Renal Flashcards
What are the functions of the kidney?
Regulation of water, inorganic ion balance, and acid/base balance
Removal of metabolic waste products from the blood and their excretion in the urine
Removal of foreign chemicals from the blood and their excretion in the urine
Production of hormones/enzymes
What hormones/Enzymes are produced by the kidney? what do they do?
Erythropoietin (stimulates RBC production)
Renin (RAAS system, increases bp/Na balance)
1, 25 dihydroxyvitamin D: active vitamin (involved in Ca balance)
How is the kidney organized? How what veins/arteries are present?
Medullary Lobes, with cortical lobules Many nephrons (renal corpuscle, tubule)
Renal artery - Interlobar artery - arcuate artery - interlobular artery - afferent arteriole (reverse for veins) efferent arteriole - capillary - veins….
Describe the nephorn’s structures
Glomerulus Bowmans space (in bowman's capsule) Proximal convoluted tubule Proximal straight tubule Descending thin limb of Henle's loop Ascending thin limb of Henle's loop Thick ascending limb of Henle's loop Distal convoluted tubule Cortical collecting duct Medullary collecting duct Renal pelvis
What are the two layers of the renal corpuscle
Parietal layer (outside) Visceral layer (touching glomerulus, podocytes)
How is the nephron vascularized?
Peritubular capillaries
What are the three processes of urine production?
Glomerular filtration Tubular secretion (capillaries -> tubules) Tubular reabsorption (tubules -> capillaries)
What is filtered by glomerular filtration?
Water, low-moleculary weight substances
Cells, proteins, protein-bound substances do not cross
How do you calculate the amount of urine excreted?
Amount filtered + amount secreted - amount reabsorbed
What is the only substance that is not reabsorbed?
Para-amino-hippurate
True/False? In a healthy person, glucose never enters the nephron
False (enters nephron but is completely reabsorbed)
How is net glomerular filtration pressure calculated?
Glomerular Capillary blood pressure - Fluid pressure in Bowman’s Space - Osmotic force due to plasma proteins (oncotic pressure)
Usually: 60 - 15 - 29 = 16
What is the glomerular filtration rate? How is it controlled? Which of those methods is under physiological control?
What is a normal GFR?
The volume of fluid filtered from the glomeruli into Bowman's space per unit time Regulated by: Net Filtration rate (most important) Membrane Permeability Surface area Available for Filtration
Normal GFR = 180 L/day
How can you increase GFR? How can you increase it?
Increase: Constrict aferent arteriole or dilate eferent arteriole
Decrease: constrict eferent arteriole or dilate aferent arteriole
All methods control Glomerular capillary pressure (increasing GFR decreases Pgc, decreasing GFR increases Pgc)
What is filtered load? How is it calculated?
When is net reabsorption present? When is net secretion present?
Total amound of any free filtered substance per unit time
Filtered Load = GFR x plasma concentration of the substance
Filtered Load > amount excreted: absorption
Filtered Load < amount excreted: secretion
What is the differene between paracellular and transcellular reabsorption?
Transcellular: from tubular lumen to tubular epithelial cell (needs transport proteins) and then into peritubular capillary
Paracellular: directly from tubular lumen to peritubular capillary through tight junctions between epithelial cells
True/False? Filtered loads are typically quite small
False
True/False? Reabsorbtion of waste products is relatively incomplete
True
True/False? Reabsorption of the most useful plasma components is relatively incomplete
False
True/False? Reabsorbtion of some substances are completely unregulated
True (eg glucose, amino acids)
What are two methods of reabsorbtion?
Diffusion
Mediated transport
Where does water reabsorption take place?
Proximal tubule
What is typically associated with mediated transport?
Sodium reabsorption (for secretion and reabsorbtion)
How does mediated transport work for eg amino acids?
AA are brought into tubular epithelial cell (Na symporter - Na enters epithelial cell as well)
AAs leave through channels
Na/K ATP ase pumps Na into peritubular capillary and K into cell