Bone Physiology

Question 1

What are the components of the skeletal system?

Answer 1

1. Bones
2. Cartilage
3. Joints
4. Ligaments
5. Connective tissues

Question 2

State the characteristic of flat bones?

Answer 2

Internal/external table
Separated by dipole
Provides protection of organs

Question 3

State the characteristic of long bones?

Answer 3

Longer than they are wide.

Useful for leverage.

Question 4

State the characteristic of short bones?

Answer 4

Same width as their length.
Allows subtle movement.
Transfers forces between bones.

Question 5

State the characteristic of irregular bones?

Answer 5

Complex shapes/functions.
Projections to increase SA.
Useful for protection.

Question 6

State where sutural bones are located within the body.

Answer 6

Between skull bone.

Question 7

Where do sesamoid bones form?

Answer 7

In tendon, arise from forces in tendons via ossification.

Question 8

What is the role of then diaphysis?

Answer 8

Medullary cavity - holds the bone marrow.
Hollow cylinder - reduces weight.

More sturdy than compact bone.

Question 9

What type of bone can you find in the epiphysis?

Answer 9

Trabecular bone

Question 10

The epiphysis has projections that allow for what?

Answer 10

Projections allow for articulations at joint.

Question 11

What is the function of articular (hyaline) cartilage?

Answer 11

Covers ends of bone for protection.

Question 12

What is the name of the structural unit of bone tissue?

Answer 12

Osteon.

Question 13

What components make up osseous tissue? State their ratios.

Answer 13

1. Ground substance (2/3 bone matrix).
2. Protein (1/3 bone matrix).
3. Bone cells

Question 14

State the journey of mesenchymal stem cells maturing into mature bone cells.

Answer 14

Mesenchymal stem cells -> Osteoblasts -> Osteocytes

Question 15

What is the role of osteoclasts?

Answer 15

Have enzymes which destroy old bone, multi-nucleated, large SA.

Question 16

Reduced activity of osteoclasts leads what?

Answer 16

Increased bone density, decreased bone reabsorption.

Question 17

What is an osteoid?

Answer 17

Immature bone, no minerals.

Question 18

What is canaliculi?

Answer 18

Cytoplasmic extensions which allow for communication and transfer minerals from neighbouring osteocytes.

Question 19

TRUE OR FALSE:

Trabecular bone have osteons.

Answer 19

False - trabecular bone does not have osteons.

Question 20

Trabeculae has cross fibres which ensures what?

Answer 20

Strength in many direction.

Question 21

State the functions of red and yellow bone marrow.

Answer 21

1. Red - provides nutrients to osteocytes.

2. Yellow - stores adipose tissue.

Question 22

Which of the two types of bone (compact/trabecular) have a blood supply?

Answer 22

Compact bone.

Question 23

What is the periosteum? State the two layers it is composed of.

Answer 23

Membrane on the outside of the bone.

1. Outer fibrous layer
2. Inner cellular layer

Question 24

What is the endosteum? Where does it line?

Answer 24

Membrane lining inside of bone - lines medullary cavity, central canals, and trabeculae.

Question 25

Intramembrane ossification forms what type of bone?

Answer 25

Flat bone formation

Question 26

Endochondrial ossification is the formation of bone from what?

Answer 26

Cartilage

Question 27

Define appositional growth.

Answer 27

Growth in width - bone deposited by osteoblasts and reabsorbed by osteoclasts.

Question 28

Intramembrane ossification forms spincules which are what?

Answer 28

Lumps of bone.

Question 29

What happens to chondrocytes within calcifying matrix?

Answer 29

Enlarge and die.

Question 30

The penetration of blood vessels/osteoblasts penetrate inside the bone to produce bone is know as what?

Answer 30

Primary Ossification Centre = diaphysis

Question 31

Where does the secondary ossification centre form?

Answer 31

Epiphysis

Question 32

The enlargement of the primary ossification centre forms what?

Answer 32

Medullary cavity.

Question 33

How does the epiphyseal line form?

Answer 33

Fusion of bone when cartilage (growth plate) turns to bone.

Question 34

What are the four requirements for bone growth?

Answer 34

Minerals Vitamins Hormones Loading/applied force

Question 35

What is the functions of osteoclasts and osteoblasts in bone remodelling?

Answer 35

Osteoclasts reabsorb bone Osteoblast form bone

Question 36

What type of bone cells detect forces in bone?

Answer 36

Osteocytes - adaption of loading.

Question 37

How are calcium levels maintained in bone remodelling?

Answer 37

Hormones control storage of calcium -> PTH stimulates bone resorption to release calcium -> calcitonin stimulates bones formation to store calcium.

Question 38

New osteons have less minerals and appear darker, where are they more apparent?

Answer 38

Periosteal surface.

Question 39

What colour do mineralised osteons appear under a microscope?

Answer 39

White.

Question 40

Peak bone mineral density occurs at how many years old?

Answer 40

30

Question 41

Women will rapidly loose their bone mineral density after what?

Answer 41

Menopause

Question 42

Describe the process of fracture repair?

Answer 42

1. Bleeding, formation of clot. 2. Formation of external/internal callus. 3. Osteoblasts break down fragments of bone. 4. External callus replaced by compact bone. 5. Internal callus unites broken ends. 6. Internal swelling causes remodelling.