Chapter 12.3, Problem 28CC

(a)

Summary Introduction

To determine: The comparison between the skeletal and smooth muscle contraction with respect to signal for crossbridge activation

Introduction: The skeletal muscles perform the function of attaching bones with the skin. The skeletal muscles perform voluntary muscular movements. The smooth muscles are present along the walls of the internal organs. They are involved in performing the involuntary muscular movements.

(b)

Summary Introduction

To compare: The skeletal and smooth muscle contraction on the basis of the source(s) of calcium required for Ca²⁺ signal.

Introduction: Calcium plays an important role in facilitating contraction by reacting with regulatory proteins. The absence of calcium prevents the interaction of actin and filament. The smooth muscles contain the same contractile elements as smooth muscles. They both contain actin and myosin that interact through the crossbridge.

(c)

Summary Introduction

To determine: The comparison between the skeletal and smooth muscle contraction on the basis of signal that releases Ca²⁺ from the sarcoplasmic reticulum.

Introduction: The Ca²⁺ plays an important role in initiating contraction of the muscles. The sarcoplasmic reticulum provides a source of Ca²⁺ for both the skeletal muscles and the smooth muscles. In addition, extracellular fluid also provides the source of Ca²⁺ for smooth muscles.