1. Chapter 9
Respiratory System

2. Points to Ponder
What are the parts and function of the upper and lower respiratory system?
What is the mechanism for expiration and inspiration?
How is breathing controlled by the nervous system and through chemicals?
Where and how is exchange of gases accomplished?
What are some common respiratory infections and disorders?
What do you know about tobacco and health?
What is your opinion about bans and legislation on smoking?

3. Organs of the Respiratory System

4. The Respiratory System
Ensures oxygen enters and carbon dioxide leaves body.
Inspiration: Inhalation
Expiration: Exhaling

5. What is the pathway that air follows?
nose pharynx larynx trachea bronchus bronchioles alveoli

6. Upper Respiratory Tract
Nose
Pharynx
Larynx

7. The Nose Opens at the nostrils/nares; leads to the nasal cavities.
Nasal cavities divided by a bone/cartilage septum.
Hairs and mucus filters air entering the cavities.
The nasal cavity has capillaries to warm and moisten the air.
Specialized ciliated cells in the narrow upper recesses of the nasal cavity act as odor receptors.
Tear glands (lacrimal glands) drain into the nasal cavities.

8. The Pharynx
Funnel-shaped cavity connecting nasal and oral cavities to the larynx.
Commonly called the “throat”.
3 portions based on location:
Nasopharynx: Where nasal cavities open above the soft palate.
Oropharynx: Where oral cavity opens.
Laryngopharynx: Open into the larynx.
Tonsils provide a lymphatic defense during breathing at the junction of the oral cavity and pharynx.

9. The Larynx
Triangular, cartilaginous structure that passes air between the pharynx and trachea.
Ie. Voice box (houses vocal cords)
At apex of triangle sits Adam’s apple.
2 mucosal folds make up the vocal cords.
Glottis: Opening between the slit of the vocal cords.
High or low pitch of voice is controlled by the tension of the vocal chords.
Moves against the epiglottis when swallowing.

10. Lower Respiratory Tract
Trachea
Bronchial tree
Lungs

11. The Trachea, ie. Windpipe
Tube connecting the larynx with the primary bronchi.
Anterior to the esophagus.
Made of connective tissue, smooth muscle and cartilaginous rings.
Lined with cilia (pseudostratified ciliated columnar epithelium) and goblet
cells to produce mucus.
Helps keep the lungs clean.

12. The Bronchial Tree
Begins with the division of trachea into left and right primary bronchi.
Lead to left and right lungs.
Bronchi continue to branch, eventually transitioning into small bronchioles about 1mm in diameter with thinner walls.
Bronchioles eventually lead to alveoli (elongated air sacs for gas exchange),

13. The Lungs Paired, cone-shaped organs in the thoracic cavity.
Consist of the bronchi, bronchioles and alveoli.
Right lung has 3 lobes; left lung has 2 lobes.
Lobes divide into lobules with bronchioles and alveoli.
Each lung is enclosed by pleura membranes.
Produce serous fluid for lubrication.

14. The Alveoli ~ 300 million in the lungs; greatly increase surface area.
Alveoli are enveloped by blood capillaries.
Alveoli and capillaries consists of one layer of epithelium; allows for gas exchange.
Lined with surfactant; act as a film to keep alveoli open.

15. Phases of Breathing/Ventilation
1. Inspiration: an active process of inhalation that brings air into the lungs
2. Expiration: usually a passive process of exhalation that expels air from the lungs

16. Inspiration The diaphragm and intercostal muscles contract
The diaphragm flattens and the rib cage moves upward and outward
Volume of the thoracic cavity and lungs increase
The air pressure within the lungs decrease
Air flows in to the lungs

17. Expiration The diaphragm and intercostal muscles relax
The diaphragm moves upward and becomes dome-shape
The rib cage moves downward and inward
Volume of the thoracic cavity and lungs decrease
The air pressure within the lungs increases
Air flows out of the lungs

18. Different Volumes of Air During Breathing
Tidal volume: the small amount of air that usually moves in and out with each breath
Vital capacity: the maximum volume of air that can be moved in plus the maximum amount that can be moved out during one breath
Inspiratory and expiratory reserve volume: the increased volume of air moving in or out of the body
Residual volume: the air remaining in the lungs after exhalation

19. Visualizing the Vital capacity

20. Nervous System Control of Breathing
Respiratory control center in the brain (medulla oblongata) sends out nerve impulses to contract muscle for inspiration.
Sudden infant death syndrome (SIDS) is thought to occur when this center stops sending out nerve signals

21. Chemical Control of Breathing
2 sets of chemoreceptors sense the drop in pH: one set is in the brain and the other in the circulatory system
Both are sensitive to carbon dioxide levels that change blood pH due to metabolism

22. Exchange of Gases in the Body
Oxygen and carbon dioxide are exchanged
The exchange of gases is dependent on diffusion
Partial pressure is the amount of pressure each gas exerts (PCO2 or PO2)
Oxygen and carbon dioxide will diffuse from the area of higher to the area of lower partial pressure

23. External Respiration
Exchange of gases between the lung alveoli and the blood capillaries
PCO2is higher in the lung capillaries than the air thus CO2 diffuses out of the plasma into the lungs
The partial pressure pattern for O2 is just the opposite so O2 diffuses the red blood cells in the lungs
Carbon dioxide transport: carbonic
H+ + HCO H2CO3 anhydrase H2O + CO2
Oxygen transport:
Hb + O HbO2

24. Internal Respiration
The exchange of gases between the blood in the capillaries outside of the lungs and the tissue fluid
PO2 is higher in the capillaries than the tissue fluid thus O2 diffuses out of the blood into the tissues
Oxyhemoglobin gives up oxygen:
HbO Hb + O2
Most CO2 is carried as a bicarbonate ion:
carbonic
CO2 + H2O anhydrase H2CO H3 + HCO3-

25. Movement of Oxygen and Carbon Dioxide in the Body

26. Upper Respiratory Tract Infections
Sinusitis: Blockage of sinuses
Otitis media: Infection of the middle ear
Tonsillitis: Inflammation of the tonsils
Laryngitis: Infection of the larynx that leads to loss of voice

27. Lower Respiratory Tract Disorders
Pneumonia: Infection of the lungs with thick, fluid build up
Tuberculosis: Bacterial infection that leads to tubercles (capsules)
Pulmonary fibrosis: Lungs lose elasticity because fibrous connective tissue builds up in the lungs usually because of inhaled particles
Emphysema: Chronic, incurable disorder in which alveoli are damaged and thus the surface area for gas exchange is reduced
Asthma: Bronchial tree becomes irritated causing breathlessness, wheezing and coughing
Lung cancer: Uncontrolled cell division in the lungs that is often caused by smoking and can lead to death

28. Health focus: Things you should know about tobacco and health.
All forms of tobacco can cause damage
Smoking increases a person’s chance of lung, mouth, larynx, esophagus, bladder, kidney, pancreas, stomach and cervix
The 5-year survival rate for people with lung cancer is only 13%
Smoking also increases the chance of chronic bronchitis emphysema, heart disease, stillbirths and harm to an unborn child
Passive smoke can increase a nonsmokers chance of pneumonia, bronchitis and lung cancer

29. Bioethical focus: What do you think?
Is it ethical to ban smoking?
Does restricting the freedom to smoke segregate people based on habit?
Are nonsmokers infringing upon smokers or are smokers infringing upon nonsmokers? Is it both?
Will this legislation help smokers quit?
Should smoking be banned in bars and casinos?
Do smoking bans hurt the economy?