Ch 6

The Hydroxyapatite, or bone salt crystals makes up the majority of the bone matrix. What percentage does the hydroxyapatite make up?

66%

What is another name for the Osteon?

A Haversian system

The Osteon is what type of structure?

A cyndrical structure parallel to the shaft of the bone.

What is The Epiphyseal Plate?

A layer of hyaline cartilage at the boundary of the epiphysis and diaphysis

Where is cartilage found?

Airways in respiratory system, auricle of ear, articulations, precursor model for bone growth, fetal long bones, and smooth surfaces where bones meet

name the types of bone cells

Osteoprogenitors, Osteoblasts, Osteocytes, and Osteoclasts

How is compact bone oriented?

Parallel oriented tubes of osteons,

Name the two types of bone coverings

Periosteum and Endosteum

Endochondral Ossification Stage 3

Primary ossification center forms in the diaphysis

When does repair start after a bone fracture?

Repair immediately starts

Endochondral Ossification Stage 4

Secondary ossification centers form in the epiphysis

The classification of bones according to what?

Shape

Endosteum

covers most internal surfaces of bones

Medullary, marrow cavity

cylindrical space in diaphysis

Periosteum

dense irregular connective tissue. covers external surfaces of bones

Zone of calcified cartilage

deposited minerals kill the chondrocytes and make matrix opaque Zones of Epiphyseal Plate

Intramembranous Ossification

develops from mesenchyme. Formation of cartilage, forming from the center and working its way out.

Diaphysis

elongated, usually cylindrical, shaft

What does articular cartilage reduce?

friction between articulating bones

Interstitial growth

from inside of the cartilage

Long bones

greater length than width

The skeletal system is an organ system with tissues that do what?

grow and change throughout life

Central Canal

carries blood vessels and nerves, centrally located in the Osteon

Bone Matrix: what are the 1/3 organic components?

cells, collagen fibers, ground substance

Zone of hypertrophic cartilage

chondrocytes not dividing, become enlarged

Interstitial Lamella

"leftover" pieces of old osteons

Compact Bone Organization

..

During aging, bone changes in two ways:

1. Loses ability to produce organic matrix, mainly collagen. 2. loses calcium (Ca++) and other bone salts

Endochondral Ossification

Begins with a hyaline cartilage model

Endochondral Ossification Stage 5

Bone replaces cartilage, except the articular cartilage and epiphyseal plates

What are bones strengthened by?

Calcification

Endochondral Ossification Stage 2

Cartilage calcifies and a periosteal bone collar forms around diaphysis

What are the two types of an Osteon Canal?

Central Canal and Perforating Canal

what are the types of Lamellae?

Concentric Lamella, circumferential lamella, and interstitial lamella

Long Bone Anatomy

Diaphysis, Epiphyses, and Metaphyses

Endochondral Ossification Stage 6

Epiphyseal plates ossify and form epiphyseal lines

True or fase: Mature cartilage is vascular

False. Mature cartilage is avascular

Endochondral Ossification Stage 1

Fetal hyaline cartilage model develops

The Intramembranous Ossification begins from the center and goes out in how many stages?

Four

Describe flat bones

Have compact and spongy (diploë) bone

Which way does appositional growth occur?

In diameter

Which way does interstitial growth occur?

In length

Bone is constantly being remodeled, it is more dense in early adulthood, and less in older adults. There are two types of bone growth, what are they?

Interstitial and appositional growth

Cartilage grows in two patters, what are they?

Interstitial growth and Appositional growth

What are the two general patters of osteogenesis?

Intramembranous and endochondral

Intramembranous Ossification Stage 4

Lamellar (secondary)

Bones

Living organs containing all four tissue types primarily connective tissue.

What are the four classifications of bones?

Long bones, Short bones, flat bones, and irregular bones

What is the first step of repair in bone?

Make a hemotoma, then it converts to cartilage, then to bone

Calcification

Minerals deposited in the matrix. Main store and source of Calcium (2+) and Phosphate (PO4---)

Describe the process of Interstitial Growth

Mitosis of chondrocytes in lacunae forms two chondrocytes per lacunae. Each synthesize and secrete new matrix, the new matrix then separates the cells.

Describe the process of Appositional Growth

Mitosis of stem cells in perichondrium adds chondroblasts to periphery. produce matrix, become chondrocytes forming new lacunae adding to the existing matrix.

There are three major types of arteries and veins in bone, what are they?

Nutrient, Metaphyseal, and Epiphyseal

What does the perforating canal provide?

Opportunity for further nutrient delivery

Intramembranous Ossification Stage 1

Ossification centers from within thickened regions of mesenchyme

Intramembranous Ossification Stage 2

Osteiod undergoes calcificaiton

mesenchyme

Stem cells

What are the functions of Cartilage?

Support soft tissues

What are the five functions of bones

Support, Protection, Movement, storage, and Hemopoiesis

The basic structural and functional unit of mature compact bone is what?

The Osteon

Ossification

The formation and development of bone, also knows as osteogenesis

What does endochondral ossification produce?

The majority of bones in the body, primarily the long bones.

What can these changes result in?

This can result in a condition called osteoporosis, decrease in bone density and bone fractures

Osteogenesis

To build bone

True or false: Periosteum does not cover articular cartilages

True. Periosteum does not cover articular cartilages

Intramembranous Ossification Stage 3

Woven (primary) bone and surrounding periosteum form.

The epiphyseal plate consists of five distinct microscopic zones, what are these zones?

Zone of resting cartilage, Zone of proliferating cartilage, Zone of hypertrophic cartilage, Zone of calcified cartilage, and Zone of ossification

Circumferential Lamella

along endosteum and periosteum

Appositional growth

along outside edge of the cartilage

What does the Periosteum act as for blood vessels and nerves?

an anchor

Metaphyses

between diaphysis and epiphysis, contains epiphysial (growth) plate

canaliculi:

between lacunae allowing metabolic interactions between osteocytes

Bone Matrix: what are the 2/3 inorganic components?

bone salt crystals: hydroxyapatite, calcium phosphate and hydroxide ( Ca10(PO4)6(OH)2 )

Where is compact bone found?

external surfaces of long and flat bones

Zone of resting cartilage

farthest from medullary cavity, nearest epiphysis, small chondrocytes in hyaline cartilage

What does the intramembranous ossification produce?

flat bones of the skull, some facial bones, the mandible, and central portion of the clavicle.

Osteoblasts

form bone matrix, builders

Where is spongy bone found?

internal surface of bones. Generally in the Epiphysis and Metaphysis of bone, it is rarely in the diaphysis.

What is the Epiphyseal Plate a site of?

interstitial growth, or bone lengthening

Describe semi-rigid connective tissue

it is not as strong as bone, more flexible, resilient

Epiphyses

knobby, enlarged regions at ends, strengthen joints, attachment site for tendons/ligaments

Osteoclasts

large, multinucleated cells that dissolve bone, releasing calcium (Ca++)

Zone of proliferating cartilage

larger chondrocytes undergoing rapid mitotic cell division, aligned like stacks of coins

What does the process of Interstitial Growth result in?

larger piece of cartilage, the newest cartilage is inside

What does the process of Appositional Growth result in?

larger piece of cartilage, the newest cartilage on outside edges

Where do chondrocytes live?

live in small spaces called lacunae

Osteoprogenitors

mesenchymal stem cells, found in endosteum and periosteum, mitotically produce more stem cells or osteoblasts

Short bones

nearly equal length and width

Describe spongy bone

open lattice of narrow plates: trabeculae

Irregular bones

other/complex shapes

What is the periosteum anchored by?

perforating fibers embedded in the bone matrix

Perforating Canal

perpendicular connections to central canal with blood vessels and nerves

Osteiod

precursor to solid bone matrix

chondroblasts

produce matrix, builders

Osteocytes

reside in lacunae; maintain matrix and communicate with osteoblasts to cause further deposit of bone matrix

Concentric Lamellae

rings of bone around central canal

Endochondral Ossification begins with a hyaline cartilage model and produces the majority of bones in the body. How many stages take place during this ossification?

six

Describe compact bone

solid and relatively dense

How does mechanical stress from exercise, or muscle contraction and gravity effect bone?

stimulates increase in bone density by increased osteoblast activity. Athletes who engage in these types of activities, on average, have greater bone density

Describe the extracellular matrix of bones

sturdy and rigid

Metaphyseal

supply area between the diaphysis and epiphysis

Epiphyseal

supply cells in epiphyseal plate

Nutrient

supply the diaphysis; nerves usually accompany these into the shaft of the bone

chondrocytes

surrounded by matrix

Articular cartilage

thin layer of hyaline cartilage on epiphyses,

Flat bones

thin surfaces

Hemopoiesis

to make blood

Zone of ossification

walls between lacunae break, forming channels that become invaded with capillaries and osteoprogenitor cells

What does the medullary cavity contain?

yellow bone marrow