Hemostasis: Renal Structure and Function Flashcards
cortex of the kidney
outer portion of kidney, has projections called renal columns, contain renal corpuscles and renal tubules (NOT loop of Henle though)
medulla of kidney
innermost portion of kidney, composed of pyramids, loops on Henle, vasa rectae, collecting tubule
pyramids of kidney
27-30 make up renal medulla, composed of interstitium, loops of Henle and vasa rectae
minor and major calyces of kidney
surround apex of renal pyramids, collect urine from collecting ducts, merge to form major calyces, urine then flows into renal pelvis
renal pelvis
funnel-like convergence at end of major calyces, carries urine to ureters
renal interstitium
hypertonic, draws h20 from thin descending limb of loop of Henle and collecting ducts.
afferent arterioles of the kidney
arise from cortical radial arteries, micro-vasculature that supplies blood to the glomerulus be filtrated
efferent arterioles of the kidney
micro-vasculature that drains blood from the glomerulus. leave glomerulus to form the peritubular capillaries
Bowman’s capsule
capsule that surrounds the glomerulus, composed of parietal layer and visceral layer of stellate cells (podocytes)
podocytes
specialized stellate cells that make up the visceral layer of Bowman’s capsule
glomerulus
bundle of specialized capillaries that facilitate the filtration of blood to form filtrate
juxtaglomerular apparatus
area where the thick ascending portion of the loop of Henle lies adjacent to the glomerulus. contains the macula densa. vital for tubulo-glomerular feedback which stimulates or inhibits renin production and secretion.
macula densa
portion of the juxtaglomeruluar apparatus that helps w/ tubulo-glomerular feedback
proximal convoluted tubue
lies in the cortex of the kidney, picks up filtrate from glomerulus, 5/6 of Na+ and H2O are resorbed into the kidney interstitium in this portion
distal convoluted tubule
follows macula densa portion of JGA, collects to the collecting duct
descending loop of Henle
follows proximal tubule, primarily in the inner medulla, permeable to water but not solute
ascending loop of Henle
ascends from hairpin turn of loop, permeable to solute but not water
collecting duct
final section of nephron, collects urine, regulated by aldosterone. has aquaporins that can allow resorption of water if needed
discuss four major non-excretory functions of the kidney
- regulates BP via renin-angiotensin-aldosterone system
- produces and secretes EPO
- produces active form of vitD
- produces renin
average daily cardiac output
~7200L/day
average daily renal blood flow
~1800L/day
average glomerular filtration rate
~180L/day
average daily urine output
~1.5L/day
what is the general fluid content of filtrate as it passes through the fenestrated glomerular capillary walls?
nearly protein-free. this barrier allows passive of electrolytes, AAs, glucose, creatinine, and some other small molecules to pass through. most common substances are Na+, K+, Cl-, urea, some glucose.
what types of cells secrete renin in the afferent arteriole of the kidney?
granular cells
what factor stimulates renin production and secretion
large urine flow, renin acts to contraction of the afferent arteriole to slow filtrate formation
proximal convoluted tubule resorption
resolves 50-60% of solute and water filtered at glomerulus. resorbs essential nutrients (organic solutes), NaHCO3 (bicarbonate), and NaCl
thin descending limb of loop of Henle resportion
permeable to water but NOT solute, pulls water OUT of solute
thick ascending limb of loop of Henle resportion
resorbs 30% of NaCl filtered at glomerulus, impermeable to H2O. plays a major role in creation of medullary osmotic gradient and counter-current exchange, can help to create either concentrated or dilute urine
distal convoluted tubule resporption
diluting segment, resorbs NaCl. HCTZ acts to block channels in this portion of the glomerulus.
collecting duct resorption
regulatory segment, regulated by aldosterone. aldosterone stimulates increase absorption of NaCl, creates a more acidic urine (removes H+ from blood),
aldosterone action
secreted by the adrenal gland on top of the kidney. affects the collecting duct. increases BP.
- drives Na/K pump to push Na INTO blood, K OUT of blood (leads to K+ increase in urine through K+ channels)
- create Na+ channels to remove Na+ from urine to be pushed back into blood
- this leads to movement of water back into blood (follows Na+ concentration increase in blood)
how is GFR assessed?
concentration of certain compounds can help determine plasma concentration, which in turn gives an idea of GFR (elevated serum creatinine indicates decreased GFR)
GFR
volume of filtrated that is formed/unit time
