Osteogenesis

Question 1

Two types of cone

Answer 1

compact and spongy

Question 2

location of compact bone

Answer 2

bone surgace

Question 3

compact bone contains a very dense matrix composed of

Answer 3

lammellae plates

Question 4

3 types of compact bone lamellae

Answer 4

1) circumferential: encircle the inner and outer surface of diaphysis
2) concentric lamellae: osteocytes in their lacunae arranged in rings
3) interstitial lamellae: remenants of the old haversian systems resulting from bone remodelling.

Question 5

in compact bone, osteocytes are located in the dense ___, found in lacunae cavities arranged in ____ ___

Answer 5

in compact bone, osteocytes are located in the dense MATRIC, found in lacunae cavities arranged in CONCENTRIC LAMELLAE

Question 6

osteocytes in the dense matrix of compact bone are supplied by blood vessel and nerves that travel through ____> 2 types.

Answer 6

Canals.
1) volkman canals: penetrate the SURFACE and connecets haversian canals

2) haversian canals: run parallel to the surface.

Question 7

Structural unit of compact bone. Components

Answer 7

a haversian system/osteon

involves 1) haversian canal that houses the blood and nerve supply
2) concentric lamellae: osteocytes in their lacunae arranged in rings.

Question 8

function of canalculi

Answer 8

cellular connections between osteoctes. allows for diffusion of nutrients from cell to cell towards the periphery of haversian system.

Question 9

location of spongy bone

Answer 9

interior of bone

Question 10

purpose of trabeculae

Answer 10

delicate network of bone for strengthening purposes.

Question 11

trabeculae is surrounding by

Answer 11

mesenchyme

Question 12

diploe

Answer 12

internal spongy bones.

Question 13

2 methods of ossification

Answer 13

1) endochondral ossification

2) intramembranous ossification

Question 14

endochondral ossification occurs

Answer 14

in long bones and at the epiphyseal plate

Question 15

6 zones of the epiphyseal plate

Answer 15

1) zone 1: resting cartilage: resting hyaline cart
2) zone 2: zone of proliferation. CHONDROCYTES multiply. form lines of lacunae (aggregates)
3) zone of hypertrophy. Lacunae grow.
4) zone of calcification. Becomes more basophillic.lacunae mesh together. Kind of hard to tell between zone 3 and 4.
5) zone of ossification. Chondrocytes die and bone is deposited.
6) zone of erosion: osteoclasts make marrow canals from newly deposited bone

Question 16

the beginning of endochondral ossification occurs in hyaline cartilage at the ____ ___ of ossification in the ____

Answer 16

the beginning of endochondral ossification occurs in hyaline cartilage at the PRIMARY CENTER of ossification in the DIAPHYSIS (in embryo)

Question 17

endocondral ossification: at the primary center of ossification, osteoblasts develop from ____ and begin to:

What happens to perichondrium?

Answer 17

osteoblasts begin to develop from MESENCHYMAL cells and begin to deposit a ring of periosteal bone for support as the internal cartilage gets erodid. the perichondrium of the cartilage becomes periosteum.

Question 18

after a boney collar is formed by original osteoblasts, outline the rest of the steps of endochonrdral ossification (DURING EMBRYO)

Answer 18

1) chondrocytes begin multiplying and enlarging. calciufication also occurs.
2) periosteal buds grow to form blood vessels that branch into enlarged lacunae that was formed during hypertrophy
3) ossification continues to occur because mesenchymal cells migrate into the cavities and differentiate into osteoprogenitor cells in the marrow spaces. Ops differentiate into osteoblasts, that can deposit collagenous osteoid and then bone into the remaining cartilagenous fragments.

4) hemopoietic stem cells also enter and begin producing marrow
5) after ossification, osteoclasts move in and resorb bone to form marrow cavities.

Question 19

After birth, what are the last stages of endochondral ossification

Answer 19

6) bone continues to grow except at articular cartilage or epiphyseal plates
7) all bone intially forms as woven bone, so it must be remodelled at the surface to form compact bone
8) secondary ossification centers form. They are separated by the primary center of ossification by the epiphyseal plate.
- allows for the deposition of bone at the EPIPHYS (tips of long bone). Epiphyseal plate and articular cartilage is left for growth spurts.
9) after growth is completed, the epiphyseal plate itself ossifies and an adult is left with the epiphyseal line.

Question 20

the primary and secondary center of ossification is separated by the

Answer 20

epiphyseal plate

Question 21

what is intramembranous ossification? what does it produce?

Answer 21

bone forms within mesenchymal membrane. produces flat bones of the skull.

Question 22

process of intramembranous ossification

Answer 22

1) mesenchymal cells differentiate into osteoblasts.
2) osteoblasts produce and deposit osteoid
3) osteoid becomes mineralized
4) osteoid becomes trabeculae, and fuse with one another to form spongy bone
4) bone marrow develops into spaces of the trabeculae
5) mesenchyme at the periphery of the bone CONDENSES to form periosteum and enosteum.
6) surface of the woven bone are remodelled to form compact bone.

Question 23

in flat bones of the skull, the layers on the surfaces are called ___ and ___ ___s, and are separated by ____.

Answer 23

in flat bones of the skull, the layers on the surfaces are called INNER and OUTER TABLESs, and are separated by DIPLOE: spongy bone between compact bone tables.

Question 24

in endochondral ossification, the osteoblasts form periosteal bone bony collar using the process of :

Answer 24

intramembranous ossification (osteoblasts–> osteoid –> mineralization –> bony collar)