Excretion Flashcards
What is a waste product of respiration?
carbon dioxide
How is carbon dioxide removed from both plants and humans?
-stomata
-lungs
What are the organs of excretion?
lungs, kidney, skin
Where is urea removed?
kidneys + skin
Where is CO2 removed?
lungs - via blood plasma
How is urea formed?
deamination
What is the process of deamination?
- amino acids filtered into liver
- excess amino acids broken down into carbohydrates + ammonia
- ammonia (toxic) is converted into urea
- amino acids + urea are released back into blood stream - via hepatic vein
The kidney contains millions of tiny structures called…
nephrons - filter the blood
Why is there high pressure in the capillaries forming the glomerulus?
efferent arteriole (exit) has a smaller diameter than the afferent arteriole (entrance)
How does the high pressure in the glomerulus help ultrafiltration?
forces small molecules (e.g. urea, glucose, amino acids) out of capillaries of the glomerulus and into BOWMAN’S CAPSULE
What molecules remain in the blood during ultrafiltration?
proteins + red blood cells - too big to fit across capillary walls
What controls the molecules entering the Bowman’s capsule?
basement membrane - surrounds capillaries of glomerulus
How are the cells lining the proximal convoluted tubule specialised for their function?
folded membrane - increase SA, many mitochondria - ATP for active transport
During selective reabsorption water moves…
into blood via osmosis
During selective reabsorption harmful substances move…
from blood into filtrate
