1. Organs Control of Respiration
Respiratory System
Organs Control of Respiration
Homeostasis

2. Path of Air through the Respiratory System
nasal cavity
pharynx
nose
mouth
glottis
larynx
trachea
bronchus (pl: bronchi)
bronchiole
lung
Made of alveoli (air sacs)

3. Functions of Respiratory Tract Organs
Nasal Cavities: warm, moisten and filter air
Larynx: vocal cords produce sound
Trachea (windpipe): permits passage of air, ciliated cells move mucus and debris toward pharynx
Bronchial Tree: bronchi and bronchioles permit passage of air
Lungs: gas exchange
vocal
cords
glottis

4. Applying Your Knowledge
Pharynx
Lung
Larynx
Bronchus
Bronchiole
Where are the vocal cords located?
Which leads to an alveolus?
Where does gas exchange take place?
Which is shared between the respiratory and digestive systems?

5. Gas Exchange in Lungs: External Respiration
Carries deoxygenated blood from heart
Returns oxygenated blood to heart
Sites of gas exchange
Exchange occurs between air in the alveolus and blood in the surrounding capillaries:
Oxygen from alveolus enters bloodstream,
Carbon dioxide from blood enters alveolus

6. Ventilation: Inspiration and Expiration
Action of intercostal muscles between ribs
Dome-shaped muscle
below lungs
Ventilation: Inspiration and Expiration

7. Control of Ventilation
Respiratory Center in Brain stimulates rhythmic inspiration, responding to levels of carbon dioxide and hydrogen ions
Chemoreceptors in arteries send signals to respiratory center in response to changing oxygen levels

8. Diffusion Controls Gas Exchanges in the Body
External Respiration
gas exchange between air in alveoli and blood in pulmonary capillaries
pO2 is higher in air, pCO2 is higher in blood
O2 diffuses into blood, CO2 diffuses into lung air
Internal Respiration
gas exchange between blood in systemic capillaries and tissue fluid
pO2 is higher in blood, pCO2 is higher in tissues
O2 diffuses into tissues, CO2 diffuses into blood

9. Specialized Components
Carbonic Anhydrase: enzyme involved in release of carbon dioxide
Hemoglobin: oxygen-carrying molecule on surface of red blood cells
Surfactant: layer of lipoprotein that lowers surface tension and prevents alveoli from closing

10. Tissue Structure
Trachea: pseudostratified ciliated columnar epithelium
Alveoli: simple squamous epithelium

11. Homeostasis Gas Exchange Regulation of Blood pH
oxygen is needed for energy release through cellular respiration
Regulation of Blood pH
When CO2 is released by tissues, levels of H+ increase and pH is lowered
When CO2 is released from lungs, H+ has been used to produce water, increasing pH to neutral level (7.4)
Carbonic anhydrase
bicarbonate ion
hydrogen ion
carbonic acid
carbon dioxide
water
Bicarbonate Buffering System of Blood

12. Applying Your Knowledge
Tissue Fluid
Hemoglobin
Carbonic Anhydrase
Blood
Alveolus
Surfactant
Diaphragm
Columnar Epithelium
Intercostal Muscle
Squamous Epithelium
Which enzyme assists in controlling blood pH? (Choices on left)
For internal respiration, where is pCO2 greater? (Choices on left)
Which one represents a muscle located below the lungs? (Choices on right)