Skeletal Muscle Introduction and Contraction

Skeletal Muscle

Introduction and Contraction

Jennifer Carbrey Ph.D.

Department of Cell Biology

Skeletal Muscle

Muscle types

General principles

Skeletal muscle structure

Mechanism of contraction

Tension

Skeletal muscle metabolism

Fiber types

Recruitment

Muscle Types

Striated skeletal muscle fiber

- large, multinucleated cells

- Somatic Nervous System

Smooth muscle cell

- small, single nucleated cells

- Autonomic Nervous System

Striated cardiac muscle fiber

- small, contain 1-2 nuclei,

- connected by specialized junctions

- Autonomic Nervous System

Shared Principles

? The sliding filament mechanism, in which myosin

filaments bind to and move actin filaments, is the

basis for shortening of stimulated muscle.

? Myosin and actin interactions are regulated by

calcium ions.

? Changes in the membrane potential lead to

contraction; called E-C Coupling (excitationcontraction coupling).

Skeletal Muscle

skeletal

muscle

muscle

cell or fiber

myofibril

sarcomere

Each muscle fiber has many myofibrils, whose

number determines the force generating capability

of the fiber.

Top image by image by OCAL (modified), , public domain , middle and bottom image by Rama (modified),

, Creative Commons Attribution-Share Alike 3.0 Unported license

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