A&P - Chapter 17 (Part 3)

Question 1

What are 5 types of muscle contractions?

Answer 1

1. Twitch
2. Tetanic
3. Tonic
4. Isotonic
5. Isometric

Question 2

Myography

Answer 2

Method of graphing the changing tension of a muscle as it contracts

Question 3

What kind of movement are twitch contractions? (3)

Answer 3

1. Quick
2. Jerky
3. Not related to normal muscle activity

Question 4

Where are twitch movements seen?

Answer 4

In isolated muscle fibres

Question 5

What are twitch contractions caused by?

Answer 5

Single contraction of muscle fibres caused by a single threshold stimulus

Question 6

What kind of movements are tetanic contraction? (2)

Answer 6

1. Sustained

2. Steady muscular contractions

Question 7

What are tetanic contractions caused by?

Answer 7

A series of stimuli bombarding a muscle in rapid succession this series of stimuli join forces to produce a long contraction

Question 8

What is tetanic contractions dependant on?

Answer 8

Ca

Question 9

Why do people have arched backs in tetanic contractions?

Answer 9

Back muscles are stronger than the front

Question 10

What kind of movement is tonic contraction? (2)

Answer 10

1. Continual

2. Partial contraction of a muscle

Question 11

What happens during tonic contraction at any one time?

Answer 11

A few muscle fibres within a muscle are contracting to produce a certain amount of tension or tone

Question 12

Flaccid

Answer 12

Muscles have less tone than normal

Question 13

Spastic

Answer 13

Muscles have more tone than normal

Question 14

What is muscle toned maintained by?

Answer 14

A negative feedback mechanism

Question 15

What do the skeletal muscles contraction strength depend on? (4)

Answer 15

1. Metabolic condition of individual fibres
2. Number of fibres contracting at the same time
   - the more you have the stronger the contraction
3. The number of motor units involved
4. The intensity and frequency of the stimulation

Question 16

What is a muscle’s max strength directly dependant on?

Answer 16

The initial length of its fibres

Question 17

Which muscle length gives you a stronger contraction? Why?

Answer 17

1. Longer muscle’s

2. Have more to contract/shorten

Question 18

What happens if sarcomeres are compressed?

Answer 18

It reduces the muscle’s contractile potential

Question 19

What happens if the sarcomeres are overstretched?

Answer 19

Actin and myosin are too far apart to bind

Question 20

When is the muscle contraction the strongest?

Answer 20

When the muscle is at its optimal length

Question 21

What can influence the strength of the contraction?

Answer 21

The load a muscle is exposed to

Question 22

What does the body try and do in response to an increase load?

Answer 22

Constant muscle length

Question 23

Threshold stimulus

Answer 23

Minimal level of stimulation required to cause a muscle fibre to contract
- muscles wont contract without it

Question 24

All-or-nothing response

Answer 24

Once stimulated by a threshold stimulus, a muscle fibre will completely contract

Question 25

What allows muscles to preform contractions that are specific to different weight loads?

Answer 25

Different muscle fibres in a muscles are controlled by different motor units with different thresholds
- all or nothing still applies but just different parts of the muscle