P6 Describe the structure and function of the Respiratory System

• You need…1. A labelled diagram

2. A description of each of the components.

3. Describe the mechanics of breathing (inspiration and expiration)

4. Describe gaseous exchange in the alveoli. Use a diagram.

Trachea(wind pipe)

Bronchus

Bronchioles

Alveoli

LungIntercostal

muscles

Ribs

Diaphragm

The Respiratory SystemThe Respiratory SystemA labelled diagramA labelled diagram

Inspiration (breathing in)

When we breathe in (inspiration):• oxygen moves through the nose and mouth• the inter-costal muscles move the rib cage up

and out• the diaphragm contracts and flattens to give

more room for the lungs to fill with oxygen.

Inspiration (breathing in)

When we breathe in, oxygen moves through the:

Alveoli are little air sacs where the exchange of gases occurs

Trachea

To the bronchi, that splits into the left and right lungs

Bronchioles are smaller branches that can be found at the end of the bronchi

Expiration (breathing out)

When we breathe out:• the rib cage relaxes as the inter-costal muscles

relax• the lungs deflate• the diaphragm relaxes and becomes larger in

its shape.

When we breathe out, carbon dioxide moves from the:

Alveoli

To the bronchioles and then towards the trachea through the bronchi

As we breathe out the carbon dioxide is expelled through the mouth and nose

Gaseous Exchange

Gaseous exchange is the exchange of oxygen and carbon dioxide over the breathing surface.

alveolioxygen (O2)

terminal air ducts

carbon dioxide (CO2)

capillary