This document discusses the four main body systems involved in nutrition: the digestive system, which breaks down food; the respiratory system, which provides oxygen; the circulatory system, which transports nutrients and oxygen; and the excretory system, which removes waste. It describes the key functions and components of each system, including how the digestive system breaks food down into nutrients, and how the circulatory system uses the heart and blood vessels to circulate oxygenated blood throughout the body.

1. UNIT 2:
NUTRITION

2. 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)

3. 1. OUR DIGESTIVE SYSTEM

4. 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.

5. ESSENTIAL NUTRIENTS
Our bodies need:
We eat and drink to get these nutrients.
Vitamins and minerals are micro-nutrients that our
bodies need but cannot make, so we have to get
them from the food we eat.
proteins fatscarbohydrates
minerals vitamins water

6. 2. OUR RESPIRATORY SYSTEM
Bronchioles: These are
small tubes inside the
lungs. At the end of each
bronchiole, there are tiny
sacs called alveoli.
Diaphragm: this is a muscle under the lungs.
It contracts and relaxes.

7. 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. OUR CIRCULATORY SYSTEM
THE HEART

8. THE BLOOD VESSELS

9. THE BLOOD
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.
Platelets
help to stop bleeding. They
cover the cuts and form a scab.

10. Circulation

11. 4. OUR 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.