Structure and Function of the Respiratory System

Running head: BIOLOGY
BIOLOGY
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BIOLOGY
Respiratory system:
Structure of respiratory system:
 The respiratory system comprises of all organs involved in breathing procedures.
These are seen to include nose, pharynx, trachea, bronchi and the lungs. The first four
component mentioned all work like a system of pipes and through this pipeline like
system, air ultimately funnels down to the lungs (Rizzo 2015)
 Very small air sacs that are called alveoli are present in the lungs mainly in the top
region of the bronchioles ( division of the bronchi). This helps in exchange of oxygen
and carbon-dioxide between the lungs and blood systems.
 The lungs are two lobed paired cone shaped organs with right lung having three lobes
and left lung having two lobes. Lungs are broken into smaller portions called
bronchio-pulmonary segments. Air enters into the lungs through system of pipes
called bronchi. These mainly start at the bottom region of trachea as left and right
bronchi and branch many times throughout lungs until they form alveoli.
 Lungs remain covered by smooth membranes called pleurae having two layers called
visceral and parietal layers helping the systems to breathe without any friction
(Beachy 2015)
 For respiration, muscles are important. Diaphragm is a large sheet like muscle
stretching across the chest under the region of ribcage. This help in expanding the
space in chest allowing more air to enter. Other muscles are muscles of ribs called
intercostals muscles and help in moving the ribcage in and out.

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BIOLOGY
Fig: structure of respiratory system: Source: (Beachy 2015)
Fig: structure of respiratory system: diaphragm; Source: (Protti et al. 2015)

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BIOLOGY
Function of respiratory system:
 The respiratory system helps in breathing which is also called pulmonary ventilation.
In this process, air is inhaled through the nasal cavities as well as the oral cavities.
This air is then seen to move through pharynx, larynx and then trachea to finally the
lungs. Then air is exhaled flowing back through the same pathway. In this oxygen and
carbon-dioxide are taken in and exhaled out respectively by the respiratory system
(Protti et al. 2015).
 Inside the lungs, oxygen gets exchanged for carbon dioxide waste through the
procedure called external respiration. This respiration tales place through millions of
alveoli which are microscopic sac like structure aiding the process
 The bloodstream helps in delivering the oxygen towards the cells and thereby
removes carbon-dioxide through internal respiration. From the capillary system,
oxygen is realised in the tissues and then into cells. Glucose breaks down in presence
of oxygen to produce energy and carbon-dioxide is released. That is carried back by
the blood again to lungs to be exhaled out (Hansen 2017).
 During exhalation, air passes from the lungs through the voice box or larynx. Air
vibrates the vocal cords to produce sound. Phonation is the creation of sound by the
different structures that are present in the region of the upper respiratory tract.
 It also plays role in olfaction or smelling which is a chemical sensation (Scanlon and
Sanders 2018)
Conditions necessary for effective gaseous exchange:
A number of conditions need to be present so that gas exchange can take place successfully.
These are as follows: