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Flashcards in Urinary System Deck (130)
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What are the functions of the kidney?

Regulation of fluid and volume, electrolyte balance, excretion of waste, production of hormones


Where does filtration and collection occur in the kidneys?

Filtration- cortex
Collection- medulla


Order these organs from start to finish: Ureter, urethra, kidney, bladder

Kidney, ureter, bladder, urethra


Outline blood flow in kidneys

Renal artery, segmental arteries, interlobar arteries, arcuate arteries, interlobular arteries, afferent arteriole, glomerulus, efferent arteriole, peritubular capillaries, interlobular vein, arcuate vein, interlobar vain, renal vein

Really, Small, Indians, Aim, Inside


After filtration in the glomerulus describe the route of the filtrate to the collecting duct?

Proximal convoluted tubule, descending loop of henle, ascending loop of henle, distal convoluted tubule, collecting duct


Where does the nephron enter the medulla?

At the bottom of the loop of henle


What force is responsible for filtration?

The difference in hydrostatic pressure and protein-osmotic pressure


Why is the glomerular filtration rate high?

To remove toxic substances quickly


How is the GFR high?

Large SA across filtration and size difference between afferent and efferent arterioles and low resistance of thin porus membrane


What is tubular reabsorption?

The process of returning substances from filtrate back to renal interstitial then renal blood vessels


What are the mechanisms of tubular reabsorption?

active transporters, osmosis, solvent drag, co-trasporters


What three barriers filter the blood?

Capillary endothelium, basement membrane, podocytes


What does the endothelial cells filtrate?

Prevents blood cells allows components to pass


What does the basal lamina filter?

Prevents large proteins


What do podocytes prevent filtration of?

Medium sized proteins


What is the definition of the GFR?

Volume of fluid filtered from the glomerular capillaries into bowmans space per min


What is the difference between paracellular and transcellular reabsorption?

Paracellular- between cells
Transcellular- through cells


How does tubular reabsorption occur in the proximal tubule?

Na+ is diffuses from lumen into tubular cell is pumped into interstitial fluid and diffuses into capillaries, water follows by osmosis, causing solvent drag, this increases conc gradients of all other ions, chloride moves down electrochemical gradient, therefore K, Ca, Mg diffuse


How does the proximal tubule increase surface area?

Tubular luminal side has villi like structures


How is glucose reabsorbed in the proximal tubule?

Secondary active transport using Na, glucose symporter then diffusion into the capillaries


What causes glucose to reach the urine?

Filtration of glucose can saturate, reabsorption can be saturated and no where else can absorb the glucose


How is phosphate reabsorbed and regulated?

Reabsorbed same as glucose, regulated by parathyroid hormone


How does Na/H exchanger allow reabsorption of Bicarbonate?

Binds to bicarbonate producing H2O and CO2 which can pass through into the proximal tubule cells and bicarbonate is reproduced using carbonic anhydrase and diffuses into blood


Why is not all H+ effective for reabsorbing bicarbonate?

Some binds to HPO4 and is excreted


How are the small proteins returned to blood?

Endocytosis in the PCT, degradation in tubular cells to amino acids diffuses into capillaries


Why is a high filtration rate needed to prevent high concentration of Urea being reabsorbed?

Urea is slightly lipid soluble so can move down concentration gradient into blood therefore high rate needed to prevent more of this


Why does water leave the descending limb by osmosis?

The solute from the ascending limb increases ISF concentration water follows by osmosis


How does the osmolarity change down the medulla?



How does the LOH and vase recta cause a counter current?

Vassa recta runs parallel and in opposite direction of LOH


Why does the osmolarity of the vassa recta increase down the medulla

As it runs down the ions of ascending limb diffuse in increasing osmolarity as it runs up by descending limb water moves in by osmosis