2. The Respiratory Systems
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3. Human Respiratory System
Functions:
Works closely with circulatory system,
exchanging gases between air and blood:
Takes up oxygen from air and supplies it to blood (for cellular
respiration).
Removal and disposal of carbon dioxide from blood (waste product
from cellular respiration).
5. Human Respiratory System Organs
1. Nose: Air enters nostrils, is
filtered by hairs, warmed,
moistened, and sampled for
odors as it flows through a
maze of nasal passages.
2. Pharynx (Throat): Intersection
where pathway for air and food
cross. Most of the time, the
pathway for air is open, except
when we swallow.
6. Human Respiratory System Organs
3. Larynx (Voice Box): Reinforced
with cartilage. Contains vocal
cords, which allow us to make
sounds by voluntarily tensing
muscles.
High pitched sounds: Vocal
cords are tense, vibrate fast.
Low pitched sounds: Vocal
cords are relaxed, vibrate
slowly.
More prominent in males
(Adam’s apple).
7. Human Respiratory System
4. Trachea (Windpipe): Rings of
cartilage maintain shape of
trachea, to prevent it from
closing. Forks into two
bronchi.
5. Bronchi (Sing. Bronchus): Each
bronchus leads into a lung and
branches into smaller and
smaller bronchioles,
resembling an inverted tree.
8. Human Respiratory System
6. Bronchioles: Fine tubes that
allow passage of air.
Epithelium of bronchioles is
covered with cilia and mucus
to trap and remove dust and
other particles.
7. Alveoli: air sacs at the end of
bronchioles where gas
exchange takes place.
9.
10. Gas Exchange
Gas exchange takes place in the alveoli.
Oxygen diffuses into the blood.
Carbon dioxide in the blood diffuses
into the alveolus.
Capillary
O2
CO2
11. How the Lungs Work
BREATHING
Lungs are sealed in
pleural membranes inside
the chest cavity.
At the bottom of the
cavity is a large, flat
muscle known as the
diaphragm.
12. How the Lungs Work
During inhalation, the
diaphragm contracts and
the rib cage rises up.
This expands the volume of
the chest cavity.
The chest cavity is sealed,
so this creates a partial
vacuum inside the cavity.
Atmospheric pressure fills
the lungs as air rushes into
the breathing passages.
13. How the Lungs Work
Often exhaling is a
passive event.
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.
Exhalation
Rib cage
lowers
Air Exhaled
14. Diseases of the Respiratory System
Asthma: Condition in which breathing is impaired by
constriction of bronchi and bronchioles, cough, and
thick mucus secretions. The severity and incidence of
asthma has risen dramatically in recent years,
especially in children. May be fatal if not treated.
Causes: Attacks may be precipitated by inhalation of
allergens (e.g.: pollen, cats, and cockroach proteins),
pollutants, infection, or emotional stress.
Treatment: Alleviates symptoms (e.g.: immuno-
suppressors, bronchodilators), but is not a cure.
15. Bronchitis: Inflammation of the mucous
membranes of the bronchi. May present with
cough, fever, chest or back pain, and fatigue.
Causes: Associated with smoking, pollution, and
bacterial or viral infections.
Pneumonia: Acute inflammation of the lungs.
Symptoms include high fever, chills, headache,
cough, and chest pain.
Causes: Bacterial, fungal, or viral infections.
Treatment: Antibiotics or other antimicrobials.
16. Lung Cancer: Cancerous growth that invades and
destroys lung tissue. Very high fatality rate.
Symptoms include bloody sputum, persistent cough,
difficulty breathing, chest pain, and repeated attacks
of bronchitis or pneumonia.
Causes: Smoking (50% of all cases) and pollution
(radon, asbestos). Smokers are 10 times more likely
to develop lung cancer than nonsmokers.
Treatment: Surgery is most effective, but only 50% of
all lung cancers are operable by time of detection.
Other treatments include radiation and
chemotherapy.
