Classification of bones based on shape:

Long bones - longer than wide, but not based on overall length

Parts of a typical long bone :
        epiphyses -ends
        diaphysis - shaft
        metaphysis - - early - epiphyseal plate, later - epiphyseal line.
        articular cartilage - hyaline cartilage
        periosteum -
                            outer fibrous layer - dense irregular connective tissue,
                            inner osteogenic layer - elastic fibers, blood vessels, and bone cells.
        medullary (marrow) cavity - red or yellow marrow
        endosteum. -  membrane contains osteoprogenitor cells and osteoclasts.

mostly dense or compact bone - spongy bone in the ends

Short bones- cube-shaped, nearly equal in length and width
Flat bones
Irregular bones- complex shapes
Sutural bones
Sesamoid bones

Bone markings:

Those involved in muscle/tendon/ ligament attachments:
        Tuberosities - large, round, roughened places
        Crest - ridge of bone

Those that are openings within bone:
        Meatus - canal-like passageway (tube)
        Sinus - air filled cavity, as in frontal bone
        Foramen - hole involved in the passage of blood vessels or nerves

Those that form joints:
        Head - expansion of a narrow neck
        Condyle - rounded surface

Epiphyseal plate:

1. Zone of resting cartilage

2. Zone of proliferating cartilage

                    3. Zone of hypertrophic or maturing cartilage

                    4. Zone of calcified cartilage

Minerals needed for proper bone maintenance include calcium, phosphorus, boron and manganese.

Vitamins needed include D, -rickets or osteomalacia,. C,  A and B12

Hormonal control of bone remodeling:

growth hormone - pituitary dwarfism/gigantism adult - acromegaly

                    testosterone (androgens) and estrogen during puberty

parathyroid hormone (PTH). increases the activity of osteoclasts, increases reabsorption by kidneys, and promotes the formation of vitamin D.

calcitonin-. inhibits osteoclasts, and increases the rate calcium is incorporated into bone.

insulin and thyroid hormones

estrogen and testosterone levels drop with age - osteoporosis.

Fracture and Repair of Bone

  • 1. Fracture hematoma - Bone cells die of ischemia. Swelling and inflammation occur.

    • 2. The infiltration of blood capillaries helps organize it into granulation tissue called a procallus.

                             Then    fibrocartilaginous (soft) callus.

                        3. Ossification
                                bony (hard) callus    . (Spongy bone)

                        4. Callus removal or remodeling.