Flashcards in Urinary System Deck (130)
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?
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