Physiological Science 111B Module 2 Lecture 1

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Red Blood Cells (Erythrocytes): Main Fxn: Transport O2 and CO2.
[Human] = 5E12 cells/L.
Most abundant cell in blood 4.6-6.2mL/mm3.
120-day life span.
Largest cell in blood (7-8um)
Contains hemoglobin (Hb) which carries blood gases.
[Hb] normally 14-16gm/100mL blood (or gm%)
Leukocytes (White BLood Cells, WBCs): 5-10,000 cells/mm3
Life Span: a few hours to several days.
There are several different types of WBCs which comprise the immune system.
WBC counts are used as a diagnostic measure of immune function.
Platelets (Thrombocytes): Main Function: Initiate Blood Clotting
[Human Blood]3E11 cells/L
0.2-0.4 mL/mm3
Life Span 8-12 days
Contain the factors involved in the clotting mechanism.
Plasma Components: 1.) Water: ~90% of plasma volume.
2.) Gases: e.g. O2, CO2
3.) Nutrients: glucose, free fatty acis, lipoproteins (cholesterol and triglycerides), amino acids.
4.) Proteins: ~7% (e.g. albumin, immunoglobulins, fibrinogens, hormones, enzymes)
5.) Ions: e.g. bicarbonate, Ca, Fe, Mg, Na, K, Cl)
Hematocrit (HCT): A clinical measurement that is the ratio of blood cells to total blood.
The normal range is 40-48%.
A low HCT is inidicative of anemia: 35-40%.
How the Blood Sample is Expressed: PLASMA: if the tube is coated with an anticoagulant.

SERUM: if blood clot is allowed so it no longer contains clotting factors (i.e. plasma without clotting factors).
Functions of Blood: 1) Transport: gases (e.g. O2, CO2, NO), nutrients, waste material, heat, proteins, hormones, enzymes, lipids.
2) Regulator of: a) acid/base status (pH buffering of H+ and removal of CO2), b) body temp. (transports heat, forms sweat).
3) Protection: a) protects itself through the clotting mech., b) contains immune cells that remove viruses, bacteria and chemicals by producing antibodies.
Neutrophils: WBC/Leucocyte
Main Function: Phagocytose and destroy invading bacteria.
[Human Blood] 5E9 cells/L
Eosinophils: WBC/Leucocyte
Main Function: Destroy parasites and modulate inflammatory reactions.
[Human Blood] 2E8 cells/L
Basophils: WBC/Leucocyte
Main Function: Release histamine in the immune response.
[Human Blood] 4E7 cells/L
Monocytes: WBC/Leucocyte
Main Function: Become tissue macrophages, which digest microorganisms as well as damaged cells.
[Human Blood] 4E8 cells/L
B Cells: Lymphocyte
Main Function: Make antibodies.
[Human Blood] 2E9 cells/L
T Cells: Lymphocyte
Main Function: Kill virus-infected cells and regulate activites of leucocytes.
[Human Blood] 1E9 cells/L
Natural Killer Cells (NK): Lymphocyte
Main Function: Kill virus-infected cells and some tumor cells.
[Human Blood] 1E9 cells/L
Nutritional Anemia Anemia = A condition characterized by low levels of Hb.: Deficiency of iron or folic acid.
Vegetarians are at risk if their vitamin and mineral intakes are inadequate.
Pernicious Anemia Anemia = A condition characterized by low levels of Hb.: Lack of intrinsic factor and vitamin B12, which is important for the incorporation of Fe and the sythensis of RBCs.
Aplastic Anemia Anemia = A condition characeterized by low levels of Hb.: Deficiency in erythroid stem cells.
Renal Anemia Anemia = A condition characterized by low levels of Hb.: May occur during kidney disease or renal failure, where EPO production decreases.
Hemorrhagic Anemia Anemia = A condition characterized by low levels of Hb.: Caused by excessive blood loss that may occur during surgery, menstruation, or injury.
Hemolytic Anemia Anemia = A condition characterized by low levels of Hb.: Caused by RBC rupture. Seen in individuals with malaria and occasionally with severe prolonged physical exertion.
Sickle Cell Anemia Anemia = A condition characterized by low levels of Hb.: A genetic disease where RBCs have defective Hb and they have a sickle, rather than a round, shape.
Problems that result in an imbalance between clot formation and dissolution.: 1)Hemophilia: genetic defect, can't activate clotting sys-> extensive bleeding, especially internally.
2)Thrombocytopenia: platelet deficiency.
3)Vitamin K Deficiency: essential for normal clot formation
4)Aspirin: reduces platelet aggregation; may cause internal bleeding or hemorrhagic stroke in aspirin-sensitive ppl. High dose of Vitamin E may do the same.
Other factors affecting platelet aggregation and clot formation: DSS: 1) Drugs: Coumadin - blood thinner prevents clots, used for heart valve replacement. Aspirin and Persantine - reduce platelet aggregation
2) Stress: catecholamine release increases platelet aggregation.
3) Smoking: increases clot formation.
Other factors affecting platelet aggregation and clot formation: HEG: 4.) High-fat diet: increases fibrinogen, platelet aggregation and tPAI.
5.) Exercise: activates fibrinolytic system.
6.) Genetically engineered tPA: enhances clot dissolution.
Components of the Cardiovascular System (CVS): 1) blood, or transport medium of substances in the body
2) vasculature, or the system of blood vessels that distributes and regulates the blood supply to the body tissues
3) heart, the pump that pushes the blood through the vasculature
Other body systems with which the Cardiovascular System interacts: 1) CNS and PNS - control CV responses and innervation of cardiac and vascular tissue
2) Muscular - acts with CNS for movement
3) Respiratory - blood carries gases and helps regulate plasma pH
4) Skeletal - bone marrow produces blood cells
5) Endocrine - hormones are carried in the blood and act on target tissues
Reasons for studying the function of the CVS: 1) to prevent Cardiovascular Disease (CVD-related deaths which are responsible for 40% of all deaths, with heart attacks the #1 cause of them
2) to prevent immune system diseases like AIDS, asthma, and multiple chemical sensitivity
3) functional and exercise performance
Where do blood cells come from?: The production of blood cells is called HEMOPOIESIS and this occurs in the marrow of bones, located in the shaft.
Ways to increase RBC Formation: 1)Blood Doping: kidney senses dec [RBC] & releases the hormone erythropoietin (EPO)->inc blood, Hb, O2 carrying capacity, performance
2)prolonged residence at high altitudes
3)Polycythemia->inc RBC, HCT->thick, viscuous blood (also applies to 1)
4)severe dehydration->inc HCT
Plateletts (Thrombocytes) are involved in blood clotting. When a vessel is injured, collagen is exposed and this stimulates PLATELET AGGREGATION and activation at the injury site which includes:: 1)Platelets release ADP
2)ADP stimulates increased platelet aggregation
3)platelets release thromboxane A2->vasoconstriction
4)ADP & thromboxane A2 form platelet plug->starts clot-formation via extrinsic or instrinsic pathway
Thromboembolism: An internal clot formed from the instrinsic pathway of clot formation in the absence of a cut in the vessel.
Thrombus: A thromboembolism that adheres to the vessel wall. i.e. an internal clot formed from the intrinsic pathway of clot formation in the absence of a cut in the vessel and which has adhered to the blood vessel wall.
Embolism: A thromboembolism that is floating in the bloodstream. i.e. an internal clot formed from the intrinsic pathway of clot formation in the absence of a cut in the vessel and which is floating in the bloodstream.
Potential Problem of an Instrinsic Clot: It can result in vessel blockage, and therefore gas exchange to the tissue supplied by that vessel is affected. This occurs during a myocardial infarcation or a stroke.
Platelet-Aggregation Inhibitors: NO and prostacyclin (PGI2) inhibit platelet aggregation so as to reduce the chance of spontaneous clot formation.
Fibrinolysis: the process by which a clot is dissolved once the vessel has healed: Plasminogen-->Plasmin-->Clot Dissolves
Enzyme: Tissue Plasminogen Activator (tPA)
Inhibitor: tPA Inhibitory (tPAI), administered during MI
Activator: Factor XII
Why must all factors involved in clot formation and dissolution remain in balance?: So that no unnecessary clots are formed and yet clots may be formed when needed to reduce blood loss during an injury.
IgM: IgM immunoglobulin serves as the B cell surface receptor for antigen attachment and is secreted in the early stages of plasma cell response.
IgG: IgG, the most abundant immunoglobulin in the blood, is produced copiously when the body is subsequently exposed to the same antigen. With IgM, it is responsible for the most specific immune responses against bacterial invaders and a few types of viruses.
IgE: IgE helps protect against parasitic worms and is the antibody mediator for the common allergic responses, such as hay fever, asthma, and hives.
IgA: IgA immunoglobulins are found in secretions of the digestive, respiratory, and genitourinary systems, as well as in milk and tears.
IgD: IgD is present on the surface of many B cells, but its function is uncertain.

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