Renal Regulation Of Urine Concen. And Dilution

Question 1

Discuss the role of the kidneys in water balance.

Answer 1

An increase intake of water, kidney lose water and increase of volume of diluted urine.
An decrease intake/ loss of water, kidney conserves water and a decrease volume of concentrated urine.

Question 2

State the functions of ADH.

Answer 2

It increases the water permeability of the principle cells of the LDT and CD.
It increases the permeability of medullary portion of the collecting duct to urea
It stimulated the the reabsorption of NaCl in the thick ascending tube of LOH, distal tubule and collecting duct.

Question 3

What effect does osmolarity and hemodynamics have on the secretion of ADH.

Answer 3

As osmolarity increase, the stimulation of the ADH secretions increase, increasing ADH
As blood pressure decreases, it stimulates the ADH Secretions, increasing ADH

Question 4

Discuss the mechanism of action of ADH on the principal cell in the late DT and CD

Answer 4

ADH increases the water permeability of the principle cells of the LDT and CD by creating aquaporin water channels to allow water to pass through.
When ADH is removed, the principle cells becomes impermeable to water again.

Question 5

Discuss the role of ADH in response to an increase in plasma osmolarity to regulate (normalize) body fluid osmolarity.

Answer 5

An increase of plasma osmolarity, increases stimulation of ADH receptors, increasing ADH production. ADH causes an increase in water permeability and increases h20 reabsorption. The increase leads to an increase urine osmolarity, decrease urine volume and decreases plasma osmolarity back to normal.

Question 6

Discuss the role of ADH in response to an decrease in plasma osmolarity to regulate (normalize) body fluid osmolarity.

Answer 6

Decrease plasma osmolarity
Decrease in stimulation of ADH receptors
Decrease ADH secretion
Decrease h2o permeability
Decrease h20 reabsorption
Decrease urine osmolarity
Increase urine volume
Increase plasma osmolarity toward normal.

Question 7

State the 2 regulatory mechanisms that maintain K+ homeostasis.

Answer 7

1. Regulate K+ across the cell membrane
2. The kidneys adjust renal K+ excretion to match dietary K+ intake.

Question 8

Describe how hormones affects the internal K+ balance.

Answer 8

The hormone insulin specifically is secreted in response to food ingestion. It stimulates the uptake of glucose and K+ in the cell. An increase in the Na/K+/ATPase ensures that the K+ does not stay in ECG causing Hyperkalemia..

Question 9

Describe how drugs affects the internal K+ balance.

Answer 9

B2 agonist causes an increase in K+ intake in the cells — hypokalemia.
B2 antagonist causes a decrease in K+ intake in the cells - hyperkalemia
A receptor agonist shifts K+ out of the cell - hyperkalemia
A receptor antagonist shifts K+ in the cell - hypokalemia.

Question 10

Describe how exercise affects the internal K+ balance.

Answer 10

Exercise results in K+ moving out the cell into the blood but at the same time causing an increase in K+ into the cell due to epinephrine secretion

Question 11

Describe how cell lysis affects the internal K+ balance.

Answer 11

Moves K+ out of the cell - hyperkalemia

Question 12

Describe how acid- base abnormalities affects the internal K+ balance.

Answer 12

Acidemia - excess H moves into the cell and K+ moves out - hyperkalemia

Alkalemia - excises H moves out of the cell and K+ moves in - hypokalemia.

Question 13

State how these factors alter K+ secretion:
Dietary K+
Aldosterone
Acid base disturbances
Tubular flow rate - diuretics
Luminal anions