Human Respiratory System Overview

The respiratory system is a vital physiological system in humans that facilitates the exchange of gases between the air and the blood and between the blood and the body's cells. It plays a significant role in supplying essential oxygen to all cells in the body and removing waste carbon dioxide. The system is responsible for breathing, which involves the inhalation and exhalation of air, as well as the exchange of gases between the air and the blood.

The system can be divided into the upper respiratory system and the lower respiratory system. The upper respiratory system includes the nose and nasal cavity, pharynx, and larynx. These structures warm and clean the air we inhale, as well as allow us to smell and speak. The lower respiratory system consists of the trachea, bronchi, bronchioles, and alveoli. The trachea is a muscular tube reinforced by cartilage rings and lined with a mucous membrane, which extends into the lungs.

The alveoli within the lungs are the microscopic air sacs where gas exchange takes place. They are elastic, thin-walled structures arranged in clumps at the ends of respiratory bronchioles. Oxygen from inhaled air diffuses into pulmonary capillaries surrounding the alveoli, while carbon dioxide from deoxygenated blood diffuses into the alveoli and is expelled through exhalation.

The respiratory system works in conjunction with the circulatory system to deliver oxygenated blood to cells and remove waste carbon dioxide through internal respiration. During internal respiration, red blood cells carry oxygen absorbed from the lungs around the body through the vasculature.

The respiratory system is regulated by the autonomic nervous system, which helps maintain a stable internal environment by controlling the rate and depth of breathing. Changes in the volume and air pressure in the lungs trigger pulmonary ventilation, causing the diaphragm and external intercostal muscles to contract and the ribcage to elevate during inhalation.

In summary, the respiratory system is a complex physiological system that plays a crucial role in maintaining the body's health by facilitating the exchange of gases between the air and the blood and between the blood and the body's cells.