As your diaphragm expands, the pressure in your thoracic cavity decreases. Air rushes into the partial vacuum, and you inhale.
It falls
It decreases.
Pressure within the thorax decreases and air is drawn into the lungs
When it contracts it causes a very significant increase in the volume of the thorax, thus reducing the pressure inside and causing negative pressure in relation to outside. Hence air moves inwards, due to the pressure difference and thus inhallation is accomplished. The reverse occurs in exhallation.
Surface tension from pleural fluid, positive pressure, and atmospheric pressure on the thorax.
up and downwnwn
-Your rib cage moves out-Your diaphragm muscles at the bottom of the thorax increase the capacity of your lungs-The pressure drops so air is sucked in-The air is cleaned of dirt and moistened-Oxygen is taken in.
In mammals the muscles that participate in the breathing process are the diaphragm and the intercostal muscles. In respiratory insufficiency other muscles can help the respiration, the muscles of the shoulders, neck, thorax and abdomen. The diaphragm (exclusive of mammals) and the intercostal muscles can contract or relax varying the volume of the thorax (the compartment where the lungs are located). The changing of the thorax volume forces inhalation or expiration. When the thorax volume is increased an internal pressure lower than the atmospheric pressure (external) is created and gases naturally enter the lungs. When the thorax volume is lowered the internal pressure rises above the external pressure and the air is expelled from the lungs.
The diaphragm divides your torso into two parts. the upper part, the chest or thorax, houses the lungs. When the diaphragm pull down, it forces air into the lungs. Whenthe diaphragm pushes up, it forces air out of the lungs.l
The internal pressure of the lungs is controlled by the diaphragm and the muscles of the thorax (chest). Inhalation is caused by increasing the volume (which lowers the internal pressure) while decreasing the volume (increases the internal pressure) leads to exhalation, similar to the way a bellows works. The elastic qualities of the lung also help the process of exhalation.
AnswerAir is actually forced into the lungs by atmospheric pressure. But here's the rest of the story. The diaphragm, a muscle below the lungs, contracts and actually makes the space in which the lungs are located, the thorax, get bigger. When this space gets bigger, the pressure inside it decreases. There is now a difference in pressure between the lung cavity and the outside air with the outside air having more pressure. Air goes from where the pressure is higher to where it is lower, and so it goes into the lungs. That's called inspiration or inhaling. When the diaphragm relaxes, the thorax gets smaller and the pressure increases in the lungs and air is forced out. Click the link for more information.
In order to decrease the pressure within our respiratory tract, we have to expand our container. Our container is basically our thorax. If we can expand our thorax, the air pressure within our thoracic cavity will fall, and air will rush into our respiratory tract. The diaphragm is our primary means to increase our thoracic cavity
they expand, or get biggerThe contraction of your intercostal muscles causes the rib cage to move up and out, thus increasing the volume of the thoracic cavity, decreasing the pressure, so air is forced in.If you're asking for GCSE, the term you need to use is the "ribs move up and out". Don't forget the contraction of the diaphragm, as it flattens it aids the increase in volume of the thoracic cavity.