major structures of urinary system
kidneys, ureters, bladder, urethra
function of urinary system
elimination of wastes/toxins, regulation of fluid and other levels/substances
relationship with cardiovascular system
production of RBCs (EPO), regulation of BP/fluid content/electrolytes, regulation of calcium
what wastes does the urinary system eliminate
metabolic wastes, N containing compounds (urea), hormones, drugs
where does urea/uric acid come from
breakdown of proteins in the liver
what electrolytes are in the blood
Na+, K+, PO4 3+
what does calcitriol do
increase in blood Ca2+
gluconeogenesis location
live and kidney cortex
when does gluconeogenesis happen
during extended fasting or starvation
what does gluconeogenesis do
produce glucose from non-carbohydrates, maintains BGL and protect the brain
kidney location
retroperitoneal
anterior surface of kidney covered by
parietal peritoneum
kidney covered by
fibrous capsule, perinephric fat, renal fascia, paranephric fat
what happens in the cortex
production of EPO and urine
what makes up the medulla
pyramids and major/minor calyxes
what does the medulla do
collect urine
renal corpuscle
glomerulus and bowmans capsule
renal tubule
proximal convoluted tubule, nephron loop, distal convoluted tubule
where does reabsorption happen
proximal convoluted tubule
principal cells
bind aldosterone and ADH
intercalated cells location
distal convoluted tubule
type A intercalated cells
H+
type B intercalated cells
HCO3-
cortical nephrons
in cortex, 85%
juxtamedullary nephrons
corticomedullary junction, 15%
what do juxtamedullary nephrons do
salt balance, activity of ADH
what are granular cells made of
modified smooth muscle
what do granular cells do
produce and store renin, restore perfusion in kidneys
where is the macula dense
distal convoluted tubule near afferent arteriole only
what does the macula dense do
detect NaCl concentration, release renin
what does filtration do
monitor BP and components, flow of blood in and out of kidneys, flow though nephron and other structures
what does reabsorption do
movement of water/substances back into plasma, a balancing act from tubules
glomerular filtration
water and solutes (no protein), pressure differences
tubular reabsorption
into the blood, passive and active processes, pertubular capillaries and vasa recta
tubula secretion
into urine
filtration details
materials from the fenestrated capillaries move thru the membrane
what does the filtration membrane block
formed elements (endothelium), large proteins (basement membrane), small proteins (slits)
mesangial cell location
capillary loops in capsule
what do mesangial cells release
cytokines, prostaglandins
what do mesangial cells do
phagocytize macromolecules
hydrostatic pressure in glomerulus
HPg
blood colloid osmotic pressure
OPg
capsular hydrostatic pressure
HPc
intrinsic controls of filtration pressure
mean arterial pressure, afferent arteriole response
extrinsic controls that adjust rate
decrease to glomerular filtration rate
ANS- decreased blood flow from afferent arteriole, mesangial cells contract
results of extrinsic controls
decreased urine production, retain fluid, maintain BP
small plasma proteins
insulin and angiotensin II
transmembrane proteins
thresholds determined by # of proteins, reabsorb all nutrients
reabsorption of glucose
active transport
reabsorption of Na+
facilitated diffusion
reabsorption of H2O
thru aquaporins, follows Na+
reabsorption of ADH
independent
reabsorption of K+
passive transport, concentration gradient set up by movement of Na+ and H2O
where is 10-20% of K+ reabsorbed
nephron loop
what are affected by aldosterone
collecting tubules and ducts
effect of ADH
reabsorb H2O
where does the exchange of water and salt occur
nephron loop, vasa recta, interstitial area
renal plasma clearance
volume of plasma that can be cleared in a given amount of time (1 min), useful for medicine dosage
how much of the kidney is renal failure
90%, damage to glomerulus and blood vessels
treatments of renal failure
peritoneal dialysis, hemodialysis, kidney transplant
urine composition
95% H2O and 5% solutes
urine pH
4.5-8
urine volume
1-2L/day
what is specific gravity
solutes
decrease urine volume
increase ADH and aldosterone, decrease ANP/fluid intake/BP, increase in fluid output
increase urine volume
decrease ADH and aldosterone, increase ANP/fluid intake/BP, diabetes mellitus and diuretics
micturition- sympathetic division of ANS
contraction of internal sphincter, inhibits detrusor muscle, storage reflex, reduce filtration in glomerulus, suppress urination
micturition- parasympathetic division of ANS
relaxation of internal sphincter, contraction of detrusor muscle, urination
where is the micturition center
pons
at what mL does urination occur
500-600mL
storage reflex
autonomic and somatic control, allows filling of bladder, detrusor muscle relaxes, internal sphincter contracts
intracellular fluid
K+, Mg2+, PO4 3-, 60%
extracellular fluid
Na+, Ca2+, Cl-, HCO3-, plasma and interstitial fluid, 40%
what causes fluid movement
hydrostatic pressure, osmosis
fluid depletion
hemorrhage, burns, vomiting, hyper secretion of aldosterone
dehydration
profuse sweating, diabetes mellitus, hypo secretion of ADH, cold exposure
hypotonic hydration
hyper secretion of ADH, more usually drinking excess water
edema
changes in cardiovascular and lymphatic system, changes in net filtration pressure at capillaries
ascites
accumulation of fluid in peritoneal cavity
pericardial effusion
fluid in pericardial cavity
pleural effusion
fluid in pleural cavity
where is the thirst center
hypothalamus → cerebral cortex
activation of thirst center
decreased salivary secretions, increased blood osmolarity, decreased blood volume → pressure
what does the release of renin do
angiotensin II → signals thirst center
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