bio homeostasis excretory Flashcards
excretory system
eliminated waste
not like digestiveki
kidneys
key organs in excretory
also regulates blood ph, salt concentrations and secretes some hormones
renal cortex
outer area of kidney
renal medulla
middle of kidney
renal pelvis
central area of kidney
nephrons
tiny filtration units in kidneys
filter
top of each nephron the bowmans castle surrounds a capillary bed called glomerulus
tubule
attatched to bowmans castle
long slender hairpin loop of tubing
reabsorbtion of useful substances
proximal tubule
loop of henle
distal tubule
duct
larger tubule that collects filtrate from nephron and returs water to blood
filtrate
contains some water and urine
urine formation
glomerular litration
tubular reabsorbtion
secretion
water reabsorbtion
glomerural filtration
blood travels from renal artery to afferent arteriole then to glomerulus
forced by blood pressure through capillaries in glomerulus to bowmans capsule
water and solutes leave body and become filtrate
blood leaves glomerulus through efferent arteriole
tubular reabsorbtion
approx 65% filtrate reabsorbed into blood through passive and active transport
na, k and more actively transported from proximal tubule back into blood
negative ions follow water and osmosis
continues through loop of henle
secretion
h and k ions actively secreted from blood to distal tube
reabsorption through collecting duct
more water is reabsorbed by osmosis back into blood
water/salt balance regulation
kidney
helps regulate blood pressure and volume
if blood too concentrated/dehydrated, hypothalamus stimulates posterior pituitary gland to release adh
osmoreceptor
cells in hypothalamus that monitor osmotic pressure in blood
adh
increases permability of cells in distal tubule and collectong duct causing more water to be reabsorbed into blood
if na levels too low in blood
kidney detects
kidney relleases renin which activated adrenal cortex to release aldosterone causing exretion of k ions and reabsorbtion of na
causes more reabsorbtion of water in blood
regulating blood ph
acid base buffer system
respiration centre
kidneys
acid base byffer system
carbonic acid/carbonate ion buffer
respiration centre
remove co2 from body
kidneys (blood ph)
can extrete h and reabsorb hco3 and can excrete h through ammonia
blood oxygen level
if o2 too low, kidneys release hormone epo to stimulate bone marrow to make more rbc
blood calcium levels
if ca2 levels too low, parathyroid gland releases pth to stimulate kidney to release calcitriol to stimulate cell of digestive tract to absorb more ca2 from food
uti
bacterial infection in kidney, ureter, bladder or urethra
pain during urination;/often/blood in
antibiotics
kidney stones
small stones develop in renal pelvis of calcium phospate proteins
passed through urinary tract, may be broken up by ultrasound
renal insuffiiency
lack of kidney function caused by
infection, injury, highblood pressure, diabetes
dialysis to clean blood
for kidney failur, transplant
