General - Excretion

excretion definition

the removal of toxic materials / the waste products of metabolism and excess materials

metabolism definition

the chemical process going on in the body

egested meaning

the removal of undigested food

what materials are excreted

excess proteins or amino acids are broken down to produce a nitrogen waste called urea

kidneys in excretion

• removes urea, water and ions from the blood → regulate body water content

  • urine

• regulate the volume and concentration of urine

skin in excretion

removes water and salt by sweating

lungs in excretion

removes carbon dioxide and water from the blood when we breathe

ureter description

tube connecting the kidney to the bladder → transfers the urine from the kidney to the bladder

bladder description

urine is stored here via the ureter

urethra description

• tube that connects the bladder to the exterior; where the urine is released

• the wall of the urethra contains ring shaped muscles called sphincter muscles

urinary system

1. blood to the kidney is travelled at high pressure - renal artery from the body’s main artery (oxygenated blood)

2. kidneys act like filters, removing urea

3. the ‘cleaned’ blood passes out through the renal vein (deoxygenated)

4. the urea is diluted with water - urine

5. urine is sent to the bladder for storage through the ureter

6. once the bladder fills, the urine passes out the urethra

general structure of the kidney

• contains a cortex and medulla

• renal artery carries blood to the kidney

• renal vein carries blood away from the kidney

• contains thousands of nephrons → filters

cortex

contains many tiny blood vessels

medulla

has bulges called pyramids