Renal 5 & 6

Question 1

In the first half of the proximal tubule, Na+ uptake into the cell is couple with _____

Answer 1

H+ or organic solutes

Question 2

Na+ - H+ antiporter couples

Answer 2

entry of Na+ with extrusion of H+ (H+ secretion leads to reabsorption of NaHCO3-

Question 3

SGLT2

Answer 3

Na+-glucose symporter in the apical membrane

Question 4

In the second half of the proximal tubule, How much of Na+ reabsorption follows transcellular and how much follows paracellular?

Answer 4

• 67% transcellular
• 33% paracellular
• Na+ is primarily reabsorbed with Cl-

Question 5

What is your urine/plasma osmolality ratio & ADH concentration if your urine is dilute and pale?

Answer 5

• x < 1.0

- low ADH

Question 6

What is your urine/plasma osmolality ratio & ADH concentration if your urine is concentrated and dark?

Answer 6

• x > 1.0

- high ADH

Question 7

Describe the thick ascending limb of the loop

Answer 7

• actively reabsorbs 25% Na+

- H2O impermeable

Question 8

Describe thin descending limb.

Answer 8

• passive H2O reabsorption

- Na+ & Cl- impermeable

Question 9

Describe thin ascending limb

Answer 9

• passive Na+ & Cl- impermeable

- H2O impermeable

Question 10

What does Angiotensin II (AT-II) do?

Answer 10

Increases reabsorption of Na+, Cl-, and H2O in proximal tubule

Question 11

What does aldosterone do? Its stimulus?

Answer 11

• Increases reabsorption of Na+, Cl-, and H2O in thick ascending loop, distal tubule, and collecting duct
• high AT-II or plasma K+

Question 12

What does Atrial Natriuretic Peptide and Urodilatin do? Stimulus?

Answer 12

• increases excretion of Na+
• decreases reabsorption of Na+ & Cl- and ADH
• stimulus is higher blood pressure or extracellular volume

Question 13

What do the sympathetic nerves do? Stimulus?

Answer 13

• increase catecholamines
• increases reabsorption of Na+ & Cl- in proximal and distal nephron
• lowered Extracellular fluid

Question 14

What does Dopamine do? Stimulus?

Answer 14

• lowers reabsorption of Na+ & Cl- in proximal tubule

- high Extracellular fluid

Question 15

What does ADH do? Stimulus?

Answer 15

• reabsorption of H2O in collecting duct

- lowered Extracellular fluid

Question 16

Insensible water loss

Answer 16

water loss from cells of the skin and respiration

Question 17

Routes of water output

Answer 17

• insensible
• sweat
• feces
• urine (main route)

Question 18

Total Body Water

Answer 18

• 50% - 70% of total body mass

- 42L

Question 19

ICF

Answer 19

• 30% - 40% of total body mass

- 28L

Question 20

ECF

Answer 20

• 20% - 30% of total body mass
• 14L
• (ISF + P)

Question 21

ISF

Answer 21

-Fluid that bathes all cells

Question 22

Plasma (P)

Answer 22

• Dynamically circulating volume, regulates composition of interstitial and transcellular water
• 3.5L

Question 23

Transcellular water

Answer 23

2L

Question 24

Positive water balance

Answer 24

-when intake exceeds loss

Question 25

Major determinant of plasma osmolality

Answer 25

Na+

Question 26

ADH (Negative) Feed back system

Answer 26

• PHYSIOLOGICAL REGULATORS (osmolality & volume and pressure)
• SENSORS (hypothalamic osmoreceptors stimulates ADH
• EFFECTOR (exocytosis of ADH from terminal axons and paraventricular neurons into blood of the post pituitary)
• TARGET cellular ADH receptors in distal tubules and collecting ducts)
• RESPONSE (change in cytoarchitecture and cellular matrix remodeling)

Question 27

ADH Stimulus

Answer 27

• ADH release - near 280 osmalality
• thirst threshold - near 298
• 10% below normal threshold

Question 28

ADH affects urea permeability where?

Answer 28

Lower collecting duct