Control Of Water Reabsorption And Body Osmolarity

Question 1

Permeability of water in the different parts of the loop

Answer 1

Varies.

Question 2

What does water move in response to in the loop

Answer 2

To physical or osmotic pressures

Question 3

Where is water absorbed

Answer 3

Only in the descending limb

Question 4

Where are solutes reabsorbed

Answer 4

Thick ascending limb

-this makes the interstitum of the medulla hyperosmotic

Question 5

What makes the interstitum of the medulla hyperosmotic

Answer 5

Solutes being reabsorbed in the thick ascending limb

Question 6

What is the driving force in making concentrated urine

Answer 6

Hyperosmotic medullary interstitium

Question 7

Collecting ducts and the hyperosmotic interstitium

Answer 7

Collecting ducts pass through it and are able to reabsorb water if ADH is present

Question 8

When can the collecting ducts reabsorb water from the interstitium?

Answer 8

If ADH is present

Question 9

Where does the production of the hyperosmotic medulla occur

Answer 9

In the loop

Question 10

Countercurrent exchange

Answer 10

Production of hyperosmotic medulla in the loop

• active reabsorption in TAL to cxn interstitium, dilute tubule
• hyperosmotic interstitium pulls water out of DTL
• flow though kidney occurs and cycle repeats

Question 11

Vasa recta and the hyperosmotic gradient

Answer 11

Blood flow is VERY SLOW so as not to disturb the gradient

Based upon RBF and things that affect it!

Question 12

What does an increased flow in the vasa recta do

Answer 12

Watches out osmotic gradient, less water absorbed.

Question 13

Urea

Answer 13

• added back to the loop to further increase the cxn
• waste product that we reabsorbs so we can reabsorbs more water
• reabsorption from CD is increased when ADH is high

Question 14

When is urea reabsorption in the CD higher

Answer 14

When ADH is present

Question 15

What does water deprivation do to plasma omsolarity?

Answer 15

Increases

Question 16

What does water deprivation do to release of ADH?

Answer 16

Increases it because the plasma osmolarity is increased

Question 17

What does an increased release in ADH during water deprivation do the blood pressure and RBF

Answer 17

Decreases both of them

Allows cxn gradient to get higher

Question 18

Vasa recta in times of water deprivation

Answer 18

Slows to allow for trapping of solutes in medulla

Question 19

What does ADH increase when there is water deprivation

Answer 19

Permeability of CDs to water

-increases urea reabsorption too

Question 20

What does the chain of events that is set off by water deprivation ultimately do

Answer 20

Reabsorbs water. Urea comes with it to increase the osmotic gradient for the next time around too

Question 21

What happens to plasma osmolarity in a water surplus

Answer 21

Lowers.

Question 22

ADH secretion in water surplus

Answer 22

Lower

Question 23

Collecting ducts during water surplus

Answer 23

Not permeable to water. Less ADH so less permeability to water

Question 24

Vasa recta in water surplus

Answer 24

Flow washes out gradient a little.

Question 25

What happens when there is a significant RBF increase?

Answer 25

Vasa recta washes out the gradient a little bit

Question 26

Where is there the greates volume of water reabsorbed?

Answer 26

PCT

Question 27

Where is there the most control of water reabsorption?

Answer 27

Collecting ducts

Question 28

Regulation of water reabsorption occurs in which segment of the nephron?

Answer 28

Collecting ducts

Question 29

What are the ways in which body water is sensed

Answer 29

Baroreceptors | Osmoreceptors

Question 30

Where are the baroreceptors that sense body water

Answer 30

Carotid bodies/aortic arches and arterial stretch

Question 31

What do the baroreceptors respond to

Answer 31

Blood pressure changes

Question 32

What is the most responsive method of sensing body water

Answer 32

Osmoreceptors

Question 33

Where are the osmoreceptors

Answer 33

Hypothalamus

Question 34

What do osmoreceptors respond to

Answer 34

ECF osmolarity, can sense swell/shrink of cell

Question 35

If the cell is shrunken, what will the osmoreceptors do

Answer 35

Increase release of ADH

Question 36

Increased ECF sodium causes osmoreceptors to do what

Answer 36

Release more ADH

Question 37

What is ADH tightly regulated by

Answer 37

Osmoreceptros

Question 38

Slight increase in Osm (plasma) causes

Answer 38

Huge increase in ADH

Question 39

What does a massive hemorrhage do to ADH

Answer 39

Increases it

Question 40

What can cause inhibited ADH secretion

Answer 40

High blood pressure/volume

Question 41

What is ADH sensitive to

Answer 41

Na+ unless massive blood loss

Question 42

If high volume, there is _____ ADH response to increased Na+ cxn in plasma

Answer 42

Less

Question 43

If low volume, there is ____ ADH response to increased Na+ concentrations in plasma

Answer 43

More

Question 44

When does maximal ADH secretion occur

Answer 44

In a patient with a massive hemorrhage AND a hypernatremia Or Dehydration due to water deprivation

Question 45

Which of the following conditions would cause a minimal ADH release

Answer 45

Hypertension and hyponatramia

Question 46

Where is ADH secreted from

Answer 46

Posteiror pituitary | -stored until needed

Question 47

Increased osmoreceptor firing, ___- ADH release

Answer 47

Increased

Question 48

Increased baraoreceptor firing, _____ ADH release

Answer 48

Decreased | High BP

Question 49

What does ADH have nothing to do with

Answer 49

Solutes in urine.

Question 50

What does ADH have an effect on

Answer 50

Water

Question 51

ADH and conservation of water

Answer 51

ADH cannot replace lost water volume nor can it stop water loss, it can only CONSERVE water

Question 52

How would you differentiate between water deprivation and diabetes insipidus

Answer 52

Both are volume depleted and hypernaremic I don't know the answer

Question 53

What does the feedback control of the kidney predict responses to?

Answer 53

- excessive water consumption - hemorrhage - decreased cardiac contractility - non functional retinal ADH receptors (Nephrogenic diabetes insipidus) - inability to secreate ADH (central diabetes insipidus) - chronic vasodilator administration - alcohol consumption

Question 54

Which of the following would allow you to differentiate between nephrogenic diabetes insipidus and severe water deprivation

Answer 54

Free water clearance

Question 55

What does ADH control

Answer 55

Volume and osmolarity of ECF

Question 56

How does ADH control the volume and osmolarity of the ECF

Answer 56

By changing volume and osmolarity of urine

Question 57

What does RAAS control

Answer 57

ECF only

Question 58

What does aldosterone of the RAAS system reabsorbs

Answer 58

Reabsorbs water and Na equally

Question 59

What is aldosterone release in the RAAS triggered by

Answer 59

AngII or high ECF K levels

Question 60

What controls ECF volume only

Answer 60

RAAS

Question 61

What controls volume and osmolarity of ECF

Answer 61

ADH

Question 62

What is AngII major stimulus

Answer 62

Increase renin

Question 63

What part of the nephron does AngII target

Answer 63

PT, TAL, DT/CD

Question 64

What is the transport effect of AngII

Answer 64

Increased NaCL and water reabsorption

Question 65

What is aldosterone' major stimulus

Answer 65

Increases AngII, increases K+ concentration in plasma

Question 66

Nephron target of aldosterone

Answer 66

TAL, DT/CD

Question 67

Transport effect of aldosterone

Answer 67

Increases NaCla and water reabsorption

Question 68

ANP/BNP major stimulus

Answer 68

Increased ECFV

Question 69

Nephron target of ANP/BNP

Answer 69

CD

Question 70

Transport effect of ANP/BNP

Answer 70

Decreases NaCl and water reabsorption

Question 71

Sympathetic major stimulus

Answer 71

Decreased ECFV

Question 72

Nephron target of sympathtics

Answer 72

PT, TAL, DT/CD

Question 73

Transport effect of sympathetic

Answer 73

Increased NaCal and water reabsorption

Question 74

ADH major stimulus

Answer 74

Decreased ECFV

Question 75

Nephron target of ADH

Answer 75

DT/CD

Question 76

Transport effect of ADH

Answer 76

Increased water reabsorption

Question 77

What is AngII stimulated by

Answer 77

Renin

Question 78

What does ANgII do

Answer 78

Increases Na and water reabsorption in PCT, TAL, and DCT

Question 79

What is a potent vasodilator for everything, and the efferent artery in the kidney

Answer 79

AngII

Question 80

What does the ANgII do to the vasa recta

Answer 80

Slows it

Question 81

When do catecholamines come into play in the kidney (NE/Epi)

Answer 81

When you are almost dead. Effective at EXTREMELY low ECV

Question 82

Where is aldosterone released from

Answer 82

Adrenal cortex. Mineralacorticoid

Question 83

Other than increased Na and water reabsorption in the DCT and CD, what else does aldosterone do

Answer 83

Increases potassium excretion

Question 84

What can high aldosterone do

Answer 84

Can cause alkalosis | -K+ excretion and H+ excretion are linked

Question 85

Causes loss of Na and water by blocking reuptake in collecting ducts. Also inhibits ADH release and function

Answer 85

ANP and BNP

Question 86

What can levels of ANP be used for

Answer 86

As a marker for severity of congestive heart failure

Question 87

What are the levels of ANP in someone with worse cardiac output

Answer 87

Higher levels of ANP

Question 88

What would happen with ANP during a massive MI

Answer 88

Heart stretches a lot, acute dump of ANP.

Question 89

What is the reason we have to pee a lot when we get in a pool

Answer 89

ANP

Question 90

If a patient has a hypothalamic tumor which produced too much ADH would there free water clearance be:

Answer 90

Lower than normal (making concentrated urine)

Question 91

Nephrogenic diabetes insipidus is a disease wher ethe V2 receptors in the kidney are unable to respond to ADH secreted from the pituitary gland. Which of the following statements would be true concerning a patient with this disease

Answer 91

Plasma osmolarity would be elevated

Question 92

Administration of a beta 1 receptor agonist (activator) would case which of the following

Answer 92

Increased GFR

Question 93

Administration of a carbonic anhydrase inhibitor would

Answer 93

Reduce HCO3 reabsorption in the PCT