Breathing & Exchange of Gases Video Lecture | Crash Course for NEET

Ans. Breathing, also known as respiration, is the process by which organisms inhale oxygen and exhale carbon dioxide. It involves the movement of air in and out of the lungs through the respiratory system. During inhalation, the diaphragm contracts and moves downward, while the intercostal muscles expand the rib cage, increasing the volume of the chest cavity. This creates a negative pressure, causing air to rush into the lungs. During exhalation, the diaphragm relaxes and moves upward, and the intercostal muscles relax, reducing the volume of the chest cavity. This increases the pressure in the lungs, forcing air out.

Ans. The exchange of gases takes place in the tiny air sacs called alveoli in the lungs. When we inhale, oxygen from the inhaled air diffuses across the thin walls of the alveoli into the surrounding capillaries. At the same time, carbon dioxide, which is a waste product of cellular respiration, moves from the capillaries into the alveoli. This exchange of gases occurs due to the difference in their partial pressures. Oxygen-rich blood is then transported to the heart, which pumps it to the rest of the body, while carbon dioxide is expelled from the body during exhalation.

Ans. Hemoglobin is a protein found in red blood cells that plays a crucial role in the exchange of gases. It has a high affinity for oxygen, meaning it readily binds to oxygen molecules in the lungs. As blood passes through the alveoli, oxygen molecules bind to hemoglobin, forming oxyhemoglobin. This binding is reversible, allowing oxygen to be released from hemoglobin when it reaches tissues with lower oxygen concentrations. Similarly, hemoglobin also helps transport carbon dioxide, binding with it and carrying it back to the lungs to be exhaled.

Ans. The respiratory system helps maintain the balance of oxygen and carbon dioxide in the body through a process called ventilation. The levels of oxygen and carbon dioxide are monitored by chemoreceptors in the brain and blood vessels. When the oxygen levels decrease or carbon dioxide levels increase, these chemoreceptors send signals to the respiratory centers in the brain, stimulating an increase in the rate and depth of breathing. This increases the intake of oxygen and the removal of carbon dioxide, restoring the balance in the body.

Ans. There are several respiratory disorders that can impact breathing and the exchange of gases. Some common ones include asthma, chronic obstructive pulmonary disease (COPD), pneumonia, and bronchitis. Asthma is characterized by inflammation and narrowing of the airways, leading to difficulty in breathing. COPD is a progressive lung disease that causes airflow limitation, making it hard to exhale. Pneumonia is an infection that inflames the air sacs in the lungs, impairing gas exchange. Bronchitis is the inflammation of the bronchial tubes, resulting in excessive mucus production and coughing, affecting the flow of air. These disorders can significantly impact the efficiency of breathing and gas exchange in the respiratory system.