Question

In human beings, lungs are divided into
A. 3 right and 2 left lobes
B. 2 right and 3 left lobes
C. 2 right and 2 left lobes
D. None of the above

Answer 1

Lung are the organ which perform breathing process which are present in the thoracic cavity and they are tow in number, they function as to purify blood by expelling out carbon dioxide form the blood and taking oxygen from the environment in the blood via alveoli, these alveoli present in the lung.

Complete answer:
Lungs are found in the mammals which one of the characteristic features of mammals, a pair of lungs are present in humans, in the thoracic cavity which is closed and below it diaphragm is present which help in breathing. Lungs are enclosed by two membranes called pleura and in between pleura, a fluid is present called pleural fluid, which provides friction less movement of the lung during breathing. Left lung have 2 lobes which are divide by oblique fissure and lobe are named as superior and inferior lobe, and cardiac notch is present where heart is located, left lung whereas right lungs have 3 lobes that are named as superior lobe, middle lobe and inferior lobe and they are divided by horizontal fissure and oblique fissure.

Inside lungs secondary and tertiary structures are found which arise from primary bronchus, when they enter into the lungs, the secondary and tertiary bronchi have cartilaginous rings. These bronchus subdivided and give rise to terminal bronchioles, which further subdivide into respiratory bronchioles. Respiratory bronchioles consist of alveolar sac and duct which receive blood and where exchange of oxygen and carbon dioxide take place.

Hence, the correct answer is option (A).

Note: Lungs are not the only organs found in all animals, some animals possess gills through which they respire and some animals show cutaneous respiration such respiration features found in fishes and amphibians, because they need some special organ to breath inside water and moist environment.