BL. session 8. bones

Question 1

when is the patella formed? example of which bone type?

Answer 1

post natal

sesamoid bone

Question 2

How do newly formed blood cells leave the bone marrow?

Answer 2

through intracellular gaps in sinusoidal vessels

Question 3

what tunica layers do capillaries have?

Answer 3

tunica intima only.

DO NOT contain tunica media or externa

Question 4

describe the layers of endothelium

Answer 4

tunica externa/adventitia (external elastic lamina)
tunica media (smooth muscle cells)
tunica intima (internal elastic lamina)
endothelium (inner endothelial cell layer)

Question 5

clinical treatment for patients with low neutrophils?

Answer 5

injection of GCSF

Question 6

what is hypoxia?

Answer 6

when tissue is depleted of oxygen supply.
- causes kidneys to secrete erythropoietin which inc RBC count.
- inc haematocrit (ratio RBC: total blood volume)
> inc risk of clotting

Question 7

which cell type increases in parasitic worm infections

Answer 7

eosinophils

Question 8

give example of bone types and their function

Answer 8

long- femur = facilitate movement. support body weight
short- wrist and ankle joints. carpals. =provide stability and some movement.
irregular- vertebrae= protect spinal chord
pelvis (sacrum) = protect organs/bladder in pelvic cavity
sesamoid- patella= protect tendons from stress
flat- sternum/ribs/cranial bones (skull) = protects internal organs. provide areas of attachment for muscles

Question 9

diff names for cancellous bone?

Answer 9

Trabecular/spongy

Question 10

diff name for cortical bone

Answer 10

compact (/periosteal?)/lamellar

Question 11

What feature of cartilage distinguishes it from most other connective tissues?

Answer 11

It is an avascular tissue

Question 12

where is elastic cartilage found

Answer 12

pinna of the ear
eustachian tube
epiglottis

Question 13

what type of cartilage is nasal cartilage? what collagen type?

Answer 13

hyaline cartilage

type 2 collagen only

Question 14

what is the function of the canaliculi?

Answer 14

allow the movement of nutrients between osteocytes

Question 15

Which component of bone impedes the free distribution of nutrients and oxygen to osteocytes?

Answer 15

extracellular matrix- impervious to aqueous solution

Question 16

what is an osteophyte

Answer 16

a spur of bone produced when bone is damaged and tries to repair itself

e.g. in rheumatoid arthritis (abnormal bone formation.)

Question 17

what is the endosteum

Answer 17

is inside (endo) the bone (osteum) lines the medullary cavity.

Question 18

what is the periosteum

Answer 18

Composed of two layers: osteogenic and fibrous.

Continuous with the joint capsule

Attached to the bone surface by collagen bundles called Sharpey fibres

Question 19

how does parathyroid hormone effect bone?

which drug is given to reverse the effects of high PTH?

Answer 19

PTH acts on osteoclasts to resorb bone and release calcium into the blood

Calcitonin acts on osteoblasts to re-use the released calcium to lay down new bone and so strengthen any bone weaknesses

Question 20

label the section through compact bone

Answer 20

A= an osteon
B= Blood and lymphatic vessels in Haversian canal
C= Periosteum
D= Concentric lamellae
E= Endosteum at junction with medullary cavity
F= Volkmann’s canal
G= Haversian system

see screenshot ‘compact bone diagram’

Question 21

what is the difference between osteoporosis and osteomalacia

Answer 21

Osteoporosis

• holes in bone
• bones broken down (reabsorption) faster than being made (build up)

Osteomalacia

• no holes
• adult form of rickets.

Question 22

clinical signs/symptoms of inflamed RH arthritis joint

Answer 22

• loss of funtion
• redness (rubor)
• heat (calor)
• pain (dolor)
• swelling (tumor)

Question 23

which cells are not found WITHIN cortical bone? found where

Answer 23

osteoclasts

found on the edges only (periosteum and endosteum)

Question 24

What are the two steps of bone remodelling

Answer 24

1)osteoclast- cutting cone
wide tunnel in the bone

2)osteoblast- closing cone
smaller tunnel of cortical bone

Question 25

what is osteogenesis imperfects

Answer 25

brittle bone disease
mutation in COL1A gene- incorrect production of collagen 1 fibres
blue sclera

Question 26

what is rickets

Answer 26

bowed legs in children
vit D deficiency
poor calcium mobilisation
weakened bones, soft bones

Question 27

what is osteomalacia

Answer 27

adult rickets

vit D deficiency > dec calcium absorption.

Question 28

which factors can lead to vitamin D deficiency

Answer 28

kidney disease (kidney usually activates vit D)
lack of sunlight
drugs e.g. phenytoin (anti epileptic) prevents vit D absorption

Question 29

what is secondary osteoporosis

Answer 29

• result of drug therapy (corticosteroids)
• processes affect bone remodelling (malnutrition/space travel)
• metabolic bone diseases (hyperparathyroidism/ metastatic cancers)

Question 30

what is achondroplasia (gene?)

how is ossification affected?

Answer 30

FGF3 gene which promotes collagen formation from cartilage (endochondrial ossification affected, intramembranous unaffected)

Question 31

which hormones are involved in type 1 and type 2 osteoporosis?

Answer 31

1- oestrogen only

2- oestrogen AND androgen

Question 32

what factors influence fracture healing

Answer 32

blood supply
age
comorbidities
diet

Question 33

what is Swiss cheese bone

how does it occur?

Answer 33

osteoporotic trabecular bone (osteoporosis structural changes)
Major risk factor for fractures in older people.

incomplete filling of osteoclast reabsorption bays

Question 34

what are the modified risk factors for osteoporosis

Answer 34

• insufficient calcium intake (700mg/day recommend)
• exercise > immobilisation leads to accelerated bone loss
• cig smoking in women

Question 35

what do people with achondroplasia look like

Answer 35

Short stature, normal sized head/torso
short long bones
strong cortical bones