Muscular system

Question 1

What are the functions of the muscular system? (3)

Answer 1

• works together with skeletal system to create movement.
• maintains posture.
• maintains bodily functions: heart pumps blood, digests food, breathing.

Question 2

What are the types of muscles? (3)

Answer 2

• skeletal muscle
• smooth muscle
• cardiac muscle

Question 3

What is a smooth muscle? (2)

Answer 3

• Found in digestive system and walls of vital organs.

- called involuntary muscles because we don’t control them.

Question 4

What are skeletal muscles? (4)

Answer 4

• they have a striped appearance, also called striated.
• responsible for voluntary movements.
• we can exercise and train them.
• responsible for good posture.
• they pull on skeletal muscles in order to create movement.

Question 5

What is a cardiac muscle? (4)

Answer 5

• has a striped appearance.
• only found in the heart.
• it can become stronger through exercise.
• its actions are involuntary.

Question 6

What is reciprocal inhibition?

Answer 6

When two muscle are working together to create opposite movement. One muscle is contracting while the other is relaxing. They never work in isolation.

Question 7

What is the antagonist muscle?

Answer 7

The muscle that is relaxing.

Question 8

What is the agonist muscle?

Answer 8

The muscle that is contracting.

Question 9

What is a stabiliser muscle?

Answer 9

Muscles in the body that act to stabilise on joint so a desired movement can be performed in another joint?

Question 10

What is the origin?

Answer 10

The site where the muscle is attached to a stable bone, which the muscle can pull against. Usually flat bone.

Question 11

What is the insertion?

Answer 11

The insertion occurs where the muscle attaches to the bone and is pulled by the action of the muscle. During contraction the muscle pulls on the bone to create movement.

Question 12

What is a fast twitch fibre? (3)

Answer 12

White muscle fibre, used for:

• power
• speed
• strength
• short distance
• contracts quickly
• aerobic and anaerobic

Question 13

What is a slow twitch fibre? (3)

Answer 13

Red muscle fibre, used for:

• longer duration
• low effort, low force
• endurance
• contracts slowly
• aerobic

Question 14

How are muscles attached to bones?

Answer 14

Tendons which are situated at the end of a muscle called a muscle belly.

Question 15

What is an isoinertial movement?

Answer 15

When a muscle is applying force and there is an increase/ decrease in in muscle length. Either concentric or eccentric.

Question 16

What is an isometric movement?

Answer 16

Muscle creates force but there’s no change in muscle length.

Question 17

What is an isokinetic movement?

Answer 17

Isokinetic exercise is a type of strength training in which specialized machines, maintain a constant speed of movement.
A machine will continually create max contraction.

Question 18

What is hypertrophy?

Answer 18

The growth and increase of the size of muscle cells.

Question 19

What is a motor unit?

Answer 19

Consists of one motor neuron and all the muscle fibres it stimulates.

Question 20

What is the all or nothing principle?

Answer 20

States that when the electrical impulses reaches a certain threshold, all of the fibres of that motor unit will contract at the same time and as forcefully as possible.

Question 21

How does the intensity of a muscular contraction vary?

Answer 21

• varying the number of motor units stimulated.

- varying the frequency at which the impulses arrive at the motor unit.

Question 22

Why is an electrical threshold relevant in muscle contractions?

Answer 22

Threshold is considered to be the level of stimulation required to trigger the smallest measurable contraction.

Question 23

What is myosin?

Answer 23

A thick protein filament that is found in myofibril.

Question 24

What is actin?

Answer 24

A thin protein filament found in myofibril.

Question 25

What is muscle atrophy?

Answer 25

A decrease in the mass of the muscle, due to not using the muscle for an extended period of time.