Respiration: Transport Of Oxygen And Carbon Dioxide

What Is Respiration?

Respiration is the process through which living organisms generate energy from food. It communicates with the environment through a two-way exchange: oxygen and carbon dioxide. Thus, it is extremely crucial for maintaining life, supplying the cell functions with the required amount of oxygen and removing metabolic by-product carbon dioxide.

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It is the system by which the body acquires oxygen and rids itself of carbon dioxide. The sub-functions associated with this component system are the nose, pharynx, larynx, trachea, bronchi, and lungs. Essentially, the task of the respiratory system—responsible for gas exchange—is to take in oxygen and give out carbon dioxide.

Anatomy Of The Respiratory System

The respiratory system consists of the upper and lower respiratory tracts. The upper respiratory tract is made up of the nose and pharynx, while the lower respiratory tracts are made of the larynx, trachea, bronchi, and lungs. Gas exchange occurs within the alveoli, which are the small air sacs within the lungs.

Mechanisms Of Breathing

Breathing is the process of inspiration and expiration. When a person inhales, oxygen enters the lungs, and while exhaling, carbon dioxide is expelled out of the system. It is performed by pressure changes in the thoracic cavity due to the contractions of the diaphragm and intercostal muscles.

Processes Of Inhalation And Exhalation

As we inhale, the diaphragm contracts, and with an increased thoracic cavity, air rushes into the lungs. On the other hand, exhaling occurs when the diaphragm relaxes, decreasing the volume of the thoracic cavity, hence pushing air out of the lungs.

Transport Of Oxygen During Respiration

Oxygen is delivered by the bloodstream from the lungs to various parts of the body. The transport of oxygen depends mainly on a protein called haemoglobin present in red blood cells.

Role Of Haemoglobin In Oxygen Transport

In the lungs, oxygen binds to a haemoglobin molecule and then travels via the circulatory system to release bound oxygen into body tissues at areas where the partial pressure of oxygen is low.

Oxyhemoglobin Dissociation Curve

The oxyhemoglobin dissociation curve is a graph showing the relationship between oxygen saturation and partial pressure of oxygen. The graph accounts for how easily haemoglobin picks up or loses oxygen under different physiological conditions.

Transportation Of Carbon-Di-Oxide During Respiration

Carbon dioxide, being the metabolic waste product, is transported from the tissues for exhalation in the lungs in the following three major ways: dissolved in plasma, as bicarbonate ions, and bound with haemoglobin.

Forms Of Carbon Dioxide Transported

Carbon dioxide directly dissolves in plasma in a small amount.

• Bicarbonate Ions: The majority of carbon dioxide is converted to bicarbonate ions, with the help of the enzyme carbonic anhydrase

• Bound to Hemoglobin: Carbon dioxide combines with haemoglobin and forms carbaminohemoglobin

Gas Exchange In The Lungs

The exchange of gases takes place in the alveoli. Oxygen diffuses into the blood while carbon dioxide moves into the alveolar air due to partial pressure gradients.

Structure And Function Of Alveoli

Alveoli are small balloon-like structures with very thin walls. They ensure the efficient exchange of gases. They are surrounded by capillaries which permit diffusion of oxygen and carbon dioxide across the membranes.

Control Of Breathing

Breathing is controlled by the medulla oblongata and pons in the brainstem. These parts monitor the amount of oxygen and carbon dioxide in the body and change the breathing depth and rate accordingly.

Role Of Chemoreceptors

Chemoreceptors present in the carotid and aortic bodies detect changes in oxygen and carbon dioxide in the blood and send signals to the brain to adjust breathing.

Cellular Respiration

Cellular respiration refers to the process by which cells obtain their energy. In this process, one glucose molecule is broken, which eventually forms carbon dioxide, water, and ATP.

Aerobic Vs Anaerobic Respiration

• Aerobic Respiration: It occurs in the presence of oxygen, and it yields a bigger amount of ATP.

• Anaerobic Respiration: It refers to an activity occurring without oxygen; with lactic acid, it yields less ATP.

Disorders Of Gas Transport

It may involve several disorders in gas transport, representing a variety of conditions that include hypoxia, hypercapnia, respiratory acidosis, and alkalosis. Common respiratory diseases like chronic obstructive pulmonary disease can result in impairment of gas exchange.

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