bones

Question 1

function of bones

Answer 1

• Provides support/protection of soft tissues and organs
  
  • Enable mpvement
  • Store minerals like Ca and P
• Producing blood cells from the marrow

Question 2

Structure :

Answer 2

• Outer layer = dense/compact bone (cortex)
  ○ Strength and support
  
  • Under cortex, porous/spongy (trabecular bone tissue)
    ○ High SA for mineral exchange
    ○ Along direction of stress = shock absorption, cushioning
  • Bone marrow
    ○ Produces blood cells
    ○ Surrounded by endosteum (bone tissue)

Question 3

what is bone tho

Answer 3

Bones are made of cells and matrix
Matrix : collagen ribres and hydroxyapatite
Cells : osteoblasts (build bone tissue) and osteoclasts ( break bone tissue) // osteoblast –> osteocytes (mature cells)

Question 4

why does the bone need to remodel

Answer 4

Why?
Bone tissue are broken and need to be replaced becayse of mechanical stress, hormone signals and metaboilic demands
–> ensures integreity of bone tissue and to continue to adapt if physcial demands change

Question 5

how does the bone remodel

Answer 5

Osteoblasts = makes new bone tissue, osteoclasts= break down old tissue

1. Resorption : osteoclasts break down and removes the old tissue
   -> acids / enzymes secreted from osteoclasts : demineralise (dissolve mineralised bone tissue that’s found in the bone matrix)
   –> osteoclasts releases the minerals from the tissue e.g. Ca back in to the blood stream
2. Reversal =
   Osteoclasts apoptosis - programmed to die
   Osteoblasts activated to arrive to the site of previous stage (resorption)
3. Formation
   Osteoblasts = make new bone tissue
   Secrete collagen and other proteins to form collagen matrix
   It mineralises (add mineral links) to form new tissue

Question 6

changes in bone over lifetime

Answer 6

Growth/Puberty : bone remodelling HIGHLY ACTIVE/ tips towards formation
Aging : gradual loss of bone mass and strength (esp estrogen levels decreasing in women) / tips towards resorption –> osteoporosis
Physcial activity can stimulate bone formation | Inactivity can cause bone loss!!
Ca and Vitamin D can increase/ maintain bone mass

Question 7

strucutre of the skeleton

Answer 7

Axial : skull, head, neck, spine, ribcage = protects the main parts/ central organs of the body
Appendicular = arms, legs, shoulders hips =. Movement and support body weights

Question 8

what is Intramembrane ossification

Answer 8

Mesenchymal cells (Stem cells) condense into connective tissue => differentiate into osteoblasts
Osteoblasts forms bone spicules
Bone spicules form the trabeculae and a woven bone strcuture
The mesencymal cells surrounding the trabeuclar forms the periosterm
Periosterm is the bone collar