1. Inquiry into Life Twelfth Edition
Lecture PowerPoint to accompany
Inquiry into Life Twelfth Edition
Sylvia S. Mader
Chapter 15
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. 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

3. The Respiratory System

4. 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

5. 15.1 The Respiratory System
The Pharynx
Connects nasal and oral cavities to larynx
Three divisions
Nasopharynx
Oropharynx
Laryngopharynx
Tonsils form a protective ring
Larynx and trachea are normally open
Esophagus is normally closed

6. 15.1 The Respiratory System
The Larynx
Passageway for air between pharynx and trachea
Vocal cords
Folds of mucosa that vibrate to make sounds
Glottis-opening between folds
Epiglottis
Prevents food from entering the respiratory tract

7. 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

8. 15.1 The Respiratory System
The Bronchial Tree
Right and left primary bronchi
Resemble trachea in structure
Branch to secondary bronchi
Eventually lead to bronchioles
As airways become smaller, walls become thinner
Lack cartilage rings
Each bronchiole leads into alveoli

9. 15.1 The Respiratory System
The Lungs
Divided into lobes
Right lung has 3
Left lung has 2
Each lobe is divided into lobules
Lobule has a bronchiole serving many alveoli
Lungs are covered by serous membrane called pleura

10. 15.1 The Respiratory System
The Alveoli
Surrounded by blood capillaries
Gas exchange occurs 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

11. 15.2 Mechanisms of Breathing
Respiratory Volumes
Tidal volume
Amount of air moving in and out with each breath
Around 70% of this air reaches the alveoli, 30% remains in the airways
Vital capacity
Maximum volume moved in and moved out in a breath
Illness can affect vital capacity
Inspiratory reserve volume
Forced inhalation (amount of air brought in above tidal volume)
Expiratory reserve volume
Forced exhalation (air exhaled beyond tidal volume)
Residual volume
Amount of air always remaining in lungs

12. Vital Capacity

13. 15.2 Mechanisms of Breathing
Understanding Ventilation
There is a continuous column of air from pharynx to alveoli
The lungs lie in the sealed-off thoracic cavity
Rib cage forms top and sides
Intercostal muscles lie between the ribs
Diaphragm forms the floor
The lungs adhere to the thoracic wall by way of the pleura

14. Inspiration

15. Expiration

16. 15.2 Mechanisms of Breathing
Control of Ventilation
Controlled by respiratory center
In medulla oblongata of brain
Inspiration
Respiratory center sends out nerve impulses to the diaphragm and external intercostals
Expiration
Respiratory center ceases to send out nerve impulses to the diaphragm and external intercostals
Input to the respiratory center
Influenced by chemical and neural input

17. 15.2 Mechanisms of Breathing
Chemical Input to 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

18. Nervous Control of Breathing

19. 15.3 Gas Exchanges in the Body

20. 15.3 Gas Exchanges in the Body
External Respiration
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

21. 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)

22. 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

23. 15.3 Gas Exchanges in the Body
Internal Respiration
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

24. 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

25. 15.4 Disorders of the Respiratory System
Disorder of the Upper Respiratory Tract
The Common Cold
Caused by viruses
Sneezing, runny nose, mild fever (in some instances)
Last a few days to a week
Antibiotics are ineffective against viral infections

26. 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

27. 15.4 Disorders of the Respiratory System
Disorder of the Upper Respiratory Tract
Sinusitis
Infection of the cranial sinuses
Nasal congestion blocks sinus openings
Symptoms include postnasal discharge, headache, and facial pain
Otis Media
Inflammation of the middle ear
Nasal infections spread to the ear by way of the auditory tubes
Antibiotics are usually an effective treatment

28. 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
Symptoms include postnasal discharge, headache, and facial pain

29. 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

30. 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

31. 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
Pulmonary tuberculosis
Caused by the bacterium Mycobacterium tuberculosis
Cells build a protective capsule (tubercle) around the bacteria

32. 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
Cystic fibrosis (CF)
Genetic in origin
A recessive condition
Mucus in the lungs becomes very thick and sticky

33. 15.4 Disorders of the Respiratory System
Disorder of the Lower Respiratory Tract
Pulmonary fibrosis
Fibrous connective tissue builds up in the lungs causing a lack of elasticity
This reduces vital capacity

34. Common Bronchiole and Pulmonary Diseases

35. 15.4 Disorders of the Respiratory System
Lung Cancer
A series of progressive steps
Thickening and callusing of mucosa of bronchi
Loss of cilia
Cancerous changes occur in callus cells
Tumors may obstruct bronchi
Cancerous cells spread to other parts of the body
Lung cancer can be caused by secondhand smoke

36. Normal Lung versus Cancerous Lung