Flashcards in Renal Deck (26):
Effect of Aldosterone
increased Na+ reabsorption
increased H+ secretion
Total Body Water
14L (plasma + ISF)
What percent of body mass is water?
Order of most water filled to least water filled cells.
Plasma (94%) --> intersitium (77%) --> bone cells (20%) --> fat cells (10%)
What provides signals to stimulate or inhibit ADH release?
Stimulate --> Hypothalamic osmoreceptors
Inhibit --> Aortic arch and carotid baroreceptors
osmolaric threshold for thirst? For ADH release?
298; 280--- (max ADH secretion is 10pmol/L in this scenario)
Blood pressure threshold for ADH release?
10% below normal; max secretion for ADH is MUCH higher here (50 pmol/L)
What does SIADH cause?
very high water retention
The 2 functions of ADH and where they operate.
(1) Increased water permeability of the UPPER AND LOWER collecting duct
(2) Increased urea permeability of the LOWER collecting duct ONLY.
Osmolar Clearance Equation
Cosm= (Urinary Osm. x Urine flow) / Plasma osm.
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:
These all DECREASE ECV.
The 3 factors which are important in stimulating renin secretion
-Sympathetic nerve activity
-Delivery of NaCl to the macula densa
Function of Angiotensin II
-stimulate ADH release
-stimulate aldosterone release (which causes Na+ reabsorption and K+ secretion)
What stimulates movement of K+ into the cells, decreasing plasma K+?
Insulin, epinephrine, and aldosterone
Where does aldosterone function?
Distal tubules + collecting duct
Effect(s) of PTH, Calcitriol and Calcitonin on plasma [Ca2+]
PTH: increases plasma Ca2+
Calcitrol: increases plasma Ca2+
Calcitonin: decreases plasma Ca2+
Effect(s) of PTH, Calcitriol and Calcitonin on plasma [phosphate]
PTH: increases plasma phosphate reabsorption AND excretion
Calcitriol (vitamin D): increases plasma reabsorption and decreases excretion
Calcitonin: decreases plasma phosphate and increases excretion
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
Na+ channels, K+ channels, and Na+/K+ pumps
Mediated by Aldosterone (can increase or decrease number of pumps)
Normal PP...AHH values
pH = 7.35-7.45
PaCO2 = 35 mmHg- 45 mmHg
A- = 10 meq/L - 15 meq/L
H+= 35mM - 45 NM
HCO3- = 22mM- 28mM