lecture 12 - renal physiology Flashcards
what are the kidneys functions?
regulation of water, Removal of waste from blood and excretion of urine, secretion of hormones
what is the gross anatomy of the renal system?
glomeruli, medulla - renal tubules, renal pelvis, blood
what do the kidneys do?
process plasma portion of blood by removing substances from it, and in a few cases, by adding substances to it, works with the CV system
what is the nephron?
vascular component (blood supply), tubular component (urine)
what is the blood flow?
aorta - renal artery - afferent arteriole - glomerulus - efferent arteriole - peritubular capillaries and vasa recta - renal vein - inferior vena cava
what does a nephron consist of?
glomerulus and tubule
what is the osmotic gradient?
collecting duct facilitates urine formation via counter current exchange
what is bowmans capsule?
wall of epithelial cells, outer layer – turns in and then has an inner layer which wraps around the other capillaries
what does GFR depend on?
diameters of afferent and efferent arterioles
what is peritubular re-absorption?
provide nutrients for tubules, and also receive the fluid that the tubules have reabsorbed.
what are the renal transport systems?
Reaches a plateau which is its maximum transport capacity – if have more glucose present and have maxed out the transporter system – glucose that doesn’t get reabsorbed – get glucose in the urine
Transporters for amino acids which get reabsorbed as well
Glucose in the urine means too much has been filtered in the system
what is the loop of henle and collecting dust?
the re-absorption of water and sodium chloride.
what is the distal convoluted tubule?
is in close proximity to the Bowman’s capsule.
what is the role of urea in concentrating urine?
Urea very useful in concentrating urine.
High protein diet = more urea = more concentrated urine.
Kidneys filter, reabsorb and secrete urea.
Re-absorption is passive
Greatest re-absorption into peritubular capillaries when urine volume per min is small (urine is concentrated).
Urea excretion rises with increasing urinary flow.
what is urea recycling?
toxic at high levels but causes a build-up of urea in inner medulla - helps create osmotic gradient so h2o can be reabsorbed
