doxosoxa's version from 2017-10-04 01:09

Section 1

Question Answer
What is Ossification?The formation of bone
What are the two types of ossification?intramembranous and endochondral

Section 2

Question Answer
What is Intermembranous?IT is where bones develop in fibrous sheets called trabeculae
What do the mesenchymal cells that are lining the trabecula differentiate into?Osteoblasts in the presence of blood vessels
What do osteoblasts do?synthesze osteoid, which is subsequentlty calcified
What are the trapped osteoblasts in the calcified matrix called?osteocytes
What do adjacent trabeculae join together to form?a spongy bone
What does the spongy bone consist of?consists of many trabeculae separated by wide spaces
When do the trabeculae at the surface of the bone stop growing and calcifying?when the spaces between them are filled in, hence converting spongy bone to compact bone
What are examples of intermembranous ossification?flat bones of the skull, part of the scapula and pelvic girdle

Section 3

Question Answer
What is Endochondral Ossification?bone develops from a preexisting model of hyaline cartilage
What are the steps in Endochondral Ossification?formation of periosteal collar in the periphery, hypertrophy of cartilage cells in the center of the cartilage models, calcification of cartilage matrix, degeneration of cartilage cells, infiltration of periosteal bud carrying blood vessels and osteoblasts in the middle of the cartilage matrix, deposition of woven bone on the calcified cartilage matrix, replacement of woven bone by lamellar bone, repetition of the above sequence of events until the entire cartilage is replaced by bone
Where does Endochondral Ossification process not take place?in the epiphyseal plate (growth plate
What is the epiphyseal plate responsible for?responsible for growth in length of the bone
What are the different zones in the epiphyseal plate?zone of reserve cartilage cells (resting), zone of cell proliferation, zone of hypertrophy, zone of calcification, and zone of ossificationWh
What is bone elongation the result of?result of interstitial growth of hyaline cartilage
When does Hyalin cartilage stop being replaced by by bone?When the epiphyseal plate fuses (in other words becomes bone)
T or F: Bone can grow by interstitial mechanism?False it can not
Why can bone not grow in interstitial mechanism? because cells cannot multiply in a calcified matrix
How does bone grow?by appositional mechanism
What does appositional growth allow bones to do?Grow in width