Intro to muscles and movement

Question 1

What does skeletal muscle consist of?

Answer 1

Muscle fibres & a fibrous or tendinous portion

Question 2

What does skeletal muscle look like under the microscope?

Answer 2

The cells are multinucleate with the sarcoplasm filled with myofibrils and mitochondria

Question 3

What is each muscle cell lined with?

Answer 3

Connective tissue

Question 4

What travels through the connective tissue around the muscle?

Answer 4

Blood vessels and nerves to supply and innervate the fibres

Question 5

What are Sharpey’s fibres?

Answer 5

Matrix of connective tissue consisting of bundles of type 1 collagen connecting periosteum to bone

Question 6

What length in terms of a factor can a skeletal muscle contract to?

Answer 6

Half of its length

Question 7

Why do longer muscle fibres allow for more movement?

Answer 7

There is a larger contraction

Question 8

What is a perimysium?

Answer 8

Sheath of connective tissue that groups muscles fibres into bundles

Question 9

What do tendons do?

Answer 9

Attach muscle to bone

Question 10

Why are the muscle fibres as long as possible?

Answer 10

To maximise the distance that the body through

Question 11

What does muscle size change by? 4 things

Answer 11

1 = increase/decrease in the diameter of the individual muscle fibres by adding new sarcomeres to existing cells 
2 = Increase in length of muscle during childhood and adolescence by the addition of new sarcomeres at the ends of muscle fibres
3 = The ability to add and lose sarcomeres does not end when normal growth ends due to the role of exercise adding / removing sarcomeres 
4 = Muscle bulk and strength decrease with age but exercise can slow down or reverse the trend

Question 12

What are the 3 types of tendons?

Answer 12

1. Cylindrical where fibres are closely packed to form a cylinder
2. Linear tendons forming a fleshy attachment and may produce a linear bridge
3. Common tendons which are attached to 2 muscles or more in 3 forms (intermediate, raphe or aponeurosis)

Question 13

Where are synovial tendon sheaths found?

Answer 13

Around the wrist and ankle

Question 14

What are the two types of innervation?

Answer 14

Sensory - muslce spindles measure the length and tendon organises tension while other nerves are involved in proprioception and pain.
Motor - Myelinated fibres from large motor neurone end in motor end plates. The transmitter ACH crosses the gap and activates the muscle fibre.

Question 15

What is an advantage of a parallel muscle?

Answer 15

It gives a large range of movement

Question 16

What is a pennate muscle built for? What structure allows this?

Answer 16

Built for power and there is a central tendon with fleshy bellies attached

Question 17

What is an antagonist muscle?

Answer 17

Muscles are attached to the opposite side of bones and oppose the movement.

Question 18

What is the role of a fixator in muscle action?

Answer 18

They stabilise the body for the required movement. Thus when the prime movers and the antagonist act together they can hold the bone in a fixed position.

Question 19

What is the role of a synergist in muscle action?

Answer 19

These act with the prime movers to refine the movement and to control any undesirable movement. Thus when a joint is capable of moving in more than one plane the synergist control the unwanted movement.