1. Unit III: Homeostasis Blood Chapter 17 pp. 575-585

2. Review 1.The most effective buffer in the intracellular fluid is: a.) phosphate; b.) protein; c.) bicarbonate; d.) carbonic acid 2.A blood pH of 7.2 caused by inadequate pulmonary ventilation would be classified as _________. 3.Tubular secretion of hydrogen ions would cease if the acidity of the tubular fluid fell below a value called the _________. 4.(T/F) The bicarbonate system buffers more acid than any other chemical buffer. 5.Acids ____________ hydrogen ions in a solution, whereas, bases _______ them.

3. Functions of Circulatory System Fundamental purpose: transport substances from place to place Transport –O 2, CO 2, nutrients, wastes, hormones, and stem cells Protection –Inflammation, WBCs, antibodies, and platelets Regulation –fluid regulation, buffering, and heat

4. Presence of Potassium in Blood >8 mEq/L in blood cardiac arrhythmias <2 mEq/L in blood: muscular weakness paralysis Normal potassium levels in serum (3.5–5.5 mEq/L) Factors Promoting HypokalemiaFactors Promoting Hyperkalemia Diuretics (Lasix) ↑ volume of urine produced Aldosteronism overstimulates sodium retention & potassium loss Chronically low body fluid pH Kidney failure Several drugs promote diuresis by blocking Na  reabsorption at the kidneys. HypokalemiaHyperkalemia

5. Centrifuge Withdraw blood Plasma (55% of whole blood) Buffy coat: leukocytes and platelets (<1% of whole blood) Erythrocytes (45% of whole blood) Formed elements Blood Composition Adults have 4-6 L of blood Plasma – –Water, proteins, nutrients, electrolytes, nitrogenous wastes, gases, and hormones (Table 18.2 p. 687) Serum –Lacks fibrinogen

6. Plasma Proteins 3 major categories of plasma proteins: –albumins - most abundant contributes to viscosity and osmolarity  influences blood pressure, flow and volume –globulins (antibodies) provide transport, clotting, and immunity alpha, beta and gamma globulins –fibrinogen precursor of fibrin  help form blood clots Plasma proteins formed by liver –except gamma globulins (produced by plasma cells)

7. Formed Elements of Blood Erythrocytes Platelets Leukocytes –Granulocytes Neutrophils Eosinophils Basophils –Agranulocytes Lymphocytes Monocytes

8. Properties of Blood Viscosity - –whole blood 5 times as viscous as water Osmolarity (total molarity of dissolved particles that can’t pass through blood vessel wall) –high blood osmolarity raises blood pressure –low blood osmolarity lowers blood pressure

9. Properties of Blood Hematocrit – (packed cell volume) –Females: 37-48% –Males: 45-52% pH: 7.35 - 7.45 RBC count: –Females: 4.2-5.4 million/µL –Males: 4.6-6.2 million/µL Total WBC count: 5000 – 10,000 /µL Volume/Body weight: 80-85 mL/kg –Female: 4-5L –Male: 5-6L

10. Erythrocytes (RBCs) Disc-shaped cell with thick rim Gas transport –increased surface area/volume ratio due to loss of organelles during maturation increases diffusion rate of substances –33% of cytoplasm is hemoglobin (Hb) O 2 delivery to tissue and CO 2 transport to lungs Carbonic anhydrase (CAH)

11. Erythrocytes and Hemoglobin Common measurements: –Hematocrit (packed cell volume) –Red blood cell count –hemoglobin concentration of whole blood men 13-18g/dL; women 12-16g/dL Values are lower in women –androgens stimulate RBC production –women have periodic menstrual losses –Hematocrit is inversely proportional to % body fat

12. Erythropoiesis 2.5 million RBCs/sec (hematocrit value of 20mL of RBC/day) Development takes 3-5 days –reduction in cell size, increase in cell number, synthesis of hemoglobin and loss of nucleus Macrophages in liver, spleen, and bone marrow Fe 2+ 90% 10% Fe 2+ transported in circulation by transferrin Average life span of RBC is 120 days Hemolysis Heme Biliverdin Bilirubin Amino acids New RBCs released into circulation RBC formation Ejection of nucleus Events Occurring in the Red Bone Marrow Multipotent stem cells Proerythroblasts stimulated by erythropoietin (EPO) Erythroblast Roughly four days of differentiation Retilculocytes remain in the bone marrow for 2 more days Start

13. Erythrocyte Homeostasis Negative feedback control –drop in RBC count causes kidney hypoxemia –EPO production stimulates bone marrow –RBC count  in 3 - 4 days Stimulus for erythropoiesis –hemorrhaging, blood loss –low levels O 2 –abrupt increase in O 2 consumption –loss of lung tissue in emphysema

14. Anemia Inefficient amount of red blood cells Causes:  inadequate erythropoiesis Kidney failure Iron-deficiency Vitamin B 12 deficiency  blood loss  RBC destruction Consequences:  Hypoxia  Decreased blood osmolarity  Decreased blood viscosity

15. Erythrocyte Disorders Sickle Cell Disease and Thalassemia Hereditary Hb ‘defect’ of African Americans and Mediteraneans –recessive allele modifies hemoglobin structure –sickle-cell trait - heterozygous for HbS individual has resistance to malaria –sickle-cell disease - homozygous for HbS individual has shortened life –low O 2 concentrations  sickle shape –stickiness  agglutination  blocked vessels  –intense pain; kidney and heart failure; paralysis; stroke

16. RBC Surface antigens Antigen-antibody complex Opposing antibodies Hemolysis Antigens and Antibodies Antigens (agglutinogens) –unique molecules on all cell surfaces used to distinguish self from foreign Antibodies (agglutinins) –secreted by plasma cells –Appear 2-8 months after birth; reach maximum at 10 yr. –Transfusion reaction Agglutination :

17. ABO Blood Groups Your ABO blood type is determined by presence or absence of agglutinogens on RBCs and agglutinins in blood plasma. most common/universal donor - type O Rarest/universal recipient - type AB Type A Type AB Type O RBCs lacking both A and B antigens. RBCs with antigen A only. RBCs with antigen B only. RBCs with both A and B antigens. Type B Surface antigen A Surface antigen B Plasma contains anti-B antibodies, which will attack Type B surface antigens. Plasma contains anti-A antibodies. Plasma has neither anti-A nor anti-B antibodies. Plasma contains both anti-A and anti-B antibodies.

18. ABO Group Genetics A and B alleles are dominant over O; but codominant to each other GenotypeAntigenPhenotype AAAA AOAA BBBB BOBB ABA and BAB OONeitherO AAB B BA A B

19. Rh Group 3 antigens: C, D, E Rh (D) agglutinogens –Rh + blood type has D agglutinogens on RBCs –Rh frequencies vary among ethnic groups Anti-D agglutinins not normally present –form in Rh - individuals exposed to Rh + blood no problems with first transfusion

20. First Pregnancy of an Rh – Mother with an Rh + infant Very few fetal cells enter the maternal circulation. Exposure to fetal red blood cell antigens generally occurs during delivery. A woman’s first infant is not affected. During First Pregnancy Hemorrhaging at Delivery Maternal Antibody Production During Second Pregnancy Rh antigen on fetal red blood cells Maternal antibodies to Rh antigen Maternal Fetal Maternal Fetal blood supply and tissue Maternal blood supply and tissue Placenta Rh + fetus Rh – mother Rh – mother Rh + fetus Maternal Fetal Maternal antibodies Hemolysis of fetal RBCs Second Pregnancy of an Rh – Mother with an Rh + Infant Maternal anti-Rh antibodies present. These antibodies destroy fetal RBCs  dangerous anemia. Need for blood cells ↑ Leave bone marrow under- development. Hemolytic Disease of the Newborn

21. Anti-A Anti-B Anti-D Blood type A+A+ B+B+ AB + O–O– Results of blood typing tests on blood samples from four individuals