, additional menstrual loss of blood brings long-term iron loss to an average of 1.3 mg/day.

True

This slow rate of absorption means that even when tremendous quantities of iron are present in the food, only small proportions are absorbed.

A) Both statements are true.

A) Keep the iron of the cell's hemoglobin in the ferric form rather than the ferrous form

The cytoplasmic enzymes keep the iron of the cell's hemoglobin in the ferrous form rather than the ferric form.

B) Red pulp

The spaces between the structural trabeculae of the red pulp are only 3 µm wide, in comparison with the 8-µm diameter of the RBC.

A) Spleen

B) Liver

A) Either of these

A) Porphyrin

Bilirubin is a bile pigment, which is release into the blood and later remvoed from the body by secretion through the liver into the bile.

A) Only the second statement is true.

After a rapid hemorrhage, the body replaces the fluid portion of the plasma in 1 to 3 days, but this response results in a low concentration of RBCs.

B) Both

When chronic blood loss occurs, a person cannot frequently absorb enough iron from the intestines to form hemoglobin as rapidly as it is lost. Remember that the hemoglobin makes up the bulk of the RBCs are is responsible for its characteristic red color.

C) None of these

Aplastic anemia results from lack of functioning bone marrow.

A) None of these

Megaloblastic anemia is characterized by RBCs that are too large and have odd shapes. These deformed RBCs result from deficiency in vitamin B12, folic acid, and/or intrinsic factor, which usually come from the stomach mucosa. In intestinal sprue, folic acid, vitamin B12, and other vitamin B compounds are poorly absorbed.

C) Hereditary spherocytosis

In hereditary spherocytosis, the RBCs are very small and spherical rather than being biconcave disks. Upon passing through the splenic pulp and some other tight vascular beds, they are easily ruptured by even slight compression.

D) When the abnormal type of hemoglobin is exposed to high concentrations of carbon dioxide, it precipitates into long crystals inside the red blood cells.

When the abnormal type of hemoglobin is exposed to low concentrations of oxygen, it precipitates into long crystals inside the red blood cells. These crystals elongate the cell and give it the appearance of a sickle rather than a biconcave disk.

B) Erythroblastosis fetalis

The antibodies from the mother make the Rh-positive cells of the fetus fragile, leading to rapid rupture. This causes the child to be born with a serious case of anemia.

C) Erythroblastosis fetalis

The extremely rapid formation of new RBCs to make up for the destroyed cells in erythroblastosis fetalis causes a large number of early blast forms of RBCs to be released from the bone marrow into the blood.

C) Only the first statement is true.

The reduced blood viscosity decreases the resistance to blood flow in peripheral blood vessels. Because of the decreased peripheral resistance, greater than normal quantities of blood flow through the tissues and return to the heart, thereby greatly increasing the cardiac output.

B) All of these

The reduced blood viscosity seen in anemia increases the amount of blood returning to the heart. To accommodate such increase in blood volume, the heart must pump harder and faster, resulting to increased cardiac workload and cardiac output.

Moreover, hypoxia resulting from diminished oxygen transport of by the blood causes peripheral blood vessels to dilate, allowing a further increase in the return of blood to the heart and increasing the cardiac output to a still higher level.

A) Both statements are true.

B) None of these

Whenever the tissues become hypoxic because of too little oxygen in the breathed air, such as at high altitudes, or because of failure of oxygen delivery to the tissues, such as in cardiac failure, the blood-forming organs automatically produce large quantities of extra RBCs.

C) Physiological polycythemia

In polycythemia vera, otherwise known as erythremia, the red blood cell count is 7 to 8 million/mm3 and the hematocrit may be 60% to 70%.

C) None of these

C) Ruddy skin complexion

Although increased blood viscosity generally decreases the rate of venous return to the heart, the increase in blood volume also seen in polycythemia vera will tend to increase the venous return. Consequently, the cardiac output is not far from normal because these two factors more or less neutralize each other.

Because the blood sluggishly passes through the skin capillaries before entering the venous plexus, a larger than normal quantity of hemoglobin is deoxygenated. The blue color of these deoxygenated hemoglobin masks the red color of the oxygenated hemoglobin, resulting in a ruddy complexion with a bluish tint to the skin.

D) Leukocytes

A) Monocyte

The polymorphonuclear cells all have a granular appearance, and for this reason, they are called granulocytes.

B) Neutrophils

Neutrophils are the most abundant among the leukocytes, comprising approximately 62% of the total. Meanwhile, basophils are the least abundant, comprising only 0.4% of the total.

B) None of these

The granulocytes and monocytes are formed in the bone marrow.

C) Thyroid

It should be thymus.

A) Only the first is true.

Normally, about three times as many WBCs are stored in the marrow as those circulating in the blood. This quantity represents about a 6-day supply of these cells.

A) Both of these

In times of serious infection, this total life span is often shortened to only a few hours because the granulocytes proceed even more rapidly to the infected area, perform their function and, in the process, are destroyed.

A) Only the second statement is true.

The monocytes have a short transit time, about 10 to 20 hours in the blood, before wandering through the capillary membranes into the tissues.

C) Lymphocyte

Lymphocytes enter the circulatory system continually, along with drainage of lymph from the lymph nodes and other lymphoid tissue.

C) Neutrophils

C) Monocytes

Once the monocytes enter the tissues, they begin to swell - sometimes increasing their diameters as much as fivefold. These cells are now called macrophages and are extremely capable of combating disease agents.

D) Eosinophils

Neutrophils and monocytes can squeeze through the pores of the blood capillaries by diapedesis.

B) Monocytes

Both neutrophils and macrophages can move through the tissues by ameboid motion.

D) All of these

C) 100 µm away

Because almost no tissue area is more than 50 µm away from a capillary, the chemotactic signal can easily move hordes of WBCs from the capillaries into the inflamed area.

D) All of these

Most natural structures in the tissues have smooth surfaces, which resist phagocytosis. However, if the surface is rough, the likelihood of phagocytosis is increased. 

Most natural substances of the body have protective protein coats that repel the phagocytes. Conversely, most dead tissues and foreign particles have no protective coats, which makes them subject to phagocytosis. 

The antibodies adhere to the bacterial membranes and thereby make the bacteria especially susceptible to phagocytosis.  To do this, the antibody molecule combines with the C3 product of the complement cascade. The C3 molecules, in turn, attach to receptors on the phagocyte membrane, thus initiating phagocytosis.

A) 3 to 20

D) Neutrophil

The pseudopodia meet one another in the opposite side and fuse. This action creates an enclosed chamber that contains the phagocytized particle.

A) All of these

C) Only the first statement is true.

The lysosomes of macrophages also contain large amounts of lipases, which digest the thick lipid membranes possessed by some bacteria such as the tuberculosis bacillus.

B) Only the first statement is true.

These bacteria are responsible for many of the chronic diseases, an example of which is tuberculosis.

C) Myeloperoxidase

D) Both statements are true.

B) None of these

The monocytes, mobile macrophages, fixed tissue macrophages, and a few specialized endothelial cells in the bone marrow, spleen, and lymph nodes form the reticuloendothelial system.

A) Only the second statement is true.

When infection begins in a subcutaneous tissue and local inflammation ensues, local tissue macrophages can divide in situ and form still more macrophages. These macrophages are called histiocytes.

D) Both statements are false.

If the foreign particles are not destroyed locally in the tissues, they enter the lymph and flow to the lymph nodes located intermittently along the course of the lymph flow. The foreign particles are then trapped in these nodes in a meshwork of sinuses lined by tissue macrophages.

A) (1) Afferent lymphatics; (2) Nodal medullary sinuses; (3) Hilus; (4) Efferent lymphatics

C) If the particle is not digestible, the macrophages form a "giant cell" capsule around the particles until such time that they can be slowly dissolved.

If the particle is digestible, the macrophages can also digest it and release the digestive products into the lymph.

"Giant cell" capsules are frequently formed around tuberculosis bacilli, silica dust particles, and even carbon particles.

D) Kupffer cells

The Kupffer cells form an effective particulate filtration system that almost none of the bacteria from the gastrointestinal tract pass from the portal blood into the general systemic circulation.

B) Only the first statement is true.

Macrophages become entrapped by the reticular meshwork of these tissues and when the foreign particles come in contact with these macrophages, they are phagocytized.

A) Only the second statement is true.

The tissue spaces and the lymphatics in the inflamed area are blocked by fibrinogen clots so that after a while, fluid barely flows through the spaces.

C) Only the first statement is true.

As a result, inflammation develops rapidly - indeed, much more rapidly than the staphylococci can multiply and spread. Therefore, local staphylococcal infection is characteristically walled off rapidly and prevented from spreading through the body.

Streptococci, in contrast, do not cause such intense local tissue destruction. Therefore, the walling-off process develops slowly over many hours, while many streptococci reproduce and migrate. As a result, streptococci often have a far greater tendency to spread through the body and cause death than do staphylococci, even though staphylococci are far more destructive to the tissues.

A) First

When the tissue macrophages are activated by the products of infection and inflammation, the first effect is rapid enlargement of each of these cells. Next, many of the previously sessile macrophages break loose from their attachments and become mobile, forming the first line of defense against infection during the first hour or so.

C) Neutrophil invasion

Within the first hour or so after inflammation begins, large numbers of neutrophils begin to invade the inflamed area from the blood. This invasion is caused by inflammatory cytokines (e.g., tumor necrosis factor and interleukin-1) and other biochemical products produced by the inflamed tissues.

The tissue macrophages are the first line of defense; the second macrophage invasion is the third line of defense; and the increased production of granulocytes and monocytes by the bone marrow is the fourth line of defense.

C) All of these

B) Only the first statement is true.

Neutrophilia is caused by products of inflammation that enter the blood stream, are transported to the bone marrow, and there act on the stored neutrophils of the marrow to mobilize these into the circulating blood.

A) After invading the inflamed tissue, monocytes are still immature cells, requiring 8 days or more to swell to much larger sizes and develop tremendous quantities of lysosomes.

After invading the inflamed tissue, monocytes are still immature cells, requiring 8 hours or more to swell to much larger sizes and develop tremendous quantities of lysosomes.

D) 3 to 4

B) Interleukin-2

It should be interleukin-1.

A) Dead monocytes

It should be dead macrophages.

B) They exhibit diapedesis.

Eosinophils exhibit chemotaxis, whereas neutrophils and macrophages exhibit diapedesis.

A) Eosinophil

Schistosomiasis is a parasitic infection found in as many as one third of the population of some developing countries in Asia, African, and South America.

A) Releasing proteolytic enzymes

It should be releasing hydrolytic enzymes. Major basic protein is a highly larvacidal polypeptide.

A) Eosinophil

Trichinosis is a condition resulting from invasion of the body's muscles by the Trichinella parasite ("pork worm") after a person eats undercooked infested pork.

B) Eosinophils

The mast cells and basophils release an eosinophil chemotactic factor that causes eosinophils to migrate toward the inflamed allergic tissue.

B) Eosinophils

B) Basophils

A) Both statements are false.

Both mast cells and basophils liberate heparin into the blood. Heparin is a substance that can prevent blood coagulation.

B) Warfarin

It should be heparin. It is mainly the mast cells in inflamed tissues that release these substances during inflammation.

A) Basophils

Although the immunoglobulin E also has a special propensity to become attached to mast cells, these cells are not leukocytes.

C) Anti-histamines

When the mast cell or basophil ruptures, it releases histamine, bradykinin, serotonin, heparin, leukotrienes, and lysosomal enzymes.

B) Both statements are true.

B) Both of these

A) Only the first statement is true.

Leukemic cells, especially the very undifferentiated cells, are usually nonfunctional for providing normal protection against infection.

B) Only the first statement is true.

Common effects of leukemia are the development of infection, severe anemia, and a bleeding tendency. These effects result mainly from displacement of the normal bone marrow and lymphoid cells by the nonfunctional leukemic cells.

D) Both statements are true.

C) Presence in lymph of certain chemicals and cells that attach to foreign organisms or toxins and destroy them

It should be presence in blood of certain chemicals and cells that attach to foreign organisms or toxins and destroy them.

D) Lymphocytes

Acquired immunity is also known as adaptive immunity.

B) Both statements are false.

The T lymphocytes are responsible for forming the activated lymphocytes that provide "cell-mediated" immunity. Meanwhile, the B lymphocytes are responsible for forming antibodies that provide "humoral" immunity.

B) Thymus

They are called T lymphocytes to designate the role of the thymus.

A) Liver

Meanwhile, the B lymphocytes are preprocessed in the bone marrow in late fetal life and after birth.

A) Only the first statement is true.

These stem cells are incapable of directly forming activated lymphocytes and antibodies. Before they can do so, they must be further differentiated in appropriate processing areas.

A) Both of these

True

This process continues until there are thousands of different types of thymic lymphocytes with specific reactivities against many thousands of different antigens. These different types of preprocessed T lymphocytes now leave the thymus and spread by way of blood throughout the body to lodge in lymphoid tissue everywhere.

D) Thymus

Otherwise, the T lymphocytes would be lethal to the person's own body in only a few days.

B) Only the first statement is true.

If a T lymphocyte reacts, it is destroyed and phagocytized instead of being released. This happens to up to 90% of the cells.

B) Only the first statement is true.

Removal of the thymus gland beyond this period diminishes (but does not eliminate) the T-lymphocytic immune system. However, removal of the thymus several months before birth can prevent the development of all cell-mediate immunity.

D) Only the first statement is true.

One can transplant organs with much less likelihood of rejection if the thymus is removed from an animal a reasonable time before its birth. This is because removal of the thymus a reasonable time before birth prevents the development of all cell-mediated immunity.

D) Both of these

False

When specific antigens come in contact with T lymphocytes in the lymphoid tissue, certain T lymphocytes become activated to form activated T cells. When specific antigens come in contact with B lymphocytes, these cells become activated to form antibodies.

B) Clone of lymphocytes

Each clone of lymphocytes is responsive to only a single type of antigen or to several similar antigens that have almost exactly the same stereochemical characteristics.

D) Only the first statement is true.

The activated T- helper cells secrete lymphokines that activate the specific B lymphocytes. Without the aid of these T-helper cells, the quantity of antibodies formed by the B lymphocytes is usually slight.

D) Helper T-cells

D) 2000 molecules per second

These antibodies are secreted into the lymph and carried to the circulating blood.

A) Memory cells

D) Both statements are false.

The constant portion of the antibody specifically attaches to a particular type of antigen. Meanwhile, the variable portion determines the biological properties of the antibody, such as its diffusivity in the tissues, adherence to specific structures, and attachment to complement complex.

B) IgG

D) Agglutination

Precipitation is a process in which the molecular complex of the soluble antigen and antibody becomes so large that it is rendered insoluble and precipitates.

Neutralization is a process in which the antibodies cover the toxic sites of the antigenic agent.

Lysis is a process in which some potent antibodies are occasionally capable of directly attacking membranes of cellular agents and thereby cause rupture of the agent.

A) Opsonization

A) Both

T-lymphocyte memory cells are formed in the same way that B memory cells are formed in the antibody system.

A) Only the first statement is true.

The three major types of antigen-presenting cells are macrophages, B lymphocytes, and dendritic cells.

C) Dendritic cells

The only known function of the dendritic cells is to present antigens to T cells.

C) Cytotoxic T-cells

Meanwhile, MHC II proteins present antigens to the helper T-cells.

C) Helper T-cells

The helper T-cells are by far the most numerous of the T cells, usually constituting more than three quarters of all of them.

C) Helper T-cells

C) Helper T-cells

B) Lymphokines

C) Helper T-cells

Eventually, this leads to the debilitating and lethal effects of acquired immunodeficiency syndrome.

D) Only the first statement is true.

The lymphokine interleukin-2 has an especially strong stimulatory effect in  causing growth and proliferation of both cytotoxic and suppressor T-cells. Several of the other lymphokines have less potent effects.

B) Interleukin-3

Almost all of the interleukins participate in the B-cell response, but especially interleukins 4, 5, and 6. In fact, these three interleukins have such potent effects on the B cells that they have been called B-cell stimulating factors or B-cell growth factors.

A) Interleukin-2

The interleukin-2 acts as an amplifier by further enhancing the helper cell response, as well as the entire immune response to an invading antigen.

A) None of these

The lymphokines stimulate the T-cells (all types), B-cells, and macrophages.

D) Both of these

D) Only the first statement is true.

he receptor proteins on the surfaces of these T-cells cause them to bind tightly to the organisms or cells that contain the appropriate binding-specific antigen.

A) Perforins

Apart from perforins, the cytotoxic T-cells also release cytotoxic substances directly into the attacked cell.

True

Indeed, some of these cells persist for months in the tissues.

A) Both statements are true.

B) Cytotoxic T-cells

B) Suppressor T-cells

Immune tolerance is an active state of unresponsiveness to specific antigens in an effort to prevent destructive over-reactivity of the immune system.

D) Both statements are true.

When specific immature lymphocytes in the thymus are exposed to a strong antigen, they proliferate considerably and then combine with the stimulating antigen. This, in turn, causes these lymphocytes to be destroyed by the thymic epithelial cells before they can migrate to and colonize the total body lymphoid tissue.

D) Only the first statement is true.

Rheumatic fever develops following exposure to a specific type of streptococcal toxin that has an epitope in its molecular structure similar to the structure of some of the body's own self-antigens.

B) Measles

Immunization against measles can be achieved by injecting attenuated, not dead organisms.

C) Botulism

Attenuated organisms are used to immunize against viral diseases. Immunity against botulism, tetanus, and other similar toxic diseases can be achieved by treating the toxins with chemicals so that their toxic nature will be destroyed, while keep their antigens responsible for immunity intact.

C) Both of these

Passive immunity is a temporary immunity which can be achieved by infusing antibodies, activated T cells, or both. These can be obtained from the blood of someone else or from some other animal that has been actively immunized against the antigen.

A) Activated T cells

In the case of poison ivy, the toxin of the poison ivy in itself does not cause much harm to the tissues. However, upon repeated exposure, it does cause the formation of activated helper and cytotoxic T-cells. After subsequent exposure to poison ivy toxin, the activated T cells diffuse from the circulating blood in large numbers into the skin to respond to the toxin.

D) IgE

C) Histamine

B) Epinephrine

Epinephrine is administered to oppose the effects of histamine.

C) Leukotriene

Leukotrienes can cause spasm of the smooth muscle of the bronchioles, eliciting an asthma-like attack, sometimes causing death by suffocation.

C) Only the first statement is true.

Histamine released locally causes vasodilation that induces an immediate red flare, as well as increased local permeability of the capillaries that leads to local circumscribed areas of skin swelling.

Administration of antihistamine drugs to a person before exposure will prevent the hives.

D) Only the second statement is true.

In hay fever, the allergin-reagin reaction occurs in the nose. Yellow fever is an acute, viral hemorrhagic disease transmitted by infected mosquitoes.

A) Leukotrienes

Leukotriences causes spasm of the bronchiolar smooth muscle. The person will have difficulty breathing unless the reactive products of allergic reaction have been removed. Administration of antihistamine medication has less effect on the course of asthma because histamine does not appear to be the major factor eliciting the asthmatic reaction.

B) Red blood cells

It it these antigens (also called agglutinogens because they often cause blood cell agglutination) that cause most blood transfusion reactions.

B) Type O

When only type A agglutinogen is present, the blood is type A.

When only type B agglutinogen is present, the blood is type B.

When both A and B agglutinogens are present, the blood is type AB.

A) Both statements are true.

C) A

Remember that the O allele is recessive to both the A and B alleles, which show co-dominance. Therefore, a genotype of OA will result to A blood type.

D) Agglutinogens: A or B

It should be agglutinogens: A and B.

A) A

O is the most common blood type, present in 47%; A is the second most common, present in 41%; B is the second least common, present in 9%; and AB is the least common, present in 3%.

True

Similarly, when type B agglutinogen is not present in the RBCs, antibodies known as anti-B agglutinins develop in the plasma.

C) Both statements are true.

A) Only the first statement is true.

 Two to eight months after birth, an infant begins to produce agglutinins - anti-A agglutinins when type A agglutinogens are not present in the cells, and anti-B agglutinins when type B agglutinogens are not present in the cells.

D) 8 to 10 years of age

This titer gradually declines throughout the remaining years of life.

B) Only the first statement is true.

Most of the agglutinins are IgM and IgG immunoglobulin molecules.

A) 2

Meanwhile, the IgM type of agglutinin has 10 binding sites.

A) Both statements are true.

The special type of IgM antibodies are called hemolysins.

C) Both statements are true.

C) Six

These types are designated C, D, E, c, d, and e. A person who has a C antigen does not have the c antigen, but the person missing the C antigen always has the c antigen. The same is true for the D-d and E-e antigens. Also, because of the manner of inheritance of these factors, each person has one of each of the three pairs of antigens.

C) D

The type D antigen is widely prevalent in the population and considerably more antigenic than the other antigens.

C) D

It must be noted that even in Rh-negative people, some of the other antigens (C, E, c, d, and e) can still cause transfusion reactions, although the reactions are usually much milder.

C) African blacks

85% of white people are Rh-positives, whereas 95% of American blacks are Rh-positives.

B) Only the first statement is true.

However, anti-Rh antibodies can develop in sufficient quantities during the next 2 to 4 weeks to cause agglutination of the transfused cells that are still circulating in the blood.

A) Erythroblastosis fetalis

Erythroblastosis fetalis is a disease of the fetus and newborn child characterized by agglutination and phagocytosis of the fetus’s RBCs.

C) Only the second statement is true.

An Rh-negative mother having her first Rh-positive baby usually does not develop sufficient anti-Rh agglutinins to cause any harm.

B) Yellow

The agglutinated RBCs subsequently hemolyze, releasing hemoglobin into the blood. The fetus's macrophages then convert the hemoglobin into bilirubin, which causes the infant's skin to become yellow (jaundiced).

C) Lymphadenopathy

It should be hepatosplenomegaly. The liver and spleen of the fetus become enlarged in an attempt to replace the hemolyzed RBCs.

B) Only the second statement is true.

One treatment for erythroblastosis fetalis is to replace the neonate's blood with Rh-negative blood.

C) D

D) Donor blood

The small amount of infused blood does not significantly dilute the agglutinins in the recipient’s plasma. Therefore, the recipient’s agglutinins can still agglutinate the mismatched donor cells.

D) None of these

B) Xenograft

Autografts and isografts virtually contain the same types of antigens as in the tissues of the recipient, and will continue to liver normally and indefinitely if an adequate blood supply is provided.

A) 5 to 15 years

Meanwhile, liver and heart allografts are successful for 1 to 15 years.

D) None of these

Glucocorticoids inhibit interleukin-2, which is an essential factor that induces T- cell proliferation and antibody formation.

Azathioprine has a toxic effect on the lymphoid system, thereby blocking the formation of antibodies and T cells.

Cyclosporine and tacrolimus inhibit the formation of helper T-cells.

D) Eventual growth of fibrous tissue into the platelet plug

It should be eventual growth of fibrous tissue into the blood clot.

A) Only the second statement is true.

Platelets are formed in the bone marrow from megakaryocytes, which are extremely large hematopoietic cells in the marrow.

D) Nucleus

Platelets do not have nuclei; therefore, they cannot reproduce.

C) Both statements are true.

B) Spleen

B) Secrete ATP and thromboxane A2, which activate nearby platelets

Platelets secrete ADP and thromboxane A2, which activate nearby platelets.

C) 15 to 20 seconds

If the trauma has been minor, the blood clot begins to develop in 1 to 2 minutes.

D) All of these

D) Serum prothrombin conversion accelarator

Factor VII is known serum prothrombin conversion accelerator, proconvertin, or stable factor.

C) Factor VIII

D) Either

B) Liver

A) Vitamin K

B) 4

B) Serum

Serum cannot clot because it lacks clotting factors.

C) All of these

All of these are contractile proteins found within the cytoplasm of platelets. They cause strong contraction of platelet spicules attached to the fibrin. This action helps compress the fibrin meshwork into a smaller mass.

C) Thrombin

Thrombin has  a direct proteolytic effect on prothrombin, tending to convert this into still more thrombin. It also acts on some of the blood­clotting factors responsible for formation of prothrombin activator.

C) All of these

All of these instances lead to the formation of prothrombin activator, which causes prothrombin conversion to thrombin.

True

Meanwhile, the intrinsic pathway begins with trauma to the blood or exposure of the blood to collagen from a traumatized blood vessel wall.

A) Factor V

Factor V is also known as proaccelerin, labile factor, or Ac globulin.

C) Both statements are true.

High molecular-weight kininogen is also known as Fitzgerald factor, whereas prekallikrein is also known as Fletcher factor.

A) Calcium

Therefore, in the absence of calcium ions, blood clotting by either pathway does not occur.

D) Clotting occurs by intrinsic and extrinsic pathways simultaneously.

D) Factor III

Factor III is known as tissue factor. 

Meanwhile, contact of Factor XII and platelets with collagen in the vascular wall initiates the intrinsic pathway.

D) Extrinsic pathway

The intrinsic pathway is much slower to proceed, usually requiring 1 to 6 minutes to cause clotting.

B) None of these

The smoothness of the endothelial cell surface prevents contact activation of the intrinsic clotting system.

A layer of glycocalyx on the endothelium repels clotting factors and platelets, thereby preventing activation of clotting.

Thrombomodulin, a protein bound with endothelial membrane, binds with thrombin and slow the clotting process by removing thrombin. It also activates protein C, which acts as an anticoagulant by inactivating activated factors V and VIII.

D) Both of these

B) Both statements are true.

The thrombin that does not adsorb to the fibrin fibers soon combines with antithrombin III, which further blocks the effect of the thrombin on the fibrinogen and then also inactivates the thrombin itself.

C) Heparin

Protein C is a plasma protein.

Thrombomodulin is a protein bound with the endothelial membrane.

Thrombostenin is a contractile protein inside the platelet.

A) Mast cells

The largest quantities of heparin are formed by the mast cells located in the pericapillary connective tissues throughout the body. The basophils, which are functionally almost identical to the mast cells, release small quantitites of heparin into the plasma.

D) Liver and lungs

Mast cells are known to produce large quantities of heparin. Large quantities of heparin might be needed in these areas because the capillaries of the liver and lungs receive many embolic clots.

B) Factor II

Plasmin, also known as fibrinolysin, digests fibrinogen, as well as factors V, VIII, and XII. Therefore, whenever plasmin is formed, it can cause lysis of a clot by destroying many of the clotting factors, thereby sometimes even causing hypocoagulability of the blood.

A) Only the second statement is true.

The plasma proteins contain a euglobulin called plasminogen that, when activated, becomes plasmin.

B) Both statements are true.

D) Liver

Therefore, diseases of the liver such as hepatitis, cirrhosis, and acute yellow atrophy can sometimes depress the clotting system.

D) Factor VIII

Vitamin K is essential in the formation of clotting factors X, IX, VII, and II (1972).

B) Only the first statement is true.

However, in person with gastrointestinal disease, vitamin K deficiency often occurs as a result of poor absorption of fats from the gastrointestinal tract because vitamin K is fat soluble and is ordinarily absorbed into the blood along with the fats.

C) Peptic ulcer

Vitamin K is fat soluble and is absorbed into the blood along with fats. Therefore, any condition that results to poor fat absorption will cause vitamin K deficiency.

The thick mucus in the gastrointestinal tract of patients with cystic fibrosis results to poor absorption of fats. Cholelithiasis and liver cirrhosis can both result to lack of bile. Lack of bile prevents adequate fat digestion and absorption.

B) Both of these

If both criteria are met, it is likely that sufficient clotting factors will be produced to prevent excessive bleeding during the operation.

B) 85% of its cases is caused by an abnormality or deficiency in factor VIII, particularly the large component.

85% of the cases of hemophilia is caused by an abnormality or deficiency in factor VIII, particularly the small component. Abnormality or deficiency of the large component will result to von Willebrand diease. 

The remaining 15% of hemophilia cases is caused by an abnormal or deficient factor IX.

D) Both statements are true.

C) Both statements are true.

Remember that platelets are especially important for repair of minute breaks in capillaries and other small vessels.

B) Spleen

Splenectomy can be used to cure thrombocytopenia because the spleen removes large numbers of platelets from the blood.

C) Roughened endothelial surface of a blood vessel

Thromboembolism can be caused by a roughened endothelial surface of blood vessels, as may be caused by arteriosclerosis, infection, or trauma.

Thromboembolism can also result from blood that flows very slowly through the blood vessels. Small quantities of thrombin and other procoagulants are always being formed from the vascular endothelium, so blood that flows very slowly through the vessels is more likely to clot.

C) Only the first statement is true.

Warfarin causes this effect by inhibiting the enzyme VKOR c1, which converts the inactive, oxidized form of vitamin K to its active, reduced form.

C) Thrombocytes and erythrocytes

C) Eosinophils

B) Erythrocyte

D) Basophils

D) Erythrocytes

C) Small lymphocytes

A) Megakaryocytes

D) Monocytes

C) Erythrocytes

C) Reticulocytes

A) Neutrophils

D) Monocytes and lymphocytes

D) Spleen

C) Leukocytes

C) Adipocytes

D) Reticular cells

D) Erythroid island

D) Sinusoidal capillaries

C) Macrophages

A) Kidney

C) Reticular cells

A) Endosteum

A) Yellow bone marrow

C) Osteocytes

B) None of these

B) Hematopoietic cords

D) Reticular fibers

A) Liver and spleen

False

 Plasma is about 55% of the total blood volume.

True

In average, males have 5.2 million RBCs whereas females only have 4.7 million.

True

Bilirubin is a brownish yellow pigment of the bile, which gives feces their characteristic color. It is produced in the bone marrow cells and in the liver as the end product of hemoglobin breakdown.

True

True

False

True

B) Deoxyhemoglobin carries oxygen.

Oxyhemoglobin carries oxygen.

B) Hemocytoblast

B) The greenish pigment, biliverdin, is recycled to the bone marrow.

D) Vitamin B12 and folic acid

Deficiency of these vitamins can result to megaloblastic or pernicious anemia.

B) Iron deficiency

D) Neutrophil

A) Monocytes

D) Allergies or intestinal parasites

D) Leukocytosis

C) Alpha and beta globulins

The alpha and beta globulins transport iron, lipids, and the fat-soluble vitamins A, D, E, and K to the cells. Like albumin, these globulins also contribute to osmotic pressure.

B) Very low-density lipoproteins (VLDL)

Low-density lipoprotein (LDL) is considered 'bad' cholesterol because high levels can lead to the buildup of plaque in the arteries. Very low-density lipoproteins  (VLDL) is also considered 'bad' cholesterol because it mainly carries triglycerides, the most common type of fat in the body.

D) Blood vessel spasm, platelet plug formation, blood coagulation

C) Tissue thromboplastin

D) A and B; neither anti-A or anti-B

B) Rh-; Rh+

B) Erythrocyte

A) Plasma

Serum and plasma both come from the liquid portion of the blood that remains once the cells are removed.

Serum is the liquid that remains after the blood has clotted. Plasma is the liquid that remains when clotting is prevented with the addition of an anticoagulant.

C) Serum

C) Oxyhemoglobin

D) 120

A) 10,000 per mm3

A) Lymphocyte

Neutrophil, basophil, and eosinophil are classified as granulocytes; while lymphocyte and monocyte are classified as agranulocytes.

C) Lymphocyte

C) Monocyte

D) B-lymphocytes

A) Aplastic anemia

False

Deoxyhemoglobin causes a darker color that appears blue through light skin.

False

Sickle cell anemia is a genetic defect in the hemoglobin molecule which will cause the cells to bend and block capillaries under reduced oxygen tension.

False

Males have more erythrocytes than females whose count is 4.2-5.4 million per cubic mm.

True

Physiologic jaundice is the buildup of bile pigments in tissues possibly caused by failure of the liver to excrete the bilirubin and biliverdin in a soluble, conjugated form. Hyper-bilirubinemia or excess bilirubin in the blood can result in serious neurological damage or death in a neonate.

False

Since reticulocytes are immature red cells, their high production rate will be evidenced as a high count, indicating that not enough time was available for maturation.

True

Conditions that lower the amount of oxygen in the blood will stimulate the formation of new cells by the increase in erythropoietin.

True

Lack of B12 or gastric intrinsic factor causes the dysfunctional production of abnormally large, irregular erythrocytes.

True

The increase in oxygen demand and 30% increase in blood volume requires the synthesis of additional red blood cells.

True

Anemia is a functional decrease inthe ability of the blood to transport oxygen and may result from decreased numbers or a decrease in the oxygen-carrying-capacity of the hemoglobin. A condition called hypochromic anemia results from an iron deficiency, although the cell count is normal.

False

Most leukocytes remain alive for up to three weeks but the T lymphocytes are known to survive up to ten years.

False

Neutrophils and monocytes are the most active phagocytes. Lymphocytes do not have the ability to engulf particles but may have lysosomes.

False

Histamines are released from whiteblood cells, especially the eosinophil, and cause an increase in capillary permeability.

True

Pus is a collection of leukocytes that have been attracted to the site of infection or inflammation.

True

One of the causes of death from leukemia is internal hemorrhage caused by a deficiency of platelets caused by the excessive division of leukocytes within a limited area.

True

Although leukemia may originate in the bone marrow, the abnormal cells may be found everywhere as they disseminate through the blood or lymph by metastasis.

True

The liver and diet are the two most significant sources of plasma proteins which are significant in preventing loss of fluids from the blood.

False

Since lipids are less dense than proteins, high density lipoprotein combinations will have less protein and more lipids.

True

In this inherited trait, there is a relative lack of LDL receptors in the liver and cholesterol is carried to other sites by the LDL such as the arteries, developing arteriosclerosis.

True

Creatinine is a waste product of muscle or brain metabolism that is excreted by the kidneys.

True

Vessel contraction may result whenever there is injury to blood vessels, and this may be sufficient to halt bleeding especially in small diameter venules and arterioles.

False

The extrinsic phase of clotting is initiated by chemicals released from damaged tissue or blood vessel cells.

True

Disseminated intravascular coagulation is caused by infection or cancer and results in random clot formation which increases the chance for hemorrhage in other areas.

True

Serum is the fluid remaining after a clot has formed and does not contain many significant clotting elements.

False

Technically speaking, these enzymes can activate plasmin which then dissolves the clot. A moving clot is properly termed an embolus.

True

In the ABO blood type system, each person will produce the opposite antibody to the factor they have on their erythrocyte.

B) 5

The average amount of blood in an adult is close to 5 liters. Males have more than females.

D) 5

Hematocrit represents about 45% of the total blood volume and is also referred to as the HCT or packed cell volume (PCV).

A) Platelets and leukocytes

The buffy coat contains the white blood cells and platelets suspended between the red blood cells and plasma.

C) Erythrocytes

Red blood cells transport most of the oxygen as oxyhemoglobin and about 8-25% of the carbon dioxide as carbaminohemoglobin.

B) 33

About one-third of the volume of an erythrocyte is hemoglobin.

B) Erythrocyte

The red blood cells gradually lose their nuclei as they leave the bone marrow and are released into the circulation.

B) Exercise

Periods of exercise, increased body temperature, large meals, and high altitudes all can cause an increase in red blood cell count.

D) Spleen

Although old cells will eventually lyse in any area, the spleen and liver contain the macrophages (reticuloendothelial system) that will actively destroy most of them.

D) Globin

The term globin refers to the protein in the hemoglobin which can readily be recycled. The heme will be degraded to bilirubin and biliverdin which are bile pigments which must be eliminated.

A) Ferritin

Ferritin is the protein which contains iron and gives the liver its color. The transferrin proteins transport iron in the blood.

D) Hemocytoblast

The hemocytoblast is the stem or parent cell population of the developing erythrocytes and other blood cells.

C) 120 days

Red blood cells will maintain their integrity and live about 120 days.

D) Kidney

Bone marrow is stimulated by erythropoietin.

C) Liver

The liver manufactures red blood cells in the fetus along with the spleen and bone marrow.

D) Megakaryoblast

The megakaryoblast becomes the megakaryocyte which differentiates and fragments into the mature thrombocytes or platelets.

D) Monocyte

The myeloblast gives rise to the granulocytes, while the monocyte arises from the monoblast which is agranular.

C) Vitamin B6

Vitamin B6, otherwise known as pyridoxine, is more important for epithelial and nerve function.

C) Monocyte

The cells called agranulocytes do not have the typical granules found in cells such as neutrophils. They are the monocytes and lymphocytes.

A) Polycythemia

Polycythemia occurs for several reasons, some related to environmental factors and others due to genetic or autoimmune factors.

Anemia is a decrease in oxygen carrying capacity of the blood.

Leukemia is a WBC malignancy.


Porphyria involves abnormal metabolism of molecules related to heme.

C) Pernicious anemia

Pernicious anemia is fatal and involves a severe drop in RBC counts.

Aplastic anemia or bone marrow suppression could have been induced by exposure to radiation or certain medications.

Hemolytic anemias arise from conditions such as sickle cell disease.

Bleeding leads to hemorrhagic anemia.

C) Neutrophils

Mature neutrophils have a complex nucleus that appears to have many segments to it.

B) Basophils

Under normal conditions, eosinophils account for around 1-3% of the differential white cell count and basophils less than 1%.

C) Neutrophils

Neutrophils account for around 54%-62% of the white cell count. Leukocyte is a general term for any white blood cell.

A) Monocytes

Although immature cells are usually larger than mature cells, the monocyte is the largest of the circulating, peripheral leukocytes.

D) Lymphocyte

Most leukocytes, especially the neutrophils, are phagocytic. However, the lymphocytes do not have phagocytic abilities but function to secrete chemicals such as antibodies.

B) Leukocytosis

Leukocytosis is a higher than normal differential white blood cell count.

Polycythemia is an increase in RBC counts.

Leukemia is a WBC malignancy.

Leukopenia is a deficiency in WBC.

C) Appendicitis

Most infections and some inflammations will elevate the white cell count but there are exceptions such as salmonella food poisoning or measles that exhibit lower counts.

A) Diapedesis

The ability to move through narrow openings and leave the circulation is diapedesis. The movement is ameboid and may be in response to an inflammation or infection.

B) Eosinophils

Eosinophils release chemicals from their granules such as histamines that cause the symptoms seen in certain allergic reactions.

A) Basophils

The basophils and tissue mast cells are sources of the anti-coagulant heparin.

A) Lymphocytes

The B-lymphocytes will respond to a foreign antigen by producing chemical antibodies which are intended to inactive the invader.

C) Acute lymphoid leukemia

Acute lymphoid leukemia (ALL) can occur at any age but is most common in children.

B) Neutrophils

Myeloid leukemia involves the granulocytes such as the neutrophil, basophil, or eosinophil.

B) Platelets

Platelets or thrombocytes are produced by the fragmentation of stem bone marrow cells called megakaryocytes.

B) 200,000 per cubic mm

Platelet counts range from 130,000 to 360,000 per cubic mm of blood.

B) Platelets

The platelets release chemicals (factors) that can initiate the clotting of blood.

B) Platelets

The platelets also play many roles in several other reactions, such as inflammation or blood pressure regulation, by releasing vasoactive compounds such as serotonin which is a neurotransmitter substance.

Basophils produce substances such as heparin.

Lymphocytes are for defense.

Monocytes are phagocytic and become tissue macrophages.

A) Water

Water accounts for 92% of the plasma. Platelets are part of the hematocrit.

D) 7%

Proteins comprise about 7% of the total plasma volume.

A) Albumin

Albumin is about 3.5-5.5g per 100 ml of plasma and is the most common protein. The globulins represent around 2.5-3.5 g.

A) Albumin

Although the majority of the osmotic molecules are the electrolytes and proteins, only the proteins are not free to cross capillary membranes and therefore exert a constant osmotic pressure. Albumin is the most common blood protein.

A) Gamma globulin

The gamma globulins will be the precursors to the functional antibodies synthesized by the lymphocytes for defense.

C) Fibrinogen

The protein fibrinogen (and prothrombin), is always present in the blood and can become activated during blood clot formation.

A) Liver

The liver is the most actively metabolic organ in the body and synthesizes most of the blood proteins and nutrients from simple compounds such as glucose and amino acids.

B) Chylomicron

The chylomicrons are comprised mainly of triglyceride lipids with some protein.

C) HDL

The high density lipoproteins (HDL) contain high concentrations of protein and lesser amounts of lipid.

D) LDL

The low density lipoproteins transport most of the cholesterol to places of deposition such as the walls of coronary arteries.

C) Urea

Urea is produced by the liver in an attempt to detoxify the amino fragments left over from protein metabolism. This functions to prevent pH alterations.

A) Collagen

Platelets are adhesive and will be attracted to collagen fibers with a strong affinity.

Vasodilation will lessen the chance for platelets to form a plug.

Serotonin is vasoactive.

Fibrinogen converts to fibrin.

D) Ca++

Calcium is a cofactor for several enzymes involved with clotting.

D) Thromboplastin

Thromboplastin is released from injured cells and complexes with calcium to begin the first clotting cascade reactions.

C) Thrombin

Thrombin arises from the first steps of clotting and requires a prothrombin activator and calcium to become active.

B) Thrombin

Thrombin acts as an enzyme to cleave fibrinogen into active fibrin molecules.

A) Fibrin

Fibrin is the active molecule that forms the network of fibrin threads in the clot that will entrap cells forming a blood clot.

D) Plasmin

Plasminogen is converted to its active form plasmin which dissolves clots.

Heparin can prevent a clot from forming but cannot dissolve it.

PDGF is platelet-derived growth factor.

B) Vitamin K

Vitamin K, otherwise known as phytomenadione or phylloquinone, is necessary for the synthesis of prothrombin, the others are anti-coagulants.

A) AB

The chance of receiving both antigen genes would express the least common type AB. O is the most common.

D) Second Rh+ fetus of Rh- mother

The Rh antibodies are only produced following prior exposure, and an Rh-mother will not produce antibodies to her Rh+ fetus unless blood is mixed; during labor when blood is mixed, the mother will produce antibodies and will develop a response to any subsequent Rh+ fetuses, causing possible erythroblastosis fetalis.

False

The lymphatic system absorbs fats and fat-soluble vitamins from the digestive system and transports these substances to the venous circulation.

False

Veins contain valves to allow for one-way movement of fluid.

False


Thymosin is a hormone which stimulates T-cell production in the thymus.

True

True

True

True

C) Veins

B) Both statements are true.

B) Subclavian trunk

A) Of the structure of their flap-like valves

D) Produce red blood cells

A) It is the site of maturation of T lymphocytes and the production of thymosin.

B) The spleen filters the blood much the same way the lymph nodes filter the lymph.

B) Hair color and texture

C) Tissues swell during inflammation because the increased permeability of capillaries causes fluids to accumulate in the area.

C) Bone marrow

Bursa of Fabricius is only found in birds.

C) Antigens may be proteins, polysaccharides, glycolipids, or glycoproteins that stimulate an immune response.

D) Tissue thromboplastin

Tissue thromboplastin is released by the platelets (thrombocytes) at the site of an injury.

B) B cells are activated when they encounter antigens that match their B cell receptors and receive cytokines from helper T cells.

B) IgA

The most abundant immunoglobulin in human milk is IgA, which represents over 90% of milk antibodies. However, IgM and IgG are also present, but in concentrations much lower than IgA.

D) Releasing interferon

C) Artificially acquired active immunity

A) Erythrocytes

Lymph contains a variety of substances including proteins, salts, glucose, fats, water, and leukocytes.

D) Right arm

The thoracic duct is the main lymphatic vessel for the return of chyle/lymph to the systemic venous system. It drains lymph from both lower limbs, abdomen (except the convex area of the liver), left hemithorax, left upper limb and left face and neck.

D) Left subclavian

B) Cortex

The outer cortex consists of groups of mainly inactivated B cells called follicles. When activated, these may develop into what is called a germinal center.

The capsule is a thin layer of dense fibrous connective tissue penetrated by various afferent and efferent lymphatic vessels.

The inner medulla contains large blood vessels, sinuses, and medullary cords.

A) Small intestine

Peyer's patches are groupings of lymphoid follicles in the mucus membrane that lines the small intestine.

D) Thymus

Sinus and nodule are parts of a lymph node.

C) Mesenteric

D) Thymus

B) Produces lymphocytes

The white pulp of the spleen is composed of lymphocytes, macrophages, dendritic cells, and plasma cells.

D) Marginal zone

B) Antibodies

C) Neutrophil

B) Interferons

False

The lymphatic system is a one-way system of vessels that returns tissue fluids to the heart.

True

Larger lymphatic vessels contain elastic fibers, smooth muscle, and valves much like veins.

False

The return of fluid is not symmetrical. The left lymphatic or thoracic ducts drains around three-fourths of the total body areas.

False

The skin has a rich network of lymphatic vessels which can acquire bacteria or other particles from shallow wounds.

True

The lymphatic system has a dual purpose in restoring lost tissue fluids and in providing mechanisms for defense.

False

Inspiration creates a negative thoracic pressure which causes lymph to return to the heart. At the same time, the positive abdominal pressure forces lymph fluid upward.

False

The thymus gland specifically differentiates thymocytes into the division of lymphocytes designated T cell or T-lymphocytes.

True

Although the T-cells originated in the thymus gland, they migrate outward and seed other areas.

False

The sinuses of the lymph nodes always contain clear lymph fluid. Although the spleen has a similar structure, the spleen is an organ served by arteries and veins.

False

Although it is true that red blood cell production by the spleen normally ceases at birth, there are some instances in which red cell production resumes such as in erythroblastosis fetalis.

False

Macrophages are phagocytic cells that belong to the reticuloendothelial system. Lymphocytes do not differentiate into phagocytic cells.

True

Tears contain bacteriocidal enzymes such as muramidase (a lysozyme) that are effective against some pathogens such as gram positive bacteria. Tears act as a chemical barrier to eye infection.

True

Inflammation is evoked by chemicals released from damaged tissues and not specific pathogens.

False

Mucous membranes act as mechanical barriers to infection and will function efficiently as long as the mucus is constantly removed and replaced.

True

Macrophages are phagocytic and therefore part of the reticuloendothelial system in a functional sense but may anatomically be found in a lymphatic area.

False

Phagocytic cells may play roles in either a non-specific or specific immune mechanism.

True

The origin of B-cells is not totally understood in humans but is probably in the bone marrow. The first discovery was in the sac in chickens called the Bursa of Fabricius, hence B-cell.

True

A clone is a sub-population of cells such as certain B or T cells that were produced from a single cell, for a specific function.

False

Antigens will bind to the amino acid area called the variable region of the immunoglobulin protein.

True

IgE can mediate anaphylaxis or severe inflammatory reactions. Although antibody production is a normal defense mechanism, the effects may be deleterious.

False

A B-cell can recognize an antigen but a T-cell usually requires an antigen-presenting cell to recognize antigens.

True

Neutralizing antibodies react with antigens and chemically block their toxicity such as tetanus antitoxin.

True

The T-cells produces lymphokines and other factors that stimulate phagocytosis, chemotaxis , and antibody production.

False

The delayed allergy pattern such as contact dermatitis is caused by T-cells.

True

Death from AIDS results from secondary conditions such as pneumonia or Kaposi's sarcoma cancer.

True

Immunosuppressive drugs such as Cyclosporine block the sites of lymphocyte recognition and subsequent rejection.

False

Systemic lupus erythematosis is a disease that produce abnormal antibodies from B-cells that attack normal tissues.

C) Birth

The shrinking of the thymus gland begins at birth at a rate of about three percent tissue loss per year.

C) Only the first statement is true.

For females, it is approximately 59% (100-41), and for males, it is approximately 53% (100-47).

A) 38 °C

The normal temperature of blood is slightly higher than normal body temperature. This is because the blood experiences friction and resistance as it flows through the vessels, producing heat.

D) It normally accounts for about 44% of the total plasma protein content, or 3.5–5.0 g/dL of blood.

Albumin normally accounts for about 54% of the total plasma protein content, or 3.5–5.0 g/dL of blood.

C) Only the first statement is true.

Unlike alpha and beta globulins, which are produced in the liver, immunoglobulins are produced by specialized leukocytes known as plasma cells.

C) B12 deficiency

B12 deficiency leads to macrocytic anemia, which would show large (macrocytic) red blood cells on the blood smear.

Hereditary spherocytosis is an autosomal dominant condition due to red blood cell membrane defect, that leads to hemolysis and microcythemia.

Sickle cell anemia is an autosomal recessive condition that leads to the formation of a defective B hemoglobin chain and eventually hemolysis.

G6PD deficiency is the deficiency in the enzyme glucose 6 phosphate dehydrogenase which leads to hemolysis when cells are faced with oxidative stress.

Iron deficiency causes microcytic anemia.

D) B12 deficiency

Microcytic anemia is characterised by a low mean cell volume (MCV) of less than 80fL, while macrocytic anemia is characterised by an MCV of greater than 100fL.

B12 deficiency leads to macrocytic anemia. Other causes of macrocytic anemia include folate deficiency and excessive alcohol consumption.

Iron deficiency anemia is the most common cause of microcytic anemia.

Sideroblastic anemia is a rare form of anemia, with characteristic ring sideroblasts seen in on bone marrow biopsy.

Thalassemia is a group of disorders with an underlying genetic cause, characterized by a defect in the synthesis of hemoglobin.

C) Hemophilia A - Factor VIII deficiency

Hemophilia A is an X-linked, recessive disorder, characterised by a defect in the coagulation pathway caused by a deficiency of factor 8. This may be inherited or arise from spontaneous mutation. The classic presentation includes significantly prolonged bleeding after surgical or dental procedures and hemarthrosis in a boy. Hemarthrosis can present with stiffness of the affected joint, warmth, and tenderness. Clinically, haemophilia A and haemophilia B (deficiency in factor IX) are indistinguishable. These diseases can be distinguished by obtaining clotting factor assays. While haemophilia B could be the answer, the question asks which is the most likely answer, and hemophilia A is more common than hemophilia B.

Von Willebrand Disease is when the Von Willebrand factor is deficient leading to platelet dysfunction. It typically presents with bleeding (e.g. petechiae and purpura).

Protein C deficiency is a disease that leads to hypercoagulation of the blood and it can, therefore, present with thrombosis and not bleeding.

A) Colonoscopy

Based on the lab findings, the patient has iron deficiency anemia (suggested by the low hemoglobin levels, low MCV, low ferritin, and hypochromic RBCs). The patient is also 70-years-old and describes a recent change in bowel habit, increasing her risk for lower gastrointestinal malignancy. As a result, the most appropriate investigation would be an urgent colonoscopy to rule out lower gastrointestinal malignancy.

A fecal occult blood test is used for population screening (if positive individuals then undergo colonoscopy), but not in the investigation of iron deficiency anemia.

If there was evidence of frank bleeding from the rectum or other sites (e.g. hematuria) or excessive bruising, coagulation studies would need to be carried out urgently. However, in this scenario, there is no clinical evidence of systemic coagulopathy and therefore the investigation is unlikely to provide much useful information. 

A CT abdomen could be considered, however it would typically be performed after colonoscopy to assess for the spread of malignancy within the abdomen and to assist with surgical planning. Some patients are unable to tolerate colonoscopy and can have a CT colonography which uses contrast to image the bowel non-invasively, however, this isn't routine for all patients.

Upper GI endoscopy would be appropriate if the patient had symptoms (e.g. dysphagia, epigastric pain, reflux) or signs (e.g. epigastric mass) of upper gastrointestinal pathology, however in this scenario, these are not mentioned, so colonoscopy would be most appropriate (bowel habit change).

B) Parvovirus B19 infection causing aplastic crisis

Aplastic crisis due to infection with parvovirus B19 is a dreaded and serious complication in patients with sickle cell anemia. This virus only infects RBC precursors in the bone marrow, resulting in impaired cell division for a few days. Healthy people experience mostly a slight drop in hemoglobin since the half-life of normal erythrocytes in the circulation is 40-60 days. In people with sickle cell disease, the RBC lifespan is greatly shortened (usually 10-20 days), and a very rapid drop in Hb occurs. Additionally, because only the RBC precursors are infected, the reticulocyte count is decreased while the white blood cells and platelet levels are not affected. The condition is self-limited, with bone marrow recovery occurring in 7-10 days, followed by brisk reticulocytosis.

Rapid hemoglobin drop could also be caused by splenic sequestration crisis, however, the spleen in this situation would be enlarged and palpable, and this also occurs most frequently in the first 5 years of life.

Acute chest syndrome and vaso-occlusive crisis do not cause a rapid drop in hemoglobin levels.

Hydroxyurea does not cause aplastic anemia, in fact, it is one of the medications that is used to treat sickle cell anemia.

C) Imatinib (tyrosine kinase inhibitors)

The first-line treatment for patients with chronic myeloid leukaemia would be tyrosine kinase inhibitors such as imatinib, which is the recommended drug of choice. It is an inhibitor of the tyrosine kinase enzyme which is encoded by BCR-ABL fusion gene (the Philadelphia chromosome) which most patients with CML have. It inhibits proliferation and induces apoptosis in cells positive for the BCR-ABL gene.

A bone marrow transplant is a treatment option for patients with CML that do not respond to treatment with tyrosine kinase inhibitors. It is not the first-line option of treatment of CML.

Hydroxyurea is the mainstay treatment for sickle cell anemia.

Chemotherapy is not a first-line treatment option for patients with CML.

D) Immune thrombocytopenia purpura

Immune thrombocytopenic purpura (ITP) is a clinical syndrome in which a decreased number of circulating platelets manifests as a bleeding tendency, causing petechiae, ecchymoses, purpura, and bleeding from venepuncture sites, nose etc., in an otherwise healthy patient. On complete blood cell count, isolated thrombocytopenia is the hallmark of ITP.  Corticosteroids remain the drugs of choice for the initial management of acute ITP, and IVIG is the second-line treatment. 

Patients with leukemia often present with symptoms of bone marrow failure such as anemia (fatigue and shortness of breath), serious infection (due to malfunction of white blood cells), and blood clotting problems (due to the low level of platelets in the blood). Splenomegaly is another examination finding in certain types of leukemia. Increased white blood cells, low red blood cells and platelets are common lab findings in a patient with leukemia.

Although the pathophysiology is different, patients with aplastic anemia present with similar symptoms as patients with leukemia. Lab findings in a patient with aplastic anemia will show a low count of all hematogenous cell lines.

Enlarged, painless, rubbery, non-erythematous, non-tender lymph nodes are the hallmark sign of lymphoma. Patients also may present with symptoms such as night sweats, weight loss, and fever which is referred to as "B" symptoms in lymphoma. 

Thus, in an otherwise healthy patient, with an unremarkable history, physical examination and isolated thrombocytopenia we can rule out leukemia, aplastic anemia and lymphoma. 

Patients with hemophilia A are men (since it is an X linked recessive disease) and usually have a classic history of hemarthrosis, and have prolonged aPTT and never isolated thrombocytopenia.

D) Hepcidin



Hepcidin, produced by the liver, reduces the level of iron in the circulation by reducing both iron absorption by the gastrointestinal tract and the release of iron into the circulation by cells that store it. Hepcidin levels are also increased during inflammation, which explains why people with chronic inflammatory conditions can develop a form of anaemia known as anaemia of chronic disease.

Transferrin is a protein that transports iron throughout the circulation.

Ferroportin is a transmembrane protein that facilitates the transport of iron out of cells that absorb or store it and into the circulation.

Albumin is the most abundant plasma protein, produced by the liver.

Fibrinogen is a plasma protein produced by the liver that forms part of the coagulation cascade.

B) Neutrophil

The neutrophil is considered to be the most important cell type in the acute cellular immune response. It is also the most abundant type of white blood cell in the circulation. Its importance is highlighted by the life-threatening emergency of febrile neutropaenia that can develop in patients receiving bone marrow-suppressing treatment for cancer who therefore have low neutrophil levels. In febrile neutropaenia, patients cannot eliminate pathogens because of their lack of neutrophils.

A) IgG

Immunoglobulin G is produced in response to secondary exposure to a pathogen, which explains why detecting immunoglobulin G against a specific pathogen in serum indicates past infection or current immunity.

A) IgG

C) IgE

E) IgA

B) Tissue plasminogen activator

Tissue plasminogen activator is a serine protease found on endothelial cells lining the blood vessels. It catalyses the conversion of plasminogen to plasmin, which is crucial for breaking down clots.

Synthetic tPA is made using recombinant technology including alteplase, reteplase and tenecteplase. It is utilized clinically for the treatment of embolic or thrombotic stroke, myocardial infarction and pulmonary embolism.

A) Fibrinogen

Fibrinogen is a glycoprotein which circulates in the blood. During tissue injury, it functions to occlude blood vessels and stop excessive bleeding. This occurs as it is converted to fibrin by thrombin and forms a platelet plug. Fibrin then reduces thrombin activity to prevent excess clotting.

von Willebrand factor is important in platelet adhesion to wound sites.

Factor VII is a serine protease initiates the process of coagulation in combination with tissue factor (factor III).

Thrombin (factor IIa) is a serine protease which converts fibrinogen to fibrin.

B) von Willebrand factor

Von Willebrand factor mediates the adherence of platelets to collagen underlying endothelial cells when they have been damaged and therefore plays a key role in blood coagulation. This role is reflected by the fact that those with a deficiency of Von Willebrand factor develop a coagulation disorder, or coagulopathy, known as Von Willebrand disease.

Protein C, Protein S, Antithrombin III and Plasmin all promote anticoagulation.

E) IgM

IgM has a pentameric structure, meaning it has 5 subunits combined to form one molecule. Meanwhile, the other immunoglobulins have a monomeric structure, except for IgA which is a monomer in serum but a dimer in secretions.

E) Increase in transport proteins

The correct answer is increase in transport proteins, as the acute phase response sees a reduction of transport proteins, such as albumin and transferrin.

• The acute phase response includes:
•      1. Acute phase protein release
•      2. Reduction of transport proteins (albumin, transferrin)
•      3. Hepatic sequestration cations
•      4. Pyrexia
•      5. Neutrophil leucocytosis
•      6. Increased muscle proteolysis
•      7. Changes in vascular permeability

B) IgE

IgE stimulates the release of pro-inflammatory molecules from mast cells and basophils when it binds to Fc receptors on these cells, which produces type I hypersensitivity reactions. This explains why testing for IgE against specific antigens is performed for allergy testing.

D) Hematopoiesis

Haematopoiesis is derived from the Greek 'haemato-' meaning blood, and '-poíēsis' which means 'to make.' Thus, haematopoiesis refers to the process of making blood cells. This can refer to the production of erythrocytes, leucocytes or platelets, but is usually used in the context of erythrocyte production.

Erythrocytes are produced in high numbers in the bone marrow of specific bones like the humerus and femur, vertebral column, ribs and clavicle, and the pelvis. These erythrocytes have a lifespan of 100-120 days, and each day sees up to 0.8-1% of them replaced by new erythrocytes.

When there is an increase in the production of leucocytes to an infectious trigger, a leukaemoid reaction can occur. A leukaemoid reaction refers to a proliferation of white cells provoked by an infectious trigger, with the common goal of removing the infection and minimizing any host damage.

However, if there is an unprovoked proliferation of red or white cells, we have a malignant proliferation. A malignant proliferation of erythrocytes can include erythrocytosis or polycythaemia; platelets can be a thrombocytosis; and white cells have many, including many types of leukaemia or lymphoma.

Yellow bone marrow, found in the diaphysis of long bones, is full of adipocytes and plays a role in fat-soluble vitamin storage.

Bone metabolism is at the discretion of local acid-base balance in the form of carbonic anhydrase II (increases the acidity) and alkaline phosphatase (increases the alkalinity), as well as systemic control through parathyroid hormone, vitamin D (i.e. the kidneys), and calcium and phosphate balance.

B) Helper T cells

Helper T cells, or CD4+ T cells, are considered to be the master controllers of immune responses because they coordinate such responses. Helper T cells are also the cell type infected and depleted by human immunodeficiency virus, which accounts for the devastating, body-wide effects of human immunodeficiency virus infection and acquired immunodeficiency syndrome.

E) -18 °C

As per standard guidelines, the storage temperature for plasma products is below −18 °C. 

Red blood cells are required to be stored between +2 °C and +6 °C, whereas platelets and leucocytes must be stored between +20 °C and +24 °C.

E) Peripheral neuropathy

There is no association between iron deficiency anaemia and peripheral neuropathy. This finding is associated with a vitamin B12 deficiency.

Features of iron deficiency can include:

• Koilonychia (spoon-shaped nails – both fingers and toes)
• Angular stomatitis and glossitis
• Dysphagia (Plummer-Vinson syndrome)

B) Raised ferritin

Microcytic, meaning small, and hypochromic, meaning pale cells, are the classic signs of iron deficiency anaemia.

Poikilocytosis is an umbrella term of having abnormally shaped RBCs which can be present in iron deficiency anaemia, as well as conditions like haemolytic anaemia, sickle cell disease or alcoholism.

Increased ferritin is the incorrect answer because in iron deficiency anaemia the iron stores are depleted and therefore ferritin, which is the bodies method of storing iron, would be expected to be low.