Muscle & Tendon

Question 1

Describe the structure of skeletal muscle (in terms of fascicles and muscle fibres)

Answer 1

Muscle -> Fascicle -> Muscle fibre -> Myofibril -> Myofilament -> Sarcomere

Question 2

What is the epimysium?

Answer 2

The epimysium is a type of connective tissue that wraps around the whole muscle (around all of the fascicles together)

Question 3

What is the perimysium?

Answer 3

The erimysium is the tissue that wraps around the groups of muscle fibres (fascicles).

Question 4

Describe the structure of muscle fibers

Answer 4

Muscle ibers are formed from the fusion of many myoblast cells.
Muscle fibres are packed with contractile myofilaments.
Muscle fibres have lots of mitochondria for energy.

Question 5

What is the fascia in muscles?

Answer 5

Fascia is the collective term for all of the connective tissue within a muscle.

Question 6

How do muscles get their blood supply?

Answer 6

Muscles are supplied by arteries which enter through the muscle belly.

Question 7

Muscle contractions massage capillaries and veins, why is this beneficial?

Answer 7

Veins don’t have muscles in their walls so struggle to push blood back up towards the heart. When muscles contract, they push the blood in the veins back up towards the heart.

Question 8

Muscle tends to be proximal in a limb and tendon is distal, why is this?

Answer 8

Having all of the muscle in the top half of a limb reduces the weight of the bottom half of the limb, making it easier to move.

Question 9

Describe the structure of a tendon.

Answer 9

Tendons are composed of bundles of collagen fibres which can be primary/ secondary/ tertiary.

Question 10

What are the qualities of a tendon?

Answer 10

Tendons have a great tensile strength and can act as an elastic energy store. Tendons are poorly vascularised so have little blood to aid healing.

Question 11

What are the 4 functions of skeletal muscle in the body?

Answer 11

1) Joint movement
2) Joint stabilisation
3) Posture control
4) Generating heat (shivering)

Question 12

What are the 8 functions of smooth muscle in the body?

Answer 12

1) Continence
2) Mastication
3) Swallowing
4) Digestion
5) Birthing
6) Vasodilation/constriction
7) Bronchodilation/constriction
8) Pupil dilation/constriction

Question 13

Sphincters, circular muscles, cutaneous muscles and joining muscles are all examples of what?

Answer 13

Skeletal muscle

Question 14

What are the 3 different types of muscle contraction?

Answer 14

1) Concentric contraction (muscle shortens)
2) Eccentric contraction (muscle lengthens)
3) Isometric contraction (muscle stays the same length)

Question 15

Explain how muscles work in antagonistic pairs

Answer 15

• The agonist/ prime mover is responsible for movement
• The antagonist is capable of reversing this movement
• Synergists can also help to modify the action without being directly involved in the movement.

Question 16

What are the origin and insertion points of a muscle?

Answer 16

The origin = the attachment point most proximal to the midline of the body.
The insertion = the attachment point most distal to the midline of the body.

Question 17

What structural features of a muscle influence its function?

Answer 17

• Size
• Shape
• No. of bellies
• Origins and insertions
• Architecture

Question 18

How do you calculate the work produced by a muscle?
( & calculate power and speed)

Answer 18

Work = force x △ distance
Power = △work ÷ △ time
Speed = △ distance ÷ △ time

Question 19

Muscle force is proportional to the PCSA, what is this?

Answer 19

PCSA = Physiological cross sectional area.

Question 20

Describe the structure of a parallel fibred muscle.

Answer 20

• Muscle fibers run parallel to line of action
• Muscles have little to no external tendons
• Sarcomeres situated in a series so the muscle is able to shorten more

Question 21

Compare the force and speed produced by a parallel fibred muscle to a pennate.

Answer 21

Parallel fibred muscles have fewer fibers in the cross section, meaning that there is a lower force but more speed.

Question 22

What is a pennate-fibred muscle?

Answer 22

A muscle with shorter muscle fibres that runs at an angle to the line of action.

Question 23

Compare the force and speed of a pennate muscle to a parallel fibred muscle.

Answer 23

Pennate muscles produce more force, less speed.

Question 24

Why is there less muscle shortening in pennate muscles?

Answer 24

In a pennate muscle, the sarcomeres are not arranged in a series.

Question 25

What is the basic function of tendons and ligaments.

Answer 25

• Tendons connect muscle to bone
• Ligaments connect bone to bone

Question 26

Why are the two different types of ligaments?

Answer 26

White ligaments (rich is collagen, not very elastic)
Yellow ligaments (lots of elastic fibres)

Question 27

What is the role of a tendon?

Answer 27

• Transmit force to the skeleton
• Minimising distal limb mass
• Elastic energy store and release
• Energy conservation
• Power amplification
• Energy absorption