The Respiratory System is one of the vital systems in the Human body plays a major role in providing adequate oxygen to all the parts of the body and
removing the waste like carbon dioxide during the process of Inhalation and
Exhalation.
A respiratory system is a group of organs like Airway, Lungs, pulmonary
vessels and respiratory muscles which are responsible for taking in
oxygen and sending out carbon dioxide.
Oxygen
is very essential for the proper function of each and every tissue within the
Human body.
The
respiratory system is divided into two main parts, Upper and
Lower respiratory tract.
A. Upper respiratory
tract: B. Lower
respiratory tract:
A. Nose A. Trachea
B. Pharynx B. Lungs (Bronchial tree
& Alveoli)
C. Larynx
Air enters the nose/ mouth and passes the sinuses (hollow
spaces in the skull). Sinuses (Frontal, Ethmoid, Maxillary and Sphenoid) help
to regulate the temperature and humidity of the air.
Then air moves into Pharynx, Both food and air passes
through the pharynx before reaching their appropriate destinations (Food to
esophagus and Air to Larynx)
Then the air passes into the larynx, which is essential
for speech, (contains twofold called vocal cords. Opening between the vocal
cords are the glottis. As the air leaves the lungs, the vocal cords vibrate and
produce sound). Then the air passes into Trachea.
Epiglottis is
like a lid over the opening of larynx, Attached to the root of the
tongue. Which closes the larynx while food passing.
The Trachea (windpipe)
filters the air that is inhaled. It branches into the bronchi (Right and left),
which are two tubes that carry air into each lung. The bronchial tubes are
lined with tiny hairs called cilia. Cilia move back and forth, carrying mucus
up and out. Mucus - a sticky fluid collects dust, germs and other matter that
has invaded the lungs. (Usually, we expel mucus when we sneeze, cough or spit).
The bronchial tubes lead to the lobes of the lungs. The right lung has three
lobes whereas the left lung has only two lobes. Smallest branches are called
Bronchioles.
— Bronchial tubes are lined with tiny hairs called
cilia, move back and forth and carrying mucus up and out.
— Mucus a sticky fluid collects dust, germs and other
matter that has invaded the lungs.
Lungs: Spongy organ present in the thoracic cavity, the left
lung is smaller than the right lung due to the presence of the heart more
towards the left.
Lobes are filled with small, spongy sacs called alveoli, and this
is where the gases exchange of oxygen and carbon dioxide occurs. The
alveolar walls are very thin. These walls are composed of a single layer of
tissues called epithelial cells and tiny blood vessels called pulmonary
capillaries. Blood passes through the capillaries.
Pleura are the outer
covering of the lungs and pleural fluid present within act as a lubricant.
Consists of two
layers
— Visceral
pleura attached to the surface of the lung; inner layer closer to the lungs
— Parietal
pleura attached to the chest wall; the outer layer, closer to the ribs
The pulmonary artery carries deoxygenated blood containing more carbon dioxide
and less in oxygen to the lungs, where the carbon dioxide gas moves from the
blood to the alveoli and oxygen moves from alveoli to blood. Finally the
Oxygenated blood (Blood containing more oxygen) goes to the heart through the 4
pulmonary veins and the heart pumps it throughout the body.
The diaphragm is a dome-shaped muscle at the bottom of the lungs
controls breathing and separate the chest cavity from the abdominal cavity.
A. Contracts - Moves downward, enlarge an area in the thoracic cavity, decreasing internal air pressure, so that air
flows into the lungs to equalize the pressure.
B. Relaxes - When the lungs are full, the diaphragm relaxes and elevates, Makes the area in the thoracic cavity smaller,
thus increasing air pressure in the chest, Air is expelled out of the lungs to
equalize pressure.
Inhalation - Air is taken in through nose/mouth. Inhalation is
initiated by the diaphragm and supported by the external intercostal muscles.
When the diaphragm contracts, the rib cage expands and the
contents of the abdomen are moved downward. This results in a larger thoracic
volume and negative pressure (with respect to atmospheric pressure) inside the
thorax. As the pressure in the chest falls, air moves into the lungs.
While taking a deep breath, the external intercostal muscles and
accessory muscles assist in further expanding the thoracic cavity.
Exhalation - is a passive process - air is moved or exhaled out. Active
or forced exhalation is achieved by the abdominal and the internal intercostal
muscles.
The lungs have a natural elasticity capacity, as they recoil from
the stretch of inhalation. Air flows back out until the pressures in the chest
and the atmosphere reach equilibrium.
During forced exhalation, expiratory muscles including the
abdominal muscles and internal intercostal muscles generate abdominal and
thoracic pressure, which forces air out of the lungs.
The average rate of breathing is dependent upon age,
For adults - The normal respiratory rate is 12 to 16 breaths per minute
(It may reach 45 breaths per minute during strenuous exercise).
The newborn –
The normal respiratory rate is about 40 breaths per minute (It may slow down to
20 breaths per minute when the baby is sleeping).
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