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the upper ventral cavity of the human body, containing the heart, lungs, and esophagus
the lower compartment containing the organs of the digestive, reproductive, and excretory systems
enables the skeleton to move where the bones come together to perform a wide range of activities
allows movement from side to side and up and down, as in the top two vertebrae of the spine
a joint that allows bones to slide over one another, as in foot bones that flex in walking
the basic contractile unit of skeletal and cardiac muscle that is the portion of myofibril between two adjacent Z lines
a layer of cells that forms a continuous sheet over the outer surface of a plant or animal
a protein that forms hair, bird feathers, human fingernails, and the horny scales of reptiles
the inner layer of skin composed of living cells and many specialized structures, e.g. sensory neurons, blood vessels, muscle fibers, hair follicles, and glands
fatty substance excreted by the oil gland and coats the surface of the skin and the shafts of hairs, preventing excess water loss and lubricating and softening the skin and hair; also is mildly toxic to bacteria
an inflammatory disorder of the sebaceous glands characterized by the skin lesions in the form of pimples, blackheads, and sometimes cysts
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