UR Last study Flashcards
GFR better filtration rate for glomerulus
150-180L/day due to
1. larger surface area
2. greater permeability from pores that are 45x leakier
3. higher blood pressure around 60 compared to 15-35
GFR too high/low
high: not enough time for reabsorption, valuables excreted
low: too much reabsorption, wastes stay
PGC, piCS, PCS, piGC
blood hydrostatic pressure, filtrate osmotic pressure, filtrate hydrostatic pressure, blood osmotic pressure
myogenic mechanism
ex1.
-decreased blood pressure
-kidney: decreased PGC and decreased arteriole stretch detected
-smooth muscle around arteriole vasodilate for AA, vasoconstrict for EA
-increased PGC, NFP, GFR
ex. 2
-increased blood pressure
-kidney: increased PGC and increased arteriole stretch detected
-smooth muscle around arteriole vasoconstrict for AA, vasodilate for EA
-decreased PGC, NFP, GFR
tubuloglomerular feedback
ex.1
-increased blood pressure
-kidney: increased PGC
-macula densa cells of JGA detect increased salt concentration delivery
-JGA secrete less NO
-less NO bind to beta 2 receptor on afferent arteriole
-vasodilate AA
-decrease PGC, NFP, GFR
neural regulation
ex.
-decreased PV, VP, VR, AP, EDV, SV, Q, arterial pressure
-baroreceptors of large veins, atria, or arterial detect
-vasomotor centre
-increased sympathetic firing to kidney release NE/E
-kidney: greater binding of alpha receptor on AA to increase vasoconstriction
-decrease PGC, NFP, GFR
*arterial pressure can directly affect PGC too
RAAS
ex.
-decreased PV
-increased salt concentration detected by macula densa, decreased arterial pressure - vasomotor centre - increased renal sympathetic firing
-JG cells secrete and release renin into blood
-combine with angiotensinogen from liver to form angiotensin 1
-ACE from lung and kidney epithelial cells to form angiotensin 2
-bind alpha receptors to vasoconstrict AA, contract mesangial cells
-decrease GFR
ANP - hormonal regulation
ex.
-increased PV
-increased atrial muscle stretch
-atrai: increased secretion and release of ANP into blood
-bind beta 2 receptors to vasodilate AA, relax mesangial cells
-increase GFR
electro- passive diffusion
cell with plasma membrane, + out, -in, IF in cell with nucleus
TRS UR3 proximal tubule picture
-glucose or amino acids move from high to low concentration on basolateral membrane (SD)
-Na and H move by secondary counter transport (apical membrane)
-same for Na and glucose/amino acids
-Na and K move by primary counter transport on basolateral membrane (ATP - ADP + Pi)
-K also moves probably with transporter from high to low concentration (membrane protein on basolateral membrane!)
Obligatory water reabsorption process
-high solute to low solute
-solute leaving = decreased osmotic pressure - solute arriving = increased osmotic pressure
-high H2O to low H2O
-H2O leaves = increased ion concentration - H2O arrives = decreased ion concentration
-SD ions leave = decreased osmotic pressure - SD ions arrive = increased osmotic pressure
-high H2O to low H2O
Aldosterone
ex.
-increased angiotensin 2
-adrenal gland: increased secretion of aldosterone
-collecting duct: increase #apical membrane channels and basolateral primary pumps
-increase sodium and water reabsorption, increase potassium secretion
-decrease sodium and water excretion, increase potassium excretion
ADH
ex.
-decreased PV, increased OP
-decreased venous, atrial, arterial pressures, hypothalamus: increased osmoreceptor firing
-posterior pituitary: increase ADH secretion and release into blood
-collecting ducts: increase aquaporins on apical membrane, increase water reabsorption
-decrease water excretion
TRS - ANP - Hormonal regulation (affect reabsorption)
ex.
-increased PV
-increased atrial muscle stretch
-atria: increased secretion and release of ANP into blood
-collecting duct: inhibit apical and basolateral paths
-decrease sodium and water reabsorption
-increase sodium and water excretion
*ANP also inhibit release of aldosterone and ADH
urinary flow
-urine leaves kidneys
-flows into ureters, bladder propelled by contractions of ureter wall smooth muscle as well as gravity
-lead to bladder structures and 3 neural pathways
micturition reflex
- mechanoreceptors send afferent signal to spinal cord
- spinal cord send efferent signal to contract detrusor and relax sphincters
*voluntary includes pons/higher brain centres to override and stimulate somatic motor to contract external urethral sphincter
bladder muscles
- detrusor: parasympathetic
- internal urethral sphincter: sympathetic
- external urethral sphincter: somatic motor
diuresis
elevated urine flow rate, diuretic, high volume dilute urine, decrease BV, decrease BP
natriuresis
elevated urine flow rate with elevated sodium content, natriuretic, high volume salty urine, decrease BV, decrease BP
stimulate thirst centre in hypothalamus
- mechanoreceptors: BV changes
- baroreceptors: BP changes
- osmoreceptors: blood OP changes (most important)
- dry mouth
- psychological and conditioned responses for thirst
hyponatremia
-large solute and water loss
-intake plain water
-decreased OP of iF and plasma (hyponatremia - low Na concentration)
-osmosis of water from IF to intracellular
-cells swell
-water intoxication symptoms
chemical buffering (first line of defense)
response to alkalosis: H and buffer separate
response to acidosis: H and buffer together
*temporarily alter hydrogen levels, does not eliminate or add
bicarbonate buffer
-H2CO3 = H + HCO3
-carbonic acid = hydrogen ion + bicarbonate ion
phosphate buffer
-H2PO4 = H + HPO4
-dihydrogen phosphate = hydrogen ion + monohydrogen phosphate
protein buffer
Hb-H = H + Hb
deoxyhemoglobin = hydrogen ion = hemoglobin
respiratory (2nd line of defense)
-response to alkalosis: reduce ventilation - increase CO2 and increase Hydrogen, move right
-response to acidosis: increase ventilation - decrease CO2 and hydrogen, move left
-CO2 + H2O = H2CO3 = H + HCO3
renal summary - acidosis
-maximize renal mechanisms 1 and 2 to secrete hydrogen and reabsorob bicarbonate
-maximize renal mechanism 3 to secrete ammonium and reabsorb bicarbonate
-secreted hydrogen combine with bicarbonate or monohydrogen phosphate to form water and CO2 to be reabsorbed or excreted in urine
formed dihydrogen phosphate and secreted ammonium excreted in acidic urine
renal summary - alkalosis
-minimize water and CO2 breakdown inside cell
-minimize glutamine movement into cell
-minimize hydrogen and ammonium secretion so little bicarbonate reabsorption
-significant amounts of filtered bicarbonate and filtered monohydrogen phosphate excreted in alkaline urine
for every…
-one filtered HCO3, one reabsorbed HCO3
-one filtered HPO4, one reabsorbed HCO3
-one glutamine, one reabsorbed HCO3
acid-alkaline imbalances
-respiratory acidosis: high H from CO2 changes, detected as high blood CO2, hypoventilation
-respiratory alkalosis: low H from CO2 changes, detected as low blood CO2, hyperventilation
-metabolic acidosis: high H from non-CO2 path, detected as low blood bicarbonate, exercise
-metabolic alkalosis: low H from non-CO2 path, detected as high blood bicarbonate, vomit, diarrhea, alkaline ingestion
