SMOOTH \ UNSTRIPED \ INVOLUNTARY \ VISCERAL MUSCLE

Question 1

These muscle are present in ?

Answer 1

Present in internal organ except heart

Question 2

Give some feature of these bones ?

Answer 2

They never attach with bone.
Sarcolemma is absent.
Myofibrils don’t show dark and light band hence they are smooth.
Cell junction hold them together and they are bundled by connective tissue.

Question 3

What are the characteristics of its muscle fiber ?

Answer 3

Spindled shape, fusiform(tapered at the end), uninucleate and do not undergo fatigue.

Question 4

What are the two types of the smooth muscle ?

Answer 4

Single unit smooth muscle

Multi unit smooth muscle

Question 5

What are single unit smooth muscle ?

Answer 5

Muscle fiber are bundled together by gap junction.
Hence they contract and relax together as a single unit.

They are present in wall of the hollow organ like - posterior 2\3rd part of oesophagus , stomach , intestine , lungs , urinary bladder etc.

Question 6

What are multi unit smooth muscle ?

Answer 6

Muscle fiber are not bundled together.
Hence they contract and relax separately

They are present in

1. Muscle of the root hairs(arrector pili muscles)
2. Larger blood vessels