Nephrology Flashcards
glomerular disorders
-Glomerulonephritis
-Nephritic/Nephrotic Syndromes
-Diabetic Nephropathy
components of nephrone
2 types of nephrons
-Juxtamedullary (left):
~ 15% of nephrons
-starts deeper and goes deeper in (inner medula)
-different/better concentration gradient
-uses more energy but concentrates heavily
-Cortical (right):
~ 85% of nephrons
-more shallow
-dont memorize numbers
roles of nephrons
-Juxtamedulary
-Primarily for urine concentration
-Reabsorb higher proportion of filtrate
-High use of energy
-Cortical
-Lower use of energy
-Less efficient at conserving fluid
-Blood flow can be directed to conserve fluid or energy
renal corpuscle
-podocytes- line the capillary -> change how much we filter
-damaged podocytes -> proteins in urine, cells in urine, glucose
filtration at the glomerular level
-Filtrate must pass through the:
-1. Fenestrated capillary membrane
-2. Glomerular basement membrane
-3. Podocyte foot processes
transmembrane transport mechanisms
-7 basic mechanisms for transmembrane transport of solutes
-1. Convective flow in which dissolved solutes are “dragged” by bulk water flow
-2. Simple diffusion of lipophilic solute across the membrane
-3. Diffusion of solute through a pore
-4. Transport of solute by carrier protein down electrochemical gradient
-5. transport of solute by carrier protein against an electrochemical gradient with ATP hydrolysis providing driving force
-6,7. Co-transport and countertransport, respectively, of solutes, with one solute traveling uphill against an electrochemical gradient and the other solute traveling down an electrochemical gradient
-active or passive
-NOT ON TEST
common nomenclature for tubular segments
-proximal tubule- prox convoluted tubule and prox straight tubule
-loop of henle- descending thin, ascending thin, and thick ascending limb of loop of henle
-distal tubule- distal convoluted tubule
-distal nephron- distal tubule, connecting tubule, cortical collecting duct
-medullary collecting duct- outer medullary collecting duct and inner medullary collecting duct
renal osmolarity
-Keep in mind that the interstitial space makes up a fraction of the actual kidney… but for demonstration purposes…
-active transport sets up concentration gradient for passive transport
-collecting duct channels are open in presence of ADH
-in presence of ADH -> H2O diffuses out of tubule and we pee concentrated urine
stepwise approach to renal filtration
-afferent arterial going into the glomulus
-efferent coming out
-all the water that leaves the tubule is reabsorbed by the afferent arteriole -> counter current multiplier
if we laid renal function out on a straight line and graphed its function
-look at the ADH and without ADH
-Cr kidney marker
kidney pain
-stretch of the capsule from inflammation
feedback loop for aldosterone secretion
-Feedback mechanism regulating aldosterone secretion
-dashed arrow indicates inhibition
-Renin is a proteolytic enzyme produced from a larger protein, prorenin
-Renin is excreted by the juxtaglomerular cells of the kidney in response to decreases in renal perfusion pressure and reflex increases in renal nerve discharge
-Once in the circulation, renin acts on angiotensinogen, to form angiotensin I, a decapeptide
-In the lung and elsewhere, angiotensin I is converted by angiotensin-converting enzyme (ACE) to angiotensin II, an octapeptide
-Angiotensin II binds to zona glomerulosa cell membrane receptors and stimulates synthesis and secretion of aldosterone
-Aldosterone promotes Na+ and water retention, causing plasma volume expansion, which then shuts off renin secretion
-In the supine state, there is a diurnal rhythm of aldosterone and renin secretion; the highest values are in the early morning before awakening
-angiotensin converting enzyme converts angiotensin 1 to 2
-changes Na, water, fluid levels
-dont really worry about this!
action of aldosterone on principle cell of collecting duct
-modulates Na reabsorption
-feedback mechanism regulating aldosterone secretion
countercurrent multiplier
-Maintains NaCl concentration gradients in medullary interstitial fluid
-Helps conserve water in response to ADH
what conditions would affect glomerular filtration
-HTN- more filtration
-hypotension- less filtration
-RTS- less filtration
-obstruction- less filtration
-hypovolemia- less filtration
-damage to glomerulus- more filtration (leaking)
-adrenal issues
-ADH
-stress- high
-chronic stress- low
bloop pressure/resistance
-two areas of resistance- afferent and efferent arterioles
-constriction at efferent arteriole- increase filtration (more pressure)
-dilate efferent arteriole- decrease filtration
-constrict afferent arteriole- decrease filtration
-dilate afferent arteriole- increase filtration (more flow)
effects of afferent and efferent tone
-RBF- renal blood flow
-case- pt with HTN taking an ACE inhibitor and NSAIDS for chronic knee pain -> acute renal failure (BOARDS AND TEST)
-PGC, glomerular capillary hydrostatic pressure
-FF, filtration fraction
diagnostic imaging- cystography
-Radiocontrast medium is instilled via urinary catheter
-May be also useful for vesicoureteral reflux evaluation (shown in pic)
-catheter inserted and balloon inflated to prevent it coming out -> contrast injected
-urine is seen flowing retrograde into ureter
-valve is incompetent
-urine flows backward
-chronic UTI
-pyelonephritis!
diagnostic imaging- urinary pyelogram
-IV contrast excreted by kidneys
-X-rays are taken at intervals
-Giving a functional image of the urinary system
-calyx, pelvis lights up
-issues with function
-decrease in contrast in certain areas -> narrowing on the right side
diagnostic imaging- CT with IV contrast
-CT scan using IV contrast used for structural evaluation of kidneys
-renal artery is bumpy -> renal artery stenosis
-string-of-beads sign
