The Kidney 3 Flashcards
how is water distributed in the body?
body = 60% water
2/3 = ICF
1/3 = ECF (80% ISF + 20% plasma)
what are the differences between ECF and ICF?
ECF = more Na+ and Cl+
ICF = more K+
what is the plasma concentration of sodium?
136-144mmol/L
what is the plasma concentration of potassium?
3.7-5.1mmol/L
what is the plasma concentration of chloride?
97-105mmol/L
what is the plasma concentration of bicarbonate?
22-30mmol/L
what is the plasma concentration of calcium?
2.12-2.54mmol/L
what is the plasma concentration of magnesium?
0.7-0.95mmol/L
what is the plasma concentration of phosphate?
0.87-1.55mmol/L
define plasma osmolarity
Osmolarity is the overall osmotic concentration of all the solutes in a solution
what is the function of osmoreceptors?
Osmoreceptors in the hypothalamus ‘taste’ the blood to detect blood water concentration - decides whether it needs to send nerve impulses to control center to release ADH to retain more water if dehydrated
Increased plasma osmolarity = increased ADH secretion
why is the cell membrane important in fluid and electrolyte balance?
it is selectively permeable - regulating the movement of water and solutes between the ECF and ICF - keeping the electrolyte balance
what are the methods of fluid output?
GI tract
lungs
skin
kidneys
what are the methods of fluid intake?
metabolic fluid
ingested foods
ingested liquids
define hypertonic
high solute concentration, low water concentration
define hypotonic
low solute concentration, high water concentration
define isotonic
fluid with the same solute and water concentrations as intracellular fluid
what is the mechanism of action for ADH?
ADH is released from posterior pituitary gland
makes walls of DCT and collecting duct more permeable to water, is reabsorbed into circulation leading to more concentrated urine
what is the mechanism of action for angiotensin II and aldosterone?
Decreased BP → increased renin secretion from kidney → splits angiotensinogen into ANGI → ACE turns ANGI into ANGII (vasoconstrictor) → increased aldosterone secretion → increased Na+ and water reabsorption results in increased BP
what is the mechanism of action for ANP?
increase blood pressure in right atrium → increased ANP → increased Na+ excretion and water loss result in decreased BP
what is hyper/hyponatraemia?
+/- blood sodium controlled by ANP and aldosterone
what is hyper/hypokalemia?
+/- blood potassium controlled by aldosterone
