Anatomy Ch 19 Blood

1. Transportation - O₂, CO₂, nutrients, wastes, hormones, proteins, etc.

2. Regulation - pH, temperature, osmotic pressure

3. Protection - immune responses, clotting

Blood is connective tissue.

• It has:
• Cells - RBCs, WBCs, platelets
• Ground Substance - plasma
• Fibers - proteins / globulins

Hematocrit represents the percentage of total blood volume that is RBCs

Hematocrit = %RBC / Volume

• Normal range for females: 38-46 %
• males: 40-54%

The normal range for men is higher because they have more testosterone which stimulates the production of EPO (erythropoietin) - the hormone that stimulates production of RBCs. Also women may have lower hematocrit values dues to blood loss during menstration.

Blood plasma is a straw-colored liquid with a small amount of solute in it (8.5%) and no formed elements.

Serum is the plasma minus the clotting agents (fibrinogen).

Of the 8.5% of solute in the plasma, 7% is proteins which are important for maintaining blood osmotic pressure.

Most of the proteins in the blood are synthesized in the liver.

Albumin - most numerous blood plasma protein - serves as transport protein for steroid hormones and fatty acids.

Immunoglobulins - Antibodies that help attack viruses and bacteria

Fibrinogen - Protein that is important in blood clotting

• 99% of blood cells are RBCs (99 out of 100) are red
• (of the 45% of whole blood that is formed elements)

Anemia refers to a low Hct (hematocrit) or low RBC count.

Polycythemia - hight Hct (high RBC)

Hemopoiesis is the process by which the formed elements of the blood are made (RBCs) - most often occurs in the red bone marrow that is found in the trabeculae of spongy bone

Blood cells are make by the red bone marrow that occupies the space between and around the trabeculae of spongy bone. Red bone marrow is a highly vascularized CT.

A bone marrow biopsy is usually taken from the iliac crest of the hip bone.

The average life span of a RBC is 128 days. They wear out because their plasma membrane is under a lot of pressure as they squeeze through capillaries. They are not able to repair themselves because they have no nucleus or organelles. When they rupture or become work out they are phagocytized by macrophages in the spleen, liver, and red bone marrow. They are broken down and recycled.

Pluripotent stem cells (hemocytoblasts) develop into:

1. Myeloid stem cells - which develop into RBCs, platelets, and 4 types of WBCs.

2. Lymphoid stem cells - develop into lymphocytes

Myeloid cells:

• 1. Proerythroblast → Erythrocyte (RBC)
• 2. Megakaryoblast → Platelets (thrombocytes)
• 3. Eosinophilic myeloblast → Eosinophil
• 4. Basophilic myeloblast → Basophil
• 5. Myeloblast → Neutrophil
• 6. Monoblast → Monocyte

Lymphoid stem cells:

• 1. T lymphoblast → T lymphocyte (T cell)
• 2. B lymphoblast → B lymphocyte (B cell)
• 3. NK lymphoblast → Natural killer cell (NK cell)

Blood cells enter the blood stream through enlarged and leaky capillaries called sinusoids (also called sinuses) that surround the bone marrow

RBC that carries the protein hemoglobin (carries oxygen)

The erythroblast or RBC is biconcave in shape because the special shape give it more surface area for gas to diffuse in and out of the cell.

RBCs make ATP anaerobically so they do not use up any of the oxygen that they are carrying.

Mature RBCs have few organelles and no nucleus because this allows for all their internal space to be available for oxygen transport.

1. Oxygen - each Hgb molecule can carry 4 O₂ molecules bound to the heme part

2. Carbon Dioxide - CO₂ binds to the globin part - 23% of total is carried back to the lungs by Hgb

3. Nitric Oxide - NO - lipid soluble hormone - causes vasodialtion - increased blood flow to tissue

No - Hgb only carries 23% or total CO₂ to the lungs

Nitric oxide is a lipid soluble hormone that binds to Hgb. The release of NO causes vasodilation in local cells - improves the blood flow and enhances oxygen delivery

Hemoglobin is made up of a protein called globin - that is made up of 4 polypeptide chains (2 identical alpha chains and 2 identical beta chains). A nonprotein pigment, called a heme, is attached to each of the 4 chains. An iron ion is attached to each of the four hemes.

1 globin in 4 chains, 4 hemes, and 4 iron ions

Oxygen binds to each iron ion in the heme so each molecule of Hgb can carry 4 O₂ molecules.

CO₂ can combine with the amino acids on the globin to be carried back to the lungs to be exhaled

You need iron because it is an important part of oxygen transport in the blood. The O₂ molecule attaches to the iron ion in the heme part of the hemoglobin. If you have bled a lot you need iron in your diet to replace the iron ions you have lost in the blood. Normally the body recycles the iron from old cells to new RBCs.

The heme group is a ringshaped nonprotein pigment with an iron ion in the center of it.

There are 4 peptide chains in each Hgb molecule

Ruptured and work out RBCs are disassembled by fixed macrophages in the liver and spleen. These Kupffer cells use phagocytosis to break down the old RBCs.

When the RBC dies the liver macrophages split it down into heme and globin portions.

The peptide chains of the globin are broken down into amino acids so they can be used to build other proteins.

The heme group is broken down into iron and bilirubin

The iron is carried by a transport protein called a transferrin to be stored in the liver until it is needed for another molecule of Hgb.

In a transfusion reaction a person receives the wrong kind of blood. The antigens on the outer surface of the cell react and make the plasma membranes of the donated RBCs weak. Hemolysis or rupture of the RBCs releases the hemoglobin to float free in the blood and cause kidney damage by clogging the filtration membrane.

Pluripotent stem cells → proerithroblast → reticulocyte → erythrocyte (after it ejects it nucleus)

A high reticulocyte count in the blood is a sign of anemia

Erythropoietin is a hormone that stimulates production of RBCs in the red bone marrow. Erythropoietin is made in the kidneys and its secretion is triggered by the hormone testosterone.

No. Of the formed elements in blood, only 1 % is WBCs

Immune response, inflammation, clean-up

• 1. PMNs - Neutrophils - first to arrive - phagocytic
• 2. Monocytes - second to arrice - develop into Macrophages to digest infection and debris.
• 3. Basophils - release mediators to intensify immune response (histamine, serotonin, heparin)
• 4. Eosinophils - lease inflammatory mediators (allergies and parasitic infections)
• 5. Lymphocytes - B and T -kill specific invaders
• NK - nonspecific - kill all invaders

WBCs are able to move by contracting their microtubules.

Chemotaxis refers to condition where inflamed tissues in the body can release chemicals that will attract phagocytes to come take care of invaders.

Margination is the ability of WBCs to exit the blood stream by sticking to the capillary wall (integrins in the WBC stick to selectins that are produced on the cell walls.

Emigration is the act of leaving the blood stream and moving into the interstitial space

Pus is the dead white blood cells that have attacked an invader. All WBCs die except lymphocytes.

PMNs or neutrophils (from myeloid cells) are phagocytic and are the first to arrive at an infection.

PMNs or neutrophils are the most numerous WBC (70%).

Fixed microphages live in the lungs (alveolar macrophages) , spleen, and liver (Kupffer cells)

An increase in the number of eosinophils is a sign of allergic reactions, parasitic infections, and autoimmune disease.

• B and T Lymphocytes are specific
• NK Lymphocytes are non-specific and will kill everything

.Emigration is the act of leaving the blood stream and moving into the interstitial space.

Margination is the ability of WBCs to exit the blood stream by sticking to the capillary wall (integrins in the WBC stick to selectins that are produced on the cell walls).

CBC = Complete Blood Cell Count

w/ differential = % of each type of WBC in the blood stream

• Neutrophils - 60 -70%
• Lymphocytes - 20 - 25%
• Monocytes - 3-8%
• Eosinophils - 2-4 %
• Basophils - < 1%

Leukocytosis - an increase in the number of WBCs in the blood. Can be caused by infection, stress, surgery, leukemia

Leukopenia - a decrease in the number of WBCs. Can be caused by chronic illness, radiation/ chemo

Monocytes turn into wandering Macrophages when the leave the blood stream and enter tissue. They can also become fixed macrophages in the lungs, liver, and pancreas.

A megakaryocyte is a large cell that splinters into fragments called platelets or thrombocytes. Thrombocytes are enclosed by plasma membrane and contain granules that help in blood clotting. The platelets themselves also work to stop blood loss by forming a platelet plug.

Thrombocytopenia means that the platelet count is very low and that a tendency to bleed from capillaries is a concern.

Thrombopoietin is a hormone produced by the liver that stimulates the megakaryocytes to break down into platelets.

If you there is a platelet count of less than 100,000 then elective surgery would be canceled.

At platelet count of less than 1,000 a person has spontaneous bleeding.

• Platelets form a clot by:
• 1. Platelet adhesion - they stick to parts of the damaged blood vessel .
• 2. Platelet release reaction - the platelets begin to unload the contents of their vessicles (mostly clotting agents).
• 3. Platelet aggregation - more platelets are attracted to the scene and being to stick to the already activated platelets - the accumulation of a large number of platelets forms a platelet plug.

• 1. Vascular spasm - smooth muscle around arteries contracts limiting blood flow
• 2. Platelet plug formation - platelet adhesion, platelet release reaction, platelet aggregation = platelet plug (plug = fibrin + platelets)
• 3. Blood clotting - blood converted from liquid to solid

Hemorrhage means to loose large amounts of blood from the vessels.

Fibrin is added to the platelet aggregation to form a more secure clot.

Several blood clotting factors (blood proteins) are made in the liver.

Alcoholics with liver disease might bleed because 1. don't eat right and probably don't get enough Vit K in their diet. 2. their liver is damaged by the alcohol so it is not synthesizing Vit K either 3. Without Vit K the liver cant make Prothrombin 2, 7, 9, and 10.

Vitamin K is requited by the liver to synthesize Prothrombin 2, 7, 9, 10 - they are fat soluble

A clot is made of platelets and fibrin.

Intrinsic clotting refers to a process that is activated by contact with collagen fibers (outside tissue damage is not needed to start the process). Extrinsic clotting is triggered by TF (tissue factors) from damaged tissue.

Yes. Thrombin, when in the presence of Ca²⁺ converts the fibrinogen (soluble) to fibrin (insoluble)

Clot retraction is the tightening of the fibrin clot. The fibrin threads that are attached to the damaged surfaces of the blood vessel slowly begin to contract. This pulls the edges of the damaged vessel closer together and reduces the risk of more injury.

Fibrinolysis is the dissolving of the clot after the bleeding crisis has been resolved. WBC and vessel endothelium contain an enzyme called plasminogen. When plasminogen is activated to plasmin it has the ability to digest fibrin threads.

Plasminogen is an enzyme that is present in WBCs and vessel endothelium. When it is activated it turn to plasmin which can dissolve the fibrin threads.

TPA is a synthetic plasminogen activator - it activates plasminogen into plasmin which will dissolve a blood clot.

Heparin, coumadin, and lovenox are anticoagulants

Anticoagulants are present in the blood to keep inappropriate clots from forming.

Clotting in an unbroken blood vessel is called thrombosis

An embolus is a blood clot that gets dislodged and travels in the blood stream. A pulmonary embolism is an embolus that lodges in the lungs

• A = A antigens; anti B antibodies in plasma
• B= B antigens ; anti A antibodies in plasma
• AB = A and B antigens; no antibodies in plasma
• O = no antigens ; A and B antibodies in plasma

Aggulination is the clumping of RBCs that is caused by antibodies in the recipients plasma attacking antigens on the donated RBCs. This causes hemolysis because the plasma membranes of the RBCs start to leak.

Rh antigens are antigens on the RBC. People either have Rh antigens Rh+ or they do no have any Rh antigens Rh-

A tansfusion reaction can kill a patient because the aggulation causes rupture of the RBCs which then leak hemoglobin into the blood stream - hemoglobin causes kidney damage by clogging the filtration membrane.

Type and cross - In the laboratory the possible donor RBCs are mixed with the recipients serum to make sure agglutination does not occur.

Type and screen - recipients serum is screened for antibodies against a set of RBCs with antigens