RESPIRATORY SYSTEM
The human respiratory system consists of the nose, pharynx, larynx and windpipe. Let's study how is oxygen taken to the body cells and how carbon dioxide is removed from it. But before to understand respiratory system, have a look on respiration and breathing.
DIFFERENCE BETWEEN RESPIRATION AND BREATHING
RESPIRATION
It is a biochemical process in which a food molecule (glucose) is broken down in the presence of oxygen, and energy is released from it. This process is called aerobic respiration. As a result of this reaction, carbon dioxide and water are produced as by-products. The following equation describes the process of aerobic respiration.
Glucose + Oxygen ------>Carbon dioxide + Water + Energy
Sometimes, food is not broken in the presence of oxygen; it is converted into lactic acid which is later converted into carbon dioxide and water. Respiration in the absence of oxygen is called anaerobic respiration. It occurs in only a few organisms. In humans, when cells cannot get oxygen fast enough especially during exercise or any hard activity, they produce energy through anaerobic respiration.
Glucose -------> Lactic acid + Energy
In the human body, respiration involves:
• Intake of oxygen
• Release of energy
•Release of carbon dioxide and water
The human body requires oxygen for the process of respiration. What do you think how oxygen is supplied to the body? It is supplied continuously through the process of breathing.
BREATHING
Inhaling of oxygen through the nose or mouth and exhaling carbon dioxide is called breathing. It is a physical process. It supplies oxygen required for respiration. Carbon dioxide and heat produced during respiration as by-products are expelled from the body through breathing. Breathing is different from burning. Burning is a process in which a substance combines with oxygen and energy is released from it. For example, natural gas, petrol, coal, etc. cannot burn themselves if oxygen is absent. In presence of oxygen, the fuel combines with oxygen to release energy. The burning process also occurs in human bodies. In humans, food combines with oxygen and energy is released from it in the form of heat, oxygen is taken inside the body to be used by cells through a system called the respiratory system.
RESPIRATORY SYSTEM
The human respiratory system consists of the nose, pharynx, larynx and windpipe.
NOSE
Air enters the nose through openings called nostrils. Hair and mucous are present inside the nose that trap the dust particles present in air. Mucous is a jelly-like thick fluid. It moists and warms the air that enters the nose. From the nose air moves into the pharynx.
PHARYNX
It is a muscular passage for both food and air. Air enters the pharynx through two internal openings in the nose. The pharynx is also covered with mucous. From the pharynx air is moved to the larynx.
LARYNX
It is a cartilaginous structure present at the upper end of the trachea. Air flows into the trachea from the larynx. The opening of the larynx is called the glottis. A flap-like muscular structure is present on the glottis, called the epiglottis. It closes the trachea when we swallow food. The larynx is also called the voice box. It contains two thin fibrous bands called vocal cords. When air vibrates, these vocal cords produce sound. Thus, the respiratory system helps in communication as well.
TRACHEA
From the larynx, air enters the windpipe called trachea. It is a 10-11 cm long tube. It contains a series of C-shaped cartilaginous rings which prevent it from collapsing. At the lower end, the trachea divides into two tubes called bronchi. They also have cartilaginous rings. They take air to the lungs. On entering the lungs, the bronchi divide and subdivide into bronchioles. Bronchioles continue to divide and open into millions of air sacs called alveoli. An alveolus is a single layer structure. It contains a rich network of blood capillaries. It is a place where a gaseous exchange occurs.
LUNGS
These are spongy sacs present in the chest cavity. In humans the left lung is slightly smaller than the right lung to accommodate the heart in the cavity. They are covered with a thin membrane. An exchange of gases takes place in lungs. Let's study how this exchange occurs.
EXCHANGE OF GASES
When air enters the lungs, alveoli are filled with it. They take oxygen from air and pass it to the blood through thin walls of alveoli. Carbon dioxide and other waste gases present in blood pass through alveoli walls and enter the lungs. These gases then move out of the body with air.
In breathing, gases are exchanged between air and the body. Have you ever thought how they move in and out of the body?
MOVEMENT OF GASES
In the human body, intake of oxygen and removal of carbon dioxide occurs in two phases, i.e. inspiration and expiration.
INSPIRATION
When we inhale air, our ribcage moves upwards. A doom-shaped muscle diaphragm, present under the ribs, moves downwards. This increases the space in the chest cavity. Because of this, our lungs expand and air moves inside the body. This is called inspiration or inhalation.
EXPIRATION
When we exhale air, the ribcage moves downwards and the diaphragm moves upwards. This decreases the space in the chest cavity. which builds pressure on the lungs. As a result, the lungs contract and air is moved out of the body. This is called expiration or exhalation. Ribcage moves downwards. If we breathe in dirty and polluted air, we are posing risks to our respiratory system.
Let's study what factors affect our respiratory system and cause disorders.
COMMON RESPIRATORY DISEASE
The following are some common problems associated with the respiratory system.
ASTHMA
It is a condition in which bronchial tubes become narrow due to inflammation. Asthma can be caused by environmental or genetical factors. It may occur due to the presence of pollen or dust in air, smoke, cold air, etc. It is treated using inhalers. Asthma can be prevented by avoiding exposure to substances that trigger its attack.
PNEUMONIA
One of the most common respiratory problems is pneumonia. It is caused by microorganisms. In this disease, alveoli are filled with pus. The patient suffers from fever, shivering, chest pain or shortness of breath. It can be prevented by take care of cleanliness, eating healthy food, having enough sleep and intake of fluids.
For more information about pneumonia click here
THE COMMON COLD
It is caused by a virus that enters the body through the nose, eyes or mouth and moves down to the respiratory system. After entering the respiratory system, it keeps multiplying. As a result, the person suffers from cold and flu. Its symptoms are a sore throat, cough, fever, pain in joints and a runny nose. Generally the common cold fades away after completing its cycle in a few days. But care is important. It can be prevented by washing hands frequently, exercising daily and avoiding contact with infected people.
TUBERCULOSIS (TB)
It is a serious disease of lungs. It is caused by a bacterium and can be spread through coughing and sneezing. A person suffering from TB feels severe pain in the chest, coughing, weight loss, fever, fatigue, chills and loss of appetite. It can be prevented by keeping yourself and your environment clean.
SMOKING
Smoking tobacco causes many diseases of the respiratory system. It may cause inflammation in the air passage and can damage alveoli and lungs. The smoker may suffer from high blood pressure, short breath, fatigue and exhaustion. It can even lead to lung cancer. It can be prevented by eliminating smoking.
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