ES. control of water and electrolytes Flashcards
how are gains and losses of water normally balanced?
gains:
water ingested
water formed in metabolism
losses:
excretion
evapouration
which factor in water balance is under homeostatic control?
urinary excretion
name parts of the kidney?
glomerulus
proximal convoluted tube
loop of henle
distal convoluted tube
collecting ducts
what is the rate of renal blood flow?
1200ml/min
what does the glomerulus do?
filtration of plasma
what is the glomerular filtration rate (GFR)?
120 ml/min
what opposes the capillary hydrostatic blood pressure?
plasma protein oncotic pressure
what is reabsorbed in the proximal convoluted tubule?
ions
small organic molecules
what happens in the proximal convoluted tubule?
obligatory reabsorption of 60 to 70% of the glomerular rate
secretion of H+
what is the loop of henle important for?
concentration of urine
what does the concentration of urine depend on?
active transport pumps in thick, ascending limb of the loop of henle
what happens in the distal convoluted tubule?
reabsorption of water (Na+, Cl+ and Ca2+)
secretion of H+ and K+
what is the activity in the distal convoluted tubule controlled by?
- aldosterone
- atrial natriuretic hormone
- ADH
- parathyroid hormone
how do collecting ducts reabsorb water?
under influence of ADH
how does water move in collecting ducts?
along osmotic gradient created by counter current exchange mechanism
what is the main control of water?
vasopressin
- antidiuretic hormone
where is antidiuretic hormone produced and released?
produced in hypothalamus and released from posterior pituitary gland
how is ADH secretion increased?
decreased ECF volume
increased ECF osmolarity
what effect does ADH have on blood vessels?
constriction
where dos majority of the control of electrolytes operate?
kidney
what does renin- angiotensin- aldosterone system do?
- promotes reabsorption of Na+ and water
- exchange for K+ and H+
what does Atrial netriuretic hormone do?
increase excretion go Na+
what hormone regulated potassium?
aldosterone
what does hypo secretion of antidiuretic hormone do?
diabetes insipidus
large volumes of insipid urine
what does hyper secretion of antidiuretic hormone do?
syndrome of appropriate ADH
excess ADH = water retention
what are k salts used in toothpaste?
desensitise hypersensitive dentine
