Skeletal System and Bone Anatomy Flashcards

A set of vocabulary flashcards covering bone shapes, internal structure, ossification processes, hormones, bone remodeling, surface features, and skeletal divisions based on the lecture transcript.

Long Bone

Bone named for its shape, being longer than it is wide.

Short Bone

Cube-shaped bone that is about as long as it is wide.

Flat Bone

Thin and broad bone.

Irregular Bones

Bones characterized by an irregular shape.

Sesamoid Bone

Specialized small, flat, and oval bone located within tendons that gives tendons a mechanical advantage for better muscle leverage.

Compact Bone

Hard and dense outer bone layer that resists linear compression (straight down) and twisting forces.

Spongy Bone

Bone found inside compact bone that allows long bones to resist compression from many directions and provides a cavity for bone marrow.

Periosteum

Covering around long bones rich with blood vessels (supplying $\frac{1}{3}$ of blood to bone) and nerves.

Perforating Fibers

Fibers that anchor the periosteum to underlying bone.

Diaphysis

The shaft of a long bone containing a hollow marrow cavity that holds red or yellow bone marrow.

Epiphysis

Each end of a long bone, covered with articular (hyaline) cartilage.

Endosteum

Thin membrane lining spongy bone that is involved in the maintenance of bone homeostasis.

Epiphyseal Lines

Structures separating the epiphyses from the diaphysis, representing remnants of childhood growth (epiphyseal) plates.

Diploe

Single layer of spongy bone located between two layers of compact bone in short, flat, irregular, and sesamoid bones.

Nutrient Arteries

Arteries that supply $\frac{2}{3}$ of the blood supply to internal bone, with the epiphysis receiving some of its blood from them.

Red Bone Marrow

Loose connective tissue that supports blood-forming hematopoietic stem cells, which decreases with age and is restricted to specific bones in adults.

Yellow Bone Marrow

Marrow composed of triglycerides, blood vessels, and adipocytes.

Ossification (Osteogenesis)

The process of bone formation.

Intramembranous Ossification

Type of ossification starting in the primary ossification center that converts mesenchymal (embryonic) tissue to osteoblasts, forming spongy bone first and compact bone second.

Endochondral Ossification

Type of ossification created by hyaline cartilage starting at the primary ossification center that converts chondroblasts to osteoblasts, forming all bones except the skull and clavicles.

Osteoblast

Cell that secretes organic matrix that calcifies to create new bone.

Osteocytes

Cells created by osteoblasts that become trapped in the lacunae.

Longitudinal Growth

Growth in bone length caused by the division of chondrocytes in the epiphyseal plate.

Zone of Reserve Cartilage

Top zone of the epiphyseal plate where cells are not involved in bone growth but can be recruited if the need arises.

Zone of Proliferation

Epiphyseal plate zone consisting of actively dividing chondrocytes.

Zone of Hypertrophy of Maturation

Epiphyseal plate zone containing mature chondrocytes.

Zone of Calcification

Epiphyseal plate zone where dead chondrocytes are calcified.

Zone of Ossification

Bottom zone of the epiphyseal plate containing calcified chondrocytes and osteoblasts.

Appositional Growth

Process by which bones grow in length and width as osteoblasts between the periosteum lay new bone.

Growth Hormone

Hormone produced by the pituitary gland that is secreted throughout life, with the highest amounts during infancy and childhood.

Testosterone

Male sex hormone active lifelong that increases appositional growth, promotes bone deposition, and accelerates closure of epiphyseal plates by age 16-17.

Estrogen

Female sex hormone that inhibits osteoclast activity and accelerates closure of epiphyseal plates by age 14-15, whose production stops with menopause.

Parathyroid Hormone

Hormone that increases blood calcium levels.

Calcitonin

Hormone that decreases blood calcium levels.

Bone Remodeling

Process where new bone is formed by bone deposition and old bone is removed by bone resorption simultaneously.

Axial Skeleton

Skeletal division protecting the body and its organs, comprising the skull (22 bones), vertebral column (33 bones), and thoracic cage (12 pairs of ribs, sternum, and thoracic vertebrae).

Appendicular Skeleton

Skeletal division allowing for movement, comprising the pectoral girdle, upper limbs, pelvic girdle, and lower limbs.

Brachium (Humerus)

The largest and strongest bone in the upper body.

Femur

The longest and strongest bone in the body, located in the femoral region.

Facet

Shallow surface where two bones connect, which can appear flat.

Fossa

Indentation in a bone where another structure fits (groove).

Fovea

Shallow pit in a bone.

Groove or Sulcus

Long indentation in a bone in which a narrow structure travels.

Canal (Meatus)

Tunnel through a bone.

Fissure

Narrow slit in a bone.

Foramen

Flat hole through a bone.

Condyle

Rounded end of a bone.

Crest

Ridge on a bone.

Head

Rounded projection on the epiphysis of a bone.

Tubercle

Small rounded projection on a bone.

Tuberosity

Large tubercle on a bone.

Epicondyle

Small projection next to a condyle.

Spine

Sharp process on a bone.

Process

Very broad term for any bony projection.

Protuberance

Outgrowth from a bone.

Trochanter

Large projection on the femur.

Line

Long, narrow ridge on a bone.

Sutures

Structures that fuse together the skull bones.

Hyoid Bone

Bone that provides attachment points for muscles involved in swallowing and speech.

Intervertebral Foramen

Opening in the vertebral column that allows spinal nerves to pass through.

Intervertebral Discs

23 fibrocartilage pads found between vertebrae that absorb shock and bind each disc.

Nucleus Pulposus

Jelly-like shock absorbent component located inside an intervertebral disc.

Annulus Fibrosus

Outer ring of fibrocartilage that contains the nucleus pulposus and joins adjacent vertebrae.