Physiology

Question 1

motor units allow what

Answer 1

simultaneous contraction

Question 2

what is motor unit recruitment

Answer 2

stimulation of more motor units, stronger contraction

Question 3

tension in the muscle is dependent on what? (3)

Answer 3

length of the muscle, thickness, frequency and summation of contraction

Question 4

What is the relationship between AP and duration of resulting twitch

Answer 4

the AP is shorted than the resulting twitch

Question 5

can cardiac muscle be tetanised?

Answer 5

no

Question 6

why can cardiac muscle not be tetanised

Answer 6

the refractory period

Question 7

two types of contraction exhibited by skeletal muscle

Answer 7

isotonic and isometric contraction

Question 8

What is isotonic contraction

Answer 8

body movements; muscle tension remains constant

Question 9

what is isotmetric contraction

Answer 9

support of objects in fixed positions, muscle tension develops at a constant

Question 10

what is the relationship between velocity of muscle and load

Answer 10

as the load on muscle increases the velocity of muscle shortening decreases

Question 11

4 examples of impaired skeletal muscle function

Answer 11

intrinsic disease of muscle, diseased NMJ, motor neurone disease, blocked input to motor units

Question 12

stretch reflex is the most simple example of

Answer 12

Monosynaptic spinal reflex

Question 13

the function of the stretch reflex

Answer 13

negative feedback that resists change in muscle length, this maintains optimal resting length of muscle

Question 14

what is the muscle spindle

Answer 14

sensory receptor

Question 15

when is the muscle spindle activated

Answer 15

by the muscle stretch reflex

Question 16

what happens when the muscle spindle is stretched

Answer 16

increase in firing in the afferent neurones

Question 17

where do afferent neurones synapse

Answer 17

within the spinal cord with the alpha motor neurones

Question 18

how is the stretch reflex co-ordinated

Answer 18

relaxation of antagonist muscle

Question 19

what muscle is involved in the knee jerk reflex

Answer 19

Quadriceps femoris

Question 20

5 reflexes that can be tested with the tendon hammer

Answer 20

knee, ankle, biceps, triceps and brachioradialis

Question 21

what spinal nerves are involved in the biceps and brachioradialis reflex

Answer 21

C5-6

Question 22

what peripheral nerve is affected by the brachioradialis and triceps jerk

Answer 22

Radial

Question 23

what spinal nerves are involved in the knee jerk

Answer 23

L3 + 4

Question 24

what spinal nerves are involved in the ankle jerk

Answer 24

S1 + 2

Question 25

what spinal nerves are involved in the triceps jerk

Answer 25

C6 + 7

Question 26

what peripheral nerve is affected by the knee jerk

Answer 26

femoral nerve

Question 27

what peripheral nerve is affected by the ankle jerk

Answer 27

tibial nerve

Question 28

what peripheral nerve is affected in the biceps jerk

Answer 28

musculocutaneous nerve

Question 29

muscle spindles can also be called

Answer 29

intrafusal fibres

Question 30

extrafusal fibres are also called

Answer 30

ordinary muscle fibres

Question 31

where are muscle spindles found

Answer 31

within the belly of muscles

Question 32

sensory nerve endings on muscle spindles are called

Answer 32

annulospiral fibres

Question 33

efferent neurones that supply muscle spindles are called

Answer 33

gamma motor neurones

Question 34

what is the role of game motor neurones

Answer 34

adjust the level of tension in the muscle spindles

Question 35

differences between skeletal muscle fibres

Answer 35

1. enzymatic pathways for ATP synthesis 2. resistance to fatigue 3. activity of myosin ATPase

Question 36

what are the type 1 fibres used for

Answer 36

prolonged low energy tasks; posture and walking

Question 37

what are the type 2a fibres used for

Answer 37

prolonged moderate energy tasks; jogging

Question 38

what are the 2x fibres used for

Answer 38

short term high intensity activities; jumping

Question 39

Investigations in neuromuscular disease

Answer 39

EMG, muscle enzymes, nerve conduction