1. 15.1 The Respiratory System
The respiratory system works with the cardiovascular system to accomplish:
The exchange of gases (O2 and CO2) between air and the blood
The exchange of gases (O2 and CO2) between blood and tissue fluid
Transport of gases to and from the lungs and the tissues

2. The Respiratory System

3. 15.1 The Respiratory System
The Nose
Contains two nasal cavities
Functions
Warms air during inhalation
Cleanses air-coarse hairs and mucus
Humidifies air-wet surfaces of membrane
Contain odor receptors
Tear glands drain into nasal cavity

4. 15.1 The Respiratory System
The Trachea
Connects larynx with primary bronchi
Supported by C-shaped cartilage rings
Cilia sweep mucus toward the pharynx
Smoking can destroy cilia

5. 15.1 The Respiratory System
The Bronchial Tree
Right and left primary bronchi
Branch to secondary bronchi
As airways become smaller, walls become thinner
Each bronchiole leads into alveoli

6. 15.1 The Respiratory System
The Lungs
Divided into lobes
Right lung has 3
Left lung has 2
Lungs are covered by serous membrane called pleura

7. 15.1 The Respiratory System
The Alveoli
Surrounded by blood capillaries
Gas exchange occurs through the moist membranes
Oxygen diffuses into blood
Carbon dioxide diffuses into alveoli
Alveoli must stay open to receive air
Surfactant helps prevent them from closing

8. 15.2 Mechanisms of Breathing
Respiratory Volumes
Tidal volume
Amount of air moving in and out with each breath
Vital capacity
Maximum volume moved in and moved out in a breath
Residual volume
Amount of air always remaining in lungs

9. Inspiration

10. Expiration

11. 15.2 Mechanisms of Breathing
Respiratory Center
Directly sensitive to CO2 and H+
When levels rise, respiratory center increases rate and depth of breathing
Indirectly responsive to O2
Chemoreceptors in the carotid and aortic bodies
Sensitive to oxygen levels in blood
When levels decrease, impulses are sent to respiratory center
Respiratory center then increases rate and depth of breathing

12. 15.3 Gas Exchanges in the Body

13. 15.3 Gas Exchanges in the Body
External Respiration (takes place in lungs)
Exchange of gas between air in alveoli and blood
Gases exert pressure
Partial pressure refers to the amount of pressure each gas in a mixture exerts
Symbolized by Pco2 and Po2
Blood in pulmonary capillaries has a higher Pco2 than atmospheric air
CO2 diffuses from blood into alveoli

14. 15.3 Gas Exchanges in the Body
External Respiration Continued
Most CO2 is carried as bicarbonate ions (HCO3-)
Carbonic anhydrase catalyzes the breakdown of carbonic acid (H2CO3)

15. 15.3 Gas Exchanges in the Body
External Respiration Continued
Pressure gradient for oxygen is the reverse of carbon dioxide
Po2 is low in pulmonary capillaries and high in alveoli
Oxygen diffuses into blood
Hemoglobin picks up oxygen and becomes oxyhemoglobin

16. 15.3 Gas Exchanges in the Body
Internal Respiration (takes place in tissues)
Exchange of gas between systemic capillaries and tissues
Partial pressure of oxygen is greater in capillaries than tissues
Oxyhemoglobin gives up oxygen which diffuses out of the blood into tissues

17. 15.3 Gas Exchanges in the Body
Internal Respiration
CO2 diffuses into the blood
A small amount combines with hemoglobin
Most CO2 combines with H2O
Carbonic anhydrase speeds up the reaction

18. 15.4 Disorders of the Respiratory System
Disorder of the Upper Respiratory Tract
Pharyngitis
Inflammation of the throat
May be caused by Streptococcus pyogenes (Strep throat)
Severe sore throat, high fever, white patches in throat region
Tonsillitis
Tonsils (lymphoid tissue) become inflamed and enlarged
Laryngitis
Inflammation of the larynx
Causes hoarseness
Persistent laryngitis is one warning sign of cancer

19. 15.4 Disorders of the Respiratory System
Disorder of the Lower Respiratory Tract
Choking
Obstruction of the trachea
Heimlich maneuver may expel blockage
A tracheostomy is the insertion of a breathing tube into the trachea

20. 15.4 Disorders of the Respiratory System
Disorder of the Lower Respiratory Tract
Acute bronchitis
Infection of the primary and secondary bronchi
Usually it is preceded by a viral infection that leads to a secondary bacterial infection
Chronic bronchitis
Airways are inflamed and filled with mucus
Bronchi have undergone degenerative change including the loss of cilia
Smoking is the most common cause

21. 15.4 Disorders of the Respiratory System
Disorder of the Lower Respiratory Tract
Asthma
A disease of the bronchi and bronchioles
Wheezing, breathlessness, coughing
Inflammation of the bronchioles
Airways are usually sensitive to specific irritants
Incurable but can be treated with medicines

22. 15.4 Disorders of the Respiratory System
Disorder of the Lower Respiratory Tract
Pneumonia
Viral or bacterial infection
Bronchi or alveoli fill with fluid
High fever, chest pain and headache

23. 15.4 Disorders of the Respiratory System
Disorder of the Lower Respiratory Tract
Emphysema
Damage to the walls of the alveoli
A chronic and incurable disease
Smoking is the major cause of this disease

24. Common Bronchiole and Pulmonary Diseases

25. Normal Lung versus Cancerous Lung