Concentration and Dilution of Urine

Question 1

(blank) is a mechanism that expends energy to create a concentration gradient. Useful in creating hypertonic urine.

Answer 1

a countercurrent multiplier system

Question 2

The countercurrent flow within the descending and ascending limb thus increases, ormultiplies the (blank) between tubular fluid andinterstitial space

Answer 2

osmotic gradient

Question 3

Where can water leave?

Answer 3

descending limb

Question 4

Where can salt leave?

Answer 4

ascending limb

Question 5

normal urine osmolarity is (blank)

Answer 5

hypertonic

Question 6

What is the normal process of creating hypertonic urine?

Answer 6

create isotonic, create hypotonic-> finish with hypertonic

Question 7

(blank) and (blank) are critical for formation of a hypertonic urine.

Answer 7

ADH and interstitial osmotic gradint

Question 8

The more your interstitial osmotic gradient the more (blank) your urine.

Answer 8

hypertonic

Question 9

What allows for water to leave in the collecting duct?

Answer 9

ADH (w/ aquaporins) : )

Question 10

An interstitial gradient is present from cortex to (blank) region throughout the kidney

Answer 10

papillary region

osmotic gradient is lowest (300) at cortex and highest (1200) at papillary region

Question 11

What is the corticopapillary osmotic gradient primarily composed of?

Answer 11

NaCl and Urea

Question 12

The corticopapillary osmotic gradient is established by (blank) and urea recycling and is maintained by (blank) in the vasa recta/

Answer 12

countercurrent multiplication

countercurrent exchange

Question 13

What does counter current multiplication in the loop of henle depend on?

Answer 13

NaCl reabsorption in the thick ascending limb and countercurrent flow in the descending and ascending limbs of the loop of henle

Question 14

Countercurrent multiplication is augemented by (blank) which stimulates NaCl reabsorption in thick ascending limb.

Answer 14

ADH

Question 15

The presence of (blank) increases the size of the corticopapillary osmotic gradient.

Answer 15

ADH

Question 16

(blank) from the inner medullary collecting ducts into the medullary interstitial fluid also is augmented by ADH

Answer 16

Urea recycling

Question 17

Vasa Recta are the capillaries that supply the loop of henle. They maintain the corticopapillary gradient by serving as (blank).

Answer 17

OSMOTIC EXCHANGERS

Question 18

(blank) equilibrates osmotically with the interstitial fluid of the medulla and papilla.

Answer 18

vasa recta

Question 19

What are the phases and what is happening during counter current multiplication (i.e. active creation of interstitial gradient)?

Answer 19

start at equilibrium-> pump ions out of ascending limb of loop of henle (water remains stuck in loop)->increased interstitial fluid osmolarity so water leaves during descending limb->increased osmolality of filtrate entering the ascending limb

Question 20

As water and solutes are reabsorbed, the loop first concentrates the filtrate and then (blank) it.

Answer 20

dilutes

Question 21

Which nephrons create the gradient?

Answer 21

juxtamedullary

Question 22

Do you get passive secretion of salt in the descending limb of the loop of henle?

Answer 22

yes PASSIVE not active

Question 23

(blank) are specialized peritubular capillaries that remove excess salt and water from the medullary/papillary region.

Answer 23

vasa recta

Question 24

Site of reabsorption, results in doubling of flow exiting from it.It provides oxygen and nutrients too!

Answer 24

vasa recta

Question 25

What is the purpose of the vasa recta?

Answer 25

to prevent salt from being washed away

Question 26

Is this true? Plasma flow exiting from the vasa recta is approximately twice that entering the vasa recta?

Answer 26

true!!

Question 27

Is this true? Plasma flow exiting from the glomerular capillaires (toward peritubular capillaries) is app. 20% less than that entering the glomerular capillaries

Answer 27

True!

Question 28

Is this true? | Approximately half of the renal blood flow goes to th renal cortex and half to the medullary/papillary region?

Answer 28

FALSE!!! 85% to cortex

Question 29

Is this true? | The mean hydrostatic pressure of peritubular capillaries is less than that of glomerular capillaries?

Answer 29

True

Question 30

Is this true? | The filtration coefficient (Kf) of glomerular capillaries is greater than for skeletal muscle capillaries?

Answer 30

True

Question 31

Where does reabsorption of urea occur?

Answer 31

inner medullary collecting duct via ADH

Question 32

Urea is reabsorbed in the innermedullary collectin ducts and then gets put back into the (blank) or (blank)

Answer 32

vasa recta or proximal tubule, or loop of henle

Question 33

What percent of urea is actually excreted?

Answer 33

40% of filtered load

Question 34

What is the diluting segment of the nephron?

Answer 34

thick ascending limb of loop of henle

Question 35

In the late distal tubule, ADH increases the H20 permeability of the (Blank) .

Answer 35

principal cells

Question 36

What are the two main functions of ADH?

Answer 36

1) Increasing the water permeability of distal tubule and collecting duct cells in the kidney 2) Increasing permeability of the inner medullary portion of the collecting duct to urea

Question 37

The main stimulus for secretion of vasopressin (ADH) is increased (blank)

Answer 37

osmolality of plasma

Question 38

(blank) Secretes in response to increases in plasma osmotic pressure is mediated by osmoreceptors in the hypothalamus.

Answer 38

ADH

Question 39

ADH make cAMP which create cascades to induce gene transcription of (blank) to collecting duct.

Answer 39

AQP

Question 40

Where is ADH located?

Answer 40

On membrane of cell

Question 41

What are 4 conditions that lead to changes in the ADH pathway?

Answer 41

``` Diabetes insipidous nephrogenic diabetes insipidous neurogenic SIADH (syndrome of inappropriate ADH release-too much ADH) Psychogenic polydipsia (drinking too much water) ```

Question 42

What is diabetes inspidious nephrogenic?

Answer 42

lack of kidney response to ADH

Question 43

What is diabetes insipidous neurogenic?

Answer 43

lack of synthesis

Question 44

What is the definition of diuresis?

Answer 44

urine flow greater than 1 ml/min

Question 45

What is antidiuresis?

Answer 45

urine flow rate is less than .5 ml/min (hypertonic urine)

Question 46

what are the four main kinds of diuresis?

Answer 46

diuresis, osmotic diuresis, water diuresis, antidiuresis

Question 47

With ADH does your osmolarity of your urine increase or decrease?

Answer 47

increases!! cuz you lose so much water and concentrate your urine

Question 48

What are the ions that leave the collecting duct w/ ADH?

Answer 48

H20, Salt and Urea

Question 49

What ions leave the collecting duct without ADH?

Answer 49

salt

Question 50

H20 is reabsorbed from the distal tubule until the osmolarity of distal tubular fluid equals that of the surrounding interstitial fluid in the renal cortex at what number?

Answer 50

300

Question 51

When you have low ADH (water diuresis) what will happen to urine flow rate, urine osmolality, urine concentration of urea and clearance rate of urea?

Answer 51

Your flow rate will increase Your urine osmolality will decrease your urine conc. of urea will decrease Your clearance rate of urea will increase

Question 52

When you have high ADH (antidiuresis) what will happen to urine flow rate, urine osmolality, urine concentration of urea and clearance rate of urea?

Answer 52

Urine flow rate will decrease Urine osmolality will increase urine concentration of urea will increase clearance of urea will decrease

Question 53

T/F? | urea contributes more to the gradient during antidiuresis than during water diuresis?

Answer 53

true

Question 54

T/F the osmotic gradient in the medullary/papillary interstitium is formed by passive transport of salt and water?

Answer 54

false

Question 55

With ADH, where do you see the greatest osmolarities within the nephron?

Answer 55

in the loop of henle and the closer you get to the end of the collecting duct towards urine

Question 56

What is the most abundant component of urine?

Answer 56

Urea

Question 57

WHy is urine yellow?

Answer 57

bilirubin breakdown product urobilin