1. Respiratory System

2. What is Respiration?
Cellular respiration = producing energy (ATP) from the breakdown of molecules in food in the presence of oxygen
Respiration = oxygen and carbon dioxide are exchanged between cells, blood, and air in the lungs
What does CPR stand for?-- cardiopulmonary resuscitation (rescue breathing combined with chest compressions

3. Human Respiratory System
Function: exchange oxygen and carbon dioxide
Structures:
Nose: filters air as it enters the body
Pharynx: tube in the back of the mouth (throat) passes air and food
Larynx: “voice box” = vocal cords (two folds of elastic tissue)
Trachea: “windpipe”
Epiglottis covers entrance of trachea when you swallow
Bronchi: large passageways leading air to each lung
Bronchioles are branches from bronchi in each lung
Lungs: gas exchange
Alveoli = tiny air sacs clustered at the end of the bronchioles and wrapped in capillaries

4. Figure 37-14 The Respiratory System
Section 37-3
Pharynx
Nose
Larynx
Trachea
Mouth
Lung
Bronchiole
Epiglottis
Bronchus
Alveoli
Bronchioles
Diaphragm
Capillaries
Edge of
pleural membrane

5. Gas Exchange 350 million alveoli in a healthy lung
Increase surface area for gas exchange across capillaries
Oxygen in alveoli diffuses across capillaries into blood
Carbon dioxide in blood diffuses across capillaries into alveoli
Very efficient gas exchange
Inhaled air contains 21% oxygen and 0.04% carbon dioxide
Exhaled air contains 15% oxygen and 4% carbon dioxide

6. Figure 37-15 Gas Exchange in the Lungs
Alveoli
Section 37-3
Bronchiole
Capillary

7. Breathing The movement of air into and out of the lungs
At the bottom of the chest cavity is a large flat muscle = diaphragm
The lungs are sealed in two sacs = pleural membranes
When you breathe in (inhale), the diaphragm contracts and expands the volume of the chest cavity, creating a partial vacuum in the pleural membranes, allowing atmospheric pressure to fill the lungs with air
When you breathe out (exhale), the diaphragm relaxes and decreases the volume of the chest cavity, increasing the pressure in the chest cavity and forcing air out of the pleural membranes

8. Figure 37-16 The Mechanics of Breathing
Section 37-3
Air exhaled
Air inhaled
Rib cage descends
Rib cage rises
Diaphragm
Diaphragm
Inhalation
Exhalation

9. How breathing is controlled
Although you can voluntarily hold your breath, eventually your body will “force” you to breathe
Breathing is controlled in the medulla oblongata in the brain, which is part of the autonomic nervous system
Cells monitor the amount of carbon dioxide in the blood and as it increases, nerve impulses cause the diaphragm to contract bringing air into the lungs

10. Tobacco creates problems
Smoking tobacco damages and eventually destroys the protective system by paralyzing cilia and trapping mucus in airways
Tobacco contains:
Nicotine = addictive, stimulate drug that increases the heart rate and blood pressure
Carbon monoxide = poisonous gas that blocks the transport of oxygen by hemoglobin in the blood
Tar = carcinogen (causes cancer)

11. Respiratory diseases caused by smoking
Chronic bronchitis = bronchi become swollen and clogged with mucus, so constant coughing to try and force the particles out
Emphysema = respiratory disease due to loss of elasticity of lung tissue making breathing very difficult
Lung cancer = deadly because it spreads to other parts of body
Heart disease = narrowing of blood vessels increases blood pressure and makes the heart work harder