Question

Why do we not get crushed under the atmospheric pressure?

Answer 1

Hint: We know that there is pressure inside our body and atmospheric pressure outside our body. If the pressure inside the body and the pressure outside that body are equal then net pressure acting on the body becomes zero. Keeping this in mind we will answer the given question.

Complete solution:
The air surrounding you is heavy, and it pushes against everything it comes into contact with. Known as atmospheric pressure, or air pressure. As gravity pulls a body to Earth, the air above it exerts a force on it.
Air, like a fluid, flows about you and seeks to crush you. Fortunately, just as the air pressure outside your body pressures inward, the pressure inside your body presses outward as well. They usually balance out, meaning you don't feel any overall force and aren't crushed. Even if the internal and external pressures aren't quite balanced, your skin, muscles, and other tissues are normally robust and flexible enough to withstand the stress. Hence we are not crushed by air.
Internal pressure in the body is created by retained water rather than by air. Internal body pressure is created and maintained by pumping water into semi-rigid cells via chemical attraction forces between water and ions like sodium.

Note:
As height rises, atmospheric pressure decreases. If a human is placed in space without a space suit there will be regular internal body pressure but no external air pressure to cancel it out. Despite this, the person will not explode since their skin is tough enough to endure the strain. Humans are harmed by vacuum exposure, and die but they do not explode due to the pressure differential.