Muscle ageing

Question 1

Structural changes in ageing muscle

Answer 1

1. reduced muscle mass
2. reduced muscle quality
3. motor unit loss

Question 2

Strength lost with age

Answer 2

lose beyond 40
drastic loss from 70

decline more apparent in men

Question 3

Lower body

Answer 3

40% decline

Question 4

Upper body

Answer 4

33% decline

Question 5

Decline in velocity and power

Answer 5

greater in women

Question 6

Why are rate of force production important?

Answer 6

prevent falls and trips

Question 7

Loss of muscle mass

Answer 7

sarcopenia/muscle atrophy

Question 8

Total fibre numbers

Answer 8

reduce
type I stay similar
type II lost most

Question 9

Muscle quality reduced

Answer 9

ageing increases fat accumulation in muscle
more fat = less muscle

Question 10

Neuromuscular alterations

Answer 10

increased age = less motor units
less motor units = less force

muscle fibres become denerated = atrophy and fibre loss

Question 11

Reinnervation

Answer 11

atrophying fibres reinnerated by remaining MU
= larger MUs
= less efficient - less force/quick = falls
preserves some muscle mass

Question 12

How does denervation and collateral re-innervaton alter muscle characteristsics?

Answer 12

increase co-expression of myosin isoforms
decrease force output
decrease velocity of contraction and hence power

Question 13

Changes occur due to excitation-coupling process

Answer 13

decrease Ca2+ release from SR

Question 14

Changes in sarcoplasmic reticulum function

Answer 14

decrease Ca2+ uptake

Question 15

Slowing of myosin molecule

Answer 15

decrease intrinsic speed of shortening

Question 16

Reduced acto-myosin cross bridge

Answer 16

decrease output per muscle fibre