Exercise Physiology - Qp10

The control of breathing involves two factors: neural control and chemical control. Neural control refers to the regulation of breathing by the central nervous system, specifically the brainstem. It involves the coordination of signals from various respiratory centers in the brain to control the rate and depth of breathing. Chemical control, on the other hand, involves the detection of changes in the levels of oxygen, carbon dioxide, and pH in the blood and tissues. These chemical changes are detected by chemoreceptors, which send signals to the respiratory centers in the brain to adjust breathing accordingly. Both neural and chemical control work together to maintain the proper balance of oxygen and carbon dioxide in the body.

The explanation for the given answer is that the pressure gradient, which is the difference in pressure between the alveoli and the blood, is relatively small. This means that there is not a significant difference in pressure driving the movement of gases across the respiratory membrane. However, carbon dioxide has a much higher membrane solubility compared to oxygen, which allows it to cross the respiratory membrane more easily. In fact, carbon dioxide has a membrane solubility that is 20 times greater than oxygen. Therefore, due to its higher solubility and the smaller pressure gradient, carbon dioxide can cross the respiratory membrane much quicker than oxygen.

Muscle cells contain molecules known as myoglobin. Myoglobin is a protein found in muscle tissue that binds to oxygen and helps store it for use during muscle contraction. This allows muscle cells to have a ready supply of oxygen for energy production. Therefore, the statement is true.

The statement is true because the Hering-Breuer reflex is indeed a safety mechanism in the lungs. This reflex helps prevent over-inflation of the lungs by sending signals to the brain to stop or decrease the rate of breathing when the lungs are stretched too much. This mechanism ensures that the lungs do not become overfilled with air, which could potentially cause damage.

The given statement is false. Pulmonary diffusion does not refer to the process of gaseous exchange in the lungs. Instead, it refers to the movement of oxygen and carbon dioxide between the alveoli in the lungs and the bloodstream. The process of gaseous exchange in the lungs is known as respiration.

The respiratory system does not only function in conjunction with the vascular system for gaseous exchange. It also plays a role in other processes such as speech production, sense of smell, and regulation of pH levels in the body. Therefore, the statement is false.

The partial pressure of oxygen in the blood in the pulmonary capillaries, which surround the alveoli, is 40mmHg. This is because oxygen diffuses from the alveoli, where the partial pressure of oxygen is higher, into the blood in the capillaries, where the partial pressure of oxygen is lower. The oxygen is then transported to the rest of the body through the bloodstream.

The statement is false because with an increase in altitude, there is actually a decrease in atmospheric pressure, not an increase. As altitude increases, the air becomes less dense, resulting in lower pressure. However, the percentages of gases within the air do remain relatively constant regardless of altitude.

Each molecule of haemoglobin, when fully saturated, can combine with four oxygen molecules, not five. The correct volume of oxygen that can be carried by a fully saturated haemoglobin molecule is approximately 1.06 ml, not 1.34 ml. Therefore, the statement is false.