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Wings may have evolved from appendages on the sides of existing limbs, which already had nerves, joints, and muscles used for other purposes. These may initially have been used for sailing on water, or to slow the rate of descent when gliding. Two insect groups, the dragonflies and the mayflies, have flight muscles attached directly to the ...
The more advanced groups making up the Neoptera have foldable wings, and their muscles act on the thorax wall and power the wings indirectly. [ 1 ] : 22–24 These muscles can contract multiple times for each single nerve impulse, allowing the wings to beat faster than would ordinarily be possible.
A fixed-wing aircraft may have more than one wing plane, stacked one above another: Biplane: two wing planes of similar size, stacked one above the other.The biplane is inherently lighter and stronger than a monoplane and was the most common configuration until the 1930s.
The muscles that control flight vary with the two types of flight found in insects: indirect and direct. Insects that use first, indirect, have the muscles attach to the tergum instead of the wings, as the name suggests. As the muscles contract, the thoracic box becomes distorted, transferring the energy to the wing.
The wings are moved by the rapid muscular contraction and expansion of the thorax. [11] The wings arise from the meso- and meta-thoracic segments and are similar in size in the basal groups. In more derived groups, the meso-thoracic wings are larger with more powerful musculature at their bases and more rigid vein structures on the costal edge. [7]
An X-ray of a human chest area, with some structures labeled. The contents of the thorax include the heart and lungs (and the thymus gland); the major and minor pectoral muscles, trapezius muscles, and neck muscle; and internal structures such as the diaphragm, the esophagus, the trachea, and a part of the sternum known as the xiphoid process.
Its wings, which were externally braced, featured swept-back wingtips with negative incidence relative to the remainder of the main-plane. [2] The Weltensegler also used a unique control system, consisting of a various pulleys and springs connected to a single control stick for the pilot, which warped the wing-tips as directed by the pilot.
It is the site of attachment for most of the muscles of mastication. Many foramina and fissures are located in the sphenoid that carry nerves and blood vessels of the head and neck, such as the superior orbital fissure (with ophthalmic nerve), foramen rotundum (with maxillary nerve) and foramen ovale (with mandibular nerve). [7]