The respiratory system has several main functions: air distribution throughout the respiratory tract, gas exchange in the alveoli of the lungs, and filtering, warming, and humidifying air. It also plays roles in smell and speech. Air follows a path from the nose through the pharynx, larynx, trachea, bronchi and bronchioles to the alveoli in the lungs where gas exchange occurs. The major breathing muscles are the diaphragm and intercostal muscles. Lung capacity is measured by tidal volume, vital capacity, expiratory reserve volume, and inspiratory reserve volume.

1. SSTRIDE 2010 Brain Bowl
Alrick Drummond, M1
CHAPTER 14: RESPIRATORY SYSTEM

2. FUNCTIONS OF THE RESPIRATORY SYSTEM
• Major Functions
• Air distribution
• Gas exchange
• Other functions
• Filter, warm and humidify air
• Is also associated with olfaction (smell) and speech

3. PATH OF AIR (FROM NOSE TO LUNGS)
Nose
Pharynx
Larynx
Trachea
Lungs

4. UPPER RESPIRATORY TRACT
• After the nose receives the air
• Head colds affect this part of the respiratory system (Nose, larynx and pharynx)
• The pharynx if broken up into different sections
• Nasopharynx
• Receives air for surroundings
• Contains the opening to the auditory (eustachian) tube
• Help keep pressure equal between the middle and external ear
• Oropharynx
• Receives food and air from the mouth
• The epiglottis stops food from getting into lungs
• Laryngopharynx
• Carries air to the trachea towards the lungs
• Contains the vocal cords

5. UPPER RESPIRATORY TRACT
• The trachea begins right under the larynx
• The trachea
• Exterior-is made of C shaped cartilage with soft
tissue in between them
• Interior-is lined with respiratory epithelium
*cool fact* the esophagus is right behind the trachea and
this is why it has C shaped cartilage instead of full rings

6. PATH OF AIR (INSIDE THE LUNG)
Main
bronchi
Bronchial
branches
Bronchiole
Terminal
sacs
Alveoli

7. PATH OF AIR INSIDE THE LUNGS
• The bronchi continue to branch out into smaller tubes
inside the lungs
• These branches are part of the respiratory tree
(remember branches of bronchi make the respiratory
tree)
• These branches become bronchioles and will end with
little elastic sacs called alveoli

8. ALVEOLI
• These alveolar sacs are where gas exchange happens
via diffusion into the capillaries
• Gas exchange happens in type I cells in the alveoli
• Oxygen then binds to the hemoglobin in blood to make
oxyhemoglobin which can carry oxygen to the cells
• Type 2 cels make surfactant, a substance that prevents
alveoli for collapsing and reduces surface tension when
we breath

9. BREATHING MUSCLES
• Eupnea-normal breathing
• Inspiration
• Diaphragm
• External intercostal muscles
• Expiration
• Internal intercostal
• Abdominal muscles
*remember that more muscles are used when a person is
breathing heavily

10. LUNG CAPACITY
• Tidal volume (TV)- the amount of air we normally breath
• Vital capacity (VC)-the largest amount of air we can breath out
at one time
• Expiratory reserve volume (ERV)-air you can force out after
tidal volume
• Inspiratory reserve volume (IRV)-air you can force in after
tidal volume

11. OTHER IMPORTANT FACTS
• The epithelium of the lung cells contain an
important structure called cilia. These structures
can be paralyzed in cigarette smokers
• There are areas in the blood vessels that detect
the amount of oxygen in the blood
• Carotid body (in the neck)
• Aortic bodies (in the chest)