Chapter 32, Problem 36A

Summary Introduction

To explain:

That skeletal muscles can contract but not lengthen from the structure of muscle fiber.

Introduction:

Skeletal, cardiac and smooth muscles are the three types of vertebrate muscle tissue.

Explanation of Solution

Skeletal muscle is a striated muscle that is attached to bones by bundles of collagen fibers called tendons. Muscle can be stretched to an extent with the opposite tension that opposes lengthening. It happens because of the presence of elastic proteins and extracellular matrix. Skeletal muscle contractions consist of a single motor neuron that causes the fibers to contract. The protein inside the skeletal muscle fiber slide past each other and gets contracted.

Conclusion

A skeletal muscle cell is a voluntary muscle cell that got elastic proteins within an extracellular matrix that can be contracted.