BODY  SYSTEMS

Nutrition is related to the obtaining of substances our body needs to survive. Several body systems are involved in this task:

• food: to obtain nutrients. Digestive system.
• air to obtain oxygen. Respiratory system.
• blood to transport nutrientes and oxygen. Circulatory system.
• urine to eliminate waste. Excretory system.

RESPIRATORY  SYSTEM

We use our respiratory system to breathe in air.

• air enters through our nose and mouth when we breathe in
• air goes down the trachea
• air is divided in the bronchi and enters the lungs
• in the lungs oxygen passes into the blood
• carbon dioxide that returns to the lungs is expelled when we breathe out

 

CIRCULATORY SYSTEM

The circulatory system moves blood around our body. This movement is called blood circulation.

Blood carries oxygen and nutrients and it also collects waste.

Blodd travels through blood vessels pumped by the heart. We can find:

• arteries: carry blood away from the heart
• veins: carry blood into the heart
• capillaries: connect arteries and veins

 

EXCRETORY SYSTEM

The excretory system eliminates the waste from the blood.

• kidneys filter the blood and reabsorb useful nutrients. Waste and water form urine.
• urine goes down the ureters to the bladder
• urine is expelled trough the urethra