Breathing Mechanism
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Breathing mechanism The movement of air in and out of the lungs is generated by the difference in air pressure inside and outside the body. The most important muscle in breathing is the diaphragm. Which is a muscular sheet between the base of the lungs and the abdominal cavity the diaphragm is assisted by the internal and external intercostals muscles (which lie between the ribs) and also assisted by the muscles in the neck and abdomen. Inhalation (breathing in) Just before inhalation the pressure inside the lungs is equal to the pressure outside of the lungs which at sea level is about 760 mmHg. For air to flow into the lungs the pressure inside the lungs must be lower than the pressure outside the lungs this is achieved by increasing the size of the lungs. In conjunction of Boyle’s law when the volume of a sealed container is increase its pressure within it is decreased. ( The most important muscle for inhalation is the diaphragm the dome shaped skeletal muscles that forms the floor of the thoracic cavity is innovated by fibres of the phrenic nerve (which emerge from the spinal cord levels 3, 4, 5) Contraction of the diaphragm caused it to become flattened and thus increasing the vertical diameter of the thoracic cavity. During normal quiet inhalation the diaphragm descends about 1 cm this produces a difference in air pressure of about 1-3 mmHg and inhalation of about 500mL of air, the contraction of the diaphragm is responsible for about 75/% of the that enters the lungs during quiet breathing. However during forced breathing the diaphragm descends about 10 cm which produced a pressure difference of about 100mmHg and inhales about 2-3 litres of air Advanced pregnancy, excessive obesity tight clothing(corsets) these elements can cause a person to have breathing difficulties as they are not able to fully descend their
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Transcript of Breathing Mechanism
Breathing mechanism
The movement of air in and out of the lungs is generated by the difference in air pressure inside and outside the body. The most important muscle in breathing is the diaphragm. Which is a muscular sheet between the base of the lungs and the abdominal cavity the diaphragm is assisted by the internal and external intercostals muscles (which lie between the ribs) and also assisted by the muscles in the neck and abdomen.
Inhalation (breathing in)
Just before inhalation the pressure inside the lungs is equal to the pressure outside of the lungs which at sea level is about 760 mmHg. For air to flow into the lungs the pressure inside the lungs must be lower than the pressure outside the lungs this is achieved by increasing the size of the lungs. In conjunction of Boyle’s law when the volume of a sealed container is increase its pressure within it is decreased. (
The most important muscle for inhalation is the diaphragm the dome shaped skeletal muscles that forms the floor of the thoracic cavity is innovated by fibres of the phrenic nerve (which emerge from the spinal cord levels 3, 4, 5)
Contraction of the diaphragm caused it to become flattened and thus increasing the vertical diameter of the thoracic cavity. During normal quiet inhalation the diaphragm descends about 1 cm this produces a difference in air pressure of about 1-3 mmHg and inhalation of about 500mL of air, the contraction of the diaphragm is responsible for about 75/% of the that enters the lungs during quiet breathing. However during forced breathing the diaphragm descends about 10 cm which produced a pressure difference of about 100mmHg and inhales about 2-3 litres of air
Advanced pregnancy, excessive obesity tight clothing(corsets) these elements can cause a person to have breathing difficulties as they are not able to fully descend their diaphragm and therefore not able to satisfy their oxygen demands.
The next most important muscles during inhalation are the external intercostals muscles when these muscles contract they elevate the ribs. As a result there in an increase in the size of the thoracic cavity. The contraction of the internal intercostals muscles is responsible for about 25% of inhaled are during quiet breathing
