Traffic - week 14 Flashcards
The Kidney is the…
major functional organ, other organs carry urine out of the body
basic functions of the kidneys (kid - front door)
- water balance and osmolarity
- electrolyte (ion) balance
- maintain plasma volume, long term regulation of blood pressure
- acid/base balance
- excrete wastes (urea, uric acid, creatinine) and other materials
- secrete erythropoietin
- secrete renin (Na+ balance)`
- converts vitamin D to its active form
nephron is the…(mattias)
functional unit of the kidney
1. arrangement forms cortex and medulla
glomerulus (cloud - perturbed - tuft -afferent and efferent- plant)
a. tuft of capillaries that filters blood
b. renal artery branches to form afferent and efferent arteriole for each nephron
(1) efferent arteriole divides to form
peritubular capillaries (supply renal tissue with blood)
tubule parts (cloud - cartoon - umbrella - collection plate - couch)
a. glomerular capsule surrounds glomerulus and collects filtrate
b. PCT
c. loop
d. DCT
e. collecting duct/tubule-drains fluid from several nephrons to renal pelvis
juxtaglomerular apparatus (jax - dracula - granola - cat tree)
a. regulates kidney function
b. macula densa
c. granular cells
2 types of nephrons (jax - dip - piano)
a. cortical - lie mainly in cortex (80%)
b. juxtamedullary - loops dip to end of medulla (important in urine concentration/conserving water)
3 renal processes - GTT
GTT
- glomerular filtration
- tubular reabsorption
- tubular secretion
glomerular filtration (glom plaza)
about 20% of plasma entering glomerulus is filtered. entire plasma volume filtered 65 times/day.
tubular reabsorption (tubing goldmine)
selective recovery of filtered substances
tubular secretion (tub)
selective transfer of materials from plasma in peritubular capillaries to filtrate
Glomerular Filtration (high cloud - perm)
filtered substances pass through highly permeable filtration membrane.
glomerular capillary blood pressure forces…(filter - afferent vs. efferent)
fluid through filtration membrane
1. higher than in other capillaries
a. diameter of afferent arteriole larger than
efferent arteriole, blood dams up and filtration occurs throughout glomerulus
autoregulation (auto soldier)
allows GFR to remain constant despite changes in BP (vasoconstriction/dilation of afferent arteriole)
sufficient in MAP 80-180 mmHg range
autoregulation - myogenic mechanism (art - constricts)
arteriolar smooth muscle constricts when stretched, relaxes with decreased pressure
autoregulation - tubuloglomerular feedback mechanism (tube feedback in car)
macula densa detects changes in rate of filtrate flow or osmotic changes and signals granular cells to release vasoactive substances
extrinsic sympathetic control (extrinsic soldier)
(1) GFR changed based on need (override autoregulation to reg BP)
(2) baroreceptor reflex
(3) can alter Kf by closing off part of capillaries and filtration slits
Tubular Reabsorption (% - nym)
- typically nephrons reabsorb 99% of the water, 100% of the sugar, 99.5% of the salt that is filtered
Na+ reabsorption (mountain pump - bedroom closet door)
- occurs via Na+-K+ ATPase in the basolateral membrane
a. creates gradients for diffusion
b. tied to reabsorption of other substances (glucose, amino acids, water, Cl-, urea)
renin-angiotensin-aldosterone system is in response to…(angie - low Na+ - bathroom)
decreased NaCl/dec. ECF volume/dec. BP, macula densa signals granular cells to release renin (an enzyme)
angiotensinogen➝ (I)
angiotensin I
angiotensin I ➝ angiotensin II in lungs (angie vaso and art - front door)
(1) vasoconstriction of arterioles
(2) stimulates thirst
(3) stimulates vasopressin release (H2O
reabsorption)
atrial natriuretic peptide (ANP) inhibits… (amp - atrium)
Na+ reabsorption. released from atria in response to increased stretch from inc ECF/inc BP
Glucose and amino acids (soccer - corner)
cotransport systems driven by Na+-K+ pumps in PCT
water reabsorption is…reaborbed…(nym)
passively reabsorbed throughout most of nephron (not ascending limb of loops)
urea reabsorption (corner)
only waste product reabsorbed