Respiratory System

To respire means to breathe.Respiration = Breathing

Get into Expert Groups

• Yellows: The nose

• Reds: The mouth as an Alternative

• Greens: The windpipe

• Blues: The lungs

The Nose

• Air is taken into and removed

from the body through the nose.

• The hairs in the nostrils help to

remove the dirt and dust that is in

the air.

Mucus lining in nasal cavity

Nasal hairs in nostrils

The Nose

• The moisture of the mucus

lining in our nasal cavity also

helps to trap contaminating

particles.

• This helps to ensure that the air

we breathe in is clean and free of

dust.

The Mouth as an Alternative

•When someone gets infected with

influenza (flu), his nose is often stuffed up

by mucus. Thus, air cannot enter the body

through the nose.

•We can still breathe through our mouth.

•However, the mouth is not a

respiratory organ.

•So, the air entering the mouth will

not be filtered, and its temperature

will not be controlled.

The Mouth as an Alternative

The Windpipe

•The air we breathe in through our nosethen moves down through the windpipe (trachea).

•The windpipe branches into two air tubes (plural bronchi or singular bronchus).

•The windpipe and air tubes transport the air to and from the lungs.

windpipe

air tubes

lungs

•The windpipe is made up of many C-

shaped rings that reinforce the front

and sides of the windpipe to protect

and maintain the airway.

•The trachealis muscle connects the

ends of the incomplete C-rings and

contracts during coughing, reducing

the diameter of the windpipe to

increase the rate of air flow.C-shaped rings

The Lungs

•The windpipe and air tubes transport the air to and from the lungs.

•The windpipe branches into two air tubes (plural bronchi or singular bronchus).

•Each air tube leads to one of the lungs.

windpipe

air tubes

lungs

•The air tubes (or bronchi) will branch out even more into small tubes, called bronchioles, in the lungs.

•The bronchioles of the air tubes will end at the tiny air sacs called alveoli .

The Lungs

14

•The bronchioles of the air tubes will end at the tiny air sacs called alveoli .

•Each alveolus is wrapped up in a fine mesh of capillaries (blood vessels).

•The blood in the capillaries transports oxygen to all parts of the body and brings carbon dioxide from all parts of the body.

•The gaseous exchange between oxygen in the air we breathe in and the carbon dioxide in the blood takes place between the capillaries and alveoli.

15

16

lungs

• This is how gaseous exchange takes place during respiration.

• When oxygen in the inhaled air reaches the

lungs, it is absorbed into the blood and transported to all parts of the body.

• Carbon dioxide is also transported by the blood to the lungs. It is then removed from the body during breathing.

The Lungs

17

Think about it…

The air we breathe in has more oxygen and less

carbon dioxide and water vapour than the air we

breathe out.

Do you agree with Joe? Why?

18

Think about it…

How does having many air sacs in the lungs help to make the exchange of gases efficient?

air sacs

blood vessels