Bone

Question 0

What r osteocytes?

Answer 0

Slim dystopias mic processes thT connect to adjacent osteocytes in a canaliculus to transport nutrients via gap junctions

Question 1

What are the trabeculae full of?

Answer 1

Bone marrow and osteocytes

Question 2

What is the fine fibourous tissue surround the canaliculi and lucunae?

Answer 2

Sheath of Neumann

Question 3

Why’s is red marrow?

Answer 3

For RBC synthesis

Question 4

What is yellow marrow?

Answer 4

Contains adipose tissue

Question 5

What is the marrow cavity lined by?

Answer 5

A thin cellular layer called the ENDOSTEUM

Question 6

Process of bone synthesis?

Answer 6

Osteoblasts fork osteoid

Osteoblasts surrounded by osteoid forms osteocytes

Question 7

Remodelling bone?

Answer 7

Osteoclasts - multinucleated monocytes release H+ and lysosomal enzymes to absorb bone producing a cutting cone.
Osteoblasts forms new osteons

Question 8

Content of bone matrix?

Answer 8

65% inorganic minerals
Calcium hydroxyapatite crystals of calcium phosphate and carbonate. Hence hard and rigid
10% water
23% type 1 collagen hence flexibility
2% non-collagen proteins

Question 9

Talk about calcium and bone?

Answer 9

Calcium require for muscle contraction, blood clotting, nerves, cell membrane permeability and controlled by parathyroid which releases PTH which triggers osteoclasts to digest bone hence release calcium into the blood.
If too much calcium in blood, calcitonin inhibits osteocytes and decreases bone absorption

Question 10

What is endochondral ossification?

Answer 10

Cartilage becomes bone. This occurs in long bones
Cartilage reabsorbed and replaced by bone.
Begins at primary centre in the diaphysis shaft and then at each end. Secondary centre is the epiphysis.
Growth occurs at the epiphyte all growth plates to extend length

Question 11

What is intermembraneous ossification?

Answer 11

Loose CT / mesenchyme becomes bone - flat
highly vascularised loose CT
Mesenchymal cells differentiate into osteoblasts surrounded by collagen fibres and GS
Cells secrete uncalcified matrix osteoids and become osteocytes

Question 12

What’s a fracture?

Answer 12

Bone breaking means blood vessels and periosteum breaks, bone matrix destroyed and bone at fracture site becomes necrotic and die.

Question 13

Bone repair?

Answer 13

1. Heamatom formation - swelling and blood clot. Macrophages remove dead tissue and osteoclasts remove dead bone
2. Fibrocartilaginous callus formation - new blood vessels, inflammatory cells invade forming pre-callus bridging fracture containing haematoma and fibrous tissue. Collagen formed over fracture by fibroblasts. Chondroblast gives rise to hyaline cartilage sleeve. Central osteoblasts invade fracture and reconstruct bone forming spongey bone
3. Bony callus - osteocallus of primary bone then calcified to secondary
4. Bone pulled and pressured to match surrounding bone to form mature bone
5. As callus forming, step last of periosteum lay down sleeve of bone. Periosteal buds invade callus to form spongey and replace cartilage similar to endochondral ossification. Spongey the. Forms compact bone.
6. Bone heals without scar.
7. New bone is wider, hence remodelling restores right size and shape.

Question 14

Overview of bone repair?

Answer 14

Break
Haematoma clot
Callus of cartilage
Primary bone
Calcification to secondary bone

Question 15

What is the process that increases diameter of bone?

Answer 15

Periosteal ossification. The periphery region of shaft have increased deposition of bone