Respiratory System

Like any other living organism on Earth, a human needs oxygen. Several minutes without oxygen can be life-threatening for the human. Oxygen consumption is a vital activity, because it is involved in many processes in our body. In some amounts, oxygen penetrates the body through the skin surface. However, this amount is not enough for a proper function of the internal human systems. Sufficient oxygen supply is provided by the respiratory system. It is a complicated system of cavities and pipes that regulate the oxygen supply to the body, as well as its transportation.

 respiratory systemThe human respiration organs include of the lungs and respiratory passages. The latter ones are subdivided into the upper (nasal cavity, oral cavity, nasopharynx, pharynx) and the lower (larynx, trachea, bronchi) respiratory passages. Correct breathing is provided by respiratory muscles. The main ones are the diaphragm, however, some other muscles are involved into the process, such as intercostal, scaleni and others.

Nasal cavity

When we breathe, the air, first of all, gets into our nose. There, it not only freely passes further, but also clears from dust, and warms up. The ciliated epithelium of the nasal mucosa filters the air by retaining small foreign particles. The mucous glands of the nasal cavity produce lysozym, that performs two functions: moisturizing and bactericidal action. After that, the clean, warm and moisturized air passes further, to the larynx.

Trachea and bronchi

The trachea divides the incoming air into two parts. Each air flow is directed to each lung along the bronchi. In their turn, the bronchi have a lot of small tubes that spread around the lungs. Thanks to this, they equally distribute the air around the lungs. Each tube has an alveolar sac on its end. The sacs release the oxygen into the blood, that transport it to other organs.

Alveoli and lungs

Lungs are a paired organ that performs gas exchange. There are about 700 million small bubbles in the lungs, called alveoli, that participate in this process. They release oxygen into the blood every time we inhale, and take out carbon dioxide every time we exhale.

It is interesting to note, that beside oxygen supply and carbon dioxide removal, the respiratory system has some other functions:

Thermoregulation: The temperature of the incoming air affects the temperature of the body in general. Moreover, when breathing out, a person releases heat into the environment, cooling down the body.

Clearance: With exhalation, the body can remove not only carbon dioxide, but also other substances like water vapor or ethyl alcohol.

Maintenance of immunity: Lung cells are capable of neutralizing viruses and pathogenic bacteria.