9.2 Flashcards
> Describe the pathway of blood flow through the kidneys
- Renal artery
- Segmental artery
- Interlobar artery
- Afferent arteriole
- Efferent arteriole
- Peritubular capillaries
- Cortical Veins
- IVC
What is the role of vasa recta?
- Reabsorb solutes and water
- Deliver other solutes
What are the three functions of the nephron?
- Filtration
- Reabsorption
- Secretion
Function of the renal corpuscle
Filtration water and solutes into the capsule space (and hence the renal tubule).
What features enhance GFR at the renal corpuscle?
- Thinness of filtration membrane
- Large surface area
- High glomerular blood pressure due to smaller efferent arteriole
What is the filtration membrane of the renal corpuscle made of? What are the functions of each of these layers?
- Fenestrated endothelium (blocks cells)
- Basement membrane (blocks large/charged proteins)
- Filtration slits between pedicels of podocytes (Blocks medium proteins)
List three functions of mesangial cells
- Contract/relax to control capillary diameter
- Phagocytoses debris, keeping glomerulus clean
- Produces intercellular matrix
What is the function of the PCT?
- Reabsorption of essential substances
What occurs in the loop of Henle?
Descending: reabsorbs water
Ascending reabsorption of Na+ and Cl-
What occurs in the DCT?
Final adjustment to concentrations in filtrate
What occurs in the collecting duct?
Water is carried through osmotic gradient; water may/may not be reabsorbed
Does the DCT or PCT contain microvilli?
PCT
Draw a diagram of the countercurrent multiplier mechanism
Descending: water out
Ascending: sodium out
The process perpetuates itself
When ADH adds aquaporins to the collecting duct, why does water diffuse out?
Because there is a high concentration gradient (countercurrent mutliplier mechanism)
Describe the influence of Aldosterone on the renal tubules and collecting ducts
Acts on distal convoluted tube, increasing reeabsorption of Na+ and secretion of K+ -> leads to increased blood pressure and blood volume
