1. Respiratory System
Respiratory Pathway

2. Respiratory System
The respiratory system is made up of the system of air tubes that carry air to and from the lungs

3. Nasal Passage
Air enters the respiratory system through nostrils, then into hollow spaces called nasal passages
Nasal passages are lined with little hairs called cilia that filter the air

4. Pharynx
The pharynx is commonly called the throat

5. Larynx The larynx is commonly called the voice box
The vocal cords are stretched across the inside of the larynx
The epiglottis blocks food from entering the larynx

7. Trachea The trachea is commonly called the windpipe
It is lined with ciliated mucous membranes

8. Bronchi
In the middle of the chest, the trachea divides into two cartilage-ringed tubes that enter the lungs called bronchi

10. Bronchioles Bronchioles are the finest branches of the bronchial tubes
Each bronchiole ends in an air sac called an alveolus

11. Alveoli
Alveoli are small cup-shaped cavities where gas exchange takes place
They look like a bunch of grapes
The lungs contain about 300 million alveoli

12. Breathing
Inhalation – is the active phase that draws air into the lungs
Exhalation – is the passive phase that forces air out of the lungs

13. Diaphragm
The diaphragm is a dome-shaped muscle at the bottom of the rib cage.

14. Breathing is an involuntary process controlled by the medulla in the brain
When the level of CO2 increases in the blood, the rate of breathing is increased

15. Inhalation The ribs are pulled up and out
The diaphragm is pulled downward
The chest cavity become larger and the lungs expand

16. Exhalation The ribs drop and relax
The diaphragm relaxes and moves upward
The chest cavity becomes smaller