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