Chapter 6: Bones and Bone Tissue Study Guide

A complete set of vocabulary flashcards covering the gross and microscopic anatomy of bone, ossification types, bone growth zones, and fracture repair based on Chapter 6 lecture notes.

Hematopoiesis

The process of blood cell formation occurring in red bone marrow.

Periosteum

A layer of connective tissue covering the outer surface of bone.

Diaphysis

The shaft of a long bone.

Epiphysis

The end of a long bone.

Osteon (Haversian system)

The basic structural unit of compact bone.

Lamellae

Layers of bone matrix arranged in concentric circles.

Canaliculi

Tiny channels that provide a means of communication between osteocytes.

Trabeculae

The bony struts found within spongy bone.

Osteoblast

A bone-forming cell responsible for building bone.

Osteocyte

A mature bone cell tasked with maintaining the bone matrix.

Osteoclast

A bone-resorbing cell responsible for breaking down bone.

Diploe

The layer of spongy bone found inside flat bones.

Inorganic Matrix

The portion of the bone matrix, approximately $65\%$, that provides hardness.

Organic Matrix

The portion of the bone matrix, approximately $35\%$, that provides flexibility and resistance to twisting.

Ossification (Osteogenesis)

The process of bone formation.

Intramembranous ossification

A type of bone development where bone forms from mesenchyme, mainly resulting in flat bones.

Endochondral ossification

A type of bone development where bone forms from a hyaline cartilage model, producing most bones in the body.

Mesenchyme

Embryonic connective tissue that serves as the starting material for intramembranous ossification.

Primary ossification center

The first area where bone formation begins during ossification.

Secondary ossification center

The area of ossification that develops in the epiphyses.

Chondrocyte

A cartilage cell.

Bone collar

An early bony covering that forms around a hyaline cartilage model during endochondral ossification.

Osteoporosis

A disease characterized by weak, brittle bones often caused by aging, estrogen deficiency, or lack of exercise.

Epiphyseal plate

A growth plate made of hyaline cartilage where long bones increase in length.

Epiphyseal line

The remnant left behind after the epiphyseal plate closes.

Appositional growth

The process by which bones increase in diameter or width.

Zone of reserve cartilage

The first zone of the epiphyseal plate closest to the epiphysis.

Zone of proliferation

The second zone of the epiphyseal plate where chondrocytes actively divide.

Zone of hypertrophy

The third zone of the epiphyseal plate.

Zone of calcification

The fourth zone of the epiphyseal plate where the cartilage matrix hardens.

Zone of ossification

The fifth zone of the epiphyseal plate closest to the diaphysis where new bone is formed.

PTH (parathyroid hormone)

A hormone that acts to raise blood calcium levels.

Calcitonin

A hormone that acts to lower blood calcium levels.

Hematoma

A blood clot that forms at a fracture site; the first stage of fracture repair.

Soft callus

Fibrocartilaginous repair tissue that forms during the second stage of fracture healing.

Bone callus

Bony repair tissue that forms during the third stage of fracture healing.