urinary system exam cards Flashcards
renal capsule
inner layer of kidneys; composed of smooth irregular CT; holds shape of kidneys and protects them
adipose capsule
middle layer of kidneys; made of adipose tissue and holds kidneys in place and protects them
renal fascia
outer layer of kidneys; made of dense irregular CT; anchors the kidney against the posterior wall of the abdominal cavity
3 layers of ureters
mucosa, muscularis, and adventitia
mucosa layer of ureters
transitional epithelium with underlying lamina propria
what is lamina propria made of?
areolar tissue
muscularis layer of ureters
3 layers of smooth muscle; inner longitudinal layer, middle circular layer, and outer longitudinal layer
adventitia layer of ureters
always adventitia; fibrous CT
mucosa layer of bladder
transitional epithelium that also contains rugae and goblet cells
muscularis layer of bladder
similar to ureter layer but contains thick detrusor smooth muscle
adventitia/serosa layer in bladder
adventitia except on superior surface where it is covered by peritoneum; fibrous CT
urethra epithelium
transitional near bladder and stratified squamous near orifice
3 parts of male urethra
prostatic, intermediate, and spongy; male urethra carries urine and semen
artery flow in kidneys
renal artery > segmental artery > interlobar artery > arcuate artery > cortical radiate artery > afferent arteriole > glomerulus > efferent arteriole
venous flow in kidneys
cortical radiate vein > arcuate vein > interlobar vein > renal vein
2 parts of the renal corpuscle
glomerular capsule and glomerulus
2 main parts of the nephron
renal corpuscle and renal tubule
parietal layer of renal corpuscle
simple squamous epithelium
visceral layer of renal corpusle
podocytes with foot processes that form filtration slits; lies on top of a basement membrane which lies on fenestrated capillary bed
anatomy of PCT
cuboidal epithelium with large mitochondria and lots of microvilli on apical side and infolded plasma membrane on basolateral side
descending limb anatomy
simple squamous epithelium
ascending limb anatomy
simple cuboidal epithelium
collecting duct anatomy
heterozygous simple cuboidal epithelium; contains microvilli and mitochondria but less than in PCT
2 types of cells in CT
principal cells and intercalated cells
intercalated cells function
maintain acid-base balance
principal cell function
maintain Na+ and H20 levels
typical capillary flow
unidirectional and arteriole end has greater HSP while venous end has greater BCOP
DCT anatomy
cuboidal cells with mitochondria and microvilli, but less than PCT cells
3 types of cells in JGA
mesangial cells, macula densa cells, and juxtaglomerular cells
where are juxtaglomerular cells found
lining the afferent arteriole
where are macula densa cells found?
lining the ascending limb
where are mesangial cells found?
sandwiches between the loop of henle and the afferent arteriole
macula densa cells anatomy
tall, densely packed cells
macula densa cells function
regulate ionic concentration through chemoreceptors that respond to NaCl filtrate concentration
mesangial cells
control HSP of glomerulus
function of juxtaglomerular cells
release renin
is renin an enzyme of a hormone?
enzyme but activates hormones
3 effects of ANG II
constricts afferent arteriole; enhances reabsorption of Na and Cl in the PCT; stimulates adrenal cortex to release aldosterone
where does aldosterone act?
principal cells
how are glomerular capillaries different?
they are longer, have greater surface area; mesangial cells can alter the surface area; filtration membrane in very porous and thin; and glomerular BP is very high
NFP
outward pressures - inward pressures; HSPgc - BCOP - HSPcs
what is osmotic pressure due to?
blood colloids
what are carrier proteins used for?
large, polar molecules; ex. glucose, amino acids, vitamins
transcellular
movement through the cell; usually requires transport proteins
paracellular
movement between cells
where does glucose reabsorption occur?
PCT
glucose reabsorption
symported with Na+ at apical surface, in which this energy created by passive movement of Na+ powers glucose movement; it then moves across the basolateral surface via carrier mediated facilitated diffusion
H+ movement in PCT
antiporter with Na+ at apical surface; Na+ moves in passively and H+ moves out actively
what solutes move passively in the PCT?
Cl-, K+, Ca++, Mg++, urea, and water (transcellular or paracellular depending on lipid-solubility and/or transport proteins)
descending limb
thin and allows movement of water but not soltues
ascending limb
thick and is impermeable to water but moves solutes out via Na+/2Cl/K+ symporter
what are main substances reabsorbed in the early DCT?
Na+ and Cl- (sometimes Ca+ depending on PTH)
late DCT and CT reabsorption
Na+ is reabsorbed and K+ is secreted; main channels are ATPase and passive K+ and Na+ channels; this area is not permeable to water unless ADH is secreted
bladder at rest
motor neurons are firing, detrusor muscle is relaxed, and sphincters are contracted
bladder when full
motor neurons stop firing, stretch receptors fire, and parasympathetic neurons fire
where is ADH released from?
posterior pituitary gland
where does ADH act?
principal cells
where does ADH bind to?
V2 receptors causing a G-protein coupled pathway to occur
renin-ANG II-aldosterone pathway
renin is released by JG cells when BP is low, and angiotensinogen is released from the liver; renin converts angiotensinogen to ANG I; ANG I converted to ANG II by ACE
5 effects of ANG II
increased sympathetic activity; increased tubular reabsorption of Na+, Cl- and secretion of K+ in the principal cells; aldosterone secretion; ADH secretion; and arteriolar vasoconstriction
what does aldosterone increase activity of?
mainly the ATPase in the basolateral surface of principal cells, but also Na+ and K+ channels on the apical surface here as well
where is ANP released from?
the atria of the heart when BP is high, causing stretching of the atria
what does ANP do?
inhibits renin formation and Na leak channels in principal cells
osmotic diuretics
inhibit H20 reabsorption by blocking Na+/glucose symporter in PCT via mannitol
thiazide drugs
target the Na/Cl symporter in the DCT
loop diuretics
targets the triple symporter in the ascending limb (Na/2Cl/K)
potassium sparing drugs
inhibit the effects of aldosterone in principal cells; inhibit K+ channel on the apical surface
what ions have higher concentrations inside the cell
K+, Mg+, HPO4-, SO4-
what ions have higher concentrations outside the cell?
Na+, Ca++, Cl-, HCO3-
PTH
released by parathyroid glands to increase calcium in the bloodstream by signalling osteoclasts to degrade done matrix; also stimulates calcitriol
calcitriol
stimulated by PTH and causes more Ca+ reabsorption to occur from foods in the GI tract
calcitonin
inhibits osteoclast activity when calcium levels are sufficient or too high
what is calcitonin stimulated by?
parafollicular cells
calcitriol vs calcitonin
calcitriol is for low calcium levels and calcitonin is for high levels
thirst mechanism
increased blood osmolarity is detected by osmoreceptors in the hypothalamus, activating the thirst centre; this caused us to be thirsty and for the stomach to expand causing more surface area for water reabsorption
cells when dehydrated
shrink due to water moving osmosis to the salty ECF
cells when overhydrated
cells swell or burst due to water moving by osmosis into the cell because ECF osmolarity is low
example of a strong acid
HCl
example of a strong base
KOH
buffer system
converts strong acids/bases into weak ones to protect the body from sharp pH changes
example of a weak acid
H2C03
example of a weak base
HCO3-
example of a buffer system that would increase pH
NaOH + H2CO3 > NaHCO3 + H20; this works because it is a strong base and a weak acid, forming a weak base and a salt
example of a buffer system that would decrease pH
HCl + NaHCO3 > H2CO3 + NaCl; this works because it is a strong acid with a weak base, forming a weak acid and salt
negative feedback loop for low pH
low pH detected by chemoreceptors in the brain and the heart; control centre is the inspiration centre in the medulla; this causes the diaphragm to contract and expel more CO2, thus less acid can form, increasing the PH
why does less CO2 increase pH?
because there is less H2CO3 that can form when there is less CO2
how is pH increased in the PCT?
through the Na+/H+ antiporter than expels H+ into the urine; it is present in the PCT cell because of the CO2+H2O>H2CO2>H+ + HCO3- reaction; HCO3- will move into the interstitial fluid via facilitated diffusion
what enzyme allows for the buffer reaction to occur?
carbonic anhydrase
increasing pH in the CT
occurs in the intercalated cells; a proton pump on the apical surface will pump H+ out into the urine and HCO3- will antiport with chloride into the interstitial fluid
what does H+ buffer with in the urine?
NH3 (forms NH4+) or HPO4– (forms H2PO4-)
decreasing the pH in the CT
proton pump on basolateral surface moves H+ into the interstitial fluid; HCO3- is sent into the urine via the chloride shift which occurs on the apical surface
what is the anatomy of adeventita?
fibrous CT w/ collagen and fat
do principal or intercalated cells have more mircovilli?
intercalated cells
how does Ca+ move within the DCT
it is antiported with Na+
major secreted substances in urine
urea, uric acid, creatinine, K+, and some water, Na+, and Cl-
what substances commonly move via the paracellular route
K+, Cl-, and urea
what is loss of BP detected by?
baroreceptors in the cartoid sinus
what does ANG II bind to?
AT1 receptors
what does aldosterone bind to?
mineralocorticoid cytoplasm receptors
