Ch. 37: Water, Electrolytes, Acid-Base Balance Flashcards
3 main functions of the kidneys?
1) form protein-free ultrafiltrate @ glomerulus
2) active resorption of solute from filtrate
3) active excretion (e.g. H+) into lumen
What is normal GFR?
100-120 mL/min
Osmolarity of extra cellular fluid (due to Na+ & anions) is kept w/in narrow range, via what processes?
1) water intake (thirst center)
2) water excretion (ADH)
What is the antagonistic system to RAAS? (to ⬇️ blood volume)
High blood volume ➡️ cardiocytes release ANP ➡️ diuresis & natriuresis (via ⬆️ GFR & inhibit Na+ reabsorption)
Antagonistic system to RAAS: MoA?
ANP binds to plasma membrane receptor ➡️ form cGMP ➡️ activate cGMP dependent protein kinases
What hormone has similar structure to ADH & is also made by posterior pituitary ➡️ can co-inact with ADH?
Oxytocin
What is osmolality? How is it measured?
particles per unit wt of solvent
Freezing point or vapor pressure depression
Diabetes insipidus vs Diabetes mellitus?
DI: problem with ADH secretion or ADH receptors/aquaporins ➡️ bland urine
DM: problem with glucose regulation ➡️ sweet urine
What promotes K+ uptake into cells?
What promotes K+ excretion into urine?
Insulin, catecholamines
Aldosterone
What is the most important buffer in the body? What regulates it?
Carbonic acid-bicarbonate system
Kidneys (slower) & respiration (faster)
What are the 3 ways the kidneys actively secrete H+ ?
1) Na+ / H + exchange
2) Reclaim bicarbonate
3) Production of ammonia & excretion of NH4+
Where is carbonic anhydrase I found?
Blood (RBCs)
Where is carbonic anhydrase II found?
Bone, kidneys (in PCT cell)
Where is carbonic anhydrase III found?
Skeletal muscle
Where is carbonic anhydrase IV found?
Kidney (PCT lumen)
