WEEK 5

Question 1

Muscle Functions

Answer 1

• stabilise joints
• move bones
• maintain posture
• propel substances around (and in/ out of) the body
• generate heat
• protect some visceral organs

Question 2

Composition of Skeletal muscles

Answer 2

• skeletal muscle fibres
• blood vessels
• nerves
• connective tissue

Question 3

Origin

Answer 3

Attachment of a muscle that remains relatively fixed during muscular contraction

Question 4

Insertion

Answer 4

Movable attachment of a muscle

• muscle pull, never push: contraction of muscle fibre shortens muscle length and pulls the insertion towards the origin

Question 5

Prime Mover

Answer 5

Muscle that provides the major force for the specific movement
- e.g. quadriceps femora’s extends the leg at the knee joint

Question 6

Antagonist

Answer 6

Muscle that oppose or revers a particular movement
- e.g. biceps femoris flex the leg at the knee joint

Prime mover and it antagonist are located on opposite sides of a joint

Question 7

Synergist

Answer 7

Helps (aids) prime movers by adding extra force to the same movement, or by reducing undesirable/ unnecessary movements

Question 8

Fixators

Answer 8

Synergistes that immobilise a bone to provide stability for the action of a prime mover

Question 9

What are the three types of muscles

Answer 9

• skeletal muscle
• cardiac muscle
• smooth muscle

Question 10

What are fascicles?

Answer 10

Bundle of fibres

Question 11

4 patterns of fascicles arrangement

Answer 11

• circular
• convergent
• parallel
• pennate

Question 12

Circular

Answer 12

• fascicles arranged in concentric rings
• form sphincters
• examples: orbiculaires oculi and orbiculaires oris

Question 13

Convergent

Answer 13

• broad origin
• fascicles converge toward a single tendon for insertion
• triangular or fan-shaped
• example: pectoralis major

Question 14

Parallel

Answer 14

• fascicles arranged parallel to long axis of the muscle
• examples: sartorius and rectus abdominis

Question 15

Pennate

Answer 15

• short fascicles that run obliquely and attach to central tendon
• types: unipennate, bipennate, multipennate

Question 16

Unipennate

Answer 16

Fascicles insert on ONLY one side of tendon (extensor digitorum Lingus)

Question 17

Bipennate

Answer 17

• fascicles insert on opposite sides of tendon
• tendons lie in the centre of the muscle and muscle fibres pass to it from two sides
• i.e. rectus femoris

Question 18

Multipennate

Answer 18

• many fascicles together
• e.g. deltoid muscle

Question 19

Shoulder Movement

Answer 19

• Trapezius m. Superior fibres (elevation)
• Trapezius m. Inferior fibres (depression)

Question 20

Back Movement

Answer 20

• erector spinae (extension i.e bend spine back)
• rectus abdominus (flexion i.e bend spine forwards)

Question 21

Chin Movement

Answer 21

• temporalis (retrusion)
• lateral pterygoid (protrusion)

Question 22

Whole leg (hip) movement

Answer 22

• gluteus medius (abduction)
• adductors (adduction)
• gluteus maximus (extension)
• iliopsoas (flexion)

Question 23

Whole arm (shoulder) movement (star jumps)

Answer 23

• supraspinatus deltoid (first 30) + middle fibres of deltoid (abductions)
• latissimus dorsi (adduction)

Question 24

Full arm (shoulder) movement (walking)

Answer 24

• Deltoid posterior fibresand Latissimus dorsi (extension)
• Deltoid anterior fibres (flexion)

Question 25

Half hand (elbow) movement

Answer 25

- triceps brachii (extension) - Brachialis (flexion)

Question 26

Hand (palm) movement (changing light bulb)

Answer 26

- biceps brachii (supination) - pronator teres (pronation)

Question 27

Hand (wrist) movement (flicking wrist up and down)

Answer 27

- extensor digitorum (extension) - flexor carpi radialis and flexor carpi ulnaris (flexion)

Question 28

Finger (knuckles) movement (sassy handbag)

Answer 28

- flexor digitorum superficialis (flexion) - extensor digitorum (extension)

Question 29

Thumb movement

Answer 29

- flexor pollicis longus (flexion) - extensor pollicis longus (extension) - abductor pollicis (abduction) - adductor pollicis (adduction)

Question 30

Half leg (knee) movement

Answer 30

- hamstring (flexion) - quadriceps femoris (extension)

Question 31

Foot movement

Answer 31

- triceps surge (plantarflexion) - extensor digitorum longus (dorsiflexon) - fibularis longus (eversion) - tibiales anterior (inversion)

Question 32

Actin-myosin crossbridge (muscle contraction)

Answer 32

1. Myosin binds actin - Myosin head attaches reversibly to high affinity active sites on the actin thin filament 2. Myosin 'power stroke' pulls actin filament, contracting sarcomere - ADP released, freeing ATP-binding site 3. ATP binding releases myosin from actin - Conformational change 4. ATP hydrolysis drives re-cocking of myosin to high energy state, but is not required for power stroke

Question 33

Length-Tension Relationship

Answer 33

The amount of tension generated by a muscle depends on how stretched or shortened it is. - If overly shortened = weak contraction • thick filaments just butt against Z discs - If too stretched = weak contraction • minimal overlap between myosin and actin results in minimal cross- bridge formation - Optimum resting length produces greatest force when muscle contracts • The nervous system maintains muscle tone (partial contraction) to ensure that resting muscles are near this length

Question 34

Force ????

Answer 34

- force is inversely related to velocity - maximum force = 0

Question 35

Naming skeletal muscle categories (6)

Answer 35

- muscle location - muscle shape - muscle size - direction of muscle fibres - number of origins - muscle action

Question 36

Naming skeletal muscle (muscle size)

Answer 36

- maximus/major = largest - minimus/minor = smallest - longus = longest - brevis = shortest

Question 37

Naming skeletal muscle (direction of muscle fibres)

Answer 37

- rectus = straight - oblique - transversus = transverse

Question 38

Naming skeletal muscle (Number of origins)

Answer 38

- bi = 2 - tri = 3 - quad = 4

Question 39

Naming skeletal muscle (location of attachment)

Answer 39

- origin = first part of name - insertion = last part

Question 40

Naming skeletal muscle (muscle action)

Answer 40

- flexor - extensor - opponents - abductor - adductor