10. Skeletal Muscles

Question 1

What is Epimyisum?

Answer 1

Fasica that envelopes the entire muscle belly

Question 2

What is Perimysium?

Answer 2

Fasica that envelopes bundles of muscle fibres (a fasicle)

Question 3

What is Endomysium?

Answer 3

Fascia that envelopes single muscle fibre cells

Question 4

What is the MT junction?

Answer 4

When mysium layers converge to form the fibrous/dense tendon.

Question 5

What is Periosteum?

Answer 5

Covers the bone and is continues with the tendon

Question 6

What interacts and how, to allow muscles to contract?

Answer 6

Myosin heads from the thick filaments bind to the thin filaments, pulling them toward the sacromere.

This process is fueled by ATP!

Question 7

What myofilaments interact in ‘sliding filament theory’?

Answer 7

Actin and Myosin myofilaments

Question 8

What is a sacromere?

Answer 8

The smallest functional contractile unit of a myofibirl

Question 9

What is the watery structure in which the cell apparatus floats and what is the name of it in skeletal muscles?

Answer 9

Cytoplasm

Sacroplasm

Question 10

What energy systems do 
Type 1
Type 2a
Type2b
..fibres use?

Answer 10

Type 1 - Aerobic
Type 2a - Mixed
Type2b - Anaerobic

Question 11

The most common exercises involve isotonic contractions.

What is an isotonic action? and what are the 2 types?

Answer 11

Where the muscle contracts and there is a change in length of a muscle
Concentric and Eccentric.

Question 12

What is a concentric/eccentric contraction?

Answer 12

Concentric - contracts and shortens in length. Origin and insertion move towards eachother (joint angle decreases)

Eccentric - contracts and increases in length. Origin and insertion move further apart (joint angle increases)

Question 13

What is an isometric contraction?

Answer 13

No change in length as force is equal

Question 14

What is an isokinetic contraction?

Answer 14

Muscles contract and maintains constant force and speed throughout. (Usually computerised equipment)

Question 15

What is an..

Agonist/Antagonist
Synergist/Fixator?

Answer 15

Agonist - prime mover
Antagonist - opposite muscle that is dialled down

Synergist - assist the movement
Fixator - make moving joint stable

Question 16

What is the name of a motor neurone that is connected to a number of muscle cells?

Answer 16

A motor unit (think movement unit!)

Question 17

A motor nerve (neurone) doesn’t stimulate a whole muscle, how does it work then?

Answer 17

Stimulates only a number of muscle fibres within the muscle

Question 18

Slow-twitch motor neurones consist of a ___ number of fibres, whilst fast-twitch motor units are ___, consisting of___ fibres

Answer 18

Slow-twitch motor neurones consist of a small number of fibres, whilst fast-twitch motor units are large consisting of many fibres

Question 19

What is the All or Nothing principle?

Answer 19

Individual muscle fibres of a motro unit will contract to their fullest extent or not contract at all.

Question 20

How are we able to sustain contractions for a long time?

Answer 20

Asynchronous firing of motor units (firing at different times)

Question 21

What is muscle tone?

Answer 21

At a given time, some muscle fibres are contracting whilst others relax to tighten the muscle, however not enough contracting to cause movement

Question 22

What is muscle tone necessary for?

Answer 22

Maintaining posture

Question 23

What is force and tension of a contraction graded by?

Answer 23

Amount of motor units recruited

Question 24

Apart from more motor units and more muscle tissue, how else can we get stronger?

Answer 24

Synchronising units to work more effectively - inter and intra muscle coordination (this comes from exercising)