Principles of Skeletal System

Question 1

List 3 ways bones can be classified

Answer 1

1. Shape
2. Region
3. Embryology

Question 2

List 2 classification of bones by region

Answer 2

1. Axial

2. Appendicular

Question 3

List 5 examples of Axial bones

Answer 3

1. Skull
2. Hyoid bone
3. Ribs
4. Sternum
5. Vertebrae

Question 4

List 3 group examples of Appendicular bones

Answer 4

1. Limb bones
2. Pectoral girdle (clavicle+scapula)
3. Pelvic girdle

Question 5

List 5 classification of bones by shape

Answer 5

1. Long bones
2. Short bones
3. Flat bones
4. Irregular bones
5. Sesamoid bones

Question 6

List 9 examples of Long bones

Answer 6

1. Tibia
2. Fibula
3. Femur
4. Metatarsals
5. Phalanges
6. Humerus
7. Radius
8. Ulna
9. Metacarpals

Question 7

List 2 examples of Short bones

Answer 7

1. Carpals

2. Tarsals

Question 8

List 4 examples of flat bones

Answer 8

1. Cranium
2. ilium
3. Sternum
4. Rib

Question 9

List 3 examples of irregular bones

Answer 9

1. Vertebrae - coccyx and sacrum
2. Mandible
3. Hyoid bone

Question 10

List 1 example of Sesamoid bones

Answer 10

1. Patella bone in the knee

Question 11

What is a sesamoid bone

Answer 11

A bone embedded within a tendon. E.g patella

Question 12

List 5 functions of skeletal system

Answer 12

1. Movement
2. Production of RBC from Bone marrow
3. Supports the body- e.g the diaphragm is supported by the rib cage
4. Protection of organs
5. Acts as reservoir e.g calcium

Question 13

List 2 classifications of bones by embryology

Answer 13

1.

2.

Question 14

Where is bone derived from

Answer 14

In the Paraxial mesoderm and the Lateral plate of the mesoderm

Question 15

Define Ossification

Answer 15

Ossification is the process of bone development. Ossification time is the time it takes a bone to finally stop growing.

Question 16

List 2 types of ossification

Answer 16

1. Intramembranous Ossification

2. Endochondral Ossification

Question 17

In what bones does Endochondral ossification occur?

Answer 17

All bones bar the skull, mandible and clavicle

Question 18

Cartilage synthesising cells are called

Answer 18

Chondrocyte

Question 19

Explain the process of Endochondral ossification

Answer 19

1. Start off with cartilage template
2. Blood vessels penetrate the exterior of the cartilage
3. Mesenchymal cell on the exterior of the cartilage differentiates into osteoblast cell which forms bones around the cartilage called bone collar.
4. Primary centre called the diaphysis is developed
5. Chondrocyte in the diaphysis enlarges and secretes an enzyme that promotes calcification.
6. Blood vessels cannot penetrate the middle
7. Leads to Chondrocyte death. Forms the Marrow cavity
8. Both ends of cartilage is called the epiphysis.
9. Epiphysis and diaphysis is separated by the epiphyseal plate (growth plate)
10. Epiphyseal plate contains chondrocyte that continues the production of cartilage - this leads to an increase in bone length.
11. Secondary centre develops close to the end of ossification- blood vessel access.

Question 20

What separates the epiphysis from the diaphysis?

Answer 20

The epiphyseal plate (growth plate)

Question 21

Match the following

Diaphysis, Epiphysis, primary centre, secondary centre

Answer 21

Epiphysis = primary centre
Diaphysis = secondary centre

Question 22

What is a bone collar in endochondral ossification

Answer 22

Bones formed from osteoblast around a cartilage to form the primary centre in early stage of endochondral ossification

Question 23

Why do osteoblast remain on bone surface even after ossification?

Answer 23

For when bone undergoes stresses and therefore undergoes bone remodelling

Question 24

Explain the process of Intramembranous Ossification

Answer 24

1. Forms from fibrous membrane
2. Mesenchymal cell differentiates into osteoblasts (in centre)
3. Starting point is the primary ossification centre
4. Osteoblast secretes osteoid (forms unmineralised bone)
5. Mesenchyme continues to differentiate into osteoblast on the outer surface.
6. Osteoid in primary ossification centre calcifies to form trabeculae(spongy bone). Osteoblast is trapped by trabeculae and is no longer penetrated by blood vessels. Reduced activity, so it differentiates into osteoclast
7. Compact bone is formed on the outer edges of the bone
8. Bone continues to grow radially
9. Trabeculae is penetrated by blood cells and undifferentiated mesenchyme to form bone marrow

Question 25

Long bones gradually shortens during ossification. True or false?

Answer 25

False. Elongates as chondrocytes on each edge continues to lay down cartilage that eventually is replaced by bone in the secondary ossification centres

Question 26

Does epiphyseal plate(Growth plate) appear on X-ray?

Answer 26

No. It is a cartilage

Question 27

Epiphyseal plate (Growth plate) is abolished with maturity. True or false?

Answer 27

True. It is replaced by bone in the secondary ossification centres

Question 28

List 5 dietary nutrients that maintains the bone

Answer 28

1. Calcium 2. Phosphorus 3. Vitamin A 4. Vitamin C 5. Vitamin D

Question 29

What is the function of Vitamin A, C and D

Answer 29

Vitamin A = essential for bone remodelling Vitamin C= essential for connective tissue Vitamin D= essential for calcium absorption

Question 30

List 2 roles endocrine activity plays in bone development

Answer 30

1. Hyperparathyroidism - as a result of too much parathyroid hormone. Causes reabsorption of bones. Too much parathyroid hormone leads to porous bone because it has been eaten away by osteoclast 2. Dwarfism/Acromegaly(particularly pronounced in the mandible) - As a result of too little/too much Growth Hormone

Question 31

List 4 features of a cartilage

Answer 31

1. It is a connective tissue 2. Forms the skeleton in parts where flexibility is required e.g at joints 3. Avascular 4. Propotion of cartilage to bone changes (decreases) as the individual develops

Question 32

List 4 features of bone

Answer 32

1. Hard form of connective tissue 2. Provides a rigid framework 3. Vascular 4. There are 2 types of bones- compact and spongy bone.

Question 33

The connective tissue covering the bone is called

Answer 33

The periosteum

Question 34

The connective tissue covering the cartilage is called

Answer 34

The Perichondrium

Question 35

The periosteum covers all parts of the bone apart from where

Answer 35

Areas where articulation occurs

Question 36

Bone is comprised of 4 cell types. List them

Answer 36

1. Osteoprogenitor cells - stem cells that can turn into any bone cell e.g bone marrow 2. Osteoblast - the builders. Responsible for laying down new organic components. Found on the outside of cell. Osteoblasts build around themselves. 3. Osteocytes- develops after osteoblast. They maintain the bone. 4. Osteoclast - Bone destroyers. They contain enzymes that break down bones and release calcium into the blood. They are present in the remodelling of bones.

Question 37

What bone cell types are involved in bone remodelling

Answer 37

osteoblasts and osteoclasts

Question 38

List 6 Structures in a compact bone

Answer 38

1. Periosteum- covers the bone 2. Lamella- laid down by osteoblasts 3. Haversian cavity- contains vascular and nerve supply 4. Lacunae - the space 5. Osteocyte - occupies the lacunae 6. Canaliculi- (minute canal that comes off the lacunae

Question 39

Cancellous bone is a type of ..

Answer 39

Spongy bone

Question 40

List 3 structures in a spongy bone

Answer 40

1. Irregular lamella 2. Has red bone marrow in between and surrounding the irregular lamella 3. Highly vascular

Question 41

List the 3 types of joints

Answer 41

1. Synovial joint 2. Fibrous joint 3. Cartilaginous joint SFC - shit football club

Question 42

List 2 things that makes a synovial joint

Answer 42

1. They are connected by a joint capsule and synovial cavity 2. Synovial fluid- reduces friction between bones Permits the largest range of movement

Question 43

List 1 thing that makes a Fibrous joint

Answer 43

1. They are connected by collagen. E.g sutures in skull They do not permit movement

Question 44

List 1 thing that makes a cartilaginous joint

Answer 44

1. They are connected by cartilage E.g Epiphyseal plate, intervertebral disc and pubic synthesis -needed during baby delivery They permit SOME movement

Question 45

List 6 types of Synovial Joint

Answer 45

1. Hinge joint e.g Knee 2. Saddle joint e.g carpometacarpal 3. Condyloid e.g metacarpophalangeal 4. Pivot e.g radioulnar 5. Ball and Socket e.g hip 6. Plane e.g intercarpal Happy Silly Cow Pissed BullShit Pie