UNIT 2:NUTRITION

Systems related to nutrition

1) DIGESTIVE SYSTEM (It takes nutrients from the food we eat)

2) RESPIRATORY SYSTEM (It takes oxygen from the air we breathe)

3) CIRCULATORY SYSTEM (It transports the nutrients we eat and the oxygen we breathe to all our body)

4) EXCRETORY SYSTEM (It removes waste substances from the body)

1. THE DIGESTIVE SYSTEM

HOW DOES THE DIGESTIVE SYSTEM WORK?

Food is digested in three stages:

1. DIGESTION:

The mouth, esophagus and stomach help

our body digest the food we eat.

2. ABSORPTION:

The small intestine absorbs the nutriens

from the food.

3. ELIMINATION:

The large intestine and rectum

transform the undigested solids

into faeces.

2. THE RESPIRATORY SYSTEM

Bronchioles: These are small tubes inside the lungs. At the end of each bronchiole, there are tiny sacs called alveoli.

1. When blood enters the heart, it’s

pumped to the lungs. In the lungs, the red blood cells

absorb oxygen.

2. That oxygenated blood is pumped to the heart again. The

heart pumps this oxygenated blood around the body.

3. THE CIRCULATORY SYSTEM

What`s blood made of?Our blood contains three types of cells.

Red blood cells absorb oxygen in the lungs and transport it

to the rest of the body.

White blood cells fight infections in our

body.

Plateletshelp to stop bleeding. They cover the cuts

and form a scab.

4. THE EXCRETORY SYSTEM

2. When the eardrum vibrates, it

makes the small bones vibrate too.

3. The cochlea detects the

vibrations and produce nerve impulses. The

auditory nerves transmit these impulses to the

brain.