Cartilage and bone

Question 1

3 examples of cartilage and where are they found?

Answer 1

hyaline - most common, larynx, trachea

elastic - external ear, epiglottis

fibrocartilage - intervertebral discs, sutures of skull

Question 2

spongey bone

Answer 2

interconnecting cavities, found inside bones forms arrow cavity

irregular trabeculae, highly vascularised

bony plates, lamellae

Question 3

cortical bone

Answer 3

outer layer of bone; surrounded by periosteum

structural unit is the osteon

rings of lamellae surround a central canal (for vasculisation)

Question 4

principle cell types for bone?

Answer 4

osteoblasts - make bone

osteocytes - maintain bone

osteoclasts - breakdown bone

Question 5

what are the stages of fracture repair?

Answer 5

Step 1: HAEMATOMA, clot forms in damaged area

step 2: SOFT FIBROCARTILAGE CALLUS, clot removed by macrophage replaced w/ a network of fibres
& cartilage called a callus!

step 3: HARD (BONY) CALLUS, callus invaded w/ blood vessels and osteoblast, replaced w/ woven bone (weak)

step 4: REMODELLING, woven bone remodelled as compact and spongey bone

Question 6

osteoarthritis Clinical condition

Answer 6

most common form of arthritis

results from hyaline articular cartilage loss, changes in and around joint

severe joint injury increases risk

ACCESS for risks - age/alcohol, steroid use, calcium, oestrogen, smoking, sedentary life

Question 7

osteogenesis imperfecta type 1 clinical condition

Answer 7

most common, loss of COLA1 allele

frequent fractures in infancy, decrease w/ growth

thin bones abnormally curved

progressive hearing loss, unstable joints, short stature

Question 8

osteogenesis imperfecta type 2 clinical condition

Answer 8

most severe, altered function of either COLA1 or COLA2 gene

lethal perinatal disease - almost all bones fracture during delivery or contractions

legal importance as can be confused w/ deliberate injury

Question 9

what is ossification?

Answer 9

the formation of bone

Question 10

how are most bone including long bones formed?

Answer 10

via ENDOCHONDRAL ossification

preexisting hyaline cartilage is replaced w/ bone

osteoid released by osteoblasts help calcification

Question 11

how are flat bones formed?

Answer 11

via INTRAMEMBRANOUS ossification

mesenchyme replaced w/ bone

mesenchyme stem cells differentiate to osteoblasts

Question 12

define gigantism

Answer 12

pre puberty

excess growth hormone can cause gigantism by promotion of epiphyseal growth plate

Question 13

define acromegaly

Answer 13

post puberty

excess GH can’t cause gigantism because growth plate has closed

increase in bone width by promoting periosteal growth; hands/feet broadened, soft tissue thickened

Question 14

define pituitary dwarfism

Answer 14

pre puberty

insufficient GH affect epiphyseal cartilage and
cause pituitary dwarfism

Question 15

define achondroplasia

Answer 15

autosomal dominant

point mutation in FGFR 3 gene

impacts endochondral ossification & promotes early growth plate closure

reduction in: proliferation of chondrocytes in growth plate cartilage, cartilage matrix production, chondrocyte hypertrophy

Question 16

state the difference of Ca2+ deficiency in children vs adults

Answer 16

in children causes rickets

in adults causes osteomalacia

Question 17

define rickets clinical condition

Answer 17

in children

bones do not harden due to a prolonged deficiency in
calcium

malformed bones

Question 18

define osteomalacia clinical condition

Answer 18

in adults significant calcium deficiency, or lack of vitamin D

Question 19

Inorganic part of bone

Answer 19

Calcium hydroxyapatite

Question 20

Organic part of bone

Answer 20

Type 1 collagen