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Human vestigiality. The muscles connected to the ears of a human do not develop enough to have the same mobility allowed to monkeys. Arrows show the vestigial structure called Darwin's tubercle. In the context of human evolution, vestigiality involves those traits occurring in humans that have lost all or most of their original function through ...
Vestigiality. In humans, the vermiform appendix is sometimes called a vestigial structure as it has lost much of its ancestral digestive function. Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. [1]
In amniotes, the clitoris (/ ˈklɪtərɪs / ⓘ KLIT-ər-iss or / klɪˈtɔːrɪs / ⓘ klih-TOR-iss; pl.: clitorises or clitorides) is a female sex organ. [ 1 ] In humans, it is the vulva 's most erogenous area and generally the primary anatomical source of female sexual pleasure. [ 2 ] The clitoris is a complex structure, and its size and ...
Gubernaculum. Sagittal section through the pelvis of a newly born female child. (Label for round ligament of uterus visible at upper right.) The paired gubernacula (from Ancient Greek κυβερνάω = pilot, steer), also called the caudal genital ligament, are embryonic structures which begin as undifferentiated mesenchyme attaching to the ...
Gallbladder. In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although the structure and position of the gallbladder can vary significantly among animal species.
Goose bumps are created when tiny muscles at the base of each hair, known as arrector pili muscles, contract and pull the hair straight up. The reflex is started by the sympathetic nervous system, which is responsible for many fight-or-flight responses. The muscle cells connected to the hair follicle have been visualized by actin ...
The trophi, or mouthparts of a locust, a typical chewing insect: 1 Labrum. 2 Mandibles; 3 Maxillae. 4 Labium. 5 Hypopharynx. Examples of chewing insects include dragonflies, grasshoppers and beetles. Some insects do not have chewing mouthparts as adults but chew solid food in their larval phase.
Skeletal muscle. Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the other being cardiac muscle and smooth muscle. They are part of the voluntary muscular system [1] and typically are attached by tendons to bones of a skeleton. [2][3] The skeletal muscle cells are much longer than in the ...