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15 Cards in this Set
- Front
- Back
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Control of renal blood flow.
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1. Myogenic (Bayliss) Mechanism - Intrinsic - arterial smooth muscle contraction - response to tension.
2. Tubuloglomerular Feedback - Macula Densa - sense NaCl- high adenosine (afferent constrict)/ low renin secretion (efferent constrict) 3. Sympathetic Nervous System - increase = constriction - trauma, shock = no GFR Also: - Hormones, autocoids and endothelial factors - angiotensin II vs. NO |
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Control of GFR: Decreased Afferent resistance.
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Renal Blood Flow Increases.
GFR Increases |
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Control of GFR: Increased Afferent Resistance.
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Renal Blood Flow decreases.
GFR decreases. |
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Control of GFR: Increased Efferent resistance.
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Renal Blood Flow decreases.
GFR increases. |
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Control of GFR: Decreased Efferent resistance.
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Renal Blood Flow increases.
GFR decreases. |
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Glomerular Filtration Rate: Calculation
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GFR = (Urinary conc of inulin x Rate of Urine Flow) /
Plasma conc of inulin |
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Clearance: Definition
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Virtual volume of blood per unit time needed to supply that amount of solute to the urine.
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Transport Maximum: Explanation
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At low concentrations all filtered substance reabsorbed.
Above a certain level no matter how much more substance is filtered no more can be reabsorbed. (TRANSPORT MAXIMUM) Maintains substance balance by excreting all substance over the level required. N.B. Does not work for substances with abnormally high Tm. |
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Characteristics of Glucose Reabsorption:
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-98% Through SGLT2 and GLUT2 in first part of proximal tubule
-2% Through SGLT1 and GLUT1 - SGLT2 grunt work. SGLT2 mops up rest of Glucose, to very low glucose levels. |
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Renal Handling of para-aminohippurate (PAH)
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- completely excreted in urine.
- 1/6th filtered 5/6ths secreted into tubule. |
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Renal Handling of Phosphate
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- 10% filtered load excreted.
- 80% reabsorbed in PCT - 10% reabsorbed in DCT. - both via HPO4- channels. |
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Na+ Reabsorption in the proximal tubule
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Early Tubule
-Na+ in H+ out (leaves cell as NaHCO3 -Na+ in cotransport with other molecules -Water follows and through paracellular transport. Late Tubule. -NaCl through cell (exchange for H+/anion) also PCT. -Water follows (also through PCT) |
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Na+ Reabsorption in the thick ascending limb of Henle.
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-NO water transport.
-Na/2Cl/K cotransporter (apical) -Na+/H+ antiport (apical) -K+ channel (apical) -K+ and Cl- channels (basal) -HCO3- transport (basal) -PCT Na+ and other cations |
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Na+ Reabsorption in the Distal Tubule/Collecting Duct
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Early Distal Tubule
- No Water Transport - Na+/Cl- cotransporter - Cl- ion channel Late Distal Tubule/Collecting Duct. - Na+ and K+ Channels - Water permeability depends on ADH. |
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Action of ADH on the collecting duct.
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-ADH binds to V2 receptors.
- activates adenylate cyclase - cAMP - Protein Kinase A - phosphorylation chain inserts aquaporins into cell membrane. - Prostaglandins, calcium, PKC inhibit this affect |
