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Stack #39725
A&P2 Test 5 #9 Urinary-Tubular Reabsorption
| Question | Answer |
|---|---|
| TUBULAR REABSORPTION: | movement of filtrate (thru tubules) into blood of peritubular capillaries |
| GFR: | amt of filtrate that flows out of all the glomeruli each min |
| Filtrate for normal adult: | 180 liters (48 gal per day) |
| Most of the Filtrate is: | reabsorbed at a rate of 123/124 mi/min (178 to 179 liters per day) |
| Allows body to retain nutrients? | tubular reabsorption |
| Reabsorption mechanisms?(2) | passive & active transport mechanisms |
| Active transport of Na+ followed by: | passive transport of water molecules controls the process of Tubular reabsorbtion |
| As Na+ is actively transported: | water follows by osmosis |
| Sodium ions are actively: | reabsorbed into the capillaries, mostly from PC & DC tubules |
| Epithelial cells thru the sys of: | renal tubules carry out the process of tubular reabsorption |
| These epithelial cells have a: | BRUSH BORDER (MICROVILLI) |
| Brush border greatly: | increases surface area |
| These cells also have cell membrane: | specializations, incl restrictive gated channels & leak channels. |
| These channels selectively: | remove Na+ from the capillaries & transfer it to the epithelial cells |
| Water follows | Na+ by osmosis |
| The epithelial cells can then use a: | system of Na+ pump channels to selectively transfer Na+ out of thier structure into the surrounding interstitial fluid. |
| Water again follows: | the Na+ by osmosis |
| The process is V discriminating: | and only certain materials are reabsorbed, |
| The material reabsorbed is: | water, glucose, amino acids & ions such as:K+,Na+,Ca++, CL-, & HCO3. |
| Glucose is readsorbed: | with an active process involving a carrier enzyme-mediated system |
| The carrier enzyme prob. exists: | in the cells of the tubule walls |
| Other molecules get: | reabsorbed just because they get caught in flow of water |
| About 80% of water is: | absorbed in the PC tubules |
| ACTIVE TUBULAR REABSORPTION: | involves the movement of glucose, amino acids, lactate, vitamins & almost all ions (such as K+ & Na+) against an electrical &/0r chemical gradient |
| PASSIVE TUBULAR REABSORPTION includes: | diffusion, facilitated diffusion and osmosis along an electrochemical gradient |
| Urea, creatinine & uric acid are: | by-products of nucleic acid metabolism |
| are by-products reabsorbed: | No |