1. 1
The Human Respiratory
System

2. • Breathing is an
involuntary action,
controlled by the
medulla oblongata
• High levels of carbon
dioxide in the
blood trigger the
breathing response
2
The Process of Breathing

3. Gas Exchange in the Lungs
• Gas exchange takes
place in the alveoli
3

4. Diffusion of Gases
• Oxygen diffuses into the blood, the oxygen molecule
attaches to the hemoglobin forming a molecule called
oxyhemoglobin
• Carbon dioxide diffuses from the blood into the
lungs, the carbon dioxide is a waste product that is
exhaled
4

5. The Mechanics for Breathing
5

6. 6
Exhalation
(Breathing Out)
Inhalation
(Breathing In)
Diaphragm relaxed Diaphragm contracted
Rib cage moves in and
down
Rib cage moves up
and out
Volume of chest smaller Volume of chest larger
Lungs squeezed Lungs expand
Air pushed out Air pulled in
Increased pressure in
the chest cavity
Decreased pressure in
the chest cavity

7. 7
Diseases of the Respiratory
System

8. 8
Bronchitis
Inflammation of the bronchi
Usually caused by infection
Also caused by irritants such
as exposure to smoke,
chemicals, or air pollution
Symptoms include throat
pain, fever, coughing, and
coughing up mucus
Treatment includes cough
medicine and antibiotics

9. 9
Emphysema
• Destruction of alveoli so
gas exchange is reduced
• Almost always caused by
smoking, but in rare cases
may be due to a genetic
disorder
• Symptoms include shortness
of breath and chronic cough
• No cure, not reversible
• Patients must be on oxygen

10. 10
Pneumonia
• Inflammation or swelling in the lungs in which air sacs fill with pus
and other fluids, making it difficult for oxygen to reach the blood.
Caused by bacteria or viruses.
• Symptoms include pain in chest, fever, chills, spitting up bloody
mucus, and coughing. Treatment: antibiotics and rest

11. 11
Lung Cancer
• Cancer that originates in the
lung, often caused by smoking
• Occurs when cells in the lungs
start to grow rapidly in an
uncontrolled manner
• No symptoms in early stages;
in later stages symptoms
include coughing, wheezing,
and loss of weight
Treatment includes removing part of
lung with cancer and using
chemotherapy and/or radiation if cancer
has spread to other parts of the body

12. 12
Asthma
• A disease of the bronchial tubes
in which airways constrict
and mucus secretion increases,
making breathing difficult
• May be caused by allergies,
infection, exertion, emotions,
and weather changes
• Common symptoms include
shortness of breath, coughing,
tightening in the chest, and
wheezing
• Is a chronic disease; people
with asthma live with it every
day and very often for their
whole lives
Treatment: inhalers,
antihistamines, steroids

13. Extreme Respiration:
Carbon Monoxide Poisoning
• CO, poisonous gas
released by cars and
cigarettes
• Binds to hemoglobin
preventing O2 from
binding as well
• Symptoms: flushing,
nausea, and pain

14. • Occurs under cold water
• Breathing and pulse slows
• Blood shunts away from skin, stomach,
and muscles and is sent to the brain,
heart, and lungs
• Conserves O2 improving chances of
survival
• See UP 78-81
Extreme Respiration:
Mammalian Diving Reflex

15. Extreme Respiration: Diving
• High pressure deeper in the
ocean
• Tanks release pressurized
air containing O2
Extreme Respiration: High Altitudes
• Low atmospheric pressure, less O2
• Hypoxia – body is deprived of O2
• Body compensates by hyperventilation
• Pulmonary Edema may result