a&p 2 ch 26/27 - urinary system

hydrostatic pressure

fluid pressure that drives kidney filtration

glomerular capillary pressure

blood pressure in glomerular capillaries

capsular hydrostatic pressure

antagonist to glomerular capillary pressure

blood colloid osmotic pressure

counters blood hydrostatic pressure to force fluids into capillaries

filtrate

stuff that gets filtered out of blood, eventually becomes urine

myogenic mechanism

as blood pressure increases, arteries constrict and prevent renal blood flow increase

renin-angiotensin-aldosterone system (RAAS)

release of renin in response to low blood pressure causes liver releases angiotensin which results in vasoconstriction and the release of aldosterone by the kidneys to absorb water

atrial natriuretic peptides

occurs in response to high blood pressure, is the antagonist to RAAS

absorption at the proximal convoluted tubes

water, amino acids

absorption at the distal convoluted tubes

solutes (sodium, chlorine)

countercurrent multiplication

the increase in exchange as blood and filtrate travel through tubules in opposite directions

vasa recta

capillaries that surround tubules, return water and solutes to the blood

medullary osmotic gradient

salt concentration is much stronger in the medulla than the cortex because of the removal of water and salt from the tubules

obligatory water reabsorption

water reabsorption that can’t be prevented, collected in proximal tubule

facultative water reabsorption

hormonal (like adh) control of water reabsorption in distal and collecting ducts. adh stimulated the creation of aquaporins, which create special water channels to get it out of filtrate and conserve it

urea

waste product excreted in pee, some escapes at collecting duct only to establish a greater concentration gradient

peristolysis

rhythmic contraction of the ureters, forcing pee down to the bladder

urine storage reflex

storage of urine in the bladder

urine micturition reflex

stretch receptors cause sphincters to relax

pH

a measure of how acidic or alkaline a solution is. lower numbers are acids, higher numbers are alkaline. narrow healthy window of 7.35-7.45

when there is an excess of hydrogen ions, is the solution acidic or alkaline?

acidic

acidosis

abnormally low blood pH, death occurs at pH 7

alkalosis

abnormally high blood pH, death occurs at pH 8

relationship between bicarbonate ions and pH

with a lower pH, bicarbonate ions can bind to H ions to make the environment more neutral