Chapter 7 Mcgraw hill

Diaphysis

shaft of a long bone

Perforating Fibers

collagen fibers that penetrate into the bone matrix

Epiphyseal Line

remnant of the epiphyseal plate, seen in adult bones

Lamellae

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

Osteocyte

a bone cell, formed when an osteoblast becomes embedded in the matrix it has secreted.

Longitudinal growth

Increases a bone's length

Greenstick fracture

bending and incomplete break of a bone; most often seen in children

Red bone Marrow

produces red and white blood cells and platelets

Yellow Bone Marrow

gradually replaces red bone marrow in adult bones; functions as storage for fat tissue and is inactive in the formation of blood cells

intramembranous ossification

process by which bone forms directly from mesenchymal tissue

Calcitonin

Lowers blood calcium levels

Medullary Cavity

cavity within the shaft of the long bones filled with bone marrow

Endosteum

membranous lining of the hollow cavity of the bone

Osteon

structural unit of compact bone

Wolff's Law

A bone grows or remodels in response to forces or demands placed upon it

Pathological Fracture

break in a bone weakened by disease

Metaphysis

flared portion of a long bone, between the diaphysis and the epiphyseal plate

Epiphysis

the end part of a long bone, initially growing separately from the shaft.

Epiphyseal Plate

Growth plate, made of cartilage, gradually ossifies

Haversian Canal

any of the minute tubes that form a network in bone and contain blood vessels.

Osteoblast

a cell that secretes the matrix for bone formation.

Appositional growth

increase in bone thickness

Ossification

process of bone formation

Osseous Tissue

connective tissue in which the matrix is hardened by the deposition of calcium phosphate and other minerals

Articular Cartilage

hyaline cartilage that covers ends of bones in synovial joints

Parathyroid Hormone

increases blood calcium levels

closed fracture

one in which the bone is broken, but there is no open wound in the skin

Nutrient foramina

minute holes in the bone surface that allows blood vessels to penetrate

trabeculae

supporting bundles of bony fibers in cancellous bone

achondroplastic dwarfism

Long bones stop growing in childhood

Normal torso, short limbs

Failure of cartilage growth in metaphysis

Spontaneous mutation produces mutant dominant allele

Hypocalcemia

an abnormally low level of calcium in the blood

soft callus

fibrous tissue formed by fibroblasts and infiltrated by capillaries

hard callus

Gradual connection of bone filaments to woven bone at a fracture site.

periosteum

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

osteogenic cells

stem cells that differentiate into osteoblasts

lacunae

small spaces between the lamellae which contain osteocytes

fracture

broken bone

osteoclast

Bone-destroying cells

osteoporosis

A condition in which the body's bones become weak and break easily.

Hydroxyapatite

Hardy crystals consisting of calcium and phosphate that form the bone matrix.

Compact Bone

Hard, dense bone tissue that is beneath the outer membrane of a bone

spongy bone

Layer of bone tissue that has many small spaces and is found just inside the layer of compact bone.

Calcidiol

modified in the liver into another inactive form of vitamin D

Calcitriol

A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.

open fracture

compound fracture; broken bone with an open wound

Spicules

small, spike shaped particles of calcium carbonate or silicon dioxide that make up the skeleton of some sponges

Hypercalcemia

an abnormally high level of calcium in the blood

kyphosis

excessive outward curvature of the spine, causing hunching of the back.

List the major function of the bones

bone function 1

provide shape, support, and the framework of the body

bone function 2

provide protection for internal organs

bone function 3

serve as a storage place for mineral salts, calcium, and phosphorus

bone function 4

play an important role in the formation of blood cells as hemopoiesis takes place in the bone marrow

bone function 5

provide areas for the attachment of skeletal muscles

bone function 6

help to make movement possible through articulation

Long bones

longer than they are wide

short bones

bones of the wrist and ankles

flat bones

bones of the ribs, shoulder blades, pelvis, and skull

irregular bones

vertebrae and facial bones

Four classes of bones

1. long bones

2. short bones

3. flat bones

4. irregular bones

sesamoid bones

round bones found near joints (e.g., the patella)

function of medullary cavity

Medullary (marrow) cavity is the hollow area in the diaphysis of a long bone that contains yellow bone marrow.

function of periosteum

Fibrous membrane covering attached by fibers

Enter into bone allowing nerves, blood/lymphatic vessels top pass through it

fibrous layer of periosteum

outer layer consisting of dense irregular connective tissue consisting of Sharpey's fibers that secure to bone matrix

osteogenic layer of periosteum

inner layer abutting bone and contains primitive osteogenic stem cells that gives rise to most all bone cells

function of articular cartilage

to reduce friction and to prevent bony surfaces from contacting one another

Diploe

spongy bone in flat bones

red marrow

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

Describe the Haversian system

Vertical canals, passway for blood vessels nerves are found in compact bone

Volkmann's canals

channels lying at right angles to the central canal, connecting blood and nerve supply of the periosteum to that of the Haversian canal

interstitial lamellae

remains of old osteons that broke down as bone grew and remodeled itself

Circumferential Lamellae

located deep to periosteum and superficial to endosteum and extend around entire circumference of the diaphysis and resist twisting of long bone

arrangement of trabeculae

organic components of bone

osteogenic cells, osteoblasts, osteocytes, bone-lining cells, osteoclasts, and osteoid

components of osteoid

Unmineralized organic blueprint to bone

Principal hydroxyapatite making up the inorganic component of bone matrix.

Calcium phosphate salt

osteogenesis

formation of bone

bone formation

osteogenesis

bone growth

increase in bone size

bone remodeling

ongoing replacement of old bone tissue by new bone tissue

intramembranous ossification

process by which bone forms directly from mesenchymal tissue

endochondral ossification

process in which bone forms by replacing hyaline cartilage

steps of intramembranous ossification

1. development of ossification center

2. calcification

3. formation of trabeculae

4. development of periosteum

Describe apositional growth?

Growth of a tissue by building on the outside of the mass

Only way bone grows

bone deposit

Occurs where bone is injured or added strength is needed; Requires a diet rich in protein; vitamins C, D, and A; calcium; phosphorus; magnesium; and manganese

osteoid seam and calcification front

sites of new matrix deposition are revealed by

bone resorption

the removal of minerals and collagen fibers from bone by osteoclasts

3 hormones that affect bone remodeling

Growth hormone (GH). ...

Parathyroid hormone (PTH). ...

Estrogens. ...

Calcitonin and thyroid stimulating hormone (TSH), both of which inhibit the activity of osteoclasts.

Calcitriol (1,25[OH]2 vitamin D3. Needed for the deposition of calcium into bone.

calcitriol

A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone. Increase

parathyroid hormone

increases blood calcium levels

Calcitonin

Lowers blood calcium levels

Release of calcitonin

Wolff's Law

that bone in a healthy person or animal will adapt to the loads under which it is placed.

Osteoporosis

A condition in which the body's bones become weak and break easily.