Renal 6

Question 1

Normal function requires ECF Osmolarity = ____ mOsm

Answer 1

300 mOsm

Question 2

___ and ____ input via diet:
–Too much
–Not enough.

Answer 2

H2O and Na+

Question 3

How are water and Na lost? 4 ways

Answer 3

–Insensible
–Sweat
–Feces
–Urine

Question 4

To a large extent, kidneys balance the books by adjusting ____ reabsorption and excretion

Answer 4

water

Question 5

Mechanisms to eliminate excess water excrete a ____ urine

Answer 5

dilute

Question 6

Mechanisms to conserve water excrete a _____ urine

Answer 6

concentrated

Question 7

Concentration and Dilution of the Urine Accomplished independently of major changes in ___ excretion

Answer 7

solute

Question 8

Renal feedback mechanisms that control the ________ concentration and osmolarity

Answer 8

extracellular fluid sodium

Question 9

_____ and ______ mechanisms that determine the intakes of water and salt, which also help to control extracellular fluid volume, osmolarity, and sodium concentration.

Answer 9

Thirst and salt appetite

Question 10

independently of major changes in solute excretion to concentrate and dilute urine are a function of what hormone?

Answer 10

ADH

Question 11

Filtrate is _____ in proximal tubule (osmolarity)

Answer 11

isosmotic

Question 12

Filtrate Becomes Becomes ______ as passes through tDL
–Water reabsorption
–No solute reabsorption.

Answer 12

hyperosmotic

Question 13

Filtrate Becomes _____ as passes through TAL and early distal tubule
–Solute reabsorption
–No water reabsorption

Answer 13

hyposmotic

Question 14

T/F: Osmolarity of fluid will vary as pass through distal tubule and collecting duct

Answer 14

True

Question 15

Osmolarity of filtrate Stays _____ in absence of ADH

Answer 15

hyposmotic

Question 16

_____ increases H2O permeability of distal tubule and collecting duct

Answer 16

ADH

Question 17

In response to _____:
Large volume of H2O diffuses into interstitium.
Enters capillaries of Vasa Recta and removed.
Creates concentrated urine

Answer 17

ADH

Question 18

The maximal concentration ability of the kidney dictates how much urine volume must be excreted each day to rid the body of metabolic waste products and ions that are ingested.

Answer 18

Obligatory urine volume

Question 19

Adult must excrete ____ mosmol daily

Answer 19

600 mOsm

Question 20

What 2 things are required for excreting a concentrated urine?

Answer 20

1. High levels of ADH

2. Hyperosmotic medullary interstitial fluid

Question 21

Surrounds collecting duct
Sets gradient for water reabsorption
Requires Counter Current Multiplier Mechanism
Function of Juxtamedullary nephrons

Answer 21

Hyperosmotic medullary interstitial fluid

Question 22

Which nephron:

• Long Loop of Henle
• Vasa Recta
• Slow flow rate

Answer 22

Juxtamedullary nephrons

Question 23

_______ is a result of:

• Active transport of Na+ and other ions by ascending limb of LOH
• Active transport of ions from collecting duct into interstitium
• Facilitated diffusion of Urea by Inner medullary collecting ducts
• Movement of only small amounts of water into medullary interstitium

Answer 23

High Interstitial fluid Osmolarity

Question 24

When there is a high level of ADH, what type of urine is produced and at what volume?

Answer 24

Small volume of concentrated urine

Question 25

When there is a low level of ADH, what type of urine is produced and at what volume?

Answer 25

Large volume of dilute urine

Question 26

In _____ of ADH Reabsorb solute Little to no water reabsorption

Answer 26

Absence of ADH

Question 27

In _____ of ADH Distal tubule and collecting ducts become highly permeable to water and reabsorb much water into cortical interstitium Medullary collecting duct cells reabsorb water but overall amounts much lower (keeps medullary interstitium from being diluted). Reabsorbed water carried away by Vasa Recta

Answer 27

Presence of ADH

Question 28

In presence of ADH, _____ and ______ become highly permeable to water and reabsorb much water into cortical interstitium

Answer 28

Distal tubule and collecting ducts

Question 29

In presence of ADH, _______ cells reabsorb water but overall amounts much lower (keeps medullary interstitium from being diluted).

Answer 29

Medullary collecting duct

Question 30

In presence of ADH, Reabsorbed water carried away by ______

Answer 30

Vasa Recta

Question 31

Waste product of protein metabolism; produced continuously by liver.

Answer 31

Urea

Question 32

Normally excrete 20-50% of filtered load Non-toxic, but constitutes an osmotic load that must be excreted Contributes 40-50% of medullary interstitial osmolarity (500-600 mOsm/L) Reabsorbed passively by medullary collecting duct cells Secreted into descending limb and thin ascending limb of Loop of Henle  Requires: ADH

Answer 32

Urea

Question 33

What percentage ranges of urea are excreted in filtered load?

Answer 33

20-50%

Question 34

What percentage is urea's contribution to the medullary interstitial osmolarity?

Answer 34

40-50%

Question 35

Concentrates urea in filtrate (water reabsorption in cortical and medullary collecting ducts) Activates carriers (UT-A1; UT-A3) for the facilitated diffusion of urea by medullary collecting duct cells

Answer 35

ADH

Question 36

Where is urea secreted along the nephron?

Answer 36

Thin limbs of loop of henle

Question 37

Where is urea reabsorbed along the nephron?

Answer 37

Medullary collecting duct

Question 38

What do you think happens to the ability to concentrate urine in someone suffering from malnutrition?

Answer 38

Decreased urea causing less ability to form hyperosmotic interstitial fluid leading to a more dilute urine

Question 39

What do you think happens to the ability to concentrate urine in someone on a high protein diet?

Answer 39

More urea causing more urea excretion causing a more concentrated urine

Question 40

Depends on anatomical relationships of loop of Henle, vasa recta, & collecting ducts. ~25% of nephrons are juxtamedullary, with long loops of Henle that extend into renal medulla parallel to vasa recta & collecting ducts. Filtrate in descending & ascending limbs of loop of Henle flows in opposite directions of blood flow in Vasa Recta Clears Reabsorbed water so does not dilute medullary interstitial fluid

Answer 40

Countercurrent Multiplier Mechanism

Question 41

What 3 structures of the nephron/kidney are involved in the countercurrent multiplier mechanism?

Answer 41

Loop of henle, vasa recta, and collecting ducts

Question 42

In the Countercurrent Multiplier Mechanism, ______ Preserves Hyperosmolarity in Medulla Interstitium

Answer 42

Vasa Recta

Question 43

In the Countercurrent Multiplier Mechanism, Vasa Recta Preserves _______ in Medulla Interstitium

Answer 43

Hyperosmolarity

Question 44

In what segment of the nephron is 70% of water reabsorbed and the filtrate osmolarity isosmotic?

Answer 44

Proximal tubule

Question 45

In what segment of the nephron is 20% of water reabsorbed and the filtrate osmolarity hyperosmotic?

Answer 45

Descending limb of Loop of Henle

Question 46

In what segment of the nephron is 0% of water reabsorbed and the filtrate osmolarity hyposmotic?

Answer 46

Ascending limb of loop of henle

Question 47

What is the reason for the variability of water absorbed in the late distal tubule and collecting ducts due to?

Answer 47

ADH