AND CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS) |ALREADY GRADED A+||BRAND NEW
VERSION!!
nephron + parts of nephron✔✔ ANSWER✔✔-functional unit of the
kidney; consists of the following:
-glomerulus: cluster of tiny blood vessels; filters blood & selectively
reabsorbs material into blood, secretes others to be secreted in urine
via hydrostatic pressure
-bowman capsule: filtrates; GRF
-basement membrane: within glomerulus; determines permeability of
solutes
-tubular components: proximal tubule, loop of henle, distal convoluted
tube, collecting tubule (SEE OTHER NOTE FOR ROLES OF EACH)
**NO ABILITY TO REGENERATE NEPHRONS; older age=decreased
nephrons=decreased kidney function
,4 parts of the nephron tubule + roles: in order✔✔ ANSWER✔✔1.
proximal tubule: drains bowman capsule; reabsorption of electrolytes
2. loop of henle: where ADH exerts effects; urine volume/concentration
3. distal convoluted tubule: reabsorb Na+, Cl-, Ca+2, Mg+2
4. collecting tubule: joins tubules to collect filtrate for urine; where
aldosterone exerts Na+ reabsorption & K+ secretion; where thiazide
diuretics inhibit Na+ reabsorption
juxtaglomerular complex: role✔✔ ANSWER✔✔-increase in BP=vessels
relax in kidneys
-decrease in BP=vessels constrict in kidneys
3 feedback mechanisms to keep blood flow + GFR consistent✔✔
ANSWER✔✔1. autoregulation/myogenic response: intrinsic ability of
arteries to constrict when blood pressure rises and to vasodilate when it
decreases.
2. humoral: vasoconstriction (angiotensin II/ADH/endothelines) or
vasodilation (dopamine, NO, prostaglandins)
3. tubuloglomerular feedback (TGF): controls rate of renin release
(enzyme needed to convert angiotensinogen to angiotensin II; also
increases Na+ reabsorption via adrenal stimulation to release
aldosterone)
**kidneys receive 20-25% of cardiac output
,3 factors: how kidneys produce concentrated or dilute urine✔✔
ANSWER✔✔1. osmolarity: exchange of solutes between descending
and ascending loops loops of henle + capillaries in medullary kidney
2. ADH + its actions: ADH present=water reabsorbed, ADH
absent=water excreted into urine
3. water permeability: increase in permeability=decrease in urine flow +
concentration
*kidneys also regulate pH via conserving or eliminating H+
renal clearance✔✔ ANSWER✔✔-volume of plasma cleared each minute
of any substance that finds its way into urine
-urine concentration x urine flow (mL/min)
-determined by ability of substance to be filtered, secreted, or
reabsorbed
-glucose=not normally detected in urine; reabsorbed in tubules
addison's disease + kidneys✔✔ ANSWER✔✔-adrenal glands do not
produce enough of the hormones cortisol or aldosterone
-causes increase in K+, decrease in Na+ d/t increase in diuresis; leads to
hypotension, shock
Atrial Natriuretic Peptide (ANP): role on kidney function✔✔
ANSWER✔✔-promotes vasodilation/acts as diuretic; secreted by cells of
atria (heart)
, -helps conserve Na+ by inhibiting aldosterone
-increases GFR & renal blood flow
renin-angiotensin-aldosterone system✔✔ ANSWER✔✔-decreased
blood pressure causes the juxtaglomerular cells of kidneys to secrete
renin - converts angiotensinogen (inactive) to angiotensin I (active)
which is then converted into angiotensin II by angiotensin-converting
enzyme (ACE)
-Angiotensin II stimulates the adrenal cortex to secrete aldosterone
-leads to absorption of Na and increased blood pressure
-once blood pressure is restored, there is a decreased drive to stimulate
renin release
high uric acid: causes + CI✔✔ ANSWER✔✔-gout, kidney stones; product
of protein metabolism
-rate of reabsorption exceeds secretion