RESPIRATION
1. Human beings
need to breathe to sustain life.
2. Breathing involves the movement of air into and out of the respiratory
system.
3. The process of breathing in is called inhalation whereas
the process of breathing out is called exhalation.
4. The respiratory system consists of the following organs:-
i. nasal cavity
ii. pharynx
iii. larynx
iv. trachea
v. bronchus
vi. bronchiole
vii. lungs
viii. rib cage
ix. diaphragm
x. intercostal muscles
LUNGS
1. The lungs are
the respiratory organs.
2. The lungs are soft and
spongy and filled with air sacs. They are situated in the thoracic cavity
and are protected by the rib cage.
3. The lungs are connected
to the trachea by two
tubes. These tubes are the left bronchus and the right bronchus. These bronchi
(plural for bronchus) divide into smaller tubes known as bronchioles.
4. The bronchioles end in clusters of tiny air
sacs called the alveoli (singular,
alveolus).
5. Air enters through the
nasal cavity, and then moves through the pharynx, larynx, trachea,
bronchi, bronchioles and finally the alveoli.
6. The exchange of
respiratory gases (oxygen and carbon dioxide) occurs through diffusion in the alveoli.
7. Oxygen from the atmospheric
air diffuses out of the alveolus into the blood capillaries. At the same
time carbon dioxide from the cells diffuses out of the blood capillaries
into the alveolus.
8. The wall of the alveolus
is one-cell thick, moist and surrounded by blood capillaries. This is to
facilitate diffusion.
FUNCTIONS OF RESPIRATORY STRUCTURE
STRUCTURE
|
FUNCTION
|
Nasal cavity
|
Warms,
moistens, and filters air as it is inhaled.
|
Pharynx
|
Passageway
for air, leads to trachea.
|
Trachea
(Windpipe)
|
The passage
leading from the pharynx to the lungs.
Rings
of cartilage in the trachea keep the trachea "open".
|
Bronchi
(Pleural)
Bronchus
(Singular)
|
Two
branches at the end of the trachea, each lead to a lung.
|
Bronchioles
|
A
network of smaller branches leading from the bronchi into the
lung tissue and ultimately to the alveoli (air sacs).
|
Lungs
|
The lungs
are the respiratory organs. They are protected by the rib cage.
|
Intercostal
muscles
|
The contraction
and relaxation of the intercostal muscles helps in the breathing
mechanism.
|
Ribs
|
Bones supporting
and protecting the chest cavity. They move to a limited degree, helping
the lungs to expand and contract.
|
Diaphragm
|
Strong
wall of muscle that separates the chest cavity from the
abdominal cavity. By moving downward, it creates suction to draw in air
and expand the lungs.
|
Alveoli(Plural)
Alveolus(Singular)
|
Very small
air sacs where gases (oxygen and carbon dioxide) are exchanged (enter
and exit the blood stream).
|
Cilia
|
Very small
hairs that have a wave-like motion. This motion carries mucus (sticky phlegm or liquid) upward and out into
the throat, where it is either coughed up or swallowed.
|
BRAIN TWIST
The process of moving air into
and out of the lungs is something most people take for granted. But for
millions of people living with asthma, this simple activity requires
significant effort.
Asthma cannot be cured, but with
proper treatment it can be effectively controlled.
Without satisfactory control of
asthma, long-term damage can occur in the respiratory system. Poorly controlled
asthma can lead to reduced physical activities, and extra visits to the
emergency department.
Asthma is a condition that affects the air
passages of the lungs.
Millions of people suffer from asthmatic attacks every day.
