13.9 Voluntary and involuntary muscles

Question 1

What are the 3 types of muscle in the human body?

Answer 1

Skeletal muscle
Cardiac muscle
Involuntary muscle

Question 2

Describe the characteristics skeletal muscles are.

Answer 2

Responsible for movement, make up majority of muscle tissue in the body e.g. biceps + triceps

Question 3

Describe the characteristics of cardiac muscle.

Answer 3

Only found in the heart.

Cells composing cardiac muscle are called ‘myogenic’ - they contract without the need for nervous stimulus, causing the heart to beat in a regular rhythm

Question 4

Cardiac muscles are myogenic. What does this mean?

Answer 4

The cells contract without the need of a nervous stimulus, causing the heart to beat in regular rhythms

Question 5

1. What are involuntary muscles also known as?
2. Where are involuntary muscles found?
3. What is their function?

Answer 5

1. Smooth muscle
2. In walls of hollow organs e.g. stomach and bladder
   - Walls of blood vessels
   - Digestive tract, where they move food along the gut through peristalsis

Question 6

What does striated mean?

Answer 6

Striped

Question 7

What is the appearance of Skeletal, Cardiac and Involuntary muscles?

Answer 7

Skeletal = Striated
Cardiac = Specialised striated
Involuntary = Non-striated

Question 8

What is the control of Skeletal, Cardiac and Involuntary muscles?

Answer 8

Skeletal = Conscious (voluntary)
Cardiac = Involuntary
Involuntary = Involuntary

Question 9

What is the arrangement of Skeletal, Cardiac and Involuntary muscles?

Answer 9

Striated = Regularly arranged so muscle contracts in one direction
Cardiac = Cells branch and interconnect resulting in simultaneous contraction
Involuntary = No regular arrangement - different cells can contract in different directions

Question 10

What is the contraction speed of Skeletal, Cardiac and Involuntary muscles?

Answer 10

Skeletal = Rapid
Cardiac = Intermediate
Involuntary = Slow

Question 11

What is the length of contraction of Skeletal, Cardiac and Involuntary muscles?

Answer 11

Skeletal = Short
Cardiac = Intermediate
Involuntary = Long

Question 12

What is the structure of Skeletal, Cardiac and Involuntary muscles?

Answer 12

Skeletal = Muscles showing cross striations are knows as striated/striped muscles. Fibres are tubular and multinucleated.
Cardiac = Cardiac muscle show striations but they're fainter than those of skeletal. Fibres are branched and uninucleated
Involuntary = Muscles showing no cross striations are called non-striated or unstriped muscles. Fibres are spindle shaped and uninucleated.