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When we were kids, we learnt to walk, run, write and speak. However, you must have noticed that we never trained our lungs to breathe. Breathing is both a voluntary and an involuntary process. You can breathe willingly and you can breathe unconsciously or when sleeping. Breathing is a continual process that is extremely important for our survival. Besides humans, all other organisms on the globe breathe for their survival. We must know the mechanism of breathing and the organs involved. Read on to know about the mechanism of breathing in humans.
Understanding breathing
The process through which environmental air enters and exits the lungs is defined as breathing. Many other respiratory organs support the breathing process besides the lungs. We breathe in the environmental air during breathing and discharge carbon dioxide that can be utilised by plants for photosynthesis. During the breathing process, we extract the oxygen from the environmental air as it is necessary for our survival.
Breathing is a continual process and is carried out throughout the lifespan of an organism. The process of taking in environmental air is called inhalation whereas discharging carbon dioxide-rich air is called exhalation. One breath for any organism consists of inhalation and exhalation once. The number of breaths in sixty seconds is defined as the breathing rate of that organism.
The breathing rate can change according to the organism’s activity. The breath rate significantly increases when a person is running or doing heavy exercise. On the other hand, the breath rate significantly decreases when a person is sitting idle. For an adult human, the normal breathing rate is around 12 -16 breaths per minute. When involved in heavy exercise or any other similar activity, the breath rate goes up to around 25 times in sixty seconds.
Mechanism of breathing in humans
When you explain the mechanism of breathing, you have to explain the inspiration and expiration process. When the air enters the lungs, there is a fall in the air pressure in alveolar spaces. Similarly, the air pressure in alveolar spaces exceeds the atmospheric pressure when lungs give out air. The flow of the air inside our respiratory organs is proportional to the pressure difference. Let us understand inspiration and expiration, which are the main processes in the mechanism of breathing.
Mechanism of inspiration
Inspiration is an active process that involves the intake of environmental air. Human lungs are placed in the thoracic cavity. When inspiration takes place, the overall volume of the thoracic cavity increases. At the same time, the air pressure inside the thoracic cavity decreases. During the inspiration process, the muscles surrounding the ribs contract. Due to contraction in intercostal muscles, an increase in the volume of the thoracic cavity is observed.
During inspiration, the diaphragm contracts which also increases the volume of the thoracic cavity. In the meantime, lungs expand during inspiration and the air pressure inside the lungs experiences a downfall. As the air travels towards the low pressure from high pressure, environmental air rushes into our lungs during inspiration. Inspiration is the first process in the mechanism of breathing which, is followed by expiration.
Mechanism of expiration
The expiration process is commenced after the exchange of gases has occurred in the respiratory tract. The discharge of carbon dioxide-rich air is called expiration. During the expiration process, the muscles surrounding the ribs contract. At the same time, the abdomen and diaphragm muscles relax and the volume of the thoracic cavity decreases.
During the expiration process, the air pressure inside the lungs increases. Since the air pressure inside the lungs becomes more than the atmospheric pressure, carbon dioxide-rich air is pushed out of the lungs. The discharge air gets out of our bodies via the nose. Expiration is a passive process that is equally important as inspiration. When you describe the mechanism of breathing in human beings, make sure you explain both, inspiration and expiration.
What is respiration in human beings?
Most of us think that respiration and breathing are used interchangeably. However, there is a difference between respiration and breathing. Respiration is a complex process that includes breathing and the diffusion/exchange of gases. The exchange of gases in human beings occurs via alveoli. Alveoli helps in the diffusion of oxygen into the blood which completes the respiration process.
The exchange of gases is important for the human body as we need to absorb oxygen in our blood. Similarly, the discharge of carbon dioxide is equally important. The gases are exchanged on the surface of the alveolus.
