OLD Bio 235 ass 3.docx - Assignment 3 Weight 5 Minimum Pass Grade 50 Each question is worth 10 marks 1 Fill in the words or phrases that best complete

OLD Bio 235 ass 3.docx - Assignment 3 Weight 5 Minimum Pass...

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Assignment 3 Weight: 5% Minimum Pass Grade: 50% Each question is worth 10 marks. 1. Fill in the words or phrases that best complete each sentence. Be as specific as possible. a. Erythrocytes contain the enzyme carbonic anhydrase , which catalyzes the conversion of metabolically produced CO 2 and water into carbonic acid(H 2 CO 3 ) , which in turn dissociates into a bicarbonate ion (H + + HCO 3 - ) b. Most old erythrocytes are removed from circulation and destroyed by cells called fixed phagocytic macrophages , as they rupture passing through the narrow capillaries of the organ called the spleen, liver and red bone marrow . c. Undifferentiated cells called pluripotent stem cells reside in the bone marrow, where they continuously divide and differentiate to give rise to each of the types of blood cells. d. The process of leukocytes squeezing through the capillary walls (endothelial cells) to exit the vasculature is known as emigration (also called diapedesis) . Once they leave the bloodstream to fight a pathological condition, they never return. e. The genetically-determined glycoprotein and glycolipid antigens found on the surface of an erythrocyte are called agglutinogen , and a person with agglutinins that react with type A and blood type B has type O blood. f. During embryonic development, ninety-nine percent of the cardiac fibers are specialized for the function called contractile function , whereas the remainder is specialized for autorhythmic function (conduction system) . g. The action potential delay at the AV node ensures that atrial excitation and contraction are complete before ventricular excitation and contraction commence. h. The end-systolic volume (ESV) is the volume of blood in the ventricle after ejection has been completed. An increase of this volume occurs when the stroke volume is decreased (SV=EDV-ESV) . i. The three cations, K + , Ca 2+ , and Na + have an important effect of heart function. Increased blood levels of Na + blocks Ca 2+ inflow and results in a decrease in the force of contraction, while an excess of K+ blocks the generation of action potentials. j. An increase in parasympathetic activity has the following effect on stroke volume: decreases SV (therefore decreasing BP) . An increase in parasympathetic activity weakens atrial contractility. Assignment 2 :: Biology 235: Human Anatomy and Physiology 1
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2. A patient has the misfortune to have both diabetes insipidus and Addison’s disease. How will those conditions affect the patient’s ability to regulate blood pressure? Changes in blood pressure are routinely made in order to direct appropriate amounts of oxygen and nutrients to specific parts of the body. Blood pressure can be altered by changes in the following: cardiac output (the volume of blood ejected from the left or right ventricle into the aorta or pulmonary trunk) which can be altered by changing stroke volume (volume of blood ejected by the ventricles during each contraction) or heart rate (Cardiac output = the stroke volume x heart rate). Blood pressure can also be adjusted by vasodilation or vasoconstriction (changes in diameter of vessels). To help regulate blood pressure the
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