Human Biology

Front 1

skeleton

Back 1

a framework of bones and cartilage that functions to support and protect intoernal organs and to permit body movement.

Front 2

compact bone

Back 2

very dense, hard bone, containing internal spaces of microscopic sixe and narrow channels that contain blood vessels and nerves. it makes up the shafts of long bondes and the outer surfaces of all bones.

Front 3

periosteum

Back 3

the membranous covering that nourishes bone.

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spongy bone

Back 4

the bone formed from a latticework of thin struts of bone with marrow-filled areas between the struts. it is found int ehends of long bones and within the breastbone, pelvis, and bones of the skull. this bone is less dense than compact bone and is made of an irregular network of collagen fibers surrounded by a calcium matrix.

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red marrow

Back 5

blood cell-forming connective tissue found int eh marrow cavity of certain bones.

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yellow marrow

Back 6

a connective tissue found int eh shaft of long bones that stores fat. it forms from red marrow, and if the need arises, it can convert back to red marrow and form blood cells.

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osteon

Back 7

the structural unit of compact bone that appears as a series of concentric circles of lucunae. the lacunae contain bone cells around a central canal containing blood vessels and nerves.

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osteocyte

Back 8

mature bone cells found in lacunae that are arranged in concentric rings around the central canal. cytoplasmic projectiopns from osteocytes extend tiny channels that connect with other osteocytes.

Front 9

osteoblast

Back 9

a bone-forming cell.

Front 10

growth plate

Back 10

epiphyseal plate, a plate of cartilage that separates each end of a bone from its shaft that permits bone to grow.

Front 11

osteoclast

Back 11

a large cell responsible for the breakdown and absorption of bone.

Front 12

osteoporosis

Back 12

a decrease in bone density that occurs when the desctruction of bone outpaces the formation of new bone, causing bone to become thin, brittle, and susceptible to fracture.

Front 13

axial skeleton

Back 13

the part of the skeleton comprising the skull, the vertebral column, the breastbone (sternum), and the rib cage.

Front 14

appendicular skeleton

Back 14

the part of the skeleton comprising the pectoral girdle (shoulders), the pelvic girdle (pelvis), and the limbs (arms and legs).

Front 15

cranium

Back 15

the skeletal portion of the skull that forms the cranial case. it is formed from eight (sometimes more) flattened bones including the frontal bone, two parietal bones, the occipital bone, two temporal bones, the sphenoid bone, and the ethmoid bone.

Front 16

vertebral column

Back 16

the backbone, it is composed fo 26 vertebrae (7 cervical, 12 thoracic, 5 lumbar, 1 sacrum, and 1 coccyx) and associated tissues. the spinal cord passes through a central canal within the vertebrae.

Front 17

vertebra

Back 17

one of a series of joined bones that forms the vertebral column.

Front 18

interverbral disk

Back 18

pads of cartilage that help cushion the bones of the vertebral column.

Front 19

pectoral guide

Back 19

the bones that connect the arms to the rib cage. the epctoral girdle is composed of the shoulder blades (scapulae) and the collarbones (clavicles).

Front 20

pelvic girdle

Back 20

the bones that connect the legs to the vertebral column. The pelvic girdle is composed of the paired hipbones.

Front 21

joint

Back 21

a point of contact between two bones; an articulation.

Front 22

sutures

Back 22

an immovable joint between the bones of the skull.

Front 23

synovial joint

Back 23

a viscous, clear fluid within a synovial cavity that acts as both a shock absorber and a lubricant between the bones.

Front 24

ligament

Back 24

a strong band of connective tissue that holds the bones together, supports the joint, and directs the movement of the bones.

Front 25

hinge joint

Back 25

a joint that permits motion in only one plane, such as teh knee joint or the elbow.

Front 26

ball-and-socket joint

Back 26

a jiont that allows motion in all directions, such as the shoulder and hip joints.

Front 27

sprain

Back 27

damage to a ligament (a strap of connective tissue that holds bones together.)

Front 28

bursae

Back 28

a flattened sac containing a thin film of synocial fluid that surrounds and cushions certain synovial joints. they are common in locations where ligaments, muscles, skin, or tendons rub against bone.

Front 29

arthritis

Back 29

an inflammation of a joint.