Respiratory System
Introduction
Respiration is the breakdown (oxidation) of digested food mostly (carbohydrate and fat), with oxygen from the air taken in the cells of animals to release energy and produce carbon dioxide.
Parts of Respiratory System
These are made up of all the organs working together to supply the blood cells with oxygen and to free the cells from carbon dioxide. These organs include the nose, mouth, trachea, bronchi, bronchioles and alveoli.
- Nose: The nose has two openings known as nostrils through which air enters into the lungs.
- Trachea: This is a ringed tube connecting the pharynx and the bronchus. It is known as the wind pipe which filters and moistens air.
- Bronchi: These are the two branches of the trachea, i.e. the left and the right trachea. Each bronchus leads air from trachea into the lungs.
- Bronchioles: These are small passages that are very many in number through which air passes into the alveoli.
- Alveoli: These are air sacs which make up the lungs and are surrounded by blood capillaries. Gas exchange takes place in the blood capillaries of the alveoli.
Functions of the Respiratory System
Breathing
This is the taking in of air (rich in oxygen) into the lungs which is inspiration and releasing of air (rich in carbon (iv) oxide) from the lungs. Which is expiration. Breathing involves the following:
i. External respiration: This is the exchange of oxygen and carbon (iv) oxide between the air and blood in the lungs.
ii. Internal respiration: This is the exchange of oxygen and carbon (iv) oxide between the blood and tissue fluid.
iii. Cellular respiration: This is respiration that occurs in the cells of the body to produce energy.
The Mechanism of Breathing
Air which is rich in oxygen and (carbon (iv) oxide) from the surrounding environment enters the body through the nose. From the nose that air get into bronchioles through the trachea, to the pharynx and the bronchus (Bronchi). From the bronchioles, the air enters the alveoli where it diffuses into the blood. The oxygen then oxidizes the digested food substances to produce energy and carbon (iv) oxide and water are given out as waste products.
Problems Connected with Breathing
These are the problems that come up when there is an alteration in the respiratory or breathing process. They include:
- Asthma: This is a disease of the bronchi and bronchioles that is marked by wheezing, breathlessness (shortness of breath) and sometimes coughs. It occurs as a result of inflammation of the airway due to irritation. Any person suffering from this ill health is allergic (sensitive in a bad way) to certain substances, such as dust, pollen, cigarette smoke and industrial fumes.
- Pneumonia: This is a viral or bacterial infection of the lungs in which the bronchi and alveoli are filled with a thick fluid making gas exchange difficult. A patient suffering from pneumonia suffers from headache, chest pain and sometimes high fever.
- Pulmonary Fibrosis: This is as a result of inelasticity of the fibrous connective tissues that build up in the lungs. Under certain conditions, for reasons that are poorly understood, lung damage leads to pulmonary fibrosis. In other words, the normal structure of the lungs is disrupted by the accumulation of fibrous connective tissues proteins.
- Pulmonary Tuberculosis: This is caused by bacteria. The bacteria cause the inelasticity of the lungs, thereby making breathing difficult
- Emphysema: This is the damage of the walls of the air sacs/ alveoli resulting in a reduced surface area for gas exchange. The surface area for gas exchange is reduced, hence the oxygen reaching the brain and heart is also reduced. When this happens, the patient may feel depressed and sluggish. Therapy for this problem includes giving up smoking, engaging in physical exercise and giving oxygen artificially.