Chapter 6 - Skeletal System Flashcards

Vocabulary flashcards covering the key structures, tissue types, cell roles, bone features, classification, formation, homeostasis, and movements of the skeletal system.

Cartilage

A component of the skeletal system that reduces friction and serves as a model for bone formation.

Tendons

Connective tissues that attach bone to muscle.

Ligaments

Connective tissues that attach bone to bone.

Proteoglycans

Large polysaccharides attached to proteins that form part of the ground substance and store water.

Diaphysis

The shaft of a long bone, composed of compact bone tissue on the outside.

Epiphysis

The end of a long bone, composed of spongy bone tissue.

Articular Cartilage

Cartilage that covers the epiphyses of a long bone to reduce friction.

Medullary Cavity

The cavity in the center of the diaphysis that contains red marrow in juveniles and yellow marrow in adults.

Epiphyseal Plate

The site of bone growth located between the diaphysis and epiphysis in juvenile bones.

Periosteum

A membrane surrounding a bone's outer surface.

Endosteum

A membrane that lines the medullary cavity inside a bone.

Compact Bone Tissue

Bone tissue located on the outer part of the diaphysis in long bones and on the thinner surfaces of other bones.

Osteon

The structural unit of compact bone, also known as a Haversian system, which includes lamellae, lacunae, canaliculi, central canals, and osteocytes.

Lamella

Rings of bone matrix that make up an osteon.

Lacunae

Spaces between lamellae in bone tissue where osteocytes reside.

Canaliculus

Tiny canals in compact bone tissue that transport nutrients and remove waste.

Central Canal

The center of an osteon containing blood vessels.

Spongy Bone Tissue

Cancellous bone tissue located in the epiphyses of long bones and the center of other bones; it lacks osteons.

Trabeculae

Interconnecting rods in spongy bone tissue whose surrounding spaces contain marrow.

Osteocytes

Bone cells that maintain the bone matrix.

Osteoblasts

Bone cells responsible for building new bone matrix.

Osteoclasts

Bone cells responsible for carving or breaking down existing bone.

Ossification

The process of bone formation, which occurs in utero.

Primary Ossification Center

The initial area where bone first begins to appear, which forms the diaphyses.

Secondary Ossification Center

The area of bone formation that forms the epiphyses of long bones.

Intramembranous Ossification

Bone formation taking place within connective tissue membranes, such as in skull bones.

Endochondral Ossification

Bone formation inside cartilage where cartilage models are replaced by bone, occurring in all bones except the skull.

Bone Remodeling

The process involving the removal of existing bone by osteoclasts and deposition of new bone by osteoblasts.

Callus

A network of fibers and cartilage formed between two broken bone fragments during repair.

Parathyroid Hormone (PTH)

A hormone stimulated by decreased blood calcium levels that causes osteoclasts to break down bone and release Ca2+ into the blood.

Calcitonin

A hormone secreted by the thyroid gland in response to increased blood calcium levels that inhibits osteoclasts and enhances osteoblast Ca2+ uptake into bone.

Hematopoietic Tissue

Tissue responsible for producing blood cells.

Red Marrow

The specific site of blood-forming cells in bone tissue.

Yellow Marrow

Bone marrow tissue composed mostly of fat.

Foramen

An opening or hole in a bone, such as the foramen magnum.

Fossa

A depression in a bone surface, such as the glenoid fossa.

Process

A prominent projection on a bone, such as the mastoid process.

Condyle

A smooth, rounded articular surface of a bone, such as the occipital condyle.

Meatus

A canal-like passageway in a bone, such as the external auditory meatus.

Tubercle

A lump, knob, or enlargement on a bone, such as the greater tubercle.

Nasolacrimal Canal

A canal located between the nasal cavity and eye that conducts tears.

Atlas

The 1st cervical vertebra, which supports and holds the head.

Axis

The 2nd cervical vertebra, which allows rotation of the head.

True Ribs

Rib pairs 1 through 7 that attach directly to the sternum via cartilage.

False Ribs

Rib pairs 8 through 12 that attach indirectly to the sternum via cartilage.

Floating Ribs

Rib pairs 11 and 12, which are sub-categorized as false ribs and are not attached to the sternum.

Acetabulum

The hip socket depression where the coxal bone articulates with the femur.

Articulation

A joint formed where two bones come together.

Synarthrosis

A nonmovable joint, such as the sutures found in the skull.

Amphiarthrosis

A slightly movable joint, such as the joints between vertebrae.

Diarthrosis

A freely movable joint, such as the knee, elbow, or wrist.

Flexion

A bending movement that decreases the angle between bones.

Extension

A straightening movement that increases the angle between bones.

Abduction

Movement of a structure away from the midline of the body.

Adduction

Movement of a structure toward the midline of the body.

Pronation

Rotation of the forearm so that the palm faces down.

Supination

Rotation of the forearm so that the palm faces up.

Rotation

The movement of a structure about its long axis.