9.02 Skeletal Muscle Fibers and Contraction

• Introduction
• Learn
• Try It
• Task
• Unit Vocab
• Course Vocab

Introduction

Have you ever heard of Botox?

Botox is a drug made from a neurotoxin produced by the bacterium Clostridium botulinum called botulinum toxin. It is used medically to treat certain muscular conditions and cosmetically to remove wrinkles by temporarily paralyzing muscles.

So, how does this bacteria’s toxin paralyze muscles? In order for a muscle to contract, it needs a specific neurotransmitter (acetylcholine) to stimulate it. Botox blocks the release of this neurotransmitter so the stimulus for muscle contraction never happens. Because of this, paralysis of the muscle occurs.

Botulism food poisoning is also caused by the same bacterium and can be fatal through the paralysis of respiratory muscles.

In this unit, we will learn about the microscopic anatomy of a muscle, the physiology of muscle contraction, and about a genetic disease affecting muscle contraction called malignant hyperthermia.

Lesson Objectives

Following successful completion of this lesson, students will be able to... Discuss the structure and function of myofilaments. Analyze and discuss the major events of muscle contraction and relaxation. Enduring Understandings The muscular system plays a major role in movement, support, and homeostasis of the human organism. The above objectives correspond with the Alabama Course of Study: Anatomy and Physiology standards: 5