Question

What are the different organs of the respiratory system?

Answer 1

Hint: The respiratory system (also called respiratory apparatus or ventilatory system) is a biological system consisting of specific organs and structures which are used for exchange of gases in animals and plants. The anatomy and physiology of the respiratory system depends on the size of the organism, the environment in which it thrives and its evolutionary history. In land animals, the respiratory surface is internalized as the linings of the lungs. Gas exchange in the lungs occurs through millions of small air sacs called alveoli in mammals and atria in birds.

Complete answer:
In humans and other mammals, the anatomy of a typical respiratory system is the respiratory tract which is divided into an upper and a lower respiratory tract. The upper tract includes the nose, nasal cavities, sinuses, pharynx and the part of the larynx above the vocal folds. The lower tract includes the lower part of the larynx, the trachea, bronchi, bronchioles and the alveoli. The significant organs involved in the respiratory system are:
1. Nose (includes nasal cavities and sinuses)
2. Mouth.
3. Throat (pharynx)
4. Voice box (larynx)
5. Windpipe (trachea)
6. Large airways (bronchi)
7. Small airways (bronchioles)
8. Lungs(containing alveoli)
The inflow of air into the lungs occurs via the respiratory airways which begins with the nose. It is also possible to begin with the mouth, which is the backup of the breathing system. However, chronic mouth breathing will lead to illnesses. The respiratory tract ends in the microscopic dead-end sacs called alveoli, which are always open. The diameters of the various sections of the alveoli can be changed with the assistance of sympathetic and parasympathetic nervous systems. In mammals, inhalation at rest occurs due to the contraction of the diaphragm which is an upwardly domed sheet of muscle separating the thoracic cavity from the abdominal cavity. The contraction of diaphragm causes itself to flatten and increase the volume of the thoracic cavity, simultaneously pushing the abdominal organs downward. Since, the pelvic floor prevents the lowermost abdominal organs from moving in that direction, the flexible abdominal contents cause the belly to bulge outwards to the front and sides, as the relaxed abdominal muscles do not resist this movement. Sinuses are hollow areas between the bones in the head that help in regulation of temperature and humidity of the inhaled air. Pharynx (throat) is the tube that delivers air from the mouth and/or nose to the trachea, i.e., the windpipe. The trachea connects the throat with the lungs through the Bronchial tubes located at its end and connected into each lung. The lungs have alveolar sacs which are tiny, balloon-shaped air sacs arranged in clusters throughout the lungs. They remove oxygen from the air and pass it into the blood.

Note:
The air that is contained within the alveoli has a semi-permanent volume of about 2.5-3.0 litres. The blood leaving the alveolar capillaries is eventually distributed throughout the body and has a partial pressure of oxygen of 13-14 kPa (100 mmHg) and a partial pressure of carbon dioxide of 5.3 kPa (40 mmHg). The primary purpose of the respiratory system is the equalization of the partial pressures of the respiratory gases in the alveolar air with those in the pulmonary capillary blood.

    Figure: Respiratory system