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muscle tissue

the body tissue that enables movement

skeletal muscle

voluntary muscle, attached to bones by tendons, that moves parts of the body

smooth muscle

elongated, spindle shaped involuntary muscles

cardiac muscle

the involuntary muscle of the heart

nervous tissue

a type of animal tissue that conducts electrical impulses


a cell that transmits electrical signals

epithelial tissue

tissue composed of cells that create a solid sheet that covers a body part

connective tissue

body tissue that supports and holds body structures together


an intercellular substance

cranial cavity

the area in which the brain rests

spinal cavity

the area that surrounds and protects the spinal chord


a sheet of muscle below the rib cage that functions in inspiration and expiration

thoracic cavity

the upper ventral cavity of the human body, containing the heart, lungs, and esophagus

abdominal cavity

the lower compartment containing the organs of the digestive, reproductive, and excretory systems

axial skeleton

the backbone, skull, and associated bones of vertebrates

appendicular skeleton

in vertebrates, the bones that form the limbs


the tough outer membrane of a bone; the point where tendons attach muscles to bones

compact bone

the layer of bone just beneath the periosteum that gives the bone its strength

haversian canal

a channel containing nerves and blood vessels making up compact bone


a living bone cell

spongy bone

the lacy network of connective tissue in the center of a bone

bone marrow

the soft tissue in the center and ends of bones where blood cells are produced


process by which cartilage is converted to bone

epiphyseal plate

the site of bone elongation at the ends of long bones


the place where two bones meet

fixed joint

a place where two bones meet but movement does not occur, as in the skull

semimovable joint

a joint that allows limited movement, as in vertebrae

movable joint

enables the skeleton to move where the bones come together to perform a wide range of activities

hinge joint

allows movement back and forth like a hinged door, as in the elbow

ball-and-socket joint

allows movement in all directions, as in the shoulder

pivot joint

allows movement from side to side and up and down, as in the top two vertebrae of the spine

saddle joint

type of joint found at the end of each thumb; allows grasping and rotation

gliding joint

a joint that allows bones to slide over one another, as in foot bones that flex in walking


a connective tissue in a joint

synovial fluid

helps protect the ends of bones from damage by friction

rheumatoid arthritis

an imune-system disorder causing painful joints


degenerative joint disease

muscle fiber

a skeletal muscle cell that runs the length of the muscle and contains many nuclei


the light and dark stripes in skeletal and cardiac muscles


a dense bundle of skeletal muscle fibers

voluntary muscle

a muscle whose movement can be consciously controlled

involuntary muscle

a muscle whose movement cannot be consciously controlled


a contracting thread in a skeletal muscle


the thick protein filament of a sarcomere


one of the two protein filaments in a muscle cell that function in contraction

Z line

boundary of sarcomere; point of anchor for tin actin filaments


the basic contractile unit of skeletal and cardiac muscle that is the portion of myofibril between two adjacent Z lines


attachment point of a tendon to a stationary bone


the attachment point of a tendon to a moving bone


a muscle that bends a joint


a muscle that straightens a joint

muscle fatigue

the physiological inability of a muscle to contract

oxygen debt

a temporary lack of oxygen availability due to exertion


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


a brown pigment that determines the color of skin; absorbs harmful ultraviolet radiation


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

exocrine gland

a gland that secretes non hormonal chemicals through a duct

sweat gland

releases excess water, salts, and urea; makes skin function as an excretory organ

oil gland

found in large numbers on the face and scalp, secretes a fatty substance known as sebum


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


framework on which the rest of the body is built

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