Lecture 11

Question 1

What are the functions of skeletal muscle?

Answer 1

• Movement
• Heat Production
• Posture
• Communication

Question 2

What are the Latin and Greek prefixes of muscle?

Answer 2

• Myo-

- Sarco-

Question 3

What are the tissues involved with the musculo-skeletal system?

Answer 3

• Bone
• Skin
• Subcutaneous fat
• Fascia (connective tissues - goes between groups of muscles)
• Muscles
• Arteries/Veins
• Nerves

Question 4

What are the different layers of connective tissues associated with the muscle and where are they?

Answer 4

• Epimysium
  > around the bulk of the muscle
• Perimysium
  > wraps around the fascicle
• Endomysium
  > around a muscle fibre (cell)

Question 5

What is the purpose of all these layers of connective tissues?

Answer 5

To transfer any force produced from the muscle to the bone.

Question 6

What is a fascicle?

Answer 6

A group of muscle cells grouped together covered by the perimysium.

Question 7

What is the name for a muscle cell?

Answer 7

• Myocyte

- Myofibre

Question 8

What is the myocyte made of?

Answer 8

Myofibrils (made of thick and thin fibres - myofilaments)

Question 9

Some features of a muscle cell?

Answer 9

• up to 40cm
• parallel
• cylindrical
• multi-nuclear
• striated (due to protein arrangement)

Question 10

What is the name given to the individual arrangements of proteins and what are its parts?

Answer 10

Sarcomere - Thick and thin filaments

Question 11

What separates sarcomeres?

Answer 11

Z disks

Question 12

What is the name of the cell membrane of the myocyte? What sits underneath this?

Answer 12

Sacolemma

Sarcoplasmic reticulum

Question 13

What is the main function of the sarcoplasmic reticulum?

Answer 13

Stores calcium

Question 14

In the sarcomere, what is the name of the thick and thin proteins?

Answer 14

Thick - Myosin

Thin - Actin

Question 15

How do these work together to form contraction?

Answer 15

The myosin have myosin heads which attach to the actin and then flex which causes the Z disks to come closer together which forms a contraction.

Question 16

How much contraction of the sarcomere can occur?

Answer 16

It can go from 2µm to 1µm, half.

Question 17

What is the name given to the overlap of actin and myosin?

Answer 17

Interdigitate

Question 18

What are the ingredients required for muscle contraction?

Answer 18

• Energy

- Calcium ions (Ca2+)

Question 19

Muscle form determines function.

Answer 19

Length - of muscle fibres
> fibre can shorten up to 50% of resting length
> large ROM = long fibres
> longer resting length = can shorten more = greater ROM

Number - of muscle fibres
> cross-sectional area
> tension (= force) is directly proportional to cross-sectional area
> greater number of fibres = greater CSA and greater tension

Arrangement - of muscle fibres
> fibres oblique to muscle tendon = pennate (structure)
> more fibres into same place
> reduced shortening but increased CSA
> clique to line pull (uni, bi, multi)

Question 20

What is the factor affecting the tension/force?

Answer 20

The amount of myofibres.

Question 21

What is the advantage of a pennate arrangement?

What is the disadvantage of a pennate arrangement?

Answer 21

More myofibres so more force.

Some long, some short fibres so less ROM.

Question 22

What are the names of the tissues in a muscle from biggest to smallest?

Answer 22

Myofibres (myocyte)

Myofibril

Sarcomere

Myofilament (thick and thin proteins - Myosin and Actin)

Question 23

Muscle tone

Answer 23

• Even relaxed muscles are slightly active
• Nerve impulses activating muscle fibres
• Does not produce movement
• Keep muscles firm and healthy
• Helps stabilise joints and maintain posture