Human Respiratory System Functions

It is a common fact that there are different bodily systems assigned with different functions. This includes the digestive system, nervous system, reproductive system, circulatory system, endocrine system, immune system, integumentary system, muscular system, respiratory system, skeletal system, urinary system, lymphatic system, etc. These systems comprise various organs, whose joint efforts help in successfully performing their individual function. This article deals with the human respiratory system functions.

Human Respiratory System

In simple words, human respiratory system can be explained as a group of organs that help us to breathe. Breathing involves inhalation of oxygen and exhalation of carbon dioxide. Even though, the process of breathing appears to be very simple, it involves the proper functioning of various organs. The human respiratory system parts include the nose, nasal cavity, pharynx, larynx, trachea, bronchi, alveoli, lungs, etc. The respiratory system organs are classified into two sections - the upper respiratory tract that includes the nose, nasal cavity, pharynx and larynx and the lower respiratory tract that contains the trachea, bronchi, alveoli and lungs. These organs enable us to breathe. But, respiratory system functions are not so simple, as we think. It involves various intricate details, that will be discussed in the following paragraph.

Functions of Human Respiratory System

Oxygen is required by the body cells for their normal functioning and this requirement is fulfilled by the human respiratory system. During this process, it helps in expelling the carbon dioxide that is discarded by the cells as metabolic waste. So, the most important and primary function of the system is to supply oxygen to the body cells. A basic idea about the respiratory system will be beneficial in understanding these functions.

During inhalation, air is drawn from the atmosphere, through the nose (sometimes, through mouth too). This is caused by the contraction of the diaphragm (the sheet of muscles that separate the thoracic cavity from the abdominal cavity) and the intercostal muscles attached to the ribs. As they contract, the volume of the thoracic cavity increases, thereby decreasing the air pressure. This results in inhalation, that is the process of drawing in air from the atmosphere, so that the thoracic cavity gets filled. Now, you know more about the role of diaphragm function in facilitating respiration.

The air taken through the nose is filtered, moistened or heated in the nasal cavity, before it passes to the pharynx. The pharynx is a pathway that is common for both air and food and is continuous with the esophagus. Pharynx function is to facilitate passage of air to the trachea. However, the pharynx opens up to the wind pipe or trachea, in order to facilitate breathing. The flap-like structure (called epiglottis) located just above the opening, closes this orifice, when food is swallowed. This structure ensures that food particles do not enter the trachea. It is near this opening that the voice box or the larynx is situated. This structure performs the function of protecting the trachea and also for production of sound.

The air enters the trachea or windpipe, which is a tube-like structure with tough covering. Trachea functions include facilitating air passage and moistening of the air. The trachea branches into two tube-like structures called bronchi. Each bronchus travels into the left and right lungs respectively. Lungs is the spongy structures that house the bronchi, which divide into numerous tubes called bronchioles. Each bronchiole ends with numerous circular sacs called alveoli. The alveoli are the basic functional units that facilitates gaseous exchange, which is the most important among the human respiratory system functions. The carbon dioxide expelled by the cells are carried by the venous blood to the alveoli. The alveoli contain numerous thin-walled capillaries through which blood passes. Inside the alveoli, the carbon dioxide is released and oxygen is drawn inside the capillaries. The oxygenated blood is carried to the heart, which pumps it to the different parts of the body. Now, you have a basic idea about the alveoli function too. So, during inhalation, oxygen is absorbed and carbon dioxide is expelled during exhalation that is caused by relaxation of the diaphragm and the intercostal muscles.

The above said is only a brief overview of the human respiratory system functions that includes many more complex and intricate details. You may also conduct a deep study into the subject, for knowing more about the system.