All organisms respire to survive. The complexity of the respiratory components varies with organisms. Some respire through the skin, while some use gills. Most vertebrates respire with the help of lungs. They are the major sites for gas exchange. Plants also possess structures like stomata and lenticels to exchange gases.
Breathing is fundamental to survival, and though we possess the ability to consciously control the rate of our breathing, it is otherwise an automatic process. There are a number of components and complex actions involved in this whole process of respiration.
Respiration in Humans
The human lungs are an astounding feature of nature. They typically pump oxygen through the airways, which reaches our bloodstream every second of our life. The anatomy of the respiratory system starts at the site where air first enters the human body—the nose. Through the nose, it reaches the pharynx and larynx. After travelling through the larynx, the air moves through the windpipe or trachea. Here, the air is moistened and cleansed before entering the lungs. Now the clean air travels into the tissues present deep inside the lungs, where the gas exchange takes place. It is eventually considered the centre for respiration.
Parts that aid in respiration
Let’s have a look at the anatomical structures that help us in this breathing process.
- Nose – The nostrils are covered with tiny hairs and act as the first line of defence. They also provide extra humidity to the air inhaled.
- Pharynx – The nasal chamber leads to the cone-shaped passage, which is common for both food and air.
- Larynx – This voice box is a hollow tube that is present in front of the neck. It keeps the food out of the lower respiratory tract.
- Trachea – The windpipe is found below the larynx and moves further down the neck. It splits into tubes called bronchi that enter the lungs.
- Lungs – Typically, the right lung is slightly larger than the left. The interior of the lungs has small air passages called bronchioles. It further divides into smaller air sacs known as alveoli. The exchange of carbon dioxide and oxygen happens here.
The mechanism of breathing or respiration is not only reliant on the above-mentioned parts but is also associated with the brain and central nervous system. Breathing is an automated function in which nerve impulses from the brain stimulate the respiratory muscles to contract, thereby producing the mechanical forces associated with exhalation and inhalation. These impulses give rise to every breath in a living individual.
Do Cells Breathe?
The energy-generating metabolic process that happens inside the cells of an organism (animals and plants) is called cellular respiration. Here, the glucose molecule is broken down to provide energy. This metabolic process can be classified into two groups—anaerobic and aerobic respiration. The main difference between aerobic and anaerobic respiration is that the former happens in the presence of oxygen, and the latter happens in the absence of oxygen.
In aerobic respiration, the glucose is broken down into water and carbon dioxide in the presence of oxygen. In anaerobic respiration, the by-products are carbon dioxide and ethanol or ethyl alcohol. Anaerobic respiration is seen in small organisms such as yeast and bacteria. Whereas most large organisms use aerobic respiration. However, sometimes our muscles do undergo anaerobic respiration during vigorous exercise. Here, the by-product is lactic acid instead of carbon dioxide.
Thus, not only in different organisms but also within the same organism, we can find different types of respiration.
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