Excretion Flashcards
What is excretion?
The removal of toxic waste substances which have been made by cells
What is egestion?
The removal of faeces from the body
Why do excess amino acids need to be broken down?
Humans cannot store excess amino acids (unlike with carbohydrates and lipids)
Why do amino acids need to be removed from the body?
Because what they are broken down into is toxic
Where is urea made?
Liver cells
What are the 3 main sections of the kidney called?
cortex, medulla and pelvis
What is the job of the nephron?
To filter the blood
What is the job of the kidney?
filters the blood + removes any excess materials and passes them to the bladder to be excreted
Is the size of the artery at the exit of the glomerulus bigger or smaller than at the entrance, and what effect does this have?
Smaller at the exit, causes a build-up of pressure
What is the effect of the pressure in the glomerulus?
Forces small molecules (urea, glucose, water and salt) across into the Bowman’s capsule
What is the solution in the Bowman’s capsule called?
Glomerular filtrate
What happens to larger molecules during ultrafiltration?
Too big to pass through cell membrane, stay in the blood
What is the job of the proximal convoluted tubule?
To reabsorb glucose and salt - creates an osmotic potential (80% water)
State the pressure of the blood from the renal artery
High pressure - helps push things out of the blood
How much water is reabsorbed in the loop of Henlé?
5%
