1. Structures and Functions
Respiratory System
Structures and Functions

2. Parts of Respiratory System
Nasal Cavity
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
Lungs
Pleura

3. Functions of the Respiratory System
Provides oxygen for the body and removes carbon dioxoide through respiration
Production of sound

4. Respiratory System
Body has an average oxygen reserve to last about 4 –6 minutes
If reserve is not replenished , death is the outcome

5. Respiratory Tract Upper Respiratory Tract Nose Pharynx Larynx
Lower Respiratory Tract
Trachea
All segments of the bronchial tree
Lung

6. Nasal Cavity Air enters body through nostrils (anterior nares)
Inside the nostrils, are 2 spaces known as nasal cavities
Nasal cavities are lined with mucous membranes

7. Nasal Cavity
Nasal Septum—divides nasal cavities into right and left sides
Three turbinates or bones that protrude into the nasal cavity—they increase surface area for filtering dust and dirt
Cilia—the hairs in your nose that trap larger dirt particles

8. Changes To The Air As It Comes In Contact With the Lining of the Nose
Foreign bodies filtered out by cilia and mucous membrane
Air is warmed
Air is moistened

9. Effect of Smoking on Cilia
Cigarette smoke paralyzes the cilia and results in accumulations of mucus and the typical smoker’s cough, which is an effort to clear the secretions

10. Sense of Smell Originates in your nose!
Olfactory nerves (which provide the sense of smell) are located in the mucus membrane.

11. Sinuses Cavities in skull Ducts connect sinuses to nasal cavity
Named: frontal, maxillary, sphenoid, and ethmoid
Give resonance to voice (nasal sound when you have a cold due to blockage or sinuses)

12. Pharynx
The throat
Common passageway for air and food
5 inches long

13. Pharynx
When food is swallowed, the EPIGLOTTIS closes over the opening to the larynx, preventing food from entering the lungs
Eustachian tube connect the middle ear to the nasopharynx

14. Larynx The voice box Triangular chamber below pharynx
Within the larynx are vocal cords (GLOTTIS)
It is composed of several pieces of cartilages – the largest is the Adams’s Apple

15. Trachea Windpipe 41/2 inches long
Walls are bands of C-shaped rings of cartilage—to keep trachea open
Lined with ciliated mucous membrane
Coughing and expectoration gets rid of dust-laden mucous

16. Bronchi and Bronchioles
Bronchial tubes have cartilaginous plates instead of rings
Bronchial tubes lead to even smaller bronchioles
Bronchioles—thinner walls of smooth muscle
At the end of the bronchiole is the alveoli
Lower end of trachea divides into right and left bronchus
Bronchi—similar to trachea with ciliated mucous and rings of cartilage
As they enter lungs divide into smaller bronchial tubes

17. Bronchi, Bronchial Tubes and Bronchioles

18. Alveoli Composed of single layer of epithelial tissue
Inner surfaces covered with SURFACTANT (keeps alveoli from collapsing)
Each alveolus is surrounded by capillaries
Oxygen and carbon dioxide exchange takes place between alveoli and capillaries

19. Lungs Fill thoracic cavity Upper part—apex Lower part—base
Lung tissue is porous and spongy—it floats
Right lung—larger and shorter (displaced by liver) Has 3 lobes
Left lung—smaller (displaced by heart) Has two lobes

20. Pleura Thin, moist, slippery membrane that covers lungs
Double-walled sac
Space is pleural cavity—filled with pleural fluid to prevent friction

21. Pulmonary Ventilation (Breathing)
Inspiration
Intercostal muscles lift ribs outward
Sternum rises
Diaphragm contracts and moves downward
This increases the volume of the lungs and air rushes in
Expiration (exhalation)
Opposite action takes place
Exhalation is a passive process

22. Breathing Process

23. Respiratory Movements
1 inspiration + 1 expiration = 1 respiration
Respiratory rate for normal adult is 14-20

24. Factors that Affect Respiratory Rate
Increases with exercise, fever, certain diseases
Age—newborn = per minute
Sleep—respirations decrease
Emotion can increase or decrease

25. Coughing
Deep breath followed by forceful expulsion of air—to clear lower respiratory tract

26. Hiccups Spasm of the diaphragm and spasmotic closure of the glottis
Caused by irritation to diaphragm or phrenic nerve

27. Sneezing
Air forced through nose to clear respiratory tract

28. Yawning
Deep prolonged breath that fills the lungs and increases oxygen within the blood

29. Control of Breathing Then the phrenic nerve stimulates the diaphragm
Chemical Factors
Depends on levels of carbon dioxide in blood
Chemoreceptors in aorta and carotid arteries are sensitive to the amount of oxygen in blood
Controlled by neural and chemical factors
Neural Factors
Respiratory center in medulla oblongota
Increase in carbon dioxide or decrease in oxygen will trigger respiratory center