Chapter 9, Problem 1RAC

Which of these is true of skeletal muscle?
a. spindle-shaped cells
b. under involuntary control
c. many peripherally located nuclei per muscle fiber
d. forms the walls of hollow internal organs
e. may be autorhythmic

Summary Introduction

Introduction:

The muscle system consists of various types of muscle that plays different types of functions. There are three kinds of muscle. They are:

1. Smooth muscle
2. Skeletal muscle
3. Cardiac muscle

Skeletal muscle is striated in appearance and possesses multiple nuclei that lie at the periphery position. They are voluntary muscle and plays a key role in body movement.

Answer to Problem 1RAC

The correct answer is option (c) many peripherally located nuclei per muscle fiber.

Explanation of Solution

Explanation/justification for the correct answer:

Option (c) many peripherally located nuclei per muscle fiber. Skeletal muscle possesses many periphery located nuclei as they develop from the fusion of many myoblast cells. Each myoblast has its own nucleus, so its fusion product which is skeletal muscle fiber has numerous nuclei. So, this is the correct option.

Explanation for incorrect answer:

Option (a) spindle-shaped. Smooth muscle appears as spindle-shaped cell. Skeletal muscle possesses a cylindrical shape. So, this is the incorrect option.

Option (b) under voluntary control. Skeletal muscle is under voluntary control. Smooth muscle and cardiac muscle are under involuntary control. So, this is the incorrect option.

Option (d) forms the walls of hollow internal organ. Smooth muscle is present at the walls of hollow internal organs. Skeletal muscle is attached to the bones. So, this is the incorrect option.

Option (e) may be autorhythmic. Smooth and cardiac muscle are autorhythmic, making this option unsuitable.