Respiratory System

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Respiratory System
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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

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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

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

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

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

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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)

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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