The Kidneys Flashcards
what is one of the main functions of the kidneys?
excrete waste prod e.g. urea
kidneys also regulate…
water potential of blood
define cortex?
outer layer of kidneys
define the process of ultrafiltration?
- as blood passes out of cortex of kidneys
- substances filtered OUT of blood
- into long tubules that surround capillaries
what happens to useful substances like glucose and RIGHT AMOUNT of water?
what is this known as?
reabsorbed back into blood
SELECTIVE REABSORPTION
blood is filtered at start of…
nephrons
define nephrons?
- long tubules
- along with bundle of capillaries
- where blood = FILTERED
how many nephrons in each kidney?
1 million
blood from renal artery enters..
- smaller arterioles
- in cortex of kidney
each arteriole splits into what?
glomerulus
define bowmans capsule?
bundle of capillaries looped inside hollow ball
where does ultrafiltration take place?
bowmans capsule
the arteriole that takes blood INTO each glomerulus is called what?
AFFERENT arteriole
the arteriole that takes FILTERED blood AWAY from glomerulus is called what?
EFFERENT arteriole
difference between afferent and efferent arteriole?
- efferent SMALLER in diameter
- so blood in glomerulus under HIGH PRESSURE
what does the high pressure cause?
- forces liquid and small mol in blood
- OUT of capillary
- into bowmans capsule
what are the 3 layers liquid and small molecules must pass through to get into the bowmans capsule and enter nephrone tubules?
- capillary wall
- basement membrane
- epithelium of bowmans capsule
what happens do larger molecules like proteins and blood cells?
- cant pass through
- STAY in blood
the substances that enter the bowmans capsule are known as what?
glomerular filtrate
process of ultrafiltration
- high hydrostatic pressure
- afferent arteriole is wider than efferent arteriole
- small mol forced out into bowmans capsule = filtrate
- large mol dont fit through gaps (gaps in capillary wall, basememnt membrane and epithelium of bowmans capsule)
process of selective absorption?
- ultrafiltration makes glomerular filtrate
- capillaries wrap around nephron and useful substances reabsorbed into blood
- PCT absorbs most of mol
- microvilli inc surface area for reasbsorption
what does PCT stand for?
proximal convoluted tubule