Question

Which of the following is a characteristic feature of the striated muscle?
A) It has repeating sarcomeres
B) They are spindle-shaped
C) It has an intercalated disc
D) None of these

Answer 1

Hint: Muscles are the group of tissues that produces force by the contraction. They contain fibres of muscle cells that are bundled together and are surrounded by thick protective tissue. There are three types of muscles-
- Smooth muscle- These are spindle-shaped non-striated muscles.
- Striated or skeletal muscles- It is a voluntary muscle attached to the skeletal system.
- Cardiac muscles- It is an involuntary striated muscle that comprises the heart walls.

Complete answer:
Let us look at the characteristics of striated muscles:
- As the name suggests, these are striated muscle fibres i.e. they show light and dark bands when seen under the microscope. These are also called skeletal muscles.
- Skeletal muscles are long cylindrical fibres consisting of repeating units called a sarcomere.
- They are multinucleated, that is they have more than one nucleus.
- Each muscle fibre is lined by a plasma membrane called sarcolemma. It encloses sarcoplasm which has the endoplasmic reticulum called the sarcoplasmic reticulum.
- These are attached to the skeletal system and help in body movement such as breathing, writing, walking etc.
- Striated muscles are responsible for maintaining body posture.
- They also protect internal organs and tissues from any injury.

The figure represents the structure of the striated muscle.

We will also look at the given options-
Option B) They are spindle-shaped: This option is incorrect as smooth muscles are spindle-shaped. Striated muscles are cylindrical and not spindle-shaped.
Option C) It has an intercalated disc: This option incorrect as we have seen striated muscles do not have an intercalated disc. Intercalated discs are found in cardiac muscles.

Hence, the correct answer is option ‘A’ i.e, It has repeating sarcomere.

Note: Following are the properties of skeletal muscle-
Excitability: ability to respond to stimulus
Contractibility: the ability to contract in response to stimulus
Extensibility: ability to extend when stretched
Elasticity: ability to return to original structure when released.