Skeletal Muscle and Movement

Question 1

What are the properties of skeletal muscle

Answer 1

It is striated and under voluntary control.

Question 2

What are the properties of visceral (smooth) muscle

Answer 2

It is non-striated and under involuntary control.

Question 3

What are the properties of cardiac muscle

Answer 3

It is striated and under involuntary control.

Question 4

How long does it usually take substantial muscle damage to repair

Answer 4

A long time.

Question 5

What is the best producer of heat in the body

Answer 5

Skeletal muscle

Question 6

Around how much of the body weight is skeletal muscle

Answer 6

40%

Question 7

What are the 6 functions of skeletal muscle

Answer 7

• Movements
• Maintenance of posture
• Heat production
• Storage
• Protection
• Blood flow

Question 8

What are 4 specialisations/characteristics of skeletal muscle

Answer 8

Irritability (excitability), contractility, extensibility and elasticity.

Question 9

What is meant in describing skeletal muscle as irritable

Answer 9

It reacts to electrical stimuli.

Question 10

What is a myofibril

Answer 10

The smallest until in the elongated part of a muscle cell.

Question 11

What is unique about the nuclei on muscle fibres

Answer 11

The nuclei are peripherally located.

Question 12

What does it indicate if the nuclei of muscle fibres migrate to the centre from the periphery

Answer 12

This indicates pathology.

Question 13

What are the two types of myofilaments

Answer 13

Thick myofilaments and thin myofilaments.

Question 14

What is the most important region of muscle fibres

Answer 14

The sarcomere.

Question 15

What is the area between two z lines in a muscle fibre important for

Answer 15

Contraction and growth.

Question 16

Which myofilaments are the mobile part of the contractile element

Answer 16

The thin myofilaments

Question 17

What happens to the myofilaments in the contractile element on extension

Answer 17

The thin myofilaments move away from the centre while the thick myofilaments remain the same.

Question 18

What happens to the myofilaments in the contractile element on contraction

Answer 18

The thin myofilaments move towards the centre while the thick myofilaments remain the same.

Question 19

What action causes the thin myofilaments to move away from the centre of the contractile element

Answer 19

Extension

Question 20

What action causes the thin myofilaments to move towards the centre of the contractile element

Answer 20

Contraction.

Question 21

What is the name given to the three connective tissue coverings

Answer 21

Fascia

Question 22

What are the three fascia

Answer 22

• Epimysium
• Perimysium
• Endomysium

Question 23

What is the outermost fascia

Answer 23

The epimysium. This covers the entire muscle.

Question 24

What are fasiculi

Answer 24

This is the name given to the unit of grouped together muscle fibres

Question 25

What is the name given to the fascia that surrounds all of the individual fasiculi

Answer 25

The perimysium

Question 26

What is the name given to the fascia that covers each individual muscle fibre

Answer 26

The endomysium

Question 27

From superficial to deep, what is the arrangement of the fascia in muscle

Answer 27

Epimysium-perimysium-endomysium

Question 28

What happens to the connective tissue coverings in intramuscular injection

Answer 28

In intramuscular injection, muscle fibres become damaged and the surrounding connective tissue proliferates.

Question 29

What is the aponeurosis

Answer 29

The flat connective sheet covering the abdomen.

Question 30

What are two skeletal muscle attachments

Answer 30

Tendon and aponeurosis.

Question 31

What is the general rule for the origin and insertion of a muscle

Answer 31

GENERALLY - - the origin is the attachment of the muscle's tendon to a stationary bone - the insertion is the attachment of the muscle tendon to a moveable bone.

Question 32

What is the exception to the general rule of origin and insertion of a muscle (that origin = attachment of muscle tendon to stationary bone and insertion = attachment of muscle tendon to movable bone)

Answer 32

The pectoralis major muscle. The origin of this is the sternum and the clavicle while the insertion is the humorous. The origin can become the insertion, for example when asthmatics are trying to get in more air.

Question 33

How many joints will a muscle act on

Answer 33

A muscle will act on as many joints as its tendon crosses.

Question 34

What are muscle fibres arranged into

Answer 34

Bundles called fasiculi.

Question 35

How are muscle fibres arranged within fasiculi

Answer 35

Muscle fibres are in a parallel arrangement however the number of muscle fibres within individual fasiculi varies and the types of muscle fibres present also varies.

Question 36

What does the arrangement of fasiculi determine in terms of the muscle as a whole

Answer 36

The shape of the muscle, the degree to which the muscle can contract and the force the muscle can generate.

Question 37

What is fasicualr arrangement a compromise between

Answer 37

Power and range of movement.

Question 38

What does the maximum force a muscle can generate depend on

Answer 38

The mass of contractile tissue.

Question 39

What does the maximum range of unrestricted movement in a muscle depend on

Answer 39

The length of muscle fibres.

Question 40

What does low power tend to mean in terms of range of movement in a muscle

Answer 40

Range of movement is increased.

Question 41

What does high power tend to mean in terms of range of movement of a muscle

Answer 41

Range of movement is decreased.

Question 42

What is an example of a high power, limited range of movement muscle and what shape does this muscle take

Answer 42

The deltoid muscle which is a pennate muscle.

Question 43

What is an example of a limited power but increased range of movement muscle and what shape does this muscle take

Answer 43

The Sartorius muscle which is a straplike muscle.

Question 44

What do bones function as when producing movement

Answer 44

Levers - a rigid rod.

Question 45

What do joins function as when producing movement

Answer 45

A fulcrum - a fixed point

Question 46

What are the muscle compartments of the upper limb

Answer 46

The anterior (flexor) and posterior (extensor) compartments.

Question 47

What are the muscle compartments of the lower limb

Answer 47

The anterior (flexor), posterior (extensor) and medial compartments.

Question 48

What is a motor unit

Answer 48

A motor neuron and all the muscle fibres it innervates..

Question 49

What are two types of muscle fibres

Answer 49

Slow muscle fibres and fast muscle fibres.

Question 50

What can change the muscle fibre composition of fascicles

Answer 50

Long term alcoholism

Question 51

What is the effect of interruption to the nerve supply of a muscle on the muscle fibre composition

Answer 51

This results in lumps of slow fibres and lumps of fast fibres.

Question 52

What are three requirements for muscle fibres

Answer 52

Innervation, blood supply and venous drainage