renal 2

Question 1

water enters the body in food and drink and by being produced in

Answer 1

metabolic rxns

Question 2

water is lost through skin and lungs ( _____ ) , and in

Answer 2

insensible loss

sweat, feces, and urine

Question 3

sodium enter and leaves the body in the same way as water, except that it is not

Answer 3

metabolically produced nor is it lost via the lungs

Question 4

normally water and salt losses equal

Answer 4

water and salt gains

Question 5

sodium and water do not undergo tubular secretion, thus amount secreted =

Answer 5

amount filtered minus amount reabsorbed

Question 6

most sodium and water reabsorption is in the ______ , but the main hormonal control of reabsorption is in the

Answer 6

proximal tubule

distal tubule and collecting duct

Question 7

sodium reabsorption is by active transport, requires

Answer 7

renal energy, is carrier-mediated, and can occur against a concentration gradient

Question 8

water reabsorption is by ______ and depends on (is coupled to) the reabsorption of _____

Answer 8

diffusion

Na+

Question 9

through the tubule and collecting duct, one step in the reabsorption of sodium is the (primary) active transport (by the Na/K pump) of sodium ______

sodium moves from the lumen of the tubule down its concentration gradient into the cells forming the tubule walls by a variety of ways:

Answer 9

out of the cells forming the tubule walls (across their basolateral membrane) and into the renal interstitial fluid

cotransport with glucose or amino acids; or countertransport with H+ ; or by diffusion through sodium channels

Question 10

coupling of water reabsorption to sodium reabsorption:

1. no water concentration gradient exists between the
2. as fluid flows down (along) the tubule, sodium is
3. these changes establish a concentration gradient for water, with the higher concentration being in the
4. the difference in water concentration causes diffusion (osmosis) of water out of the tubule lumen and
5. from the renal interstitial fluid, water, sodium, and everything else dissolved in the interstitial fluid move together by

Answer 10

1. fluid (filtrate) in the lumen of the first portion of the proximal tubule and the nearby renal interstitial fluid
2. actively removed from the lumen into the interstitial fluid, thereby increasing the water concentration (lowering osmolarity) in the tubular fluid and decreasing the water concentration (raising osmolarity) in the nearby interstitial fluid
3. tubular fluid
4. across the tubular cells’ plasma membrane and/or tight junctions into the interstitial fluid (assuming the tubule wall is water permeable, which it always is in the proximal tubule)
5. bulk flow into the peritubular capillaries as the final step in reabsorption

Question 11

large amounts of sodium and water are reabsorbed in

Answer 11

the proximal tubule, and the rate of this water reabsorption is not regulated

Question 12

in the collecting duct (and late distal tubule), the water permeability

Answer 12

can vary greatly and is under physiological control

Question 13

in the collecting duct and late distal tubule, the posterior pituitary hormone antidiuretic hormone (ADH) also called vasopressin, stimulates

Answer 13

the insertion of aquaporins into the tubular cell luminal membranes, thereby greatly increasing the water permeability of the membranes and increasing the rate of water reabsorption

Question 14

without ADH, the wall of the collecting duct has limited water permeability ; thus, very little water is reabsorbed from the collecting duct when

Answer 14

ADH secretion is low, and a large amount of water is left behind in the tubule to be excreted in the urine

Question 15

diabetes insipidus

Answer 15

pituitary fails to release ADH or kidneys fail to pay attention to it; patient can produce 25 L urine/cay

Question 16

water diuresis

Answer 16

increased urine production but not increased solute excretion

Question 17

osmotic diuresis

Answer 17

increased urine flow as a result of increased solute excretion