Topic 3

Question 1

Describe the different types of attachments of skeletal muscle organs –
tendinous, fleshy, raphe

Answer 1

Fleshy: Muscle fibres attatch directly to bone with small amounts of connective tissue

Tendon: Muscle fibres attach to a cord of connective tissue that then attaches to bone

Raphe: Muscle fibres attach to a sheet of connective tissue that then attaches to bone

Question 2

Classify skeletal muscle, using the following terms:

• parallel
• strap
• fusiform
• triangular(radiate)
• flat (quadrilateral)
• oblique
• unipennate
• bipennate
• multipennate • circular

Answer 2

Parallel

Strap: Long & flat

Fusiform: The ‘classic’ shape

Triangular/ radiate: Broad origin & narrow insertion

Flat/ quadrilateral: Fibres in same axis as tendon

Unipennate: Fibres attach to one side of tendon only

Oblique

Bipennate: Fibres attach to both sides of central septum & tendon

Multipennate: Group of several bipenate ‘units’

Question 3

Effects of Orientation of Muscle Fibres in terms its final contracted length and the force it can exert

Answer 3

On final contracted length & force exerted

Parallel muscles:

• Maximum shortening of muscle belly (up to 1/2 of muscle length)
  Larger range of movement BUT with less force/ power

Oblique muscles:

• Less shortening of muscle belly
• Less range of movement but MORE force/ power

Question 4

Define the following terms relating to skeletal muscle contraction:

• isometric
• isotonic
• eccentric
• Concentric

Answer 4

• Isometric: Occurs when tension is generated in a muscle but the length and angle of joint does NOT change
• Isotonic: Muscle contraction the changes the length
• Eccentric: Muscle contraction resulting in lengthening of muscle
• Concentric: Muscle contracting resulting in shortening of muscle

Question 5

What is an action?

Answer 5

The movement produced when a muscle contracts concentrically in isolation

Question 6

What are the functions of a agonist, antagonist, fixator/ stabiliser and a synergist?

Answer 6

Agonist: Muscle producing the desired movement by contracting (prime mover)

Antagonist: Muscles which must relax to allow the desired movement to occur

Fixator/ stabiliser: stabilise a body segment so that another muscle can perform an action. A fixator is a stabiliser that acts to eliminate the unwanted movement of an agonist’s origin

Synergist: Assists the agonist to produce the desired movement by cancelling the unwanted action of the agonist