Question

How much amount of volume of air is in lungs as FRC?
A. 1500 ml to 1600 ml
B. 2100ml to 2500ml
C. 2500ml to 3000ml
D. 1600ml to 2100ml

Answer 1

Hint: The lungs are the double membranous respiratory organs of the higher organisms. The space between the two membranes is filled with pleural fluid and is termed as pleural cavity.

Complete Answer:
- Lungs are the spongy pair of organs that are involved in the respiration process. It is located in each side of the chest that is thorax. The windpipe that is named as trachea conducts the inhalation of air inside the lungs through bronchi. The bronchi is divided into smaller branches and become microscopic.
- The bronchioles consist of microscopic air sacs named as alveoli where the oxygen gets absorbed into the blood and carbon dioxide the waste products travel to the alveoli from the blood this process is termed as exhalation.
- The alveoli consist of a thin layer in between that is termed as the interstitium that contain the blood vessels and cells that support the alveoli. The lungs are covered with thin double layered tissue that is called the pleura.
- The tissue is similar to the tissue found in the chest cavity therefore, it is also called pleura cavity. Layer of fluid acts as the lubricant allow the lungs to work smoothly and to get expand while breathing and contract while exhaling.
- Now, the functional residual capacity that is FRC represents the breathing cycle point where the tissue of lungs recoil and the chest wall expands outward is balanced. The amount of air left after expiration is the FRC, there is no exertion by the diaphragm or respiratory muscles.
- It is the total of residual volume (RV) and expiratory reserve volume (ERV). The RV is 1.2 litres and ERV is 1.1litres. Therefore, the amount of volume of air is in the lungs as FRC is 2100m to 2500ml.

Thus, the correct option is ‘B’. 2100ml to 2500ml.

Note: The pericardium is the double walled sac found in the heart and the root of the vessels. The two layers are named as serous and the fibrous layer and it consists of pericardial cavity. It works the same as the pleural cavity but remember both are different.