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37 Cards in this Set
- Front
- Back
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What are some common conditions that produce negative sodium balance?
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Diarrhea
Diuretic medication Insufficient aldosterone (aka ADH) |
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What are some common conditions that cause a positive sodium and water balance
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excess steriods
congestive heart failure salt-retaining renal disease |
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How much filtered solute and water is reabsorbed in the proximal tubule?
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this reabsorbs 60-80%
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What kind of fluid transfer happens in the distal convoluted tubule?
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some reabsorption of water and ions (iso/hypo-osmotic)
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What determines the ability to produce concentrated urine proportional to?
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this is proportional to the number of juxtamedullary nephrons
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What three layers make up the filtration barrier?
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capillary endothelium
basement membrane capsular epithelial cells (the podocytes/foot processes) -so urine flows between podocytes |
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What three types cells make up the juxtaglomerular apparatus?
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Macula densa cells
extraglomerular mesangial cells granular cells |
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What is the function of the juxtaglomerular apparatus?
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this helps control the GFR
controls renin secretion |
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What do mesangial cells do?
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these are between capillary loops, contract in response to angiotenisn II
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What does the vasa recta do? where are they located
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this follows the loop of henle of juxtamedullary nephrons.
these are found in medulla |
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What is the order of the renal blood flow?
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Afferent arterole-> glomerulus capillary bed-> efferent arterole-> peritubular capillary bed-> to vein
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What supplies blood to medullary tissue?
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the vasa recta
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What types of nerves are renal nerves?
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these are sympathatic
Alpha 1 receptors (No parasympathetic) |
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Where are the renal sympathetic nerves primarily located?
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on afferent arterioles (blood leading into glomerulus)
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How does SNS stimulation affect RBF and GFR
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this tends to be reduced, but the release of PGE2 and PGI2 opposed the effect.
so minimal RBF and GFR are minimized |
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What do granular cells do when innervated by the SNS?
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they release renin
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what is the typical GFR?
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120-125ml/min
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What is tubular reabsorption?
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this is from the tubular lumen to the PTC
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What is tubular secretion?
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from PTC to tubular lumen
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How much of the CO do kidneys receive?
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1/4th
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What is the filtration fraction equation?
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FF= GFR/RPF
RPF= (1-Hct)RBF RPF= renal plasma flow, RBF= renal blood flow GFR= glomerular filtration rate |
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What does Angiotensin II (ADH, ATP, endothelin)
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this decreases RBF and GFR
constricts EFFERENT arteriole more. |
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What do sympathetic nerves do to RBF?
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these cause vasoconstrioction via Alpha 1 receptors. decreasing RBF and GFR
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What are 4 vasodilators? what do they do?
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Atrial natriuretic peptide, glucocorticoids, NO, prostaglandins.
these increase RBF and GFR |
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What is the range of autoregulation of RBF and GFR?
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80-180mmHg
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What are the two mechanisms of Autoregulation of RBF and GFR?
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myogenic mechanism
tubuloglomerular feedback |
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What arteriole is affected during autoregulation?
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The afferent arterole resistance is what is affected during autoregulation
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What is the myogenic mechanism of autoregulation of RBF and GFR?
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this is intrinsic to the vascular smooth muscle, it contracts in response to stretch
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What is the tubuloglomerular feedback mechanism of autoregulation?
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This if flow dependent.
Increased GFR increases NaCl delivery to loop of henle. Increased NaCL is sensed by macula densa. This increases resistance of afferent arteriole (slowing RBF and GFR) May be Adenosine that causes this |
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What is the fluid in bowmans capsule?
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this is essentially protein free filtrate of blood plasma
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How do concentrations of things in plasma relate to things in glomerular filtrate?
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they should be the same in plasma and glomerular filtrate- unless it is bound to protein.
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What are the main barriers to proteins being filtered out of the glomerlulus?
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the basal lamina and filtration slits are the main barriers to proteins being filtered out.
filtered by size, larger proteins not filtered |
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What does the starling equation describe?
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this is used to describe the glomerular filtration rate
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What is the starling equation
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GFR= Kf [(Pgc-Pbc)-(Pigc-Pibc)]
Kf=filtration coefficient Pgc- Blood pressure (driving force for GFR) Pbc- backpressure in bowmans capsule (retards GFR) Pigc- oncotic pressure of glomerular capillary blood Pibc- oncotic pressure in bowmans capsule (usually zero) |
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What drives the oncotic pressure of the glomerular capillary blood?
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this is due to proteins that are unable to cross the barrier. retards GFR, increases as more plasma is diverted into the bowmans capsule
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What is an alterternate equation for GFR?
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GFR= Kf X NFP
Kf= capillary filtration coefficient NFP= net filtration presure |
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what is the equation for net filtration pressure?
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(Pgc-Pbc)-(Pigc-Pibc)
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