Final answer:
The claim that only about half the volume of inspired air reaches the alveoli is false. Not all the inspired air reaches the alveoli due to anatomical dead space, but not as much as half. Residual volume aids in preventing alveolar collapse.
Step-by-step explanation:
The statement that only about half the volume of inspired air reaches the alveoli during each inspiration is false. When we breathe in, the air travels through the nasal cavity, pharynx, and trachea into the lungs, reaching the alveoli where gas exchange takes place. However, not all of the inspired air reaches the alveoli due to the anatomical dead space, which is the volume of the airways where no gas exchange occurs. Although it is not half, a certain portion of the inspired air fills this space.
Moreover, the function of the residual volume is to prevent the alveoli from collapsing by maintaining a constant volume within the alveoli, even after exhalation, which helps in keeping them open for the next cycle of gas exchange.
In the human respiratory system, the statement that 'The bronchioles branch into bronchi' is false; it is actually the other way around as bronchi branch into bronchioles. Lastly, the lungs receive mostly deoxygenated blood for oxygenation, but some oxygenated blood can be found due to the mixing of blood in the heart and the bronchial circulation.