Physiology 5 - Endocrine Control of Fluid Volume

Question 1

Hormonal control of salt and water balance only affects which parts of the nephron?

Answer 1

Distal convoluted tubule and collecting ducts

Question 2

What is the role of ADH?

Answer 2

Increase water reabsorption

Question 3

What is the role of aldosterone?

Answer 3

Increase sodium reabsorption and potassium secretion

Question 4

Aldosterone results in increased secretion and hence excretion of which two ions?

Answer 4

Potassium and hydrogen

Question 5

What is the role of ANP?

Answer 5

Decrease sodium reabsorption

Question 6

Parathyroid hormone is responsible for increasing the reabsorption of which ion?

Answer 6

Calcium

Question 7

Parathyroid hormone is responsible for decreasing the reabsorption of which ion?

Answer 7

Phosphate

Question 8

In the late portion of the distal tubule, which ions are reabsorbed in the basal state?

Answer 8

Calcium, sodium, potassium

Question 9

In the late portion of the distal tubule, which ion is secreted in the basal state?

Answer 9

Hydrogen

Question 10

In the late portion of the distal tubule, what change occurs in reabsorption/secretion in response to aldosterone?

Answer 10

Potassium is secreted, not reabsorbed

Question 11

Where is ADH formed?

Answer 11

Hypothalamus

Question 12

Where is ADH secreted from?

Answer 12

Posterior pituitary gland

Question 13

What is the half life of ADH?

Answer 13

10-15 minutes

Question 14

What is the most important stimulus for ADH release?

Answer 14

Hypothalamic osmoreceptors in response to increased plasma osmolarity

Question 15

Is ADH secreted in response to dehydration or over-hydration?

Answer 15

Dehydration

Question 16

Is ADH secreted in response to a high or low plasma osmolarity?

Answer 16

High

Question 17

Which receptor does ADH bind to on the basolateral membrane of the distal tubule and late collecting duct?

Answer 17

Vasopressin 2 receptor

Question 18

Binding of ADH to its receptor on the cells of the distal tubule/collecting duct has what effect on the cells?

Answer 18

Increased permeability to water

Question 19

How does binding of ADH cause the cells of the distal tubules/collecting ducts to become more permeable to water?

Answer 19

Insertion of aquaporins

Question 20

Does a high ADH concentration cause urine to be hypertonic or hypotonic?

Answer 20

Hypertonic

Question 21

What happens to the amount of solute excreted in urine in response to ADH?

Answer 21

It is the same as always

Question 22

What condition occurs in individuals who cannot produce or respond to ADH?

Answer 22

Diabetes insipidus

Question 23

Nephrogenic diabetes insipidus is very common in individuals who are prescribed which drug long term?

Answer 23

Lithium

Question 24

What effect does alcohol have on ADH release?

Answer 24

Inhibits

Question 25

Where is aldosterone secreted from?

Answer 25

Adrenal cortex

Question 26

What two things activate secretion of aldosterone?

Answer 26

Raised plasma potassium concentration and activation of RAAS

Question 27

What happens to the plasma volume and blood pressure in response to aldosterone?

Answer 27

Increased

Question 28

Under normal circumstances, is potassium excreted in the urine?

Answer 28

No

Question 29

A decrease in plasma sodium promotes the indirect secretion of aldosterone how?

Answer 29

Secretion of renin

Question 30

When secreted, renin combines with what to form angiotensin I?

Answer 30

Angiotensinogen

Question 31

Which part of RAAS is responsible for stimulating the adrenal cortex to secrete aldosterone?

Answer 31

Angiotensin II

Question 32

What are the three factors which cause increased renin release from granular cells?

Answer 32

Low pressure in the afferent arteriole, low sodium concentrations in the tubular fluid, increased sympathetic activity

Question 33

How does aldosterone allow more sodium to be reabsorbed from the tubular fluid?

Answer 33

Increased number of Na+/K+ ATPase pumps

Question 34

Where is ANP released from?

Answer 34

Atrial muscle cells

Question 35

ANP is released in response to what?

Answer 35

Stretch of atrial muscle cells

Question 36

What effect does ANP have on plasma volume?

Answer 36

Decreased