function and physiology of genitourinary system Flashcards
what is the name of the process where kidneys filter blood plasma under pressure ?
ultrafiltration
what is the name of the process where useful substances are reclaimed ?
selective reabsorption
what is kidney function important for ?
removing waste
homeostasis
how many nephrons are there per kidney ?
1000000 per kidney
where is urea formed ?
from the metabolism of amino acids in the liver
what is the chain of the break down of amino acids ?
amino acids ——-> ammonia ———-> urea
why is ammonia converted into urea ?
less toxic for excretion
what is a waste product of normal muscle turnover ?
creatinine
what organ removes creatinine ?
kidney
travels in blood to kidney
what does renal failure results in ?
accumulation of creatinine in serum
how do you know renal failure may occur ?
levels of creatinine in the blood
what does the nephron consist of ?
bowman’s capsule
proximal convoluted tubule
loop of Henle
distal convoluted tubule
collecting duct
what is the glomerulus ?
is a capillary bed preceded and followed by arterioles
what are capillary typically followed by ?
venules
what is ultrafiltration ?
particles are filtered mainly according to size
cells and large proteins are too big to fit through so remains in blood
what is glomerular filtration rate (GFR)?
the amount of liquid passing from the glomerulus to bowman’s capsule via ultrafiltration
what is average GFR per minute ?
100ml per minute
what can GFR measure ?
kidney health
what is paracellular reabsorption ?
reabsorbed between cells
what is transcellular reabsorption ?
reabsorption through cells
name 4 types of transport
- diffusion
2.osmosis
3.active transport
4.cotransport
what are the three environments separated by cell membrane when discussing solute movement ?
- tubular lumen
2.epithelial cell - interstitial fluid
what are ATPases ?
active transport using ATP
what are cotransporters ?
transporters which move two substances using the energy of one of them
what are channel proteins used in ?
facilitate diffusion / osmosis
where is the site of maximal reabsorption ?
proximal convoluted tubule
how does the loop of Henle maximises reabsorption of water ?
has an ascending and descending limb
has a counter-current system
what happens to ions (Na+ and Cl- ) in the ascending limb ?
actively transported
making the surrounding interstitial space hypertonic
hypertonic tissue / plasma near the descending limb draws water out by what process ?
osmosis
is the distal convoluted tubule permeable or impermeable to water ?
impermeable
what ion is reabsorbed in response to parathyroid hormone ?
Ca2+
is the collecting duct permeable or impermeable to water ?
impermeable
when does the collecting duct reabsorbs water ?
in response to ADH
What are the two types of regulation in kidney function ?
control of quantity of substance reabsorbed
control of volume of liquid filtered by glomerulus
how much glucose should be in the urine
near 0
all glucose should have been reabsorbed
what is the equation to work out the amount excreted ?
Amount excreted = amount filtered - amount reabsorbed
if there is too much glucose in the filtrate , what effect does this happen on reabsorption
not all can be reabsorbed
what does osmoreceptors detect ?
increase in blood osmolality and trigger release of ADH
What is ADH produced by ?
neurosecretory cells in hypothalamus
where releases ADH ?
released from posterior pituitary gland
what does ADH enable ?
reabsorption of water from the collecting duct
does ADH increase or decrease uptake of water ?
increase uptake of water
where is aldosterone released from ?
adrenal gland
where does aldosterone act on ?
distal convoluted tubule
what effect does aldosterone have on sodium and calcium uptake ?
increases uptake by activating Na+ / K+
what is renin produced from ?
prorenin
what does renin do to blood pressure ?
increases blood pressure
what is renin-angiotensin-aldosterone system ?
- Stimulus: Decreased bloodflow through kidneys
- Renin produced in kidneys (converted from prorenin in the blood)
- Results in angiotensin I production (from angiotensinogen)
- Angiotensin I converted to Angiotensin II in lungs (Angiotensin-Converting
Enzyme – ACE) - Angiotensin II increases blood pressure directly (vasoconstriction, sympathetic
activity, stimulates thirst) and by inducing aldosterone and ADH release (which
increase blood volume) - Increasing blood pressure increases bloodflow
what is vitamin D active form and where is it converted ?
calcitrol
kidney
where does vitamin D3 get produced ?
in the skin from cholesterol when exposed to uv radiation
