support

Question 1

Type I fibres

Answer 1

need to have a small cross-sectional area so that there is a minimal distance for oxygen to diffuse from the capillaries to the mitochondria

Question 2

Type II fibres

Answer 2

have fast actin-myosin ATPase - can use ATP very quickly and generate a lot of power.
Because it’s impossible to store much ATP, Type II fibres have to replace it very quickly and to do that they rely on anaerobic metabolism.
Thus, type II fibres don’t need many mitochondria

Question 3

anaerobic metabolism is associated with…

Answer 3

the rapid onset of fatigue due to changes that affect the homeostasis of the muscle cells.

Question 4

the human body has

Answer 4

206 bones

Question 5

structural role of bones

Answer 5

1. Enable movement
2. support/form structure
3. Protection for internal organs

Question 6

bone’s role in homeostasis

Answer 6

Storehouse for essential minerals
* 85% of phosphorus
* 99% of calcium
site of metabolism
endocrine functions

Question 7

cortical bone

Answer 7

Compact/dense (80% of total bone mass)
External layer
10% porous
Provide strength to structure

Question 8

Cancellous bone

Answer 8

trabecular/spongy (20% of total bone mass)
Highly porous (50-90%)
Network of thin porous trabeculae (hydraulic properties) in directions of stress - shock absorption
large bone SA for mineral exchange
“inside”

Question 9

Collagen and Hydroxyapatite Form Bone Matrix

Answer 9

Collagen cross links
* provides elasticity
Hydroxyapatite crystals
* Source of Pi and Ca2+
* Provides rigidity

Question 10

Brittle bones

Answer 10

too much hydroxyapatite

Question 11

Bendy bones

Answer 11

too much collagen

Question 12

flat bones form via…

Answer 12

Intramembranous Ossification

Question 13

long bones form via…

Answer 13

Endochondral Ossification

Question 14

Long bone structure

Answer 14

Marrow cavity
Major blood supply
Epiphysis (trabecular/spongy bone)
Metaphysis (trabecular and cortical)
Diaphysis (cortical)
Endosteum
Periosteum

Question 15

Longitudinal growth involves:

Answer 15

• Chondrocyte proliferation and hypertrophy
• Calcification of hypertrophic cartilage and apoptosis
• Degradation of transverse septa, vascular invasion
• New bone formation on calcified remnants by osteoblasts – primary spongiosa

Question 16

post-natal growth

Answer 16

• limbs continue to develop until cessation of growth at 13-18 years of age through growth plates
• Joints are cartilaginous at birth - Epiphyses ossify in post-natal development

Question 17

Osteoporosis

Answer 17

• characterised by compromised bone structure and strength, predisposing to an increased risk of fracture
• disrupted/thin/weak rods - some disconnected
• more osteoclasts than osteoblast (imbalanced bone remodelling)

Question 18

Oestrogen

Answer 18

• Acts on both osteoclast and osteoblasts to:
  Decrease bone resorption and increase bone formation
• A marked decrease in oestrogen during menopause is associated with rapid bone loss via: Increase in bone resorption and decrease bone formation

Question 19

Testosterone

Answer 19

• Increase bone formation
• A source of oestrogen
• Reduces with age > bone loss and fracture

Question 20

Primary Risk factors for Osteoporosis

Answer 20

Age – older higher
Gender - female higher risk (post menopause)
Fracture previously
Height/BMI – short and frail = higher risk
Genetics

Question 21

Lifestyle Risk factors for Osteoporosis

Answer 21

Exercise that increase bone mass - weight bearing exercise
Bone responds to load/unload
Mass increases in response to load

Question 22

Osteoclast

Answer 22

break down bone

Question 23

Osteoblast

Answer 23

build new bone