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23 Cards in this Set
- Front
- Back
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Define Renal blood flow.
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the amount of blood flowing into the kidney /minute
--> 20% of the CO = 1100 mls/min |
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Define Renal plasma flow.
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amount of plasma flowing into the glomeruli/ min
→ RPF= (1-Ht) x RBF = 0.55 x 1100= 605 mls/min |
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What is filtration fraction?
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GFR/RPF
=125/605=20% |
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What is Vasa recta?
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(meaning straight vessels), vessels branching off the efferent arterioles coming of the glomerulus of the juxta-medullary nephrons, that run parallel to the loop of Henle. They have got a role in the maintenance of the counter-current exchange.
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What is Pressure diuresis?
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due to the lack of ability to autoregulate RBF in the juxtamedullary nephrons; ↑RBF there-->washout of solutes in that region -->↓concentrating ability of the kindneys
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Define Glomerular filtration.
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it is the process by which water and solutes (protein-free version of the plasma) leaves the intravascular compartment through the filtration barrier and into Bowman's capsule(which is topologically outside the body).
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Is the glomerular filtrate totally protein-free?
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No.
Total protein concentration is very low. Many small proteins that have low plasma concentrations, such as peptide hormons, are freely or nearly freely filtered. |
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What is the fraction of endothelial surface area in the glomerulus that is occupied by fenestrae?
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10 %
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What is the selectivity of the filtration barrier to filtered solutes based on?
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1- molecular size (freely filtererd if < 7000 Da)
2- electrical charge-->negative charge is a hinderence to filtration in 'large' molecules. |
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What percentage of the albumin present in plasma is actually filtered?
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0.02%
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What determines K+ excretion?
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the amount of K+ intake
this is adjusted via controlling the amount of K+ secreted in the DCT and cortical collecting ducts |
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What cells secrete K+?
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the principal cells in:
1-DCT 2- Cortical collecting ducts |
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What cells reabsorb K+?
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type A intercalated cells
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How can the total body water be measured?
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using dilution markers that diffuse throughout the total body water. e.g.
isotopically labelled water (using deuterium (2H) or trituim (3H) |
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What markers are used to determine the ECF compartment volume?
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Inulin, mannitor, radiosodium, radiochloride, and thiosulfate.
Those does not cross into the intra-cellular compartment |
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What markers are used to determined the intravascular compartment volume?
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radio-labelled albumin
dye Evans blue that binds to albumin |
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What is ADH?
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-is a peptide
-produced by a group of hypothalamic neurons, in the supra-optic nucleus whose cells bodies terminate in the posterior pituitary -stimuli to its release come from: 1-osmoreceptors 2-baroreceptors |
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What are the stimulants for thirst?
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- decreased ECF volume
-increased osmolality -dryness of the mouth -angiotensin II: decreased ECF-->angiotensin II is secreted--> stimulate thirst center in the brain |
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How do you convert mg/dL of glucose to mmol/L?
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divide by 18
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what is 'filtered load'?
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it equals:
GFR x plasma concentration |
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What is SGLUT-1?
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co-transporter of glucose, studied in the rats, found to transport 2 Na+ and 1 glucose
associated with GLUT-1 SGLUT-2 is present in the PCT's to transport glucose |
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Define the splay.
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the rounded curve representing the ‘actual’ glucose reabsorption compared to the ‘ideal’curve
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Define active transport.
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Is the process by which a substance is moved 'up' its electrochemical gradient, requires energy
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