Muscle Physiology

Question 1

Cardiac muscle is connected by

Answer 1

Intercallated disks

Question 2

skeletal muscle is

Answer 2

striated and multi-nuclear with nucleus around the outside

Question 3

Skeletal muscles are arranged in increasing groups from

Answer 3

Myofibrils –> muscle fibres –> fascicles –> muscle itself

Question 4

Small motor units are controlled by.

Largest motor neurons are controlled by ..

Answer 4

Smallest and most excitable motor neurons.

Large motor neurons which are least excitable

Question 5

… motor units are recruited first

Answer 5

Small

Question 6

When AP are received constantly and temporal summation is at a peak this is …

Answer 6

tetanus

Question 7

If an action potential is received before sarcoplasmic reticulum fully recharged this is called … The result is

Answer 7

temporal summation - the force of contraction increases due to more binding sites being exposed

Question 8

Muscle responses are graded and affected by

Answer 8

frequency of potential and number of motor units recruited

Question 9

“strong” muscles have … motor units

Answer 9

large

Question 10

Motor units are

Answer 10

groups of muscle fibres connected to a single motor neuron and single action potential

Question 11

the three types of muscle contraction are

Answer 11

isometric, concentric and eccentric

Question 12

Cross bridging cycling is facilitated through

Answer 12

ATP –> ADP cocking and moving

Question 13

Calcium binding to troponin causes

Answer 13

movement of tropomyosin to allow binding sides to open

Question 14

Calcium binds to

Answer 14

troponin

Question 15

Sodium influx following ACh binding causes depolarisation and then…

Answer 15

voltage sensitive calcium channels open on sarcoplasmic reticulum causing calsium efflux

Question 16

Action potentials are transmitted by which neurotransmitter

Answer 16

Acetycholine

Question 17

Binding sites on actin to myosin heads are blocked by

Answer 17

tropomyosin

Question 18

A single myosin fibre has … heads at each end

Answer 18

2

Question 19

Sarcomeres are separated by

Answer 19

Z lines

Question 20

the functional unit of the muscle is

Answer 20

sarcomere

Question 21

The covering of muscles is

Answer 21

epimysium around whole muscle, perymysium around fascicles and endomysium around each muscle fibres

Question 22

Skeletal muscles are arranged in increasing groups from

Answer 22

Myofibrils –> muscle fibres –> fascicles –> muscle itself