Bones

Question 1

Functions of bones:

Answer 1

• support
• storage of Calcium, phosphates and fats
• blood cell production in marrow
• protection of organs
• leverage for muscles

Question 2

what are the 6 types of bones:

Answer 2

1) Long
2) Short
3) Flat
4) irregular
5) Sesamoid
6) Sutural

Question 3

description of Flat bones;

Answer 3

• Internal table and External table with Diploe in between

Question 4

What are sutural bones?

Answer 4

• Tiny bones between the major skull bones

Question 5

What are sesamoid bones? with an example

Answer 5

Bones that develop in tendons, eg Patella

Question 6

What is the diaphysis and its components?

Answer 6

• the shaft of long bones between growth plates (metaphysis)

- made of medullary cavity and compact bone

Question 7

what is the epiphysis and its components?

Answer 7

• the end of long bones

- Made of trabecular spongey bone

Question 8

what is Bone tissue made of?

Answer 8

1) Ground substance
2) Protein (mostly collagen fibres)
3) Bone cells

Question 9

what is ground substance for bone tissue?

Answer 9

• minerals
• hydroxyapatite crystals
• calcium ions
• salts

Question 10

What are Osteoblasts and their life cycle?

Answer 10

• bone builder cells

- mature into osteocytes when they become trapped in the bone they produced

Question 11

What are osteocytes?

Answer 11

• mature bone cells that maintain the bone matrix

- live in a lacunae

Question 12

What are osteoclasts?

Answer 12

• Bone destroyer cells

- Multinucleated, secrete enzymes and acid to dissolve the bone matrix

Question 13

what is bone matrix?

Answer 13

the fluid made of ground substance and protein that calcifies into bone

Question 14

life cycle of bone cells:

Answer 14

mesenchymal stem cells differentiate into osteoclasts, which secrete bone matrix until trapped and then mature into osteocyte

Question 15

Structure of compact bone:

Answer 15

• Central canal for blood vessels
• Lamellae (concentric rings) around central canal
• Osteon is a series of lamellae
• Lacunae indents housing with osteocytes

Question 16

What makes up spongey (trabecular bone)?

Answer 16

1) trabeculae
2) red marrow
3) yellow marrow

Question 17

Structure of trabecular bone?

Answer 17

• no osteons
• many random trabeculae cross bridges
• red marrow between trabeculae
• yellow bone marrow is found in medullary cavity

Question 18

purpose of red marrow?

Answer 18

• to produce red blood cells

- provide osteocytes with nutrients

Question 19

purpose of yellow bone marrow?

Answer 19

• to store fat

Question 20

what is the periosteum?

Answer 20

a double layered membrane on the perimeter of bone

Question 21

what are the 2 layers of the periosteum?

Answer 21

• outer fibrous layer

- inner cellular layer

Question 22

what is the endosteum?

Answer 22

The membrane lining the medullary cavity, central canals and trabeculae

Question 23

Name the 2 types of ossification:

Answer 23

1) Intramembranous ossification

2) Endochondral Ossification

Question 24

what is the name given to bone growth?

Answer 24

Appositional bone growth

Question 25

where does intramembranous ossification occur?

Answer 25

• flat bone formation in babies skulls

Question 26

describe the process of intramembranous ossification

Answer 26

• Begins in mesenchymal/connective tissue
• Mesenchymal stem cells aggregate and replicate into a ringed circular structure
• They differentiate into osteoblasts and secrete osteoid
• Osteoid gets calcified forming bone and entrapped osteoblasts mature into osteocytes

Question 27

what is the purpose behind endochondral ossification?

Answer 27

• to lengthen bones/grow

Question 28

Describe the process of endochondral ossification:

Answer 28

• Chondrocytes in the calcifying matrix enlarge and die
• Osteoblasts encase the diaphysis in a thin layer of bone
• Blood vessels penetrate the diaphysis to form the primary ossification centre
• the primary ossification centre enlarges
• Secondary ossification centres form at the epiphysis

Question 29

what is the name of the growth plate?

Answer 29

epiphyseal cartilage (cartilage of the epiphysis)

Question 30

Describe appositional bone growth:

Answer 30

• Osteoblasts make new bone around perimeter of old bone

- Osteoclasts break down the old bone

Question 31

What are the requirements for bone growth?

Answer 31

• Minerals
• Vitamins
• Hormones
• Loading

Question 32

when does bone mass peak?

Answer 32

in our 30s

Question 33

what happens to menopausal women in terms of bone density?

Answer 33

rapid decline and may result in osteoporosis

Question 34

describe the process of fracture repair:

Answer 34

1) bone bleeds and forms a clot (haematoma)
2) Formation of a cartilaginous external callus and trabecular internal callus
3) External callus is replaced by bone and internal callus bridges the gap with spongey bone
4) Bone is left with a permanent swelling due to external callus