Physiology- Renal II

Question 0

Major function of nephrons

Answer 0

Reabsorption of NaCl and water

Question 1

3 basic process involving formation of urine

Answer 1

Ultrafiltration of plasma by glomerulus
Reabsorption of water and solutes from ultrafiltrate
Secretion of of selected solutes into tubular fluid

Question 2

What gets reabsorbed in proximal tubule

Answer 2

65% of filtered:
Na
Cl
K
Water
Urea
90% of filtered:
Bicarbonate
Almost all of filtered:
Glucose
Amino acids
Phosphate

Question 3

What gets secreted at proximal tubule

Answer 3

Hydrogen ions
Drug toxins
Organic acids and bases
-bile salts
-oxalates
-irate
-catecholamines

Question 4

How much NaCl is reabsorbed in loop of henle?

Answer 4

25%

Question 5

How much water is reabsorbed in loop of henle

Answer 5

15%

Question 6

What is loop of henle responsible for

Answer 6

Urinary concentrating ability

-generation of hypertonic medullary interstitium=countercurrent multiplication

Question 7

What gets reabsorbed in loop of henle

Answer 7

NaCl
Water
Calcium
Magnesium

Question 8

Major segments of loop of henle

Answer 8

Descending thin limb

Question 9

Descending thin limb highly permeable to

Answer 9

Water

Question 10

Descending thin limb impermeable to

Answer 10

NaCl

Question 11

Ascending thin limb does reabsorption of

Answer 11

NaCl

Question 12

Ascending thin limb impermeable to

Answer 12

Water

Question 13

Ascending thick limb does reabsorption of

Answer 13

NaCl
Na
K
2Cl

Question 14

Ascending thick limb impermeable to

Answer 14

Water

Question 15

Which part of loop of henle is the primary target of loop diuretics

Answer 15

Ascending thick limb

Question 16

How does loop of henle contribute to urine concentrating ability

Answer 16

By establishing hypertonic medullary interstitium

Question 17

How is hypertonic medullary interstitium created

Answer 17

Reabsorption without water dilutes tubular fluid and increases osmolality of interstitial fluid surrounding thick ascending loop of henle

Question 18

What is reabsorbed at distal tubule

Answer 18

5% NaCl

Ca

Question 19

What works to reabsorbe NaCl at distal tubule

Answer 19

Thiazides

Question 20

What is ca reabsorption stimulated by in distal tubule

Answer 20

Parathyroid hormone

Question 21

Major divisions of collecting duct

Answer 21

Cortical collecting duct

Medullary collecting duct

Question 22

Role of collecting duct

Answer 22

Regulates final composition of urine
Reabsorbs 4-5% of filtered Na
Important for regulation of salt and water balance

Question 23

2 cell types in cortical collecting duct

Answer 23

Principal

Intercalated

Question 24

Principal cells are site of action of

Answer 24

Aldosterone

Question 25

What is reabsorbed in principal cells

Answer 25

Na | Cl

Question 26

What is secreted in principal cells

Answer 26

K

Question 27

What is permeability of water in principal cells dependent on

Answer 27

ADH

Question 28

Intercalated cells responsible for regulation of

Answer 28

Acid base balance

Question 29

What is reabsorbed at intercalated cells

Answer 29

K | Bicarbonate

Question 30

What is secreted at intercalated cells

Answer 30

H

Question 31

What is reabsorbed at medullary collecting duct

Answer 31

NaCl Water (controlled by ADH) Urea

Question 32

What is secreted at medullary collecting duct

Answer 32

H

Question 33

Mechanisms that control tubular reabsorption

Answer 33

``` Glomerular balance Peritubular capillary and renal interstitial fluid physical forces Pressure naturesis/diuresis Hormonal control Sympathetic nervous system ```

Question 34

Glomerular balance

Answer 34

Intrinsic ability of tubules to increase their absorption rate in response to increased tubular load (increased tubular inflow) -total rate of absorption increases as filtered load increases

Question 35

Peritubular capillary and renal interstitial fluid physical forces

Answer 35

Hydrostatic and colloid osmotic forces govern rate of reabsorption across peritubular capillaries

Question 36

Aldosterone secreted by

Answer 36

Adrenal cortex

Question 37

What is aldosterone's site of action

Answer 37

Principal cells of cortical collecting tubule

Question 38

Effects of aldosterone

Answer 38

Increases Na and K reabsorption

Question 39

Secretion of aldosterone stimulated by

Answer 39

Increased extracellular K concentration Increased angiotensin II levels -typically occur in conditions associated with Na and volume depletion or low BP

Question 40

3 main effects of angiotensin II

Answer 40

Stimulates aldosterone secretion Constricts efferent arterioles Directly stimulates reabsorption in proximal tubules, loop of henle, distal tubules, and collecting ducts

Question 41

Antidiuretic hormone

Answer 41

Increases water permeability of distal tubule, collecting tubule, and collecting duct -helps body conserve water in times of ECF volume depletion

Question 42

Atrial natriuretic peptide secreted by

Answer 42

Cells in cardiac atria

Question 43

What stimulates release of atrial natriuretic peptide

Answer 43

Distension by increased plasma volume

Question 44

What does atrial natriuretic peptide do?

Answer 44

``` Directly inhibits reabsorption of Na and water by renal tubules, especially collecting ducts Inhibits renin (thus, aldosterone), which indirectly inhibits Na and water reabsorption ```

Question 45

What does activation of sympathetic nervous system decrease excretion of?

Answer 45

Na Water (By constricting renal arterioles, reducing GFR)

Question 46

Sympathetic nervous system increases

Answer 46

``` Renin release Na reabsorption (low levels of stimulation) in proximal tubule, thick ascending loop of henle -does this by activating adrenergic receptors in renal tubular epithelial cells ```