muscles

Question 1

smooth muscle

Answer 1

found in places where there is regulation (arteries)

• unstraited
• long and spindle line muscle fibres
• under involuntary control
• myofibrils are arranged irregularly

Question 2

cardiac muscle

Answer 2

• straited in apperance
• involuntary control
• it has its own ability to contract does not need nervous system
• somatic and autonomic nervous system

Question 3

skeletal muscle

Answer 3

• straited
• logitudinal bundles of muscle fibres
• involuntary and volunatry control

Question 4

micro view of skeletal muscle features

Answer 4

sacrolemma: cell membrane
myfibrils: muscle fibres that make up the muscle fibres
sacromere: energy of the myofibril
z-line: seperate each of the sacromere
actin (thin) and myosin (thick)

Question 5

sliding filament theory

Answer 5

• as the mysoin and actin slide it gives rise to light or dark area
• contraction: actin is pulled together over the myosin (creates overlap)
• extension: actin is pulled away from the myosin (increase 2 disc line)

Question 6

what are the different shapes of muscle

Answer 6

• fusiform (muscles that run longitudinaly to the tendon)
• penniform (fibres that run on an angle to the skeleton tendon)
• unipennate (fibres that come off an angle of the tendon)
• bipennate (fibres that come of the sides of the tendon)
• mutipennate (fibres that come off either side of multiple tendons)

Question 7

white muscle fibre types

Answer 7

• Large diameter
• Good for power and speed activities
• Fast contraction speed (ie “fast twitch” – FT)
• Fatigue rapidly

Question 8

red muscle fibre types

Answer 8

Small diameter
• Good for endurance activities & continuous contractions
• Slow contraction speed (ie “slow twitch” – ST)
• Fatigue resistant

Question 9

silding filament theory 6 steps

Answer 9

1. Influx of Ca++ ions to expose the actin binding sites
2. Binding of myosin to actin
3. Power stroke – causing filaments to “slide”
4. Binding of ATP to myosin to cause disconnection from actin
5. Hydrolysis of ATP to re-energise and replenish the crossbridge
6. Transport of Ca++ ions back to the sarcoplasmic reticulum
   (via calcium pump)

Question 10

concentric contraction

Answer 10

tension developed in the muscle is sufficent to overcome any load (muscle shorten)

Question 11

eccentric contraction

Answer 11

tension developed in the muscle is insufficent to overcome the load (muscle lengthens)

Question 12

isometric contraction

Answer 12

the tension matches the load and there is no change in the muscle length

Question 13

head and neck muscles strengh exercises:

Answer 13

• head curls
• lateral raise
• shoulder shrugs
• neck stretches
• neck rotation

Question 14

trunk extensor strengthening

Answer 14

• erector spinae muscles
• curl the trunk to train the smaller parts of the muscles
  (back extension)
• romanian deadlift

Question 15

trunk rotation strengthening exercises

Answer 15

• trunk rotation (superman one leg one arm)

- abdominal crunch with a twist

Question 16

trunk flexion

Answer 16

• abdominal crunches

Question 17

special considerations

Answer 17

• Use of isometric exercises in preference to isotonic exercises
• neck rolling, only roll half the way not 360 degrees
• preventing lower back pain: strong abdominals & hamstrings+ flexible iliopsoaslimit APT
• Problem - invoking psoas major m. during some exercises

Question 18

what does a motor unit comprise of

Answer 18

• a motor neuron, plus

* all the attached muscle fibres

Question 19

recruitment of muscle fibres difference

Answer 19

• Small motor units produce precise movements

- Large motor units produce gross movements

Question 20

muscle tone

Answer 20

Asynchronous motor unit contraction causes a constant

state of low-level tension on the muscle.

Question 21

3 factors affecting tension in the muscle

Answer 21

1- frequency of stimulation (single/mutiple stimultions)
2- number of motor units recruited
3- the length of the muscle (length/tension)

Question 22

treppe

Answer 22

increase in tension without summation

Question 23

temporal summation

Answer 23

increase frequency of stimulation we do no allow the muslces to relax the tension

Question 24

incomplete tetancy

Answer 24

tension is high however muscles can sill relax

Question 25

complete tetanus

Answer 25

no relaxation of muscle those binding sites are continusly open

Question 26

fatigue

Answer 26

muscles runs out of ATP and the body needs to replensih the ATP decrease frequency

Question 27

3 phase of a muscle twitch

Answer 27

1- latent period 2- contraction phase 3- relacation

Question 28

number of motor units recruited

Answer 28

Stimulation voltage is to: - recruit motor units - Sub threshold stimulus - Threshold stimulus - Recruitment - Maximal stimulus

Question 29

degree of muscle stretched

Answer 29

- Unstretched muscle: - Mod. stretched muscle: - Overstretched muscle:

Question 30

latent period

Answer 30

- sacrolemma and t-tubules depolarize - Calcium released into the cytosol - crossbridges begin to cycle but no visible shortening of muscle

Question 31

contraction period

Answer 31

- sacromeres shorten result of myosin crossbridges cycyling and continues into the peak of developing tension - speed depends on weight being lifted and fibre type

Question 32

relaxation period

Answer 32

Calcium activley transported back into terminal cisterneae | - cross bridges cycling decreases and ends

Question 33

force production is affected by

Answer 33

1. Temporal summation 2. Motor unit recruitment 3. The length of the muscle

Question 34

temporal summation

Answer 34

Force production is affected by the firing rate of the MN. As the rate of firing increases, so also does the tension developed in the attached muscle fibres, as well as the whole muscle.

Question 35

motor unit recruitment

Answer 35

Stronger stimuli cause multiple motor unit recruitment. Red (ST) fibres tend to be recruited first, followed by white (FT) fibres, which require higher threshold voltages.

Question 36

length tension relationship

Answer 36

Force production is affected by the length of the muscle at any given moment. This is determined by the number of cross bridge links that can be made within each sarcomere

Question 37

early improvments in strength are due to

Answer 37

• tug of war analogy: Changes in the involvement of motor units • co-contraction of antagonist muscles (muscles that oppose the action of the prime mover) • Disinhibition of the agonist (the body’s protective mechanism).

Question 38

the rate at which force is produced is due to a number of factors

Answer 38

* The number of sarcomeres in series | * The rate at which cross bridges work.

Question 39

the rate that cross bridges work is dependant on what

Answer 39

``` • ST fibres (Red) - cross bridges work at a slower rate - useful for sustained contractions. • FT fibres (White) - cross bridges work at a fast rate - but fatigue more quickly. ```

Question 40

what muscles fibres does the gastrocnemius and soleus have

Answer 40

``` gastrocnemius m. • high FT fibres • power muscle • explosive actions soleus m. • high ST fibres • endurance muscle • postural actions ```

Question 41

aggregrate muscle actions

Answer 41

When a group of muscles are contracting on one side of a joint, it usually means that another group is lengthening on the opposite side.

Question 42

modes of contraction

Answer 42

``` CONCENTRIC CONTRACTION tension > resistance muscle shortens • ECCENTRIC CONTRACTION tension < resistance muscle lengthens • ISOMETRIC CONTRACTION tension = resistance muscle length remains unchanged ```