Zoology MCQs for NEET — Practice Questions with Answers

The left lung is slightly smaller than the right lung to accommodate the space for the heart. The heart is located towards the left side of the chest, necessitating the left lung to be slightly smaller in size. This anatomical arrangement allows the heart to fit snugly between the lungs.

Silicosis is a lung disorder related to profession, particularly affecting workers who inhale silica dust over long periods. This condition is common in occupations such as mining, quarrying, and sandblasting. Silica dust causes inflammation and scarring in the lungs, leading to difficulty in breathing.

Bronchitis can be caused by an initial viral infection that is followed by a secondary bacterial infection. The viral infection damages the bronchial tubes, making them more susceptible to bacterial invasion. This dual infection process is why bronchitis often starts with a viral illness and then worsens due to bacterial involvement.

Lung cancer is characterized by the formation of masses of undifferentiated cells in the tracheal walls. These undifferentiated cells can form tumors that obstruct the airways, leading to issues with breathing and other respiratory functions.

The ventral respiratory center is responsible for exciting both inhalation and exhalation during rapid breathing. It plays a crucial role in regulating the rhythm and depth of breaths during situations that require increased respiratory effort.

During normal breathing, the ventral respiratory center does not play a significant role. It is more actively involved during forceful breathing, such as during exercise or stress, where it helps in controlling the intensity of respiratory efforts.

The full form of Hb is Haemoglobin. Haemoglobin is a protein in red blood cells that carries oxygen from the lungs to the rest of the body. It also returns carbon dioxide from the body to the lungs so it can be exhaled.

Maximum amount of O₂ is transported in humans by RBCs (Red Blood Cells). RBCs contain haemoglobin which binds to oxygen and facilitates its transport from the lungs to the tissues where it is needed for cellular respiration.

CO₂ produced by cells enters red blood cells (RBCs) and is converted into bicarbonate ions (HCO₃^-) by the enzyme carbonic anhydrase. These bicarbonate ions then move out of the RBCs into the blood plasma. Thus, CO₂ is transported in the blood plasma mainly in the form of bicarbonate ions (HCO₃^-).