1. The Respiratory System Lesson 1:29
The Respiratory System
Lesson 1:

2. Lesson Objectives
Upon completion of this lesson, students should be able to …
Define and spell the terms to learn for this chapter.
Explain the purpose and function of the respiratory system.
List and explain the structures and functions of the organs of the respiratory system.
Explain the different respiratory volumes and capacities.

3. Critical Thinking Question
How might you describe the breathing process to a patient?

4. The Process of Breathing
When we breathe we inhale oxygen and exhale carbon dioxide
This exchange of gases gets oxygen to, and carries carbon dioxide away from the cells of the body
Respiration is achieved through the mouth, nose, trachea, lungs, and diaphragm
Oxygen enters the respiratory system through the mouth and the nose

5. The Path of Oxygen When Breathing
Passes through the larynx
Into the trachea
Into the alveoli
Then diffuses through the capillaries into the arterial blood
The waste-rich blood from the veins releases carbon dioxide into the alveoli

6. The Path of Oxygen When Breathing
The diaphragm helps pump air into, and carbon dioxide out of, the lungs
Upon exhalation, the carbon dioxide follows the same path out of the lungs by which oxygen flowed into the lungs

7. The Respiratory System

8. Upper and Lower Respiratory Tracts
The upper respiratory tract consists of:
The nose
Paranasal sinuses
The pharynx (or throat)
The lower respiratory tract includes:
The larynx (or voicebox)
Trachea (which splits into two main branches called bronchi)
Tiny branches of the bronchi called bronchioles
The lungs

9. Organs of the Respiratory System
Upper Respiratory
Lower Respiratory 9

10. Critical Thinking Question
What is the common name for “upper respiratory infection?” 10

11. Functions of the Nose Cleanses inhaled air
Cilia and mucus catch airborne particles
Prevents particles from entering airway
Moistens inhaled air by producing mucus
Warms the inhaled air
Turbinate bones, or conchae, create a maze
Air circulates through and warms
Assists with drainage
Sinuses
Nasolacrimal duct drains from eyes 11

12. Critical Thinking Question
Why does your nose run when you cry? 12

13. Internal Structure Septum Conchae Palatine bone of the skull
Cartilaginous structure
Lined with mucous membrane
Divides nose into left and right
Conchae
Inferior, middle, superior
Connect eustachian tube, sinuses, and nasolacrimal duct
Palatine bone of the skull
Makes up the hard palate
Separates the nose from the mouth 13

14. The Nose 14

15. The Pharynx Musculomembranous tube about 5 inches long
Common path for air and food
Branches into trachea (air passageway) and esophagus (food passageway)
Contains the tonsils
Three parts
Nasopharynx
Oropharynx
Laryngopharynx 15

16. Critical Thinking Question
Based on the names of the parts of the pharynx, where do you think each is located? 16

17. Note the parts of the pharynx and how they are named.17

18. Critical Thinking Question
What happens to the pharynx when it gets to this point? 18

19. The Larynx (The “Voice Box”)
Muscular and cartilaginous structure
Protected by cartilage
Thyroid cartilage
Epiglottic cartilage
Cricoid cartilage 19

20. Critical Thinking Question
Why would cartilage be a good material for protection? 20

21. The Larynx (The “Voice Box”)
Thyroid cartilage:
Largest of the larynx cartilages
Commonly known as the “Adam’s apple”
Epiglottic cartilage:
Also called the epiglottis
Closes over the trachea (windpipe) during swallowing to keep food out of the trachea 21

22. The Larynx (The “Voice Box”)
Cricoid cartilage:
Allows for large boluses of food to be swallowed
Landmark for cricoidotomy when airway is obstructed 22

23. The Larynx Also known as the “voice box”
Contains false and true vocal cords
Long and relaxed vocal cords produce low sounds
Short, tense vocal cords produce higher-pitched notes
Functions in producing vocal sounds 23

24. The Trachea
Cartilaginous tube about 1 inch wide and 4.5 inches long that extends between the larynx and the main bronchi
Interior of the trachea is lined with mucous membrane and cilia that trap foreign matter
Most important function of the trachea is to serve as an open passageway through which air reaches the lungs
Epiglottis is a flap of tissue that covers the trachea when swallowing occurs to prevent food from entering the trachea

25. Main Branches of the Trachea
Extend into the lungs called the bronchi 
Are the passageways for air between the trachea and the lungs
The right bronchus is the longer, larger branch moving down the right side of the heart
The left bronchus is shorter and more vertical, as it makes room for the heart in the chest cavity

26. Main Branches of the Trachea
After entering the lungs at the hilum, the bronchi subdivide into the bronchial tree, which continues to branch into smaller and smaller branches called bronchioles

27. Bronchi Branches of the trachea – one bronchus to each lung
Provide passageway for air into the lungs
Bronchi subdivide into progressively smaller branches called bronchioles
Bronchioles terminate in air sacs called alveoli 27

28. Alveoli Small air sacs at the terminal end of bronchioles
They are elastic – expand and contract with inhalation and exhalation
Surrounded by network of capillaries for gas exchange
Capillary network creates the respiratory membrane 28

29. Structure of the Lungs Contain bronchi, bronchioles, and alveoli
2 lungs separated by the mediastinum
Right has 3 lobes; left has 2 lobes
Are spongy, porous, and highly elastic
Pleural membranes
Line the outer surface of the lungs and interior of thoracic cavity
Pleural lining produces a lubricant called surfactant 29

30. Critical Thinking Question
Why is the outside lining of the lungs lubricated? 30

31. Functions of the Lungs
The most important function is to bring air into contact with the blood and facilitate the exchange of gases in the alveoli
Supply oxygen
Remove wastes and toxins
Defend against intruders
Completes these functions with:
36 types of specialized cells
Cilia 31

32. Critical Thinking Question
Why do you think a person’s immunity is affected when cells of the lungs are damaged or destroyed by illness or smoking? 32

33. External Respiration Actions of External Respiration Processes
Ventilation – exchange of air between body and environment
Inhalation – taking air and fresh oxygen into the lungs
Exhalation – sending air out of the lungs and removing carbon dioxide
Processes
Air travels through pharynx to trachea and lungs
Oxygen delivered to blood in lungs
Carbon dioxide removed from blood 33

34. Muscles that Control Breathing
Diaphragm
Forms floor of thoracic cavity
Separates the abdomen from the thoracic cavity
Intercostal muscles
Between the ribs
External intercostals
Internal intercostals 34

35. Action of the Diaphragm
Contracts and moves down
Causes a decrease of pressure, or negative thoracic pressure, within the chest cavity
Air enters the lungs to equalize the pressure during inhalation 35

36. Intercostal Muscles External intercostal muscles
Assist inhalation
Raise the rib cage
Enlarge the thoracic cavity
Internal intercostal muscles
Assist exhalation
Reduce the size of the thoracic cavity
Force air from lungs 36

37. Check Your Learning! Do Not Use Your Book!
Name the respiratory muscle that is described.
Pulls the ribs upward and outward
Forms the floor of the thoracic cavity and separates the abdomen from the thoracic cavity
Pulls the ribs downward and inward
External intercostal
Internal intercostal
Diaphragm 37

38. Respiratory Volumes and Capacities
Used to measure lung volume and capacity
Needed for pulmonary function tests
Used in diagnosis of respiratory disorders
Used in human performance testing
Assesses physical capabilities of healthy individuals 38

39. Critical Thinking Question
When might human performance testing be used? 39

40. Lung Volumes Tidal Volume (VT) Inspiratory Reserve Volume (IRV)
Volume of air entering or leaving the lungs during a single breath
Inspiratory Reserve Volume (IRV)
Volume of air that can be inspired over and above the resting tidal volume
Expiratory Reserve Volume (ERV)
Volume of air that can be expired after a normal expiration 40

41. Lung Volumes Residual Volume (RV)
Volume of air remaining in the lungs after a maximal expiration, which can be estimated as 25 percent of the vital capacity 41

42. Lung Capacities Inspiratory Capacity (IC) Vital Capacity (VC)
Maximum volume that can be inspired after a normal expiration = VT + IRV
Vital Capacity (VC)
Maximum volume that can be expired after a maximal inspiration = VT + IRV + ERV
Functional Residual Capacity (FRC)
Volume of air left in the lungs after a normal expiration = ERV + RV
Total Lung Capacity (TLC)
Volume of the lungs when fully inflated = VC + RV (or 1.25 x VC) 42

43. Other Respiratory Measurements
Respiratory Rate (f)
Number of breaths per minute
Minute Ventilation (VE)
Total volume of air expired per minute = VT x f
Dead Space (VD)
Volume of inspired air that is not available for gas exchange
Alveolar Ventilation (VA)
Volume of air that reaches the alveoli per minute = (VT – VD) x f 43

44. Questions? 44