Chapter 9, Problem 13RAC

Summary Introduction

Introduction:

Muscle contraction occurs when the neural signal reaches to the target muscle fiber. The muscle fiber consists of two main components that lead to the contraction of the muscle. The two components are:

1. Electrical component: The electrical component consists of the structures that respond to electrical signals. It includes the structure such as sarcolemma, T tubules, sarcoplasmic reticulum.
2. Mechanical component: The contractility property of muscle is achieved by the two structures of mechanical components that are myofibrils and myofilaments.

The myofibrils consist of bundles of protein filament known as myofilament. The actin and myosin are the two types of myofilament found in the myofibrils. The actin myofilament is made up of three proteins that are the G actin, tropomyosin, and the troponin whereas the myosin is made up of elongated myosin molecules.