BOnes

lacune

Hollow where osteocytes reside

I.O. Formation

1. Bone forms from mesenchymal cells or connective tissue 2. Meschymal cells make Blood, Cartilage, Adipose, and Bone 3. In bone: Osteoprogenitor cells, Osteoblasts, Osteocytes

E.O. Formation

1. Starts as chondrocytes or cartilage 2. Center cartilage cells die and create spaces for osteoblasts 3. Osteoblasts lay down bone matrix allows arteries to com in, creates primary ossification center 4. Secondary ossification in epiphysis

periosteum

A dense fibrous membrane covering the surface of bones (except at their extremities) and serving as an attachment for tendons and muscles.

osteons

Are made of concentric layers of matrix called lamella, containing collagen fibers and mineral salts. Overall

osteoblasts

Bone-forming cells. Both

osteoclasts

Break down bone. Only E.O

perforating canal

Canals that run at right angles to the long axis of the bone, connecting the vascular and nerve supplies of the periosteum to those of the central canals and medullary cavity

chondrocytes

Cartilage cells- may start E.O.

lamellae

Concentric rings made up of groups of hollow tubes of bone matrix concentric layers of bone matrix

Pituitary Dwarfism

Defenition: Proportional short stature due to a decrease in human growth hormone; usually tumor in pituitary gland; proportional torso and limbs Causes: Tumor on pituitary gland BEFORE puberty Axial and Appendicular, IO and EO

Osteogenesis imperfecta (OI) Brittle bone disease

Define: Brittle bones due to defective collegen fibers; all bones break easily Causes: Genetic defect in collagen gene Axial and Appendicular, IO and EO

Acromegaly

Define: Increase of human growth hormone caused by a pituitary tumor that occurs AFTER puberty; enlarged flat bone and some long bone growth; above average height Causes: Tumor on pituitary gland AFTER puberty Mostly Axial, some Appendicular, IO mainly

Pituitary Gigantism

Define: Increase of human growth hormone caused by a pituitary tumor that occurs BEFORE puberty; enlarged long bone and flat bone; above average height Causes: Tumor on pituitary gland BEFORE puberty Axial and Appendicular, IO and EO

Fibrodysplasia Ossificans Progressive (FOP)

Define: Many different types of tissues turn into bone throughout life; causes immobility at joints Causes: Genetic defect in a gene called BMP-4 (protein) Axial, IO

Achondroplasia

Define: Short limbs due to stunted cartilage growth from birth; normal torso development; not proportional stature with normal torso Causes: Genetic defect in cartilage growth protein Appendicular, EO

Parts of a long bone

Epiphysis Epithelial plate Metaphases Diaphysis

capillaries

Microscopic vessel through which exchanges take place between the blood and cells of the body

Spongey bone

Mostly Epiphysis I.O. Open network of trabeculae no osteons withstand stress rom a variety of directions reduce weight of overall bone

Compact bone

Mostly in Diaphysis Marrow Cavity E.O. Osteons are aligned strengthen bone Tissue of bone is parallel to stress

endochondral ossification

Starts as cartilage long bone osteoclasts form marrow cavity osteoblasts replace chondrocytes Starts with Chondrocytes which are cartilage Compact, some spongy Appendicular

Functions of bone

Structure and Support Storage of minerals and lipids Movement Leverage Protection

Mesenchymal

The beginning tissue of I.O.

central canal

The hollow center of an osteon, also known as a Haversian canal. The central canal contains blood vessels, lymphatic vessels, and nerves. Bone is laid down around the central canal in concentric rings called lamellae.

trabeculae

The interconnecting tiny arches of bone tissue found in spongy bone are called

Classes of bone

flat long short irregular sesamoid sutural

intramembranous ossification

flat bone axial spongy mesenchymal cells osteoblasts- osteocytes Trabeculae FOP- Many types of tissue turn into bone when damaged

canaliculi

little channels that connect lacunae

osteocytes

mature bone cells help maintain minerals in bone tissue and continue to strengthen the growing bone Both

yellow marrow

soft, fatty material found in the medullary cavity of long bones

osteoprogenitor

stem cells derived from mesenchyme which produce other stem cells and osteoblasts

red marrow

thick, bloodlike material found in flat bones and the ends of long bones; location of blood cell formation