Class notes Life Sciences (Biology) Life Sciences, ISBN: 9781776113316

Biology : The excretory system



Excretory Organ Waste excreted substance Chemical excreted

Kidneys Nitrogenous waste Urine Water
Non-nitrogenous Salts
waste Urea
Uric acid
Creatinine

Lungs CO2 product of Exhaled air CO2 and water
cellular respiration

Skin Helps maintain body Sweat Water
temperature( secretio Salts
n =sweat) Urea
creatinine

Gut/Colon Into small intestine faeces bile pigments
=defaecication Cholesterol

* Liver Not an excretory Bile pigments Bile pigments broken
organ down from
Urea= excess amino haemoglobin
Many waste products acids
formed in liver

Nitrogenous waste
Non-nitrogenous
waste

, The Urinary System

-maintains homeostasis



Structure Function

Inferior Vena Cava Carries purified deoxy blood to heart

Kidneys Filter nitrogenous waste out of blood
Regulate water/salt balance(osmoregulatory)


Aorta Carries oxy blood with nitrogenous waste to
the body cells

Motor nerve Stimulates contraction of bladder wall

Sphincter muscle Controls flow of urine

urethra Carries urine to exterior

bladder Stores urine

ureter Carries urine to bladder

Renal vein Carries purified blood to inferior Vena Cava

Renal artery Carries oxygen and nitrogenous waste to
kidney

*Renal gland Secrets aldosterone( role in urine formation)




The Kidney