Bones and Joints

Question 1

What is the function of bones

Answer 1

support, protection, mineral store and blood formation

Question 2

what types of bones are there

Answer 2

flat, sutural, short, irregular, sesamoid and long

Question 3

what are the components of bones

Answer 3

compact v spongey 
blood vessels
medullary cavity
bone marrow
membranes - periosteum (outside) + endostium

Question 4

what is the structure of compact/cortical bone

Answer 4

circular structures - osteons/ haversian system
central haversian canal
horizontal perforating/volkamanns canals
osteocytes and concentric rings of bone matrix (lamellae) around haversian canal

Question 5

what are the components of osteons

Answer 5

central haversian canal
rings of lamella bone
osteocytes

Question 6

what is the structure of spongey/trabecular bone

Answer 6

less dense than compact bone, porous
network of lamellated trabeculae filled w bone marrow
no haversian system

Question 7

what cells are bones composed of

Answer 7

osteoclasts
osteoblasts
osteocytes

Question 8

what is in the ECM of bones

Answer 8

hydroxyapatite crystals (calcium phosphate)
collagen (type 1)
water

Question 9

what is the function of hydroxyapatite

Answer 9

makes bone stiff + able to support structures

high strength under compression

Question 10

what is the function of collagen

Answer 10

gives bone flexibility + reduce risk of fracture

high strength under tension

Question 11

how is bone a dynamic tissue

Answer 11

• fracture healing

- mechanical adaptation

Question 12

what are osteoclasts, describe them and function

Answer 12

large multinucleated cells derived from haematopoietic stem cells
found on bone surface
function - resorb bone matrix
ruffled border - releases acid to dissolve bone matrix
howship’s lacunae - resorption pits

Question 13

what are osteoblasts

Answer 13

immature bone cells created from osteopregenitor cells in peri and endosteum 
function - produce bone matrix = osteoid and initiate calcification
become osteocytes once surrounded by matrix 

(on outisde in histology)

Question 14

whats the function of osteoblasts

Answer 14

produce bone matrix = osteoid and initiate calcification

Question 15

whats the function of osteoclasts

Answer 15

resorb bone matrix

ruffled border - releases acid to dissolve bone matrix

Question 16

what are osteocytes

Answer 16

mature bone cells found inside lacunae

numerous processes lying in canaliculi

Question 17

what are canaliculi

Answer 17

connect lacunae to eachother allow communication between cells

Question 18

describe the ECM for bones

Answer 18

minerals, collagen and water
strongly cross-linked & large ‘gaps’ within fibres
gaps provide space fro crystals

Question 19

what is osteoporosis

Answer 19

resorption > formation

Question 20

what is pagets disease

Answer 20

increased resorption/formation

Question 21

osteopetrosis

Answer 21

decreased resorption

Question 22

what is bone mass controlled by

Answer 22

genes and environment

Question 23

what is ossification

Answer 23

bone formation

Question 24

what are the 2 types of ossification

Answer 24

endochondral

intramembranous

Question 25

explain endochondral ossification

Answer 25

``` bone forms as cartilage model first blood vessels invade cartilage cartilage replaced w bone cartilage remains in epiphyseal growth plate growth plate eventually ossifies ```

Question 26

explain intramembranous ossification

Answer 26

no cartilage model mesenchymal cells develop into osteoprogenitor cells that develop into osteoblasts that deposit bone residual mesechymal cells develop bv and marrow this occurs in adult bone also

Question 27

what are the two types of bone growth

Answer 27

appositional and interstitial

Question 28

what is appositional growth

Answer 28

bone grows in thickness, transverse plane

Question 29

what is interstitial growth

Answer 29

bone grows in length

Question 30

what is a joint

Answer 30

union between 2 or more rigid components (bone or cartilage) | articulation

Question 31

what types of joints are there

Answer 31

fibrous cartilaginous synovial

Question 32

what are fibrous joints and examples

Answer 32

``` dense fibrous connective tissue high tensile strength little movement cranial structures periodontal ligament (teeth) interosseus membranes, between bones ```

Question 33

what are cartilaginous joints and what types are there

Answer 33

layers of cartilage | sychondroses (primary) and symphyses (secondary)

Question 34

describe synchrondroses joint

Answer 34

allow for bone growth (endochondral ossification) disappear in adults no movement - hyaline cartilage

Question 35

describe symphyses joint

Answer 35

``` secondary cartilaginous doesnt ossify w age found in midline of body limited movement e.g. in vertebrae ```

Question 36

what are synovial joints, name their common features

Answer 36

``` greatest movement fibrous capsule synovial membrane articular cartilage synovial cavity ```

Question 37

what are the types of synovial joints

Answer 37

``` hinge pivot ellipsoid ball and socket plane saddle ```

Question 38

what affects joint stability

Answer 38

shape of joint surfaces fibrous capsule and ligaments muscles

Question 39

Which part of synovial joints produces the synovial fluid and whats it purpose

Answer 39

synovial membrane - reduces friction between the articular cartilages during movement

Question 40

why are flexion and extension opposite in arm and e

Answer 40

due to limb rotation in development of child upper limb - lateral rotation lower limn - medial rotation + more rotation

Question 41

why is limb rotation and evolutionary process important

Answer 41

more efficient weight bearing and locomotion

Question 42

joints have rich blood + nerve supply, what is common around joints

Answer 42

anastomoses (joining of vessels) | blood flow can take alternative routes if a vessel is blocked

Question 43

what is hiltons law

Answer 43

the nerve supplying a muscle that crosses a certain joint, also innervates this joint

Question 44

what colour is the densest material in a CT scan

Answer 44

white