In humans, the anatomical features of the respiratory system include airways, lungs as well as the respiratory muscles. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood. This exchange process happens in the alveolar region of the lungs.
Respiratory disease is a medical term that encompasses pathological conditions that affect the organs and tissues that make gas exhange possible in higher organisms, and includes conditions of the upper respiratory tract, trachea, bronchi, bronchioles, alveoli, pleura and pleural cavity, and the nerves and muscles of breathing. These disease can range from mild and self-limiting, such as the common cold, to life-threatening entities like bacterial pneumonia, pulmonary embolism and lung cancer.
The respiratory system can be further divided into an upper respiratory tract and a lower respiratory tract based on anatomical features. The upper respiratory tract includes the nasal passages, pharynx and the larynx, while the lower respiratory tract is comprised of the trachea, the primary bronchi and lungs.
The main function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen all over the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale the carbon dioxide outside of our body. This exchange of gases is the respiratory system’s means of getting oxygen delivered to the blood.
The respiratory system lies dormant in the human fetus at time of pregnancy. At birth, the respiratory system becomes fully functional upon air exposure, althoughsome lung development and growth continues all throughout childhood. Pre-term birth can lead to infants with under-developed lungs.
Smoking and air pollution are two of the most common causes of respiratory problems.