Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Phys Exam 4: Ch 27
Tubular Processing of the Glomerular filtrate
| Question | Answer |
|---|---|
| Define Excretion | Filtration - Resorption + Secretion |
| How do you calculate filtration rate? | FR = [plasma] x GFR |
| What is the average daily value for GFR | 180 L/day |
| What 2 substances are completely reabsorbed? | Glucose, AAs |
| What 3 substances that are almost completely reabsorbed? | Bicarb ions, Na+, Cl- |
| What substance is not reabsorbed at all? | Creatinine |
| Which is larger, filtration & resorption, or excretion? | Filtration & reabsorption |
| Is absorption very selective or less selective? | Very selective, esp in contrast to filtration |
| Refresh: active transport | moves a solute against an electrochemical gradient and requires energy derived from metabolism (ATP) |
| Refresh: primary active transport | liked directly to cellular hydrolysis of ATP |
| Refresh: secondary active transport | Utilized (but is not directly linked to) ATP hydrolysis |
| Refresh: osmosis | movement of water in the direction of ion transport |
| Refresh: passive diffusion | Cl- and urea move down gradients set up by osmosis |
| Refresh: transcellular movement of molecules | passage through a tubular cell |
| Refresh: paracellular movement of molecules | passage between tubular cells across tight jxns |
| What causes transport maximum? | Due to saturation of proteins involved in active transport |
| What is the normal glucose filtration rate? | 125 mb/min |
| What is normal plasma [glucose]? | below 200mg/100mL |
| What happens if plasma [glucose] is above normal? | If levels are above 200mg/100mL some glucose appears in the urine. Some nephrons below average value |
| Describe cells in the proximal tubule | Abundant mitochondria, extensive surface area (brush border, basal channels), high carrier [protein] |
| What gets reabsorbed in the proximal tubule? | ~65% of the filtered Na+, Cl-, HCO3-, K+, and all glucose & AAs |
| How does the proximal tubule neutralize HCO3-? | Secretion of H+ neutralized HCO3- to water and CO2 via the Na-H antiporter |
| What substances are secreted by the proximal tubular cells and are not reabsorbed? | Organic acids & bases, oxalate, catecholamines, salicylates, penicillin |
| How is Cl- resorption enhanced? | Na+ resorption increases lumen negativity |
| What increases [Cl-]? | Osmotic removal of water |
| What is ionically co-transported w/Cl-? | Na+ |
| What maintains a low intracellular [Na+]? | Na-K-ATPase pump in the basolateral membrane |
| What carries in most of the Na+? | The 1-Na, 2-Cl, 1-K co-transporter on the apical surface |
| What is the fxn of the Na-H counter-transport? | Moving Na+ into the cell from the luminal side |
| What is the fxn of principal cells? | Reabsorb Na, secrete K, using the Na-K-ATPase pump |
| What is the effects of the presence of aldosterone on the principal cells? | Increases the concentration of the Na-K-ATPase pumps, and the specific Na-channel proteins by inducing synthesis of these pumps |
| What does ADH do to the permeability of the late distal tubule and cortical collecting tubule? | The tubule & duct are impervious to water except in the presence of ADH |
| Where are principal cells found? | The late distal tubule & cortical collecting tubule |
| What is the fxn of intercalated cells and where are they found? | Reabsorb HCO3- & K+, secrete H+, are found in the late distal tubule and cortical collecting tubule |
| How is H+ secreted in the late distal tubule and cortical collecting tubule? | H+-ATPase pump |
| What is the fxn of the medullary collecting duct? | Location of final fine-tuning of Na+ & water excretion |
| What happens to urea in the medullary collecting ducts? | Urea is reabsorbed into the interstitial fluid of the medulla, raising osmolality |
| What happens to H+ in the medullary collecting ducts? | secreted against a large concentration gradient using H+-ATPase pump |
| What controls water permeability of the medullary collecting ducts? | Vasopressin (ADH) |
| How does an increased renal arterial pressure cause an increase in urine output? | Slight increase in GFR, increase in peritubular capillary hydrostatic pressure, and reduction in AngII production |
| How does AndII influence urine output? | |
| How does aldosterone influence urine output? | |
| How does ADH/vasopressin influence urine output? | Increases water permeability of the late distal tubule and collecting duct. Stimulates movement of aquaporin to the cell membrane, and several aquaporin proteins fuse to form a water channel |
| What is glomerulotubular balance? | The resorption rate of the proximal tubule increases in response too increased flow/increased GFR |
| What happens in the presence of ADH? | Water is reabsorbed back into the body, decreasing the amount of urine |
| What happens in the absence of ADH? | Water is excreted, increasing the amount of urine |
| When are ANP & BNP (atrial natriuretic peptide) secreted, and what do they do? | |
| How does parathyroid hormone (PTH) influence urine output? | |
| What are the 4 parts of the renal tubule? | Proximal tubule, Loop of Henle, Distal tubule, Collecting tubule |
| What are the 3 parts of the Loop of Henle? | Thin descending, Thin & Thick ascending |
| What are the 2 parts of the distal tubule? | early & late distal tubule |
| What are the 2 parts of the collecting tubule? | cortical collecting tubule, medullary collecting tubule |
Created by:
hclark86
Popular Physiology sets