Renal

Question 1

Effect of Aldosterone

Answer 1

increased Na+ reabsorption

increased H+ secretion

Question 2

Total Body Water

Answer 2

42L

Question 3

ICF Volume

Answer 3

28L

Question 4

ECF Volume

Answer 4

14L (plasma + ISF)

Question 5

ISF Volume

Answer 5

10.5L

Question 6

Plasma volume

Answer 6

3.5 L

Question 7

What percent of body mass is water?

Answer 7

50-70%

Question 8

Order of most water filled to least water filled cells.

Answer 8

Plasma (94%) –> intersitium (77%) –> bone cells (20%) –> fat cells (10%)

Question 9

What provides signals to stimulate or inhibit ADH release?

Answer 9

Stimulate –> Hypothalamic osmoreceptors

Inhibit –> Aortic arch and carotid baroreceptors

Question 10

osmolaric threshold for thirst? For ADH release?

Answer 10

298; 280— (max ADH secretion is 10pmol/L in this scenario)

Question 11

Blood pressure threshold for ADH release?

Answer 11

10% below normal; max secretion for ADH is MUCH higher here (50 pmol/L)

Question 12

What does SIADH cause?

Answer 12

very high water retention

Question 13

The 2 functions of ADH and where they operate.

Answer 13

(1) Increased water permeability of the UPPER AND LOWER collecting duct
(2) Increased urea permeability of the LOWER collecting duct ONLY.

Question 14

Osmolar Clearance Equation

Answer 14

Cosm= (Urinary Osm. x Urine flow) / Plasma osm.

Question 15

ECV

Answer 15

Effective Circulating Volume

The portion of ECF volume within the vascular system that is effectively perfusing the tissues.

Should be the same as ECF but can vary in disease:

• CHF
• Hepatic Cirrhosis
• Pleural Effusion

These all DECREASE ECV.

Question 16

The 3 factors which are important in stimulating renin secretion

Answer 16

• Perfusion pressure
• Sympathetic nerve activity
• Delivery of NaCl to the macula densa

Question 17

Function of Angiotensin II

Answer 17

• stimulate ADH release
• stimulate thirst
• stimulate aldosterone release (which causes Na+ reabsorption and K+ secretion)

Question 18

What stimulates movement of K+ into the cells, decreasing plasma K+?

Answer 18

Insulin, epinephrine, and aldosterone

Question 19

Where does aldosterone function?

Answer 19

Distal tubules + collecting duct

Question 20

Effect(s) of PTH, Calcitriol and Calcitonin on plasma [Ca2+]

Answer 20

PTH: increases plasma Ca2+
Calcitrol: increases plasma Ca2+
Calcitonin: decreases plasma Ca2+

Question 21

Effect(s) of PTH, Calcitriol and Calcitonin on plasma [phosphate]

Answer 21

PTH: increases plasma phosphate reabsorption AND excretion
Calcitriol (vitamin D): increases plasma reabsorption and decreases excretion
Calcitonin: decreases plasma phosphate and increases excretion

Question 22

Filtration Factor

Answer 22

GFR/RPF ratio

Question 23

Diffusion-Trapped Ions

Answer 23

Mainly functions in distal tube and collecting duct.

NH3+ binds with H+ to form NH4+.

NH4+ is charged and is therefore lipid impermeable, thus trapping H+ from diffusing back into the cell. Body makes extra NH3+ during chronic acidosis

Question 24

Principle Cells

Answer 24

Na+ channels, K+ channels, and Na+/K+ pumps

Mediated by Aldosterone (can increase or decrease number of pumps)

Question 25

Normal PP…AHH values

Answer 25

pH = 7.35-7.45
PaCO2 = 35 mmHg- 45 mmHg
A- = 10 meq/L - 15 meq/L
H+= 35mM - 45 NM
HCO3- = 22mM- 28mM

Question 26

Equation for RBF

Answer 26

RBF= effective RPF/ [1-hematocrit]

ERPF = clearance