22256559
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
about 4 years ago
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| Question | Answer |
| Proximal Tubule Na+ Reabsorption - Na+ moves into cell via ...exchanger and ...symporter - ...maintains low Na+ in cell - negative charge on lumen repels Cl-, HCO3- etc. | 1. Na+/H+ 2. Na+/nutrient (Glucose, AA etc.) 3. Na+/K+ ATPase |
| Thick Ascending Limb Na+ Reabsorption - ... cotransporter to transport Na+ - ... maintains low Na+ in cell - K+ channels allow K+ out into filtrate, creating ... and driving Na+ into cell | 1. Na+/K+/2Cl- 2. Na+/K+ ATPase 3. positive charge |
| Distal Tubule Na+ Reabsorption - cotransporter transports Na+ in - ... keeps Na+ concentration in cell low | 1. Na+/Cl- 2. Na+/K+ ATPase |
| Collecting Duct Na+ Reabsorption -2 cell types: ... cells (Na+), ...cells (H+) - In ... cell, ....and Na+/K+ ATPase | 1. Principle 2. Intercalated 3. Principle 4. Na+ channels |
| What is the definition of clearance? What is the equation? What is the unit? | 1. The volume of plasma cleared of a substance in a given time 2. C=(ion concentraton in urine*volume of urine)/ion concentration in plasma 3. mL/min |
| Clearance Values: ...: <120ml/min eg. most solutes No change: .../min eg. ... ...:>120ml/min eg. ... | 1. Reabsorption 2. 120, inulin 3. Secretion, PAH |
| Describe the mechanisms of ADH in the collecting duct | 1. ADH binds to V2 2. Activates G protein/adenylyl cyclase 3. PKA causes translocation of AQP2 to membrane 4. H20 can enter via aquaporins |
| H20 Reabsorption depends on which 3 factors? | 1. Osmosis 2. Sodium reabsorption (bc H20 reabsorption coupled with Na+, bulk flow) 3. Tubule permeability - increased by AQP1/tight junctions on membrane |
| Making Concentrated Urine How is the concentration gradient created? 1. ...pumps Na+ out via Na+/K+/2Cl- co transporter | Thick ascending limb |
| Making concentrated urine How is water removed from the LoH? 2. ... picks up ..., loses ... (osmosis) as it descends due to increasing solute concentration down the medulla | 1. Descending limb 2. Na+ 3. H20 |
| Making concentrated urine Why does osmolarity decrease up the ascending tubule? 3. ... impermeable to H20 - solutes move out, H20 remains - Osmolarity decreases up ascending tube | Thin ascending limb |
| Name the 3 places of urea reabsorption and their mechanism? | 1. Proximal Tubule-passive reabsorption 2. LoH- apical secretion via VTA2 3. Inner Medullary Collecting Duct- Reabsorbed into cell via VTA1 and leaves cell into interstitium via VTA3 |
| Osmolality Ranges: Plasma: ...mosm/kg Urine: ...mosm/kg Concentrated if >plasma Dilute if <plasma Main determinant is ... | 1. 285-295 2. 50-1400 3. Sodium |
| Potassium is the major ... in body, determines ... | 1. Intracellular cation 2. Resting membrane potential |
| What is Renal Plasma flow? What is it measured by? What is it usually? | 1. Amount of blood to kidneys/time 2. PAH because no reabsorption 3. Usually 600mL/min |
| What is the equation for renal blood flow? | Plasma flow- (1-haematocrit aka RBC proportion) = 600/0.55 |
| Sodium reabsorption occurs in: PCT (...%) Thick Ascending Limb (...%) DCT (...%) Collecting Duct (...%) | 1. PCT: 65 2. Thick Ascending Limb of LoH: 25 3. DCT: 2-5 4. CD: 5 |
| What are the 4 factors increasing K+ secretion? | 1. Na+ entry through Na+ channels 2. Aldosterone, which stimulates K+/Na+ channels 3. High tubular flow rate 4. Alkalosis, which enhances K+ movement |
| What are the sites of K+ reabsorption? | 1. Thick ascending limb via Na+/K+/2Cl- cotransporter 2. Distal tubule via K+/H+ exchanger 3. In CD by intercalated cells with K+ channels or K+/Cl- cotransporter - outweight by principal cell K+ secretion |
| Principle cells reabsorb ... and secrete... | Na+ K+ |
| What is the role of ADH in urea recycling? | ADH increases water permeability but not urea permeability in outer medullary/cortical collecting ducts, allowing urea to concentrate in the tube As a result, there is a concentration gradient of urea created within the tube, driving urea reabsorption later on in the inner medullary collecting duct |
| What measures clearance experimentally vs. clinically? | Experimentally: inulin Clinically: creatinine |
| ... supplies blood without washing gradient away via counter current exchange Counter current exchange is when loops slow blood flow so reabsorbed solutes can reenter interstitual fluid/mantian concentration gradient | Vasa Recta |
| Urea is .... at the level of the renal corpuscle and undergoes ... in the kidney as majority is | 1. Freely Filtered 2. Recycling 3. Reabsorbed |
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