Functional Anatomy

Question 1

Epimysium

Answer 1

connective tissue that encases the muscle belly

Question 2

Myofibril

Answer 2

an individual strand of muscle containing sarcomeres

Question 3

Sarcomere

Answer 3

Contractile unit of muscle, comprised of actin and myosin filaments

Question 4

Actin

Answer 4

Thin protein filament in a sarcomere

Question 5

Myosin

Answer 5

thick protein filament in a sarcomere

Question 6

Force Velocity relationship

Answer 6

The force a muscle can produce is dependent upon the velocity at which the contraction occurs.

Question 7

Force Velocity relationship - Concentric

Answer 7

Highest force is produced at the slowest contraction velocity.

Question 8

Force Velocity relationship - Eccentric

Answer 8

Highest force is produced with maximal velocity

Question 9

Force Length Relationship

Answer 9

The force length relationship looks at how much force a muscle can produce at different lengths of the muscle across the range of movement.

Optimal force production at midrange of muscle movement due to maximal cross bridge formation.
Minimal force generate at fully contracted or fully extended positions.

Question 10

Neuron

Answer 10

A nerve cell that carries signals either to or from the CNS to the muscles. Made up of dendrite, cell body & axon.

Question 11

Dendrite of sensory neuron

Answer 11

Sensory receptors that receive the sensory information and pass it on to the cell body of the sensory neuron.

Question 12

Axons of motor neurons

Answer 12

Carry motor information away from the cell body, towards the muscle fibres in order for the muscle fibres to be stimulated to create movement.

Question 13

Motor Unit

Answer 13

A single motor neuron and all the muscle fibres it innervates.

Question 14

Spinal Cord

Answer 14

Part of the central nervous system, transmits motor information to the muscles from the brain, and sensory information from the muscles back to the brain.

Question 15

All or Nothing Principle

Answer 15

When the nerve impulse (or action potential) reaches the threshold level for the motor unit, all muscle fibres will contract at maximum force at the same time. If the threshold in not reached, no contraction will occur

Question 16

Type 1 Muscle Fibre Characteristics

Answer 16

• High fatigue resistance - will not fatigue quickly which is required for an event lasting nearly 2 hours.
• High oxidative density - enables high level of oxygen at working muscles
• Slow contraction speed - allows them to keep contracting for endurance running
• High capillary density-allows more oxygen to be transferred to the muscles to meet the aerobic requirements of the marathon runner
• Uses aerobic energy system which will allow the runner to exercise continually by providing a constant supply of ATP.

Question 17

Type 2b Muscle Fibre Characteristics

Answer 17

• Fast contraction speed -White in colour
• Low capillary density
• High ATP store
• Low number of mitochondria
• Large fibres
• Produce a high force
• Low fatigue resistance
• Uses anaerobic energy system

Question 18

Fibre type 2b vs 2a

Answer 18

• Type IIB have a faster contraction speed than IIA
• Type IIB have a lower capillary density than IIA
• Type IIB have a higher ATP store than IIA
• Type IIB have a lower number of mitochondria than IIA
• Type IIB have larger fibres than IIA,
• Type IIB can produce a higher force than IIA
• Type IIB fatigue more quickly than IIA
• Type IIB use only the anaerobic energy system, IIA use a combination of anaerobic and aerobic

Question 19

Concentric Contraction

Answer 19

Contraction in which the sarcomere shortens

Question 20

eccentric contraction

Answer 20

a contraction in which the sarcomeres lengthen under

Question 21

isometric contraction

Answer 21

A contraction where there is no change in length of the sarcomeres

Question 22

isokinetic contraction

Answer 22

Contraction where the joint velocity is constant throughout the entire range of motion