Building and maintaining the skeleton L3

Question 1

Function of bones (2)

Answer 1

Protect organs

provide support and rigidity in limbs

Question 2

How is the form of the skeleton determined

Answer 2

genetic & functional signals

Question 3

What is bone formed from in the head

Answer 3

neural crest–>develops membrane, which then ossifies and forms bone

Question 4

What is bone formed from in the body

Answer 4

Cartilaginous (made of cartilage models) apart from clavicle

Question 5

Name three things migrated neural crest cells form

Answer 5

dorsal root ganglia
sympathetic chain ganglia
cells of the adrenal medulla

Question 6

How do individual vertebrae know the identity they should become?

Answer 6

Patterning genes = hox genes

Question 7

What are patterning genes called

Answer 7

hox genes

Question 8

What do hox genes not control

Answer 8

Do not control the building of the vertebrae or any bones (just give the signal for what identity the bone should have)

Question 9

When do limb buds develop?

Answer 9

4-5 weeks

Question 10

Which limbs develop first?

Answer 10

The forelimb

Question 11

What process forms the digits

Answer 11

programmed cell death

Question 12

What does the apical ectodermal ridge control

Answer 12

signalling from the root to the tip of the limb

–> gives a signal to grow length wise

Question 13

What does the zone of polarizing activity control

Answer 13

signalling from side-side on the limb

Question 14

Endochondral ossification

Answer 14

develops in pre-existing cartilage (body of the skeleton)

Question 15

intramembranous ossification

Answer 15

membrane models (skull and clavicle|)

Question 16

Order of bone structure

Answer 16

Epiphysis
Physis (epiphyseal growth plate)
Metaphysis
Diaphysis

Question 17

What causes a bone to ossify

Answer 17

the invading blood vessels

Question 18

Where does ossification begin

Answer 18

the diaphysis

Question 19

Where is the second ossification

Answer 19

At the end of long bones, under the influence of blood vessels

Question 20

Where does cartilage expand

Answer 20

in the epiphyseal plate, driving the plates apart from the metaphysis.

Question 21

What happens at puberty

Answer 21

sex hormones released cause cartilage to stop growing

Question 22

What is left behind as a mark of bone growth

Answer 22

A epiphyseal line

Question 23

What are bones and cartilages

Answer 23

connective tissue

Question 24

What are chondrocytes

Answer 24

produce and maintain the cartilaginous matrix

Question 25

What are chondrocytes derived from

Answer 25

chondroblasts | which secretes matrix and then tombs itself trapping itself, converting into a chondrocyte

Question 26

Disadvantage of cartilage

Answer 26

it can't adapt once laid down, avascular (v low blood supply)

Question 27

What do chondrocytes lie in

Answer 27

lacuna

Question 28

How do bones grow in diameter

Answer 28

laying bone on the outer surface, under the periosteum

Question 29

How do bones grow in length

Answer 29

extensions at the cartilaginous growth plate Cartilage proliferates from the epiphysis forcing apart the ends of the bone by stretching muscles and tendons that cross along the bone

Question 30

Why is it hard to tell a fracture on a kid

Answer 30

they have growth plates

Question 31

What do long bones consist of (2)

Answer 31

Cortex | Cancellous bone

Question 32

What is the cortex

Answer 32

outer-shell of bone, made of compact bone, not very porous

Question 33

What are circumferential lamellae called

Answer 33

osteons (layers and layers of bone with cells trapped between)

Question 34

What is cancellous/trabecular bone

Answer 34

At the end of long bones---> spongy network of bony tissue

Question 35

What is the middle off the shaft like in long bones

Answer 35

completely hollow

Question 36

Bone made off (3)

Answer 36

Cells Fibres Mineralised ground substance

Question 37

Osteoblasts

Answer 37

lay down unmineralised material (osteoid)

Question 38

What is osteoid

Answer 38

Unmineralised material

Question 39

Key feature about bone

Answer 39

it can adapt rapidly by altering the way you load it

Question 40

What detects change in bone loading

Answer 40

osteocytes

Question 41

What are osteoclasts

Answer 41

multi-cellular derived in similar way to macrophages

Question 42

What do osteons drill through to create structure

Answer 42

woven bone

Question 43

What is the canal formed in the middle of osteons

Answer 43

Haversian canal (surrounded by concentric lamellae, with osteocytes trapped in them)

Question 44

What happens to bones when loading is less server

Answer 44

Cortical bone is made into less dense cancellous bone (particularly at the end of long bones)

Question 45

Osteoclasts

Answer 45

destroy bone -- resorption

Question 46

Osteoporosis =

Answer 46

deposition & resorption out of balance --> bone thinning--> fracture

Question 47

Three types of joints

Answer 47

fibrous Cartilaginous Synovial

Question 48

Main issue of synovial joints

Answer 48

articular cartilage can be worn down easily

Question 49

5 stages of fracture healing

Answer 49

Haematoma Subperiosteal &; endosteal cell prolifertion Callus- woven bone Consolidation -(woven bone to lamellar bone) Remodelling