Transcript Respiratory System File

The Respiratory System - Obj. 12
How (& where) the body exchanges gases
(O2 & CO2) with the outside
environment.
Closely connected with the circulatory and
digestive systems
Respiration refers to all parts of the
process of supplying oxygen and
eliminating carbon dioxide
The Respiratory System cont’d
Most organisms on earth are
aerobic i.e. oxygen is needed
for their cells to function.
It’s needed for cellular respiration
(process that uses oxygen to
produce energy, and produces
carbon dioxide waste).
Obj. 12
Two major requirements of every respiratory system
1. The respiratory surface must be large enough for gas exchange to
occur fast enough to meet the needs of the organism.
2. Respiration must occur in a moist environment, so that the oxygen and
carbon dioxide are dissolved.
The lung
The internal respiratory surface
that is connected to the air by
means of internal passageways.
Characteristic of air breathing
vertebrates.
Lung systems vary by species, but all consist of three basic elements:
1. One or two lungs with a moist respiratory surface.
2. A way to use force to bring air in contact with the lung surface.
3. A circulatory system to carry gases between the lungs and other
cells of the body.
Mammalian Respiration
Subdivided into 4 categories:
Breathing - Inspiration (the act of taking air in) and
expiration (breathing out)
External Respiration - The exchange of oxygen and carbon dioxide
between air and blood.
Internal Respiration - The exchange of oxygen and carbon dioxide
between blood and the cells of surrounding tissue.
Cellular Respiration - complex cellular reactions that take place
in the mitochondria of cells (uses O2 to produce energy and
CO2)
The Respiratory Tract
fig.10.4-10.7
pg.335-337
Lungs are fragile, delicate structures.
Located deep within the body in the thoracic cavity (made of bone {ribs} and
muscle) which protects them from damage and water loss.
So how does air reach the lungs?
-
Nasal Cavity
Pharnyx
Glottis
Larnyx
Trachea
The Upper Respiratory Tract - Obj 13
Made up of:
Nasal Cavity: air enters the nasal cavity through the
nose. The air is filtered, moistened and warmed, to
protect the delicate surface of the lungs.
Pharynx: A section of alimentary canal that connects
the mouth and nasal cavity to the larynx and
esophagus.
Glottis: The opening of the trachea.
pg.335-336
Larynx: voice box, houses vocal cords.
Trachea: a flexible tube also known as the
windpipe. The trachea carries air to the
bronchi.
The upper respiratory tract is lined with ciliated
cells that secrete mucus which traps dust and
bacteria. The cilia moves this material up to the
nose and mouth where it can be expelled by
coughing or sneezing (fig. 10.5).
The Lower Respiratory Tract
Consists of:
bronchi - at armpit level the trachea
divides into 2 smaller passages the
bronchi (1 is called a bronchus).
One bronchus enters each lung.
bronchioles - when the bronchi enter
the lungs they branch many times
to form a network of very fine
tubes called bronchioles
Obj.13 pg.336-337
alveoli - Each bronchiole ends in a grape like
cluster of tiny sacs called alveoli ( singular
alveolus).
- Their walls are only one cell thick and
are next to capillaries, this is where air
exchange occurs.
- exchange usually takes place via simple
diffusion, but some is through facilitated
diffusion which allows for more oxygen
pickup.
each lung is divided into lobes:
right - 3 lobes
left - 2 lobes (leaves room for heart)
lobes consist of lobules, each of which has
its own bronchiole
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Gas Exchange
Gas exchange occurs across cell
membranes. Oxygen entering the
alveoli dissolves in the fluid lining
and diffuses into the bloodstream
within the capillaries.
Gas diffuses from high to low
concentration.
O2 diffuses from air to blood while CO2
diffuses from blood to air
The Mechanics of Breathing Obj. 14
● Breathing occurs because air
moves from an area of higher
pressure to lower pressure.
● Intercostal muscles control the
air pressure inside the lungs
by manipulating the ribs.
● The diaphragm separates the
thoracic (chest) cavity from the
abdominal (stomach) cavity.
pg.338-342
Inhalation happens when...
The intercostal muscles contract
which lift the rib cage up and
out
The diaphragm contracts and pulls
down
The pressure in the lungs decrease
with the extra expansion
Air moves in
Exhalation happens when...
The intercostal muscles relax which
allows the rib cage to move down and
in
The diaphragm relaxes and moves up
The pressure of the lungs increases
forcing air out.
Respiratory Diseases
Obj.15 pg.343348
We don’t realize how important our ability to breathe is until it is compromised
in some way
Disorders and diseases can cause problems in our ability to breathe or exchange
oxygen for carbon dioxide.
Environmental quality and personal lifestyle choices impact on the health of our
lungs and entire bodies.
Common respiratory diseases include:
1) lung cancer
2) pneumonia
3) asthma
4) emphysema ** discuss only
5) bronchitis ** discuss only
(fig 10.12 pg 343).
1.Lung Cancer
Lung cancer is the uncontrolled and invasive growth of
abnormal cells in the lungs. This is usually the result of
cigarette smoking.
Symptoms are usually delayed. They include:
chronic coughing
coughing up blood
weight loss and loss of appetite
shortness of breath
chest pain
fever
Treatment may be surgery, radiation therapy, and chemotherapy.
2. Pneumonia
Pneumonia occurs when the alveoli
inflame and fill with liquids.
This prevents the intake of oxygen.
The main causes of pneumonia include
infection by bacteria, viruses, fungi and
other agents.
lobar (effects a lobe) and bronchial
(effects patches of the lung) (Fig
10.16)
Treatment with antibiotics is successful as
a cure.
3. Asthma - p. 346 & 348
Asthma is extreme sensitivity of the lungs which
result in obstruction of the airways.
The symptoms occur as attacks. The airway swells, the
bronchial muscles tighten and increased mucous is secreted
into the airway. This makes breathing difficult.
Common triggers include:
colds and chest infections
exercise and sports
exposure to pollen, flowers, grass, plants or trees
tobacco smoke, dust, cold air, pets, mould or mildew, air pollution
Treatment includes medications and avoidance of triggers.
Impact of Environmental Factors on Asthmatics
Obj 16
The following factors have a big impact on asthmatics:
Cigarette smoke – A well-known trigger that can cause an asthma attack.
Also contains carcinogens, which can cause cancer (lung cancer).
Allergens (dust, mould, food) – These are small particles found in the air
we breathe.
Most are removed in the upper respiratory tract when we inhale, but some
make it into the lungs and can cause an allergic reaction that triggers an
asthma attack.
Perfumes and petrochemical fumes – Odours or fumes that can cause an
allergic reaction and trigger an asthmatic attack.