Formation of Bone in the Early Skeleton - INTRAMEMBRANOUS OSSIFICATION - notes

Question 1

All of the flat skull bones and the clavicles are made from a fibrous connective
tissue called?

Answer 1

mesenchyme

Question 2

What is step one in Intramembranous ossification?

Answer 2

Ossification centers (REGIONS OF BONE FORMATION) appear in 
the mesenchyme.

Question 3

What cells produce the the bone matrix?

Answer 3

Osteoblasts

Question 4

What is the bone matrix also called?

Answer 4

Osteoid

Question 5

What grows and expands as a series of trabeculae that grow outward from the ossification centers.

Answer 5

Spongy bones or woven bone

Question 6

What grows into the woven bone as it forms?

Answer 6

Bloodvessels

Question 7

What happens in step 2 in Intramembranous ossification?

Answer 7

The periosteum(soft tissue) forms on the surface of the bone.

It also provides osteoblasts on top of the mesenchyme so that the compact one can be made.

Question 8

What happens in step 3 of Intramembranous ossification?

Answer 8

Compact bone forms beneath the periosteum.

aka Bony Collar

Question 9

What happens in Step 4 of Intramembranous ossification?

Answer 9

Blood vessels inside the bone turn into red bone marrow.

Question 10

What is not fully ossified at birth?

Answer 10

Skull bones

Question 11

When do skull bones become ossified?

Answer 11

Around age 2

Question 12

Until then what are the parts of the skull bones called and what are they made of?

Answer 12

They are called Fontanels or soft spots.

They are made up of mesenchyme.