1. THE RESPIRATORY SYSTEM

2. THE RESPIRATORY SYSTEM
O2 is essential for survival and every one of our cells need O2 to live.
The air we breath contain about 21% O2.
The respiratory system brings O2 into the lungs and eliminates CO2. This process is called respiration.
This process involves inhalation and exhalation (or inspiration and expiration).

3. THE RESPIRATORY SYSTEM
The organs of the respiratory system include the:
Nose
Pharynx
Larynx
Trachea
Bronchi
Lungs
Alveoli

4. THE RESPIRATORY SYSTEM
The Nose
The only external visible part of the respiratory system.
During inhalation, air enters the nares (nostrils)
The mucosa lining of the nasal cavity (interior of the nose) warms and moistens the air as it enters.
The mucous in the nose also helps to trap bacteria and debris.
Cilia moves this debris toward the pharynx where it is swallowed and digested by gastric juices

5. THE RESPIRATORY SYSTEM
The Pharynx
Also called the throat
A muscular passageway about 5 inches long
It is a common passageway for food and air
Air enters through the nasopharynx, descends through the oropharynx and then into the larynx.
Food follows the same passageway, but, instead of going into the larynx it goes into the esophogus.

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7. THE RESPIRATORY SYSTEM
The Larynx
Also called the voicebox, it is located below the pharynx and made of hyaline cartilage
Channels air and food along the proper route.
Contains a spoon shaped flap called the epiglottis, which protects the larynx from food entering it. (when we breath, it is open, when we swallow food, it closes)
The epiglottis only works when we are conscious.

8. THE RESPIRATORY SYSTEM
The Trachea
Also called the windpipe, the trachea is about 4 inches long and made of C-shaped rings of hyaline cartilage.
Air enters the trachea from the larynx.
The trachea is lined with cilia which move mucous, bacteria and debris away from the lungs so it can be swallowed or spat out.
FYI – smoking destroys cilia

10. THE RESPIRATORY SYSTEM
THE BRONCHI
The trachea divides into a rt. and lt. primary bronchi.
The rt. bronchus is wider, shorter, and straighter than the lt.
By the time air reaches the bronchi, it is warm, cleaned of impurities and humidified.
Each bronchi subdivide into smaller and smaller branches (secondary and tertiary bronchi).
The smallest bronchi are called bronchioles
Bronchioles then become terminal bronchioles and then alveoli
Alveoli are the sites of gas exchange.

11. THE RESPIRATORY SYSTEM
Inside the alveoli there are capillaries. This is where then exchange of O2 and CO2 takes place.
Blood in the capillaries picks up the O2 from the alveoli and then the blood is returned back to the left side of the heart and pumped throughout the rest of the body.
The alveoli pick up the CO2 for exhalation.

13. THE RESPIRATORY SYSTEM
THE LUNGS
The main component of our respiratory system is our lungs.
The rt. and lt. lung are divided into lobes. The Rt. has 3 lobes and the Lt. has 2.
Each lung is covered by a sac called the pleura. The pleural fluid in the pleural sac prevents the layers from rubbing together.
Our diaphragm separates our abdominal cavity from our lungs.
The ribs protect the lungs.

14. THE RESPIRATORY SYSTEM
RESPIRATION
Air enters our body through the nose or mouth and passes through the pharynx.
Air then passes into the larynx.
The epiglottis prevents food from entering the airway during swallowing. During inhalation, the epiglottis lifts up to let air pass over the larynx. Air then passes from the larynx into the trachea.
The trachea then divides into the right and left bronchus. Each bronchus then enters a lung and divides into smaller bronchioles and then divides more into alveoli.

15. RESPIRATION Air enters through nose of mouth and into the pharynx
Air passes into the larynx
Epiglottis opens and air enters the trachea
Air enters the Lt. and Rt. bronchus
Air enters the bronchioles and then the alveoli
RESPIRATION