The process by which energy is released by the breakdown of food is known as respiration. The normal respiration rate in an adult is 14 to 18 per minute with a tidal volume of about 500 ml. The rate and depth of respiration are adjusted according to the requirement of the body. 

Organs involved in respiration in human

The main organs of the human respiratory system are the nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, and lungs. These organs work in coordination to assist in breathing. Breathing and respiration are different from each other. Breathing comprises inhalation and exhalation. When we take the air in through the nostrils, it is called inhalation or inspiration. 

Breathing out air is called exhalation or expiration. Respiration is the process of breaking down simple molecules like glucose to produce energy. Thus, respiration is a crucial process to produce energy for the proper functioning of the human body. 

Types of Respiration

The meal (glucose) is broken down to release energy. There are two forms of respiration based on the usage of oxygen: aerobic respiration and anaerobic respiration.

• Aerobic Respiration:

In this process, glucose is broken down with the help of oxygen. Along with the release of energy, glucose breaks down into carbon dioxide and water.

 • Anaerobic respiration:

This is when glucose is broken down without the need for oxygen. Along with the release of energy, glucose breaks down into alcohol and carbon dioxide. Yeast, for example, can thrive in the absence of oxygen and obtain energy through anaerobic respiration. 

Breathing

Breathing is the process by which air moves in and out of the lungs and is carried out by numerous respiratory organs such as the nostrils, pharynx, larynx, trachea, bronchi, bronchioles, lungs and alveoli. 

• The breathing rate is the number of times a person breathes in a minute.
• When you breathe, you alternate between inhaling and exhaling.
• A breath is defined as one inhale followed by one exhale. 

When a person needs additional energy, he or she breathes quicker. As a result, our cells receive more oxygen. It accelerates the breakdown of food, releasing more energy. At rest, an adult human breathes 15–18 times per minute on average. The breathing rate might increase to 25 times per minute during vigorous exercise.

What are the ten organs of the respiratory system?

• Nostrils: A pair of openings in the nose which lead to the nasal passage. 

• Nasal cavity: It is divided by the nasal septum into two nasal passages. The internal walls of the nasal passages are lined with numerous minute hair and mucus. This helps to trap dust and other particles and prevent them from entering the nasal chamber. 

• Pharynx: The pharynx is a hollow tube that connects to the top of the trachea and the oesophagus. It is the common passageway for food and air. 

• Larynx: The larynx is a cartilaginous box-like structure that contains vocal cords. It produces sound, so it is also known as the sound or voice box. It is situated right at the junction of the pharynx and trachea. 

• Trachea: The trachea is a tube-like structure that goes up to the middle of the thoracic cavity, where it bifurcates into a pair of bronchi. On the walls of the trachea, there are C-shaped cartilaginous rings called tracheal rings. These rings give support to the wall of the trachea and help to keep the airway open. 

• Bronchi: The two branches of the trachea, right and left bronchi, enter the lungs from their respective sides, where they keep dividing till they form numerous minute branches called bronchioles. 

• Lungs: Lungs are large, conical, air-filled structures situated in the chest (thoracic) cavity on either side of the chest. Each lung is covered by a two-layered membrane called pleura. A pleural liquid is filled between the two layers. This liquid reduces the friction on the lung’s surface. The lungs’ purpose in the human body is to provide a surface for gaseous exchange. 

Lungs are filled up with a large number of air sacs that are present at the end of each bronchiole. These air sacs are called alveoli. Alveoli are small spherical air pockets with a rich supply of blood capillaries in their thin walls. Alveoli provide increased surface area for the exchange of gases. 

Conclusion 

To obtain energy from food, all living organisms need respiration. The entire process of breathing is a form of respiration. Gas exchange, endogenous and foreign agent metabolism and defence against diseases and harmful chemicals are all roles performed by the respiratory system. The respiratory rhythm is maintained by the respiratory centre (present in the medulla) to suit the demands of the body. The chemosensitive areas of the brain recognise the changes in the concentration of carbon dioxide (CO2) and send signals to the respiratory centre to adjust the respiratory rhythm accordingly. Therefore, it is one of the most important and complex tasks executed by our bodies.