NEET Practice Questions (MCQs) with Answers & Solutions

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^-).

silicosis,and fibrosis are respiratory disorders associated with occupation 

Hamburger's phenomenon, also known as the chloride shift, refers to the exchange of chloride ions (Cl^-) with bicarbonate ions (HCO₃^-) across the red blood cell membrane. This process helps maintain ionic balance and pH in the blood during the transport of carbon dioxide.

The respiratory movements are primarily controlled by the medulla oblongata, which is part of the brainstem. The medulla oblongata contains the respiratory centers that regulate the rate and depth of breathing by sending signals to the respiratory muscles.

At higher CO₂ concentration, the oxygen dissociation curve of hemoglobin shifts to the right. This is known as the Bohr effect. Higher levels of CO₂ result in a lower pH, which causes hemoglobin to release oxygen more readily. This shift to the right indicates that, at a given partial pressure of oxygen, hemoglobin will have a lower affinity for oxygen, facilitating oxygen release to tissues.

The chloride shift, also known as the Hamburger phenomenon, is essential for the transport of carbon dioxide (CO₂). When CO₂ enters red blood cells, it is converted to bicarbonate (HCO₃^-) and hydrogen ions (H⁺) by the enzyme carbonic anhydrase. The bicarbonate ions are then exchanged for chloride ions (Cl^-) from the plasma to maintain electrical neutrality, facilitating the transport of CO₂ in the blood.

The volume of air inspired or expired with each normal breath is known as tidal volume. Tidal volume is the amount of air that is inhaled or exhaled during normal, quiet breathing, which is typically about 500 mL in a healthy adult.

The oxygen-hemoglobin dissociation curve shifts to the right when there is a decrease in pH, which indicates increased acidity. This phenomenon is known as the Bohr effect, where higher concentrations of hydrogen ions (lower pH) reduce hemoglobin's affinity for oxygen, facilitating oxygen release to the tissues.