Water and Electrolytes Flashcards
what gains water in the body
water ingested and water formed in metabolism
what loses water
urine, faeces
sweat and expired air
do we gain or lose more water every day
even
what part of water balance is under homeostatic control
urination
what are the features of the kidney
glomerulus
proximal convoluted tubule
loop of henle
distal convoluted tubule
collecting ducts
label this
what does the glomerulus do
involved in renal blood flow and filtration of plasma
what is the renal blood flow rate
1200ml per minute
what is ithe glomerular filtration rate
120ml per minute
what are the filtration pressures
pressures that vary along the length of glomerular capillary form afferent arterioles
what is the capillary hydrostatic pressure
45-50mmHg
what is the plasma protein oncotic pressure
25-35mmHg
what is the capsular pressure
10mmHg
what is the net filtration pressure
10-15mmHg
what does the proximal convoluted tubule absorb
60-70% of the glomerular filtrate
what is absorbed in the proximal convoluted tubular
ions and small organic molecules
what is secreted in the proximal convoluted tubule
hydrogen ions
how are things absorbed in the proximal convoluted tubule
active transport and facilitated diffusion
is there any control of reabsorption in the proximal convoluted tubular
very little
what occurs in the loop of henle
this is important for concentration of urine
length of the loop correlates with the ability to concentrate urine
what is the countercurrent exchange mechanism
this is how urine is concentrated in the loop of henle, and the concentration depends on active transport pumps in the thick ascending limb of the loop of henle
what is the net reabsorption of liquid in the loop of henle
10%
what is absorbed in the distal convoluted tubule
sodium
chloride
calcium
what is secreted in the distal convoluted tubule
hydrogen
potassium
what hormones control the activity of the distal convoluted tubular
aldosterone
atrial natriuretic hormone
ADH
parathyroid hormone
what happens in the collecting ducts of the kidney
water reabsorpiton, under the influence of ADH, and there are membrane channels for water reabsorption
how does water move along the collecting ducts
along osmotic gradients created by the counter current exchange mechanism