Chapter 15- Muscle structure and physiology (4)

Question 1

Smooth muscle contraction is similar to skeletal muscle contraction in what ways:

Answer 1

1- Actin and myosin slide over one another

2- Calcium is involved

3- ATP is required

Question 2

Does smooth muscle contain troponin?

Answer 2

No

Question 3

Nervous innervation differs functionally from the skeletal muscle in 3 key ways:

Answer 3

1- In skeletal muscle, activation is binary whereas in smooth muscle, activation is graded.

2- Skeletal muscle is innervated by the somatic nervous system whereas smooth muscle is innervated by the autonomic nervous system.

3- Can be made to contract by other factors including local humoral factors, circulating hormones or mechanical stimulation, e.g, hormones can cause smooth muscle to contract.

Question 4

What are the two types of smooth muscle:

Answer 4

1- Single unit

2- Multi-unit

Question 5

What are the features of single unit smooth muscle?

Answer 5

They are individual fibres joined by gap junctions.

Produce slow, steady contractions often over a large area

Question 6

What are the features of a multi unit smooth muscle?

Answer 6

No gap junctions, therefore require a rich nerve supply.