Intake of fluids or other substances by cells of the skin or mucous membranes; the passage of digested foods from the gastrointestinal tract into blood or lymph.
An electrical signal that propagates along the membrane of a neuron or muscle fiber (cell); a rapid change in membrane potential that involves a depolarization followed by a repolarization. Also called a nerve action potential or nerve impulse as it relates to a neuron, and a muscle action potential as it relates to a muscle fiber.
Abnormal joining of parts to each other.
Fat cell, derived from a fibroblast.
A type of gland in which the secretory products gather at the free end of the secreting cell and are pinched off, along with some of the cytoplasm, to become the secretion, as in mammary glands.
Growth due to surface deposition of material, as in the growth in diameter of cartilage and bone. Also called exogenous growth.
The usually single, long process of a nerve cell that propagates a nerve impulse toward the axon terminals.
Thin, extracellular layer between epithelium and connective tissue consisting of a basal lamina and a reticular lamina.
Striated muscle fibers (cells) that form the wall of the heart; stimulated by an intrinsic conduction system and autonomic motor neurons.
A type of connective tissue consisting of chondrocytes in lacunae embedded in a dense network of collagen and elastic fibers and an extracellular matrix of chondroitin sulfate.
Point of contact between plasma membranes of tissue cells.
A microscopic tube running the length of the spinal cord in the gray commissure. A circular channel running longitudinally in the center of an osteon (haversian system) of mature compact bone, containing blood and lymphatic vessels and nerves. Also called an haversian canal.
Cell of mature cartilage.
An amorphous extracellular matrix material found outside connective tissue cells.
One of the most abundant of the four basic tissue types in the body, performing the functions of binding and supporting; consists of relatively few cells in a generous matrix (the ground substance and fibers between the cells).
A neuronal process that carries electrical signals, usually graded potentials, toward the cell body.
The primary germ layer that gives rise to the nervous system and the epidermis of skin and its derivatives.
A gland that secretes hormones into interstitial fluid and then the blood; a ductless gland.
A primary germ layer of the developing embryo; gives rise to the gastrointestinal tract, urinary bladder, urethra, and respiratory tract.
The layer of simple squamous epithelium that lines the cavities of the heart, blood vessels, and lymphatic vessels.
The tissue that forms the innermost and outermost surfaces of body structures and forms glands.
A gland that secretes its products into ducts that carry the secretions into body cavities, into the lumen of an organ, or to the outer surface of the body.