Excretory System

It consists of the urinary system and the sweat glands.

THE URINARY SYSTEM

The urinary system is formed by the kidneys, the ureters, the bladder, and the urethra. 

The filtered waste substances in the kidneys are mixed with water to make urine. This leaves the kidneys through the ureters and accumulates in the bladder. When the bladder is full, urine is expelled from the body through the urethra.

Excretory system

Kidneys: these are two bean-shaped organs that filter the blood and return the clean blood back to the circulatory system.

Bladder: This is a muscular cavity where urine is stored. It is shaped like a bag. 

Ureters: these are two tubes that link the kidneys to the bladder.

Urethra: this is a tube which links the bladder to the exterior. 

Kidneys

Sweat glands

When we do sport or when we get hot, we sweat. Sweat is a mixture of water and waste substances, and it is produced in the sweat glands in your skin.

Each sweat gland is formed by a large tube. The lower end of the tube acts as a filter, and at the top of the tube there is a pore that opens up to the outside. 

Sweat gland

The functions of the sweat glands are: 

a) To filter blood. They collect waste substances and water from the cells and expel them from the body as sweat.

b) To control body temperature. When it is hot, we sweat. This causes our body to cool down. 

Here is a video that you can watch: