1. Unit 3.3 The Respiratory System

2. Function of the Respiratory System
Oversees gas exchanges (oxygen and carbon dioxide) between the blood and external environment
Exchange of gasses takes place within the lungs in the alveoli(only site of gas exchange, other structures passageways
Passageways to the lungs purify, warm, and humidify the incoming air
Shares responsibility with cardiovascular system

3. Organs of the Respiratory system
Nose
Pharynx
Larynx
Trachea
Bronchi
Lungs – alveoli

4. Upper Respiratory Tract
Figure 13.2

5. Anatomy of the Nasal Cavity
The cavity is lined with respiratory mucosa
Moistens air
Traps incoming foreign particles
Function of the sinuses
Lighten the skull
Act as resonance chambers for speech
Produce mucus that drains into the nasal cavity

6. Structures of the Larynx
Thyroid cartilage
Protrudes anteriorly (Adam’s apple)
Epiglottis
Routes food to the larynx and air toward the trachea
Vocal cords (vocal folds)
Vibrate with expelled air to create sound (speech)

7. Trachea (Windpipe) & Bronchi
Lined with ciliated mucous cells
Beat continuously in the opposite direction of incoming air
Expel mucus loaded with dust and other debris away from lungs
Right bronchus is wider, shorter, and straighter than left
Bronchi subdivide into smaller and smaller branches called bronchioles

8. Lungs Top of the lung is the apex, the bottom is the base
Left lung – 2 lobes
Right lung – 3 lobes (because the heart is on the left)

9. Bronchioles & Alveoli Bronchioles - smallest branches of the bronchi
Alveoli – site of gas exchange

10. Respiratory Membrane (Air-Blood Barrier)

11. Inspiration

12. Exhalation

13. Lung Capacity

14. Non-respiratory Air Movements
Can be caused by reflexes or voluntary actions
Examples
Cough and sneeze – clears lungs of debris
Laughing
Crying
Yawn
Hiccup