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The muscles of respiration are the muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity. The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during quiet breathing. The elasticity of these muscles is crucial to the health of the respiratory system ...
The muscle fibres of the diaphragm radiate outward from the central tendon. While the diaphragm is one muscle, it is composed of two distinct muscle regions: the costal, which serves as the driver in the work of breathing, and crural diaphragm, which serves as an "anchor;" attaching the muscle to the lower ribs and lumbar vertebrae.
Respiration is the rhythmical process of breathing, in which air is drawn into the alveoli of the lungs via inhalation and subsequently expelled via exhalation. When a human being inhales, air travels down the trachea, through the bronchial tubes, and into the lungs. The entire tract is protected by the rib cage, spine, and sternum. In the ...
Breathing is normally an unconscious, involuntary, automatic process. The pattern of motor stimuli during breathing can be divided into an inhalation stage and an exhalation stage. Inhalation shows a sudden, ramped increase in motor discharge to the respiratory muscles (and the pharyngeal constrictor muscles). [5]
The lungs are not capable of inflating themselves, and will expand only when there is an increase in the volume of the thoracic cavity. [6] [7] In humans, as in the other mammals, this is achieved primarily through the contraction of the diaphragm, but also by the contraction of the intercostal muscles which pull the rib cage upwards and outwards as shown in the diagrams on the right. [8]
Air enters the lungs as the diaphragm strongly contracts, but unlike during traditional relaxed breathing the intercostal muscles of the chest do minimal work in this process. The belly also expands during this type of breathing to make room for the contraction of the diaphragm. [3]
This is achieved by the muscles of respiration, through the contraction of the diaphragm, and the intercostal muscles which pull the rib cage upwards as shown in the diagram. [72] During breathing out the muscles relax, returning the lungs to their resting position. [73]
Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration. In most fish , and a number of other aquatic animals (both vertebrates and invertebrates ), the respiratory system consists of gills , which are either partially or completely external organs, bathed in the ...