Tag: respiration in humans

Insects respire via a tracheal system, which is a network of air tubes that brings oxygen directly to the body cells without the need for blood transport, known as direct respiration. Human beings, prawn, and fish rely on indirect respiration via blood and specialized respiratory organs.

The conducting part of the respiratory system includes the nose, pharynx, larynx, trachea, bronchi, and bronchioles. Its primary functions are to transport, filter, warm, and humidify the air. The alveoli are the specific site for gas exchange, which is part of the respiratory zone, not the conducting zone.

Statement (c) is correct as functional residual capacity is the volume of air remaining in the lungs after a normal expiration. Statement (d) is correct as total lung capacity is the maximum volume of air the lungs can hold after a forced inspiration. Statement (a) is incorrect because inspiration is primarily facilitated by the diaphragm and external intercostal muscles, not internal ones. Statement (b) is incorrect because a healthy human typically breathes about 6000-8000 ml of air per minute.

Respiratory quotient if the protein is 0.8-0.9

In the alveoli, O2 is 104 and CO2 is 40. In oxygenated blood, O2 is 95 and CO2 is 40. In tissues, O2 is 40 and CO2 is 45.

Gas exchange occurs across the respiratory membrane, which consists of the alveolar wall and the capillary wall.

Respiratory bronchioles are the final branches of the bronchial tree, which then divide into alveolar ducts that lead to the alveolar sacs.

The alveolus is the functional unit of the lung where the actual exchange of oxygen and carbon dioxide takes place.

Alveolar air contains approximately 13.1% oxygen and 5.3% carbon dioxide, reflecting the exchange that has occurred with the blood.

The total surface area of the alveoli in human lungs is estimated to be between 70 and 100 square meters, facilitating efficient gas exchange.