The Bone/axial

Question 1

Osteocytes

Answer 1

• mature bone cells
• bone cells that have migrated to the bone
• communicating w/ other bone cells thru canela

Question 2

Osteoblasts

Answer 2

• bone forming cells (blasting out bones)
• found outside of the bone
• lay down matrix in order to for, bone

Question 3

Osteoclasts

Answer 3

• break down and remove bone
• helps us maintain strength

Question 4

Compact bone

Answer 4

• dense and solid
• forms walls of bone
• arranged into osteons with central canals and lamellae

Question 5

Spongy bone

Answer 5

• open network of struts and plates
• internal layer surrounds medullary cavity
• arranged into trabeculae

Question 6

Intramembeanous ossification

Answer 6

1. Differentiation of mesenchymal cells directly intomosteoblasts
   > stem cells get some signals from other cells surrounding it and those signals start turning into osteoblasts
   > tissue is highly vascularized
   > osteoblasts cluster tgthr to secrete matrix in ossification centers
2. Formation of bony spicules
   > osteoblasts become surrounded by matrix and become osteocytes
   > developing bone grows outward from ossification centers
   (picture is of step 2)

Question 7

Endochondral ossification steps

Answer 7

1. Hyaline cartilage model forms in shape of bone
2. Chondrocytes within headline model die, creating spaces
3. Periosteal collar forms around shaft of presumptive bone
4. Primary ossification center is formed when Mesenchymal stem cells invade bony collar via blood vessels, differentiate into osteoprogenitor cells and begin depositing matrix
5. Secondary ossification centers form Periosteal collar forms around when capillaries migrate to centers of shaft of presumptive bone epiphyses (ends of long bone)
   (#5 pictured below)

Question 8

Endochondral ossification

Answer 8

• epiphyses (ends of long bone) will become filled with spongy bone
• epiphyseal plate (”growth plate”) of cartilage separates epihysis from diaphysis (shaft)
• Osteoblasts invade shaft side of growth plate and replace cartilage with bone while cartilage plate enlarges through growth = increase in length of bone

Question 9

Go over slides 12 and 13

Answer 9

Talks about compact bone, central canal, lamellae, etc.

Question 10

Periosteum

Answer 10

• outer connective tissue covering of bone
• serves as an anchor for our muscles that are going to attach to our bone
• attaches directly to bone, contains vessels and nerves
• has outer fibrous layer
• inner cellular layer with osteoprogenitor cells

Question 11

Osteoporosis

Answer 11

• Can result from increased bone resorption, decreased bone deposition, or both
• osteoclasts = eating up more bone tissue than they should -> go into overdrive
• osteoblasts = they arent depositing enough new bone -> can’t keep up

Question 12

Why do postmenopausal women get osteoporosis

Answer 12

Estrogen activates bone formation via osteoblasts, so it’s absence can = decreased bone formation

Question 13

Functions of Bone

Answer 13

• protects internal organs
• stores and releases fat
• produces blood cells
• stores and releases minerals
• facilitates movement
• supports the body