2. Respiratory system (RS) is one of the vital systems in the body
Respiratory system (RS) is one of the vital systems in the body. RS can be divided to:
Upper respiratory tract
lower respiratory tract

4. Upper respiratory tract
Nose, mouth
Nasal cavity
Pharynx
Larynx
Epiglottis

5. Lower Airway
Trachea
Bronchi
Alveoli
lung

6. Nose, mouth and nasal cavity: pass air to the pharynx
Pharynx located dorsal to the Nasal Cavity but superior to the Larynx. it is a common pathway for food and air. It divided to:
Nasopharynx
Oropharynx
laryngopharynx

7. epiglottis acts as a lid or flap that covers the larynx and trachea (airway) so food does not enter the lungs.

11. Bronchi
Single one called bronchus c-shaped cartilage rings with smooth muscle each bronchi divides into bronchioles terminate in air sacs called alveoli

13. Alveoli
air sacs
alveolar wall membranes one cell thick and surrounded by capillaries
gaseous exchange takes place here

15. Lung It is the primary organ of the respiratory system
They fill the thoracic cavity (along with the heart) from clavicle to the diaphragm
Right lung has three lobes
Left lung Has two lobes, which allows room for the heart
Surrounded by a serous membrane called the Pleura
Has a visceral and a parietal layer

17. Pleural membrane each lung enclosed in pleura
parietal pleura lining the pleural cavity
visceral pleura cover the lung
There is a lubricating fluid between the two membranes

18. Diaphragm muscle separating chest and abdomen.
inspiration, diaphragm contracts and increases thoracic space so air will flow in.
expiration, diaphragm relaxes and decreases thoracic space so air will flow out.

20. MUSCLES OF RESPIRATION
Inspiratory muscle:
Diaphragm (contraction)
external intercostal muscle
accessory muscle of inspiration
Expiratory muscle
Internal intercostal muscle
Muscles of the abdominal wall can be used both in inspiration and expiration

24. Breathing rate
At rest: breaths / minute During exercise: at maximum exercise in adults