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

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

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

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

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

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

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

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

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

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

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)