Kidneys Flashcards
Describe the composition of the medulla
Composed of renal pyramids separated by renal columns. The renal pyramids empty urine into the calyces that drain into the renal pelvis. From the pelvis urine enters ureters and is transported to the bladder
Two main divisions of the kidney
Outer cortex and inner medulla
Describe what makes up the cortex and their brief functions
Millions of nephrons. Filtrate occurs in glomerulus which receives blood from affernt arterial’s. glomerular blood is drained into efferent arterial. Filtrate from the glomerulus goes through the proximal convoluted tubule the loop of Henley, the distal convoluted tubule, and then enters the collecting duct which goes into the medulla.
Name for things that the kidney regulates
Plasma volume, concentration of waste products in blood, concentration of electrolytes in plasma, plasma pH
What can be filtered by the glomerulus
Small molecules – water electrolytes – large molecules cannot be filtered
What is glomerular filtrate Chin right and what is the normal rate in men and women
Volume of filtrate produced by both kidneys per minute. Hundred and 15 mL per minute in women, hundred and 25 mL per minute in men
What controls GFR
Construction/dilation of afferent arterial arterioles. Sympathetic innervation causes constriction. Intrinsic mechanisms inside the kidney also help regulate
Describe autoregulation of kidneys
Decreased blood pressure leads to dilation of a Farrant arterial. Increased blood pressure constricts afferent arterial. GFR remains constant
Reabsorption in PCT
65% of filtered salt and water. Sodium is actively transported and chloride follows by electrical attraction and water follows the salt out of the PCT
Describe water and salt reabsorption – where it occurs
65% in PCT, 20% in descending loop of Henley. These always occur. Additional 15% may be absorbed later depending on hydration
What happens in a sending the loop of Henley
Sodium is actively transported out and chloride follows. Potassium comes in by NA/K pumps. Urine is highly diluted at end
What is the countercurrent multiplier and what is the countercurrent exchanger
Multiplier – loop of Henley. Exchanger – vasa recta
What ADH does
Insert aqua Porins into plasma membrane of collecting duct to allow water to leave the collecting duct
Formula for excretion
Excretion = filtration + secretion - reabsorption
Inulin’s role in determining GFR
Inulin cannot be secreted or reabsorbed therefore the volume of inulin excreted is equal to the volume filtered. Thus GFR is 120 mL per minute
