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Biology
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2. 37-3 The Respiratory System
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3. Purpose and Function of the System
TWO MAIN FUNCTIONS
1) To put Oxygen (O2) into the blood.
2) To get the carbon dioxide (CO2) out of the blood/body.
Why does our body need the Oxygen??
At our cells it combines with glucose (our food) to form usable ATP energy (through cell respiration).

4. The Human Respiratory System
The respiratory system consists of the:
nose
pharynx
larynx
trachea (epiglottis)
bronchi
bronchioles
lungs
diaphragm
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5. The Human Respiratory System
Pharynx
Nose
Larynx
Trachea
Mouth
Lungs
Epiglottis
Bronchus
Bronchioles
The respiratory system is responsible for the exchange of oxygen and carbon dioxide. Air moves through the nose, pharynx, larynx, trachea, and lungs. After reaching the lungs, the trachea branches into smaller and smaller tubes called bronchioles, which end in alveoli, or air sacs.
Diaphragm
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6. The Human Respiratory System
Pharynx
Nose
MOUTH AND NOSE
Mucus moistens air and traps particles of dust or smoke.
Cilia sweep particles and mucus to the throat.
Mucus and particles are either swallowed or spit out.
The respiratory system is responsible for the exchange of oxygen and carbon dioxide.
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7. The Human Respiratory System
Pharynx
Nose
Pharynx
(a.k.a = throat) cavity in back of mouth that leads to the place where your esophagus and larynx meet
The respiratory system is responsible for the exchange of oxygen and carbon dioxide.
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8. The Human Respiratory System
Trachea, or windpipe. Built of strong cartilage rings.
The epiglottis covers the entrance to the trachea when you swallow.
Trachea
Epiglottis
The respiratory system is responsible for the exchange of oxygen and carbon dioxide.
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9. The Human Respiratory System
Larynx
Larynx
a.k.a. = voicebox
At the top of the trachea.
It contains two elastic folds of tissue called vocal cords.
The respiratory system is responsible for the exchange of oxygen and carbon dioxide. Air moves through the nose, pharynx, larynx, trachea, and lungs.
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10. The Human Respiratory System
Bronchi
two large passageways in the chest cavity
Each bronchus leads into one of the lungs.
Lined with cartilage and ciliated
Lungs
Bronchus
The respiratory system is responsible for the exchange of oxygen and carbon dioxide. Air moves through the nose, pharynx, larynx, trachea, and lungs. After reaching the lungs, the trachea branches into smaller and smaller tubes called bronchioles, which end in alveoli, or air sacs.
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11. The Human Respiratory System
Bronchioles.
smallest air tubes which branch off from the bronchi and end at the alveoli or air sacs
Bronchioles
The respiratory system is responsible for the exchange of oxygen and carbon dioxide. After reaching the lungs, the trachea branches into smaller and smaller tubes called bronchioles, which end in alveoli, or air sacs.
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12. The Human Respiratory System
Alveoli
site of respiratory gas exchange by diffusion
resemble bunches of grapes
Alveoli
Bronchiole
The respiratory system is responsible for the exchange of oxygen and carbon dioxide. After reaching the lungs, the trachea branches into smaller and smaller tubes called bronchioles, which end in alveoli, or air sacs.
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13. The Human Respiratory System
moist surface aids exchange
each alveolus is surrounded by capillaries (oxygen in--carbon dioxide out)
Pulmonary artery
Pulmonary vein
The respiratory system is responsible for the exchange of oxygen and carbon dioxide.
Capillaries
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Gas Exchange
Gas Exchange
Gas exchange takes place in the alveoli.
Oxygen diffuses into the blood. O2
Gas exchange occurs by diffusion across the membrane of an alveolus and a capillary.
Capillary
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Gas Exchange
Carbon dioxide in the blood diffuses into the alveolus. O2
CO2
Gas exchange occurs by diffusion across the membrane of an alveolus and a capillary. 
Capillary
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Breathing
HOW YOUR LUNGS WORK…
The air pressure around us is what forces your lungs to fill up.
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Breathing
Diaphragm
sheet of muscle separating the thoracic (chest) cavity from the abdominal cavity
During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.
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Breathing
During inhalation, the diaphragm contracts and the rib cage rises up.
This expands the volume of the chest cavity.
During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.
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Breathing
When the rib cage lowers and the diaphragm relaxes, pressure in the chest cavity is greater than atmospheric pressure.
Air is pushed out of the lungs.
Air Exhaled
Rib cage lowers
During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.
Exhalation
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20. How Breathing Is Controlled
Breathing is controlled by the medulla oblongata.
The medulla oblongata monitors carbon dioxide in the blood.
As carbon dioxide increases, nerve impulses make the diaphragm contract, bringing air into the lungs.
The higher the carbon dioxide level, the stronger the impulses.
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21. Some Respiratory System Malfunctions

22. pneumonia: alveoli fill with fluids and mucus resulting in coughing and breathing difficulties

23. asthma: allergic reaction in which bronchiole contractions create breathing difficulties

24. emphysema: air sacs lose their elasticity and breakdown resulting in a loss of respiratory surface in the lungs --shortness of breath is the chief symptom (smoking frequently leads to this disorder)

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37-3
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37-3
Air passes through the trachea into two large passageways in the chest cavity known as the
bronchi.
alveoli.
epiglottis.
bronchioles.
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37-3
The function of the cilia lining the respiratory surfaces is to
improve the amount of oxygen and carbon dioxide exchanged in the lungs.
cover the opening of the trachea when you swallow.
move air in and out of the lungs.
sweep trapped particles and mucus away from the lungs.
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28. Copyright Pearson Prentice Hall
37-3
Oxygen diffuses from the alveolus into the blood because
blood entering the capillaries of the lungs is oxygen-poor.
blood entering the capillaries of the lungs is oxygen-rich.
air entering the lungs has more carbon dioxide than oxygen.
air entering the lungs has less oxygen than is found in the blood.
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37-3
A stimulant drug found in tobacco that increases the heart rate and blood pressure is
tar.
carbon monoxide.
nicotine.
carbon dioxide.
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37-3
A respiratory disease that results in the loss of elasticity in the tissues of the lung is
chronic bronchitis.
lung cancer.
emphysema.
pneumonia.
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31. END OF SECTION