For other uses, see Fiction (disambiguation). An illustration from Lewis Carroll's Alice's Adventures in Wonderland, depicting the fictional protagonist, Alice, playing a fantastical game of croquet. Fiction is a story or similar work derived from imaginationâin other words, not based strictly on history or fact.
In human physiology, the muscles of respiration are those 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.Additional 'accessory muscles of respiration' are typically only used under conditions of high metabolic demand (e.g. exercise) or respiratory dysfunction (e.g. an asthma attack).dditional 'accessory muscles of respiration' are typically only used under conditions of high metabolic demand (e.g. exercise) or respiratory dysfunction (e.g. an asthma attack).
The muscles that contribute to quiet breathing are the external intercostal muscles and the diaphragm. (The external and internal intercostals are the muscles that fill the gaps between the ribs.) When drawing breath (i.e., during inspiration), the external intercostal muscles and diaphragm contract simultaneously.uring inspiration, the diaphragm contracts strongly, causing a large expansion of the thorax vertically. At the same time, intra-abdominal pressure increases and causes the abdomen to bulge. During expiration, the diaphragm relaxes and the abdominal muscles contract, causing the abdomen to flatten out.