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Modern Biology Chapter 46

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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
neuron
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
matrix
an intercellular substance
cranial cavity
the area in which the brain rests
spinal cavity
the area that surrounds and protects the spinal chord
diaphragm
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
periosteum
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
osteocyte
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
ossification
process by which cartilage is converted to bone
epiphyseal plate
the site of bone elongation at the ends of long bones
joint
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
ligament
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
osteoarthritis
degenerative joint disease
muscle fiber
a skeletal muscle cell that runs the length of the muscle and contains many nuclei
striation
the light and dark stripes in skeletal and cardiac muscles
fascicle
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
myofibril
a contracting thread in a skeletal muscle
myosin
the thick protein filament of a sarcomere
actin
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
sarcomere
the basic contractile unit of skeletal and cardiac muscle that is the portion of myofibril between two adjacent Z lines
origin
attachment point of a tendon to a stationary bone
insertion
the attachment point of a tendon to a moving bone
flexor
a muscle that bends a joint
extensor
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
epidermis
a layer of cells that forms a continuous sheet over the outer surface of a plant or animal
keratin
a protein that forms hair, bird feathers, human fingernails, and the horny scales of reptiles
melanin
a brown pigment that determines the color of skin; absorbs harmful ultraviolet radiation
dermis
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
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
acne
an inflammatory disorder of the sebaceous glands characterized by the skin lesions in the form of pimples, blackheads, and sometimes cysts
skeleton
framework on which the rest of the body is built