Muscle fibres (fasicles)

Question 1

Muscles fibres

Answer 1

All skeletal muscle is made up of fascicles (bundles of muscle fibres), but fascicle arrangements vary considerably, resulting in muscles with different shapes and functional
capabilities

Question 2

Convergent fibres

Answer 2

Fascicles converge towards a single tendon of insertion
e.g pectoralis major

Question 3

Pennate fibres

Answer 3

The fibres are short and they attach obliquely to a central tendon that
runs the length of the muscle

Question 4

Unipennate fibres

Answer 4

The fascicles insert into only one side of the tendon, as in the
semimembranosis of the leg

Question 5

Bipennate fibres

Answer 5

In which the fascicles insert into the tendon from opposite sides so the muscle ‘grain’ resembles a feather. The rectus femoris of the quadriceps is bipennate

Question 6

Multipennate fibres

Answer 6

Which looks like many feathers side by side, with all their quills inserted into one large tendon. The deltoid muscle, which forms the roundness of the shoulder, is multipennate

Question 7

Fusiform fibres

Answer 7

Fusiform muscles are sometimes included in the parallel muscle group, but are more,spindle-shaped, with a muscle belly that is wider than the origin and insertion. Fusiform
muscle fibres, such as those of the biceps muscle in the arm, run in the same direction as the tendon, or longitudinally.

Question 8

Slow twitch fibres

Answer 8

Best suited to endurance activities

Question 9

Fast twitch fibres

Answer 9

Are best suited to high intensity (anaerobic ) strength & power
activities

Question 10

Slow twitch advantages

Answer 10

contract slowly with less force.

have an increased capacity to use oxygen.

have the capacity to contract for longer time
periods.

don’t fatigue easily.

have high capillary density.

have high mitochondria density.

have high myoglobin concentration.

have high fat stores.

Question 11

Fast twitch advantages

Answer 11

contract rapidly.

contract with greater force.

have a large fibre diameter.

have the capacity to contract for only shorter
time periods.

fatigue easily.

have high phospho-creatine stores.

have high glycogen stores.

Question 12

All or nothing principle

Answer 12

Muscular movement is subject to the all or nothing principle. When the electrical impulse reaches a certain threshold, all of the fibres of that motor unit will contract at the same time and as forcefully as possible.
However, until this threshold is reached or surpassed, none of the fibres will contract