| What is alveolar ventilation? | Alveolar ventilation is the volume of air reaching the alveoli Formula: A = (Vt - Vd) x Bf Where VA= Alveolar Ventilation, VT = Tidal Volume, VD = Dead Space and Bf = Breathing Frequency |
| What happens between the alveoli and pulmonary circulation during the process of gas exchange? | Gas exchange occurs at the alveoli in the lungs and takes place by diffusion. The alveoli are surrounded by capillaries so oxygen and carbon dioxide diffuse between the air in the alveoli and the blood in the capillaries. |
| Define diffusing capacity of the respiratory membrane | Diffusing capacity of the respiratory membrane is defined as the volume of gas that will diffuse through the respiratory membrane for a partial pressure difference of 1mmHg. |
| What factors influence diffusion of oxygen? | Oxygen has been utilised in aerobic respiration as venous blood that returns to the heart has a PO2 of 40mmHg. A blood passes through the capillary bed, partial pressure of oxygen substantially increases highlighting a reoxygenation of the blood, due to the partial pressure gradient. Eventually there is an equilibrium and the oxygenate arterial blood returns to the left atrium and is ejected by the left ventricle. |
| What factors influence diffusion of carbon dioxide? | Intracellular PCO2 accumulates due to aerobic respiration. Rapidly diffuses into the tissue capillaries, due to the partial pressure gradient. Partial pressure gradient decreases rapidly. |
