Importance Of Inspiration And Expiration

1) Inspiration and expiration are defined as the inhalation and exhalation of air into the lungs (Oxford University Press, 2010). The diaphragm is the key muscle in respiration. Its dome-shaped skeletal muscle separates the thoracic and abdominal cavities, consisting of muscle fibres and tendons. The fibres run upwards from their origin at the inner part of the thoracic cage and then arc towards the midline. During ordinary, quiet respiration, the diaphragm contracts and moves downward in inspiration and the diaphragmatic parietal pleura descends. Drawing down the visceral pleura so that the airways and alveoli expand and air is forced in. The diaphragm then relaxes in expiration and the recoil of the elastic tissues in the lung ejects air from the alveoli and airways. Movement of the ribcage also contributes to respiration by increasing the diameter of the chest, thus increasing the thoracic capacity and creating a lower pressure in the lungs allowing air to be sucked in. The joints between the posterior ends of the ribs and the transverse processes of the vertebrae enable a pivoting motion of the ribs upwards and outwards to increase the lateral diameter of the chest, while the anterior ends of the ribs move up and out to increase the anteroposterior diameter. The diaphragmatic movement provides approximately 75% and movement of the ribcage contributes 25% to the expansion in thoracic volume (Naish, Revest, & Syndercombe, 2009).

2) As exercise intensifies and the body’s need for fresh oxygen increases, the ventilation rate responds accordingly. The metabolic byproducts of exercise build up as a result of cellular respiration, and the amount of carbon dioxide (CO2) in the system also increases to act as a buffer against these ac...

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...iovascular system sedentary periods become even easier for the heart by comparison. The heart eventually becomes more efficient, and no longer needs to beat as quickly to supply the body with blood while at rest. Stroke volume increases at rest. Resting heart rate is able to slow down because the heart is now trained to pump a larger quantity of blood with every beat. Improved circulation. In response to the need to supply the muscles with more oxygen during exercise, the body increases its number of capillaries, the smallest blood vessels in the body. Existing capillaries also open wider. Blood pressure decreases by up to 10 mmHg. An mmHg is a unit used for measuring pressure levels. Blood volume increases. The body produces a greater number of red blood cells in order to keep the muscles supplied with oxygen during heavy exercise (Fitness Health & Wellness, 2010).