A&P I Chapter 6: Skeletal System (Bones and Bone Tissue)

lacunae, chondroblasts

Chondrocytes are mature cartilage cells within the ______ and they are derived from the _______

perichondrium, fibroblasts

perichondrium, chondroblasts

lacunae, chondroblasts

lacunae, fibroblasts

fibroblasts, lacunae

living cells (osteocytes) and mineralized matrix

bone is made up of....

organic: collagen fibers

inorganic: hydroxyapatite (Ca plus PO4)

mineralized matrix includes...

rich

bone has a _________ blood supply

reinforced concrete

bone matrix is similar to....

collagen and proteoglycans

bone matrix organic components include.....

crystallized CaPO4 (hydroxyapatite)

bone matrix inorganic components include.....

osteoblasts

collagen and proteoglycan produced by the E.R. and packaged by the golgi while precursors of hydroxy apatite stored in vesicles

Ossification (osteogenesis)

How are osteoblasts released?

ossification/osteogenesis

formation of bone by osteoblasts

gap junctions

how osteoblasts communicate

matrix

osteoblast cells surround themselves by __________ during ossification

osteocytes

mature bone cells surrounded by matrix

lacunae, with extensions in canaliculi

osteocytes are located at....

direct passage of nutrients between osteocytes

osteocytes facillitate...

osteoclast

large, multinucleated cells with a ruffled boder

breakdown of bone matrix

reabsorption (osteoclasts)

secrete H+ ions, decalcifies

osteoclasts ___________ in an acidic environment that ____________ matrix

osteocyte secretion

secrete enzymes, digest the protein components of the matrix

collagen

The flexible strength of bone occurs because

hydroxyapatite

collagen

osteoclasts

periosteum

PPI's taken for stomach acid inhibition could also inhibit H+ pumps in osteoclasts. Therefore, they might not be able to create acidic environment to dissolve bone. This would cause a decrease in blood Ca2 levels

Calcium in blood, blood calcium levels going down

Some patients take ATP powered H+ pump inhibitors, also known as proton pump inhibitors (PPI's), to control acid reflux. Predict the effect if any, of long term, high dose of PPI's on blood Ca2+ levels. *

woven bone

collagen fibers are randomly oriented

woven bone remodeling

removing old bone and adding new

lamellar bone

woven bone is remodeled into.......

NOT strong at all- weak

how strong is woven bone?

lamellae

Mature lamellar bone is organized into sheets called....

trabeculae

plates of bones with spaces between and looks like a sponge

trabeculae location

interior of the skull bones, vertebreae, sternum, pelvis, ends of long bones

trabeculae function

immense strength and support

less matrix and more space

spongy bone has......

mechanical stress

In spongy bone, interconnecting rods /plates of bone are (trabeculae) oriented alnng the lines of.....

spongy bone appearance

spaces filled with marrow and blood vessels

more matrix with less space

compact bone has.....

the blood vessels

In compact bone, lamellae is oriented along.........

osteons (haversian system)

compact bone is compromised of functional units called.........

haversian system

blood vessel filled central canal

centra canal

In osteons, concentric lamellae of bone surround the......

osteocytes and fluid

In osteons, lacunae and canaliculi contain....

circumferential lamellae

outer surfaces of compact bone are formed by...

interstitial lamellae

What is between the osteons?

remodeling

remnants of osteons are replaced through.......

False

The lamellae found inside osteons are circumferential lamellae.

True

False

volkmann canals

perpendicular canals that deliver blood to central canals of the osteons

long bones

upper and lower limbs

short bones

carpals and tarsals

flat bones

ribs, sternum, skull, scapulae

irregular bones

vertebrae facial

structure of long bone

diaphysis, epiphysis, epiphyseal plate, medullary cavity

diaphysis (shaft)

mostly compact bone, medullary cavity contains marrow

epiphysis (ends of long bone)

mostly spongy bone

epiphyseal plate (growth plate)

hyaline cartilage; site of bone growth in length until the plate becomes ossified

medullary cavity

red marrow-> blood cell production

yellow marrow-> adipose tissue

periosteum

double layered CT on the outer surface

endosteum

single layer of CT that contains bone cells and lines all internal surfaces within bone cavities

diaphysis or epiphysis

flat bones don't have...

compact bone

FLAT bones have sandwich of spongy bones between....

diaphysis and is NOT elongated

short and irregular bone does not have......

short and irregular bone

compact bone that surrounds spongy bone center; similar to structure of epiphysis of long bones

diaphysis

A fracture in the shaft of the bone is where?

epiphysis

articular cartilage

diaphysis

perichondrium

ossification (osteogenesis)

formation of new bone by osteoblatsts is called......

intramembraneous ossification

preexisting connective tissue membrane

endochondral ossification

preexisting cartilage (e goes with e)

produce woven bone that is then remodeled into lamellar bone

both methods of ossification.....

fifth week of development

embryonic mesenchymal membrane condenses at…….

eighth, 2

ossification begins at ___________ week of development and is complete by ____ years of age

skull bones

mandible

diaphysis of clavicles

MOST of remaining bones of skeletal system

Intramembraneous ossification occurs in which bones?

centers of ossification

locations in membrane where ossification begins

fontanels (soft spots)

large membrane-covered spaces between developing skull bones; unossified

1. Ossification centers appear in the fibrous connective tissue membrane.

2. Osteoid is secreted within the fibrous membrane and calcifies.

3. Woven bone and periosteum form.

4. Lamellar bone replaces woven bone, just deep to the periosteum. Red marrow appears.

the four parts of intramembraneous ossification are.....

1. mesenchymal cells in CT differentiate into OPC's

2. OPC'S differentiate into osteoblasts

3. Osteoblasts produce bone matrix and become osteocytes

4. Trabeculae of woven bone develop

5. Spongy bone forms as more trabeculae join together

6. Cells within spaces form red marrow and cells surrounding bone form perosteum

7. Osteoblasts form periosteum from outer surface compact bone

8. Remodeling converts woven lamellar bone

steps for intramembranous ossification in order are......

example long bone

what should result after endochondral ossification?

*

steps for endochindral ossification

chondroblasts

mesenchymal cells differentiate osteochondral progenitor cells become

where joints will form

these cells in the hyaline cartilage model are surrounded by perichondrium except....

bony collar

the perichondrium becomes the periosteum, and then becomes the...

place in the correct order

perichondrium*

calcified cartliage

internal condrocytes, hypertrophy and cartliage matrix become....

calcified cartliage

a primary ossification center forms once blood vessels and osteoblasts invade the.......

medullary cavity

osteoclasts erode the central portion of diaphysis, which creates the.......

red bone marrow

cells within the cavity specialize and ____________ is created

epiphyses

secondary ossification occurs in.......

medullary cavity

secondary ossification follows the same pattern as primary but without the______

bone

all cartilage is replace with __________ in secondary endochondral ossification

epiphyseal line

the epiphyseal plate ossifies into the........

fully developed

In mature bone, spongy and compact bone are......

3,2,1

Arrange the following events in order.

1. Osteochondral progenitor cells become osteoblast

2. Connective tissue membrane is formed

3. Osteoblasts produce woven bone

3,2,5,1,4

Arrange the following events in order.

1. Chondrocytes die

2. Cartliage matrix calcifies

3. Chrondorcytes hypertrophy

4. Osteoblasts deposit bone

5. Blood vessels grow into lacunae of teh calcified cartilage*

As osteocytes migrate into developing bone and remove cartilage, the cartilage calcifies, diffusion of nutrients ceases, and the chondrocytes die.

Instead, when bone matrix is laid down, osteocytes' cell processes meet forming canaliculi. Thus, these cells receive nutrients through these processes

During endochondral ossification, calcification of cartilage results in the death of chondrocytes. However, ossification of the bone matrix does not result in the death of osteocytes. Explain*

•Cartilage matrix is semisolid (pliable) when compared with bone matrix, which is solid (rigid). The advantage of covering articulations (joints) with cartilage is that it provides a flexible, smooth surface for bone movement.

A major impetus for many joint replacement surgeries is degeneration of the articular cartilage, as movement of a joint without articular cartilage is quite painful.

Explain why it is advantageous for the articular cartilage to never become ossified.

bone length and bone width

unlike cartilage, bone only show appositional growth in......

epiphyseal plate

growth in bone length occurs at the......

appositional, existing

new cartilage by interstitial growth is followed by ____________ bone growth on the surface of ______________ cartilage

zone of resting cartliage

nearest to epiphysis, slowly dividing chondrocytes

zone of proliferation

rapidly dividing chondrocyte columns -> new cartilage (interstitial growth)

zone of hypertrophy

chondrocytes mature and enlarge closer to diaphysis

zone of calcification

dead hypertrophied chondrocytes within calcified cartilage matrix

zone of ossified bone

osteoblasts lay down new bone by appositional growth on the cartilage surface

the epiphyseal plate

The spurt growth in puberty results from cell proliferation and hypertrophy in...

the epiphysis

compact bone

the epiphyseal plate

epiphyseal line

spongy bone

periosteum, medullary

osteoblasts from the _______________ lay down bone under the periosteum which gradually increases the amount the bone surrounding the ________________ cavity