renal physiology test 3 Flashcards
how does the renal system regulate pH?
by retention of HCO3
remember excretion of HCO3 is bascially the same as adding 1 Hydrogen
-kidneys also produce new HCO3 by metabolizing gluatamine, which makes NH4 and HCO3
what are some other renal functions?
production of erythropoietin=more RBCs
Gluconeogenesis, particularly during a fasting state
what are the two basic parts of the kidney?
renal cortex and renal medulla(innermost)
what do we find within the medulla?
renal pyramids that contain nephrons
each pyramid is connected to what?
renal pelvis or urine drainage tube, by a papilla
the kidney is supplied with blood via the renal artery which enters the organ at the hilum. This branches into what?
afferent arterioles, which feed capillary beds known as glomerular capillaries.
why are glomerular capillaries important?
supply the nephrons with blood
this is where filtration occurs
glomerulo capillaries feed into what?
efferent aterioles which form a secondary capillary network called the peritubular capillaries.
where does reabsorption/secretion occur?
at the peritubular capillaries
is the hydrostatic pressure higher in the glomerular capillaries or the peritubular capillaries?
the glomerular capillaries (60 mmHg) peritubular capillaries (13 mmHg)
what regulates the hydrostatic pressure?
changes in the afferent/efferent arterioles
when the glomerulus is covered by epithelial cells what is it called?
bowman’s capsule
list the order of tubes in the nephron
bowman’s capsule ->proximal tube->loop of henle->distal tubule->collecting duct->renal pelvis and ureter
where does reabsorption and secretion occur within the nephron?
proximal tube
loop of henle
distal tube
**peritubular capillaries
where does filtration occur?
bowman’s capsule/bowman’s capsule
**glomerular capillaries
what are the two types of nephrons
cortical nephrons-cortex region (70%)
juxtamedullary nephrons-medulla (30%)
how is the blood supply different between cortical nephrons and juxtamedullary nephrons?
- cortical nephrons: peritubular capillaries are tightly associated with loop of henle
- juxtmedullary nephrons: efferent arterioles extend part of the way down the loop of henle and form vasa recta
what is the formula for urinary excretion rate:
(filtration rate-reabsorption)+secretion=excretion
-what comes out into proximal tube, minus what gets taken back out into peritubular, plus what comes out of peritubular.
are waste products generally filtered or reabsorbed?
filtered, Thus a high Glomerular filtration rate (GFR) ensures rapid removal form the blood
T/F for most substances, filtration rates and reabsorption rates are very high compared to the proportion which is excreted. Thus small changes in filtration or reabsorption translate to large changes in excretion?
True
how much water do we excrete per day usually?
1 liter
how much sodium do we excrete per day?
150 mmol
how much glucose do we excrete per day?
0 g
how much creatinine do we excrete per day?
1.8 g
the glomerular capillary membrane is selective for what?
small positively charged molecules