The Urinary System and Balance Part 1

Question 1

True or False: The concept of balance is to maintain homeostasis, what goes in must come out eventually.

Answer 1

True. Input+production=utilization+output

Question 2

What factors affect plasma composition?

Answer 2

1. Kidneys regulate water and solute content, which determines volume
2. acid-base balance
3. Exchange between different compartments of the body.

Question 3

What are the different sources of body water input and output?

Answer 3

Input-Ingestion

Output-Feces, Sweating/Hemorrhage/Respiration, Urine

Question 4

What does it mean when there is balance in the water/solute balance?

Answer 4

That the input matches the output. Homeostasis.

Question 5

What does positive balance mean?

Answer 5

There is more going in than going out.

Question 6

What does negative balance mean?

Answer 6

There is more going out than in.

Question 7

Cells in the DCT and collecting ducts regulate balance. What are the cells and what do they affect?

Answer 7

Principal cells-water and electrolytes

Intercalated cells-acid-base balance

Question 8

True or False: Solute concentrations have no affect on water balance and movement.

Answer 8

False.

Question 9

In regards to water reabsorption in the PCT, is it considered active transport or passive transport?

Answer 9

Passive

Question 10

In regards to water reabsorption in the DCT and Collecting Ducts, is it considered active or passive transport?

Answer 10

Passive, but it requires aquaporons to get the water through the tight junctions.

Question 11

Normovolemia is…..

Answer 11

normal blood volume

Question 12

Hypervolemia is….

Answer 12

high blood volume due to positive water balance

Question 13

Hypovolemia is….

Answer 13

low blood volume due to negative water balance

Question 14

True or False: Water moves from an area of high solute concentration to low solute concentration.

Answer 14

True.

Question 15

When fluid is moving down the descending limb of the Loop of Henle, which way is it moving in the vasa recta?

Answer 15

Up

Question 16

When fluid is moving up the descending limb of the Loop of Henle, which way is it moving in the vasa recta?

Answer 16

Down

Question 17

What is the reason for concurrent flow in the Loop of Henle and vasa recta?

Answer 17

It facilitates reabsorption.

Question 18

Explain the control of water balance and osmolarity by antidiuretic hormone.

Answer 18

ADH stimulates the insertion of auqaporin-2 into the apical membrane of the DCT and CD, letting water be reabsorbed through osmosis. When osmolarity is up, the membrane is more permeable to water.

Question 19

The descending limb of the loop of Henle is permeable to what?

Answer 19

Water only, solutes can’t be transported.

Question 20

The ascending limb of the loop of Henle is permeable to what?

Answer 20

Solutes only, they need to be actively transported.

Question 21

Fluid in the descending limb of the loop of Henle’s osmolarity ______ as it descends

Answer 21

increases

Question 22

Fluids in the ascending limb of the loop of Henle’s osmolarity ________ as it ascends

Answer 22

decreases

Question 23

Fluid in the PCT is at _______ mOsm

Answer 23

300 mOsm

Question 24

Fluid in the DCT is at ________ mOsm

Answer 24

100 mOsm

Question 25

Cortical ISF is at _______ mOsm.

Answer 25

300 mOSm

Question 26

Why is the countercurrent multiplier important?

Answer 26

it facilitates reabsorption in DCT and CD

Question 27

Where are Urea transporters located?

Answer 27

PCT, CD, and descending vasa recta (located on the ascending limb of the loop of Henle)

Question 28

What is important about Urea?

Answer 28

It is approximately 40% of the osmolarity of the gradient.

Question 29

What does the anatomical arrangement of the vasa recta prevent?

Answer 29

the diffusion of water and solutes from dissipating the medullary osmotic gradient.

Question 30

What does water permeability depend on and where are the transporters located?

Answer 30

Water permeability depends on water channels called aquaporins. Aquaporin-3 is present in the basolateral membrane ALWAYS. Aquaporin -2 is present in apical membrane only when ADH is present in blood.

Question 31

What is the range of osmolarity of urine?

Answer 31

100-1400 mOsm

Question 32

Where does most water reabsorption occur in the renal tubules?

Answer 32

Proximal Convoluted Tubule

Question 33

Where does the regulation of water reabsorption in the renal tubules occur?

Answer 33

Distal Convoluted Tubules and Collecting Ducts

Question 34

Can pure water be excreted as urine?

Answer 34

No, there will always be solutes and wastes filtered from the kidneys

Question 35

How does the movement of water and solutes in the loop of Henle establish an osmotic gradient in the renal medulla?

Answer 35

It is a countercurrent multiplier, meaning that on the descending limb, the osmolarity of the filtrate increases due to water moving into the ISF and on the ascending limb, the osmolarity of the filtrate decreases because of solute transportation into the ISF. This movement creates the Medullary Osmotic Gradient.

Question 36

Name two stimuli for ADH release from the posterior pituitary.

Answer 36

1. blood volume

2. blood pressure

Question 37

What effect does ADH have on principal cells?

Answer 37

ADH increases their permeability to water by making aquaporin-2 present on the apical side.