- Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.
- In vertebrates, it is composed of blood cells suspended in a liquid called blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), platelets and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes) and white blood cells, including leukocytes and platelets. The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates transportation of oxygen by reversibly binding to this respiratory
- gas and greatly increasing its solubility in blood. In contrast, carbon
- dioxide is almost entirely transported extracellularly dissolved in
- plasma as bicarbonate ion.
- Blood cells: Erythrocytes, biconcave discs, that transport oxygen. Lack
- nuclei, mitochondria; generate ATP exclusively by anaerobic metabolism.
- Contains hemoglobin, an iron containing protein that reversibly bonds
- with oxygen. Kidneys secrete a hormone called ERYTHROPOIETIN, which
- stimulated the production of red cells by the bone marrow. RBC's have a
- life expectancy of 120 days. After that they are removed by the spleen
- and liver and used to produce bile.
describe/identify the functions of blood
- Blood doesn't have "a" function, it has several. It carries food
- and oxygen to cells, it carries waste away from cells, and serves as a
- carrier for various disease-fighting cells such as the "white" blood
- cells. It also has a means of puncture-proofing the body: it clots,
- sealing up small holes quickly. Blood is also important in maintaining a constant temperature in your body.
define/identify the composition of blood
- Blood is composed of cells, or formed elements, suspended in clear,
- straw-colored liquid called plasma. The cells include erythrocytes (red
- blood cells), leukocytes (white blood cells), and platelets or
- thrombocytes (clotting cells) and constitute about 45 per cent of the
- total blood volume. The remaining 55 per cent of blood is plasma, a
- solution of water, proteins, sugar, salts, hormones, and vitamins.
What are the components of blood?
Human blood consists of about 22 percent solids and 78 percent water. The components of human blood are:
, in which the blood cells are suspended, including:
Red blood cells (erythrocytes)
- carry oxygen from the lungs to the rest of the body.
- White blood cells (leukocytes) - help fight infections and aid in the immune process. Types of white blood cells include:
- Lymphocytes.Monocytes.Eosinophils.Basophils.Neutrophils (granulocytes).
- help in blood clotting.
- Chemical substances, including:
Gases, including:Oxygen.Carbon dioxide.Nitrogen.
Where are blood cells made?
Blood cells are made in the bone marrow. The bone marrow is the spongy material in the center of the bones that produces about 95 percent of the body's blood cells. There are other organs and systems in our bodies that help regulate blood cells. The lymph nodes, spleen, and liver help regulate the production, destruction, and differentiation (developing a specific function) of cells. The production and development of new cells is a process called hematopoiesis. Blood cells formed in the bone marrow start out as a stem cell. A "stem cell" (or hematopoietic cell) is the initial phase of all blood cells. As the stem cell matures, several distinct cells evolve such as the red blood cells, white blood cells, and platelets. Immature blood cells are also called blasts. Some blasts stay in the marrow to mature and others travel to other parts of the body to develop into mature, functioning blood cells.
What are the functions of white blood cells?
The primary function of white blood cells, or leukocytes, is to fight infection
. There are several types of white blood cells and each has its own role in fighting bacterial, viral, fungi, and parasitic infections. Types of white blood cells that are most important for helping protect the body from infection and foreign cells include the following:
White blood cells
: Help heal wounds not only by fighting infection
but also by ingesting matter such as dead cells, tissue debris and old red blood cells.
Are our protection from foreign bodies that enter the blood stream, such as allergens. Are involved in the protection against mutated cells, such as cancer.
What is the function of platelets?
The primary function of platelets, or thrombocytes, is blood clotting. Platelets are much smaller in size than the other blood cells. They group together to form clumps, or a plug, in the hole of a vessel to stop bleeding.
- They are biconcave discs approximately 7.2 �m in diameter. The cells appear
- darker at the periphery and light in the center. The color of red blood
- cells is due to the eosinophilia of hemoglobin. Mature erythrocytes are
- anucleated and lack organelles
define/identify the cellular elements of blood
- Switch to the 100x lens and examine the red blood corpuscles. They
- are biconcave discs approximately 7.2 �m in diameter. The cells appear
- darker at the periphery and light in the center. The color of red blood
- cells is due to the eosinophilia of hemoglobin. Mature erythrocytes are
- anucleated and lack organelles.
- Platelets (2–5 �m) in diameter are fragments of cytoplasm
- surrounded by a plasma membrane. The cytoplasm stains blue and contains
- azurophilic granules.The platelets can occur singly or in clumps.
- Granulocytes (polymorphonuclear leukocytes)Neutrophils can be recognized by their segmented nuclei and
- the presence of abundant, small, pale staining granules in their cytoplasm.
- Often the individual granules are barely distinguishable. Examine a number
- of neutrophils under oil immersion until you can quickly identify them.
- In good preparations, you may be able to see that there are two types
- of granules present, the more abundant, smaller specific granules which
- stain light pink and the larger, non-specific azurophilic granules which
- stain red-purple. Under normal conditions, neutrophils constitute 60–70%
- of the total leukocyte count.
- The specific granules
- of the eosinophil are large and distinctive. These may be located even
- under low power by their large bright red-staining, refractile granules.
- The nucleus of the eosinophil is also segmented, but it is usually bi-lobed
- and paler staining than the neutrophil nucleus. The granules may be seen
- very clearly in cells which have had their cell membranes ruptured during
- preparation. The granules will then be spread apart and are easily seen
- to be large and oval. Eosinophils constitute up to 3% of the leukocytes.
- BasophilsBasophils make up less than 0.5% of the leukocytes and are difficult
- to find. The granules are very large, purple staining and not of uniform
- size. The nucleus, which is often difficult to see clearly because of
- the granules, maybe segmented. Because they are relatively rare, they
- may not be on every slide.
- Nongranular leukocytes (mononuclear leukocytes)
- These cells do not contain specific
- granules. The lymphocytes vary in size from 6 �m (slightly smaller
- than an RBC) to large cells up to 15 �m in size. The small lymphocytes
- have only a thin rim of sky-blue cytoplasm. Their nuclei of densely-stained
- chromatin are generally round or slightly indented on one side. Medium
- and larger lymphocytes have larger, round nuclei centrally located in
- a sky-blue cytoplasm. A few azurophilic granules may be present in the
- cytoplasm. Lymphocytes normally constitute 20–30% of the total leukocyte
- count, with small lymphocytes predominating.
- The monocyte is usually the largest leukocyte present (15–20
- �m). The nucleus of the monocyte, which is usually bean or U-shaped and
- is eccentric, may have a "lumpy" appearance which is seen by
- focussing up and down. The chromatin appears as a fine lacy network. The
- cytoplasm is gray in color and opaque and usually contains fine granules.
- The monocyte can sometimes be confused with a medium or large lymphocyte
- or with an immature neutrophil. A medium lymphocyte usually contains denser
- chromatin and sky-blue cytoplasm. A young neutrophil (called a band),
- contains a U-shaped nucleus with condensed chromatin and a cytoplasm filled
- with small granules.
discus/identify the structure and function(s) of each cellular
describe/identify, briefly, the structure of hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates.
Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, and mesangial cells in the kidney. In these tissues, hemoglobin has a non-oxygen-carrying function as an antioxidant and a regulator of iron metabolism.
describe/identify the destruction process of red blood cells
A feedback loop involving erythropoietin helps regulate the process of erythropoiesis so that, in non-disease states, the production of red blood cells is equal to the destruction of red blood cells and the red blood cell number is sufficient to sustain adequate tissue oxygen levels but not so high as to cause sludging,thrombosis, or stroke. Erythropoietin is produced in the kidney and liver in response to low oxygen levels. In addition, erythropoietin is bound by circulating red blood cells; low circulating numbers lead to a relatively high level of unbound erythropoietin, which stimulates production in the bone marrow.
discuss/identify the ABO and Rh blood grouping
Blood type O: the Americas
Blood Type A: Central and Eastern Europe
- People with blood type O are said to be "universal donors" because their blood is
- compatible with all ABO blood types. It is also the most common blood type in populations
- around the world, including the USA (1) and
- Western Europe (2, 3). Among indigenous
- populations of Central and South America, the frequency of O blood type is extremely high,
- approaching 100%. It is also high among Australian aborigines.
Blood type B: Asia
- Type A is common in Central and Eastern Europe. In countries such as Austria, Denmark,
- Norway, and Switzerland, about 45-50% of the population have this blood type, whereas
- about 40% of Poles and Ukrainians do so.The highest frequencies are found in small, unrelated populations. For example, about 80%
- of the Blackfoot Indians of Montana have blood type A.
Blood type AB is the least common
- Blood type B is relatively common in Chinese and Indians, being present in up to 25% of
- the population. It is less common in European countries and Americans of European origin,
- being found in about 10% of these populations.
- Blood type AB individuals are known as "universal receivers" because they can receive
- blood from any ABO type. It is also the rarest of the blood groups. It is most common in Japan, regions of China,
- and in Koreans, being present in about 10% of these populations.
discuss/identify the importance if blood grouping
- An individual's blood differs from that of the other due to types of
- substances on the red blood cells. These substances are called antigens.
- We also know that there are antibodies in our plasma. These antibodies
- do not react to our own tissues but react with antigens on the red blood
- cells of another person. Thus we can group people on the basis of their
- antigens and antibodies into four groups: A, B, O and AB. People whose
- blood is A have antigen A and carry antibody B, Group B people have
- antigen B and antibody A and Group O people don not have either antigen A
- or antigen B. but both antibodies are present.When blood is
- given to the patient (blood transfusion), it will be dangerous if the
- recipient patient gets blood with antigen against which he has
- antibodies. This will clump the red blood cells, transfused from the
- donor; the person who gives blood. This is a serious reaction. Thus it
- is vitally important to know blood groups of both the donor and the
- recipient. If the recipient belongs to group A, he will not be able to
- receive blood from group B donors. So same blood groups can be
- transferred and received.
decsribe/identify, briefly, the proccess of clot lysis and its significance
list/identify examples of anticoagulants
- Types of Anticoagulants
- The multilevel cascade of blood clotting system permits enormous amplification of its triggering signals. Moving down the extrinsic pathway, for example, proconvertin (VII), Stuart factor (X), prothrombin, and fibrinogen are present in plasma in concentrations of <1, 8="" 150="" and="" 4000="" mg="" ml-1="" respectively="" thus="" a="" small="" signal="" is="" very="" quickly="" amplified="" to="" bring="" about="" effective="" hemostatic="" control="" br="">
- On the other hand, clotting must be very strictly regulated because even one inappropriate clot can have fatal consequences. Indeed, blood clots are the leading cause of strokes and heart attack, the two major causes of human death.
Endogenous Inhibitors of Clotting
Thrombin plays a pivotal role in blood coagulation and Nature has designed several serine protease inhibitors (SERPINS) to regulate the its activity. These include antithrombin (major), heparin cofactor II, a2-macroglobulin, and a1-proteinase inhibitor.
Antithrombin is present in the plasma in significant concentrations (~2-3 mM). Antithrombin primarily neutralizes factor Xa and thrombin, in addition to inhibiting most active serine proteases of the clotting system. (To view a structure of antithrombin click here.)
Protein C is another plasma protein that limits clotting by being activated by thrombin to proteolytically inactivate proaccelerin (V) and antihemophilic factor (VIII).
Thrombomodulin, a cell membrane bound glycoprotein lining the vascular endothelium, specifically binds thrombin so as to convert it to a form with decreased ability to catalyze clot formation but with a >1,000-fold increased capacity to activate protein C.
Exogenous Inhibitors of Clotting
The control of clotting is a major medical concern. Several inhibitors have been developed with different mechanisms of anticoagulant action. These include the heparins, the coumarins, and the 1,3-indanediones.
define/identify, in brief, the coagulation process
- The process of blood
- clotting and then the subsequent dissolution of the clot, following repair of
- the injured tissue, is termed hemostasis.
- Hemostasis, composed of 4 major events that occur in a set order following the
- loss of vascular integrity:
- 1. The initial phase of the process is vascular
- constriction. This
- limits the flow of blood to the area of injury.
- 2. Next,
- platelets become activated by thrombin
- and aggregate at the site of injury, forming a temporary, loose platelet plug. The protein fibrinogen is primarily responsible
- for stimulating platelet clumping. Platelets clump by binding to collagen that
- becomes exposed following rupture of the endothelial lining of vessels. Upon
- activation, platelets release the nucleotide, ADP and the eicosanoid, TXA2
- (both of which activate additional platelets), serotonin, phospholipids, lipoproteins, and other proteins
- important for the coagulation cascade. In addition to induced secretion,
- activated platelets change their shape to accommodate the formation of the
- 3. To insure
- stability of the initially loose platelet plug, a fibrin mesh (also called the clot) forms and entraps the plug. If the plug contains only
- platelets it is termed a white thrombus;
- if red blood cells are present it is called a red thrombus
- 4. Finally, the
- clot must be dissolved in order for normal blood flow to resume following
- tissue repair. The dissolution of the clot occurs through the action of plasmin
- In embryos they are produced in their GALL
- BLADDER, then in their LIVER, and starting from the second half of their
- lives – in their BONE MARROW. They are oval single-nucleus cells. Only
- in mammals they lose their nuclei and adopt the form of flattened
- circles, thinner in the centre.
- In erythrocyte cytoplasm – HAEMOGLOBIN (red) that enables transport of
- oxygen and carbon dioxide. In the human body there are about 4,3 million
- (women) and 4,8 million (men) of erythrocytes in 1 millilitre of blood.
describe/identify plasma components and the funtion of its constituents
- Plasma is a yellowish solution consisting of about 91% water, and
- the other 9% is a host of substances indispensable to life. Among them
- are: nutrients such as glucose, fats, and amino acids;
- chemicals important to the body, such as sodium, potassium, and
- calcium; special proteins, such as fibrinogen, albumin, and various
- globulins that produce antibodies, which fight off viruses and other
- unwelcome intruders in the body; and hormones, which are regulatory
- substances such as insulin, and epinephrine, more familiarly known as
- adrenaline, which speeds up the heart rate whenever some emergency
- requires a greater blood flow to the muscles.
- The role of plasma in the body is to help transport food and oxygen to the
- cells of the body and to carry wastes away from the cells. In addition,
- with its potent arsenal to draw upon, plasma plays a crucial role in
- maintaining the body's chemical balance, water content, and temperature at
- a safe level. That is, the plasma serves the body by helping to maintain
- homeostasis, or a stable internal environment in the body. In fact,
- essentially all the organs, tissues, and fluids of the body perform
- functions that help to maintain the body as a stable system. By analyzing
- plasma, medical doctors can find out what types of nutrients are
- circulating throughout the body, and they can measure the levels of
- hormones and other constituents that plasma helps to transport.
- The cellular portion of blood normally makes up about 45% of the blood
- volume and it consists primarily of three cellular components (Table 1):
- white blood cells (WBCs, also known as leukocytes),
- platelets, and red blood cells (RBCs, also known as
- erythrocytes). The WBCs constitute the blood's mobile security
- system. Some WBCs are endowed with the curious ability to wiggle out of
- the bloodstream and back in again. The WBCs can move like an amoeba,
- slipping through thin walls of capillaries and wandering among cells and
- tissues. They converge together in great numbers wherever invading
- bacteria, viruses, fungi, or parasites gain entry into the body,
- destroying them by swallowing them or by synthesizing antibodies,
- which are complex proteins that react with and destroy these foreign
- substances. Whenever white cells mobilize for action, the body
- compensates by manufacturing more. Double the usual number may appear in
- the blood within hours. Often this rising white cell count, as physicians
- describe it, serves as an early tip-off that a dangerous infection has
- entered the body
define/identify thrombosis and embolism
Embolism is the term that describes a condition where an object called an embolus is created in one part of the body, circulates throughout the body, and then blocks blood flowing through a vessel in another part of the body. Emboli (plural of embolus) are not to be confused with thrombi (plural of thrombus), which are clots that are formed and remain in one area of the body without being carried throughout the bloodstream.
Thrombosis is the formation of a blood clot (thrombus) inside a blood vessel, obstructing the flow of blood through the circulatory system.
- When a blood vessel is injured, the body uses platelets (thrombocytes) and fibrin to form a blood clot to prevent blood loss. Alternatively, even when a blood vessel is not injured, blood clots may form in the body if the proper conditions present themselves. If the clotting is too severe and the clot breaks free, the traveling clot is now known as an embolus.
- Thromboembolism is the combination of thrombosis and its main complication, embolism.
- When a thrombus occupies more than 75% of surface area of the lumen of an artery, blood flow to the tissue supplied is reduced enough to cause symptoms because of decreased oxygen (hypoxia) and accumulation of metabolic products like lactic acid. More than 90% obstruction can result in anoxia, the complete deprivation of oxygen, and infarction, a mode of cell death.
Emboli (plural of embolus) are not to be confused with thrombi (plural of thrombus), which are clots that are formed and remain in one area of the body without being carried throughout the bloodstream.
What are different types of embolism?
What are different types of embolism?
- Though most people are familiar with the term pulmonary embolism, describing an embolus that clots an artery carrying blood to the lungs, there are several other types of embolism. These include:
- Brain embolism - a clot that can prevent blood flow to the brain and can cause an ischemic stroke
Retinal embolism - small clots that can block blood flow to the retina of the eye and can cause sudden blindness in an eye
Amniotic embolism - amniotic fluid during pregnancy that can form clots and reach the lungs, resulting in pulmonary amniotic embolism
Air embolism - air bubbles that form clots in the arteries and block blood flow, often seen in SCUBA divers who rise to the surface too quickly
Thromboembolism - a blood clot (thrombus) that breaks free to form an embolus, capable of causing a heart attack
Cholesterol embolism - cholesterol from plaques in a blood vessel break free and form a blockage
Fat embolism - fat droplets enter the blood stream and block blood flow, usually a side-effect of certain surgeries or bone fractures
Septic embolism - embolism infected with bacteria containing pus
Foreign body embolism - any other small particle or object that enters the circulatory system and manages to block the flow of blood.
What is Blood?
Blood is the life-maintaining fluid that circulates throughout the body's:
What is the function of blood?
Blood carries the following to the body tissues:
Blood carries the following away from the body tissues:
- Waste matter
- Carbon dioxide
What is a complete blood cell count (CBC)?
A complete blood cell count is a measurement of size, number and maturity of the different blood cells in a specific volume of blood. A complete blood cell count can be used to determine many abnormalities with either the production or destruction of blood cells. Variations from the normal number, size, or maturity of the blood cells can be used to indicate an infection or disease process. Often with an infection, the number of white blood cells will be elevated. Many forms of cancer can affect the bone marrow production of blood cells. An increase in the immature white blood cells in a complete blood cell count can be associated with leukemia. Anemia and sickle cell disease will have abnormally low hemoglobin.
TestUsesComplete blood count (CBC), which includes:white blood cell count (WBC)red blood cell count (RBC)platelet counthematocrit red blood cell volume (HCT)hemoglobin concentration (HB) - the oxygen-carrying pigment in red blood cellsdifferential blood countTo aid in diagnosing anemia and other blood disorders and certain cancers of the blood; to monitor blood loss and infection; to monitor a patient's response to cancer therapy, such as chemotherapy and radiation.Platelet countTo diagnose and/or monitor bleeding and clotting disorders.Prothrombin time (PT)To evaluate bleeding and clotting disorders and to monitor anticoagulation (anti-clotting) therapies.