1. how is air drwan into the lungs and forced out of the lungs?
2.how do pressure gradient play a role an dhow are these pressure crreated?
Your exact answers are at the following link:
http://www.leeds.ac.uk/chb/lectures/anatomy7.html
To answer your first question, air is drawn into the lungs and forced out of the lungs through a process called breathing or respiration. The main muscles involved in this process are the diaphragm and the intercostal muscles.
When you inhale, the diaphragm contracts and moves downward, while the intercostal muscles between the ribs contract and expand the chest cavity. This creates a larger space in the chest, causing the air pressure inside the lungs to decrease. As a result, air from the atmosphere with higher pressure flows into the lungs through the nose or mouth, down the trachea, and into the bronchial tubes.
When you exhale, the diaphragm and intercostal muscles relax, which leads to a smaller chest cavity. This causes the air pressure inside the lungs to increase, forcing air out of the lungs and back into the atmosphere.
Now, moving on to your second question about pressure gradient and how it is created. A pressure gradient is a difference in pressure between two points, and it plays a crucial role in various physiological processes, including breathing.
In the context of breathing, the pressure gradient is created by the muscular actions mentioned earlier. When the diaphragm and intercostal muscles contract, they change the volume of the chest cavity, which consequently alters the pressure within the lungs. This change in pressure creates a gradient, with higher pressure outside the lungs (atmospheric pressure) compared to the lower pressure inside the lungs. This pressure gradient allows for the movement of air into the lungs during inhalation.
It's important to note that the concept of pressure gradient applies to other physiological processes as well, not just breathing. For example, blood flow in the circulatory system relies on pressure gradients created by the contraction of the heart.
For more detailed information and visual aids, you can refer to the link provided: http://www.leeds.ac.uk/chb/lectures/anatomy7.html