Osmoregulation Flashcards
what is the cortex of the kidney
it is the kidneys outer layer protecting the structures underneath
what is the Nephron
it extends from the cortex to the medulla and are the site of ultrafiltration, urine formation and selective reabsorption
what is the renal tube
the tube of each nephron is lined with microvilli in order to increase surface area for absorption
what is ultrafiltration
it is carried out in the bowman’s capsule
everything except erythrocytes and large proteins are forces out of the blood into the bowman’s capsule due to high pressure caused by a difference in diameter of the afferent and efferent arterioles
afferent arteriole is much wider
what is selective reabsorption
water, amino acids, glucose and ions are selectively absorbed first in the proximal convoluted tube
after the PCT water is absorbed into the blood via osmosis in the ascending limb of the loop of Henle
ions are reabsorbed in the ascending limb of then loop of Henle
how is urine excreted
it is formed in the collecting duct. it then travels down the ureters to the bladder, and it then passes through the urethra to be excreted
what are osmoreceptors
they are in the hypothalamus and they detect water composition in the blood.
if water levels drop it secretes the Antidiuretic hormone and signals for the release of the posterior pituitary gland into the bloodstream
what happens when ADH reaches the cells inn the ducts
they become more permeable to water therefore enabling them to reabsorb more water
what does increased ADH concentration cause
it constricts the blood vessels inducing a higheer blood pressure
What happens in the loop of henle
Water is reabsorbed into the blood via osmosis in the descending limb and ions are reabsorbed in the ascending limb
What is aldosterone
It maintains electrolyte concentration in extracellular fluids
It does this by enhancing sodium reabsorption and potassium secretion
What does angiotensin 2 do
It causes an increase in ADH and causes aldosterone release
