Excretory System Introduction & Kidney

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Remember Recall that the numerous reactions take place in the cells in the body These chemical reactions that take place within the body which are necessary for the maintenance of life are known as metabolism Metabolism produces metabolic wastes.

Wastes that chemical reactions produce: These chemical reactions produce numerous waste products. For example: Carbon dioxide (from respiration) Excess water (from respiration) Urea (breakdown of proteins) Bile pigments (breakdown of red blood cells)

The Excretory System of Human Beings Human beings have an excretory system which consists of: Kidneys Skin Liver Lungs

Note Well Excretion must not be confused with the removal of the faeces, that is defaectaion from the anus Defaection refers to the removal of undigested food from the body through the anus However, excretion refers to the removal of the waste products of metabolism of the body

Diagram of the Human Excretory System

Parts of the excretory system Kidney Ureter Bladder Urethra

Kidney – 3 main parts cortex, medulla, pelvis

Functions of the kidney Filter waste materials from the blood Controls the amount of water in the body