Question

Number Of Alveoli in human being is about
A)One million
B)More than two million
C)More than five million
D)More than seven million

Answer 1

1)Lungs are respiratory organs which are made up of small sac-like structures known as alveoli.
2)They are made up of only one layer.

Complete answer:
Option A: Alveoli are tiny sacs in your lungs that take up the oxygen you breathe in and keep your body going so for more consumption of oxygen for our lungs we need more alveoli. Therefore , this is the incorrect option.

Option B: From the upper explanation we understood that for more gaseous exchange we need more alveoli and also they are involved in 3 breathing processes - Ventilation , diffusion , perfusion . Therefore to perform these processes we need more alveoli than 2 million so this is the incorrect option.

Option C: We have learnt from the upper explanation that alveoli are the centre of your respiratory system's gas exchange. The alveoli pick up the incoming energy you breathe in and release the outgoing waste product you exhale , Therefore the number of alveoli used is much higher than 5 million , so this is the incorrect option.

Option D: Alveoli are the basic and functional unit of the lung. You have about 480 Million alveoli located at the end of bronchial tubes. When you breathe in , the alveoli expand to take in oxygen when you breathe out, the alveoli shrink to expel carbon dioxide. Therefore from the upper 3 statement we conclude that we need more than 7 million alveoli for the functioning of the lung. Therefore, this is the Correct option.

Hence, the correct answer is option (D)

Note: Diseases Of Respiratory System ( Alveoli)
1)Chronic obstructive pulmonary disease (COPD) - Airway obstruction from damaged alveoli walls
2)Asthma - Inflammation narrows your airways and blocks them.
3)Lung cancer - Cancer can start in your alveoli.
4)Pneumonia - The alveoli fill the fluid , limiting oxygen intake.
5)Idiopathic pulmonary fibrosis - The walls surrounding the alveoli become scarred and thickened.