21. Which of the following statements are true in order todecrease glomerular hydraulic pressure?

1. the afferent arteriole will constrict.

2. the afferent arteriole will constrict.

3. the afferent arteriole has no effect on glomerular filtrationpressure

4. the afferent arteriole will dilate.

22. An example of reabsorption in the nephron is

1. movement of Na+ from the proximal convoluted tubule into theperitubular capillaries

2. movement of histamine from the peritubular capillaries intothe proximal convoluted tubule

3. movement of histamine from the peritubular capillaries intothe proximal convoluted tubule

4. movement of K+ from the peritubular capillaries into thedistal convoluted tubule

23. the major site of amino acid absorption is the

1. liver

2.stomach

3. large intestine

4. small intestine

24. a negative feedback mechanism in response to reduced intakeof salt (NaCl) is likely to include

1. an increase in blood volume due to increase in ADH

2. an increase in renal blood flow due to an increase in waterreabsorption

3. an increase in secretion of renin by the juxtaglomerularcells

4. a decrease in secretion of aldosterone and increased Na+excretion

25. Renin is secreted by

1. speciallized cells in the nephron and convertsangiotensinogen into anglotensin 1.

2. lung capillary endothelial cells and converts angiotensin 1into angiotensin 2.

3. the atria in response to increased stretch and causes a lossof Na+ and water

4. adrenal cortex and promotes K+ secretion in the proximalconvoluted tubule.