8.1 The Control Of Movement

Question 0

All animal movement depends on muscle ____.

Answer 0

contractions

Question 1

Ultimately, the purpose of the brain is to control behaviours, and behaviours are ____.

Answer 1

movements

Question 2

Vertebrate muscles fall into three categories: ____ muscles, which control the digestive system and other organs; ____ or striated muscles, which controls the movement of the body in relation to the environment; and ____ muscles (heart muscles), which have properties intermediate between those of smooth and skeletal muscles.

Answer 2

smooth : skeletal : cardiac

Question 3

Each muscle is composed of many ____.

Answer 3

fibres

Question 4

Although each muscle fibre receives information from only one ____, a given axon may innervate more than one muscle fibre.

Answer 4

axon

Question 5

For example, the eye muscles have a ratio of one axon per three muscle fibres, and the bicep muscles of the arm have a ratio of one axon to more than 100 fibres. This difference allows the eye to move more ____ than the biceps.

Answer 5

precisely

Question 6

A ____ ____ is a synapse between a motor neuron axon and a muscle fibre.

Answer 6

neuromuscular junction

Question 7

In skeletal muscles, every axon releases acetylcholine at the neuromuscular junction, and acetylcholine always excites the muscle to ____.

Answer 7

contract

Question 8

A deficit of acetylcholine or its receptors ____ movement.

Answer 8

impairs

Question 9

Each muscle makes just one movement, contraction. There is no message causing ____; the muscle simply relaxes when it receives no message to contract.

Answer 9

relaxation

Question 10

Moving a leg or arm back-and-forth requires opposing sets of muscles, called ____ ____.

Answer 10

antagonistic muscles

Question 11

At your elbow, for example, your ____ muscle brings your hand toward your shoulder and your ____ muscle straightens the arm.

Answer 11

flexor : extensor

Question 12

Muscle contractions, being chemical processes, ____ ____ in the cold.

Answer 12

slow down

Question 13

A fish has three kinds of muscles: red, pink, and white. Red muscles produce the slowest movements, but they do not ____. White muscles produce the fastest movements, but they ____ rapidly. Pink muscles are intermediate in speed and rate of ____.

Answer 13

fatigue

Question 14

Human and other mammalian muscles have various kinds of muscle fibres ____ ____, not in separate bundles as an fish.

Answer 14

mixed together

Question 15

Our muscle types range from ____ fibres with fast contractions and rapid fatigue too ____ fibres with less vigourous contractions and no fatigue.

Answer 15

fast-twitch : slow-twitch

Question 16

We rely on our slow-twitch and intermediate fibres for ____ activities.

Answer 16

nonstrenuous

Question 17

Slow-twitch fibres do not fatigue because they are ____ – they use oxygen during their movements.

Answer 17

aerobic

Question 18

Prolonged use of fast-twitch fibres results in fatigue because the process is ____ – using actions that do not require oxygen at the time but need oxygen for recovery. Using them builds up an ____ ____.

Answer 18

anaerobic : oxygen debt

Question 19

Your muscles use ____, and after a while your glucose supplies begin to dwindle. Low glucose activates the gene that inhibits the muscles from using glucose, thereby saving glucose for the brains use.

Answer 19

glucose

Question 20

People vary in their percentages of fast-twitch and slow-twitch fibres, for reasons based on both ____ and ____.

Answer 20

genetics and training