Key Terms

Key Terms

when a bone moves away from the midline of the body
(AChE) enzyme that breaks down ACh into acetyl and choline
globular contractile protein that interacts with myosin for muscle contraction
movement of the limbs inward after abduction
joint that allows slight movement; includes syndesmoses and symphyses
angular movement
produced when the angle between the bones of a joint changes
appendicular skeleton
composed of the bones of the upper limbs, which function to grasp and manipulate objects, and the lower limbs, which permit locomotion
appositional growth
increase in the diameter of bones by the addition of bone tissue at the surface of bones
any place where two bones are joined
auditory ossicle
also, middle ear, transduces sounds from the air into vibrations in the fluid-filled cochlea
axial skeleton
forms the central axis of the body and includes the bones of the skull, the ossicles of the middle ear, the hyoid bone of the throat, the vertebral column, and the thoracic cage, or ribcage
ball-and-socket joint
joint with a rounded, ball-like end of one bone fitting into a cuplike socket of another bone
also, osseous tissue, connective tissue that constitutes the endoskeleton
bone remodeling
replacement of old bone tissue by new bone tissue
process of deposition of mineral salts in the collagen fiber matrix that crystallizes and hardens the tissue
cardiac muscle
tissue muscle tissue found only in the heart; cardiac contractions pump blood throughout the body and maintain blood pressure
eight bones that comprise the wrist
cartilaginous joint
joint in which the bones are connected by cartilage
movement of a limb in a circular motion.
S-shaped bone that positions the arms laterally
compact bone
forms the hard external layer of all bones
condyloid joint
oval-shaped end of one bone fitting into a similarly oval-shaped hollow of another bone
coxal bone
hip bone
cranial bone
one of eight bones that form the cranial cavity that encloses the brain and serves as an attachment site for the muscles of the head and neck
movement downward of a bone, such as after the shoulders are shrugged and the scapulae return to their normal position from an elevated position; opposite of elevation
central shaft of bone, contains bone marrow in a marrow cavity
joint that allows for free movement of the joint; found in synovial joints
bending at the ankle such that the toes are lifted toward the knee
movement of a bone upward, such as when the shoulders are shrugged, lifting the scapulae
endochondral ossification
process of bone development from hyaline cartilage
skeleton of living cells that produce a hard, mineralized tissue located within the soft tissue of organisms
epiphyseal plate
region between the diaphysis and epiphysis that is responsible for the lengthwise growth of long bones
rounded end of bone, covered with articular cartilage and filled with red bone marrow, which produces blood cells
movement of the sole of the foot outward, away from the midline of the body; opposite of inversion
secreted cellular product external skeleton that consists of a hard encasement on the surface of an organism
movement in which the angle between the bones of a joint increases; opposite of flexion
facial bone
one of the 14 bones that form the face; provides cavities for the sense organs—eyes, mouth, and nose—and attachment points for facial muscles
also, thighbone, longest, heaviest, and strongest bone in the body
fibrous joint
joint held together by fibrous connective tissue
also, calf bone, parallels and articulates with the tibia
flat bone
thin and relatively broad bone found where extensive protection of organs is required or where broad surfaces of muscle attachment are required
movement in which the angle between the bones decreases; opposite of extension
extends from the elbow to the wrist and consists of two bones: the ulna and the radius
gliding movement
when relatively flat bone surfaces move past each other
joint in which the tooth fits into the socket like a peg
Haversian canal
contains the bone’s blood vessels and nerve fibers
hinge joint
slightly rounded end of one bone fits into the slightly hollow end of the other bone
only bone of the arm
hydrostatic skeleton
skeleton that consists of aqueous fluid held under pressure in a closed body compartment
hyoid bone
lies below the mandible in the front of the neck
extension past the regular anatomical position
intervertebral disc
composed of fibrous cartilage; lies between adjacent vertebrae from the second cervical vertebra to the sacrum
intramembranous ossification
process of bone development from fibrous membranes
soles of the feet moving inward, toward the midline of the body
irregular bone
bone with complex shapes; examples include vertebrae and hip bones
point at which two or more bones meet
layer of compact tissue that surrounds a central canal called the Haversian canal
lateral rotation
rotation away from the midline of the body
long bone
bone that is longer than wide, and has a shaft and two ends
lower limb
consists of the thigh, the leg, and the foot
medial rotation
rotation toward the midline of the body
five bones that comprise the palm
one of the five bones of the foot
motor end plate
sarcolemma of the muscle fiber that interacts with the neuron
long cylindrical structures that lie parallel to the muscle fiber
small structures that make up myofibrils
contractile protein that interacts with actin for muscle contraction
movement of the thumb toward the fingers of the same hand, making it possible to grasp and hold objects
osseous tissue
connective tissue that constitutes the endoskeleton
also, osteogenesis, process of bone formation by osteoblasts
bone cell responsible for bone formation
large bone cells with up to 50 nuclei, responsible for bone remodeling
mature bone cells and the main cell in bone tissue
cylindrical structure aligned parallel to the long axis of the bone
also, kneecap, triangular bone that lies anterior to the knee joint
pectoral girdle
bones that transmit the force generated by the upper limbs to the axial skeleton
pelvic girdle
bones that transmit the force generated by the lower limbs to the axial skeleton
one of the bones of the fingers or toes
pivot joint
joint with the rounded end of one bone fitting into a ring formed by the other bone
planar joint
joint with bones whose articulating surfaces are flat
plantar flexion
bending at the ankle such that the heel is lifted, such as when standing on the toes
movement in which the palm faces backward
anterior movement of a bone in the horizontal plane
bone located along the lateral, or thumb, side of the forearm; articulates with the humerus at the elbow
process by which osteoclasts release minerals stored in bones
movement in which a joint moves back into position after protraction
one of 12 pairs of long, curved bones that attach to the thoracic vertebrae and curve toward the front of the body to form the ribcage
rotational movement
movement of a bone as it rotates around its own longitudinal axis
saddle joint
joint with concave and convex portions that fit together; named because the ends of each bone resemble a saddle
plasma membrane of a skeletal muscle fiber
functional unit of skeletal muscle
flat, triangular bone located at the posterior pectoral girdle
sesamoid bone
small, flat bone shaped like a sesame seed; develops inside tendons
short bone
bone that has the same width and length, giving it a cube-like shape
skeletal muscle tissue
forms skeletal muscles, which attach to bones and control locomotion and any movement that can be consciously controlled
bone that supports the structures of the face and protects the brain
smooth muscle
tissue occurs in the walls of hollow organs such as the intestines, stomach, and urinary bladder, and around passages such as the respiratory tract and blood vessels
spongy bone tissue
forms the inner layer of all bones
also, breastbone, long, flat bone located at the front of the chest
movement of the radius and ulna bones of the forearm so that the palm faces forward
short fiber of connective tissue that holds the skull bones tightly in place; found only in the skull
suture bone
small, flat, irregularly shaped bone that forms between the flat bones of the cranium
hyaline cartilage covers the end of the bone, but the connection between bones occurs through fibrocartilage; symphyses are found at the joints between vertebrae
joint that is immovable
bones joined by hyaline cartilage; synchondroses are found in the epiphyseal plates of growing bones in children
joint in which the bones are connected by a band of connective tissue, allowing for more movement than in a suture
synovial joint
only joint that has a space between the adjoining bones
one of the seven bones of the ankle
thick filament
group of myosin molecules
thin filament
two polymers of actin wound together along with tropomyosin and troponin
thoracic cage
also, ribcage, skeleton of the chest, which consists of the ribs, thoracic vertebrae, sternum, and costal cartilages
also, shinbone, large bone of the leg that is located directly below the knee
lamellae that are arranged as rods or plates
acts to block myosin binding sites on actin molecules, preventing cross-bridge formation and preventing contraction until a muscle receives a neuron signal
binds to tropomyosin and helps to position it on the actin molecule, and also binds calcium ions
bone located on the medial aspect, pinky-finger side, of the forearm
vertebral column
also, spine, surrounds and protects the spinal cord, supports the head, and acts as an attachment point for ribs and muscles of the back and neck