CHAPTER 10Muscular Tissue

Copyright © 2007 by John Wiley & Sons, Inc.

Principles ofHuman Anatomy

Eleventh EditionGerard J. Tortora

&

Mark T. Nielsen

Motion Locomotion Localized movement Movement of substances w/in the body

Stabilization Posture Sphincters

Thermogenesis Heat is a by-product of muscle contraction ~85% of all body heat from muscle contraction

Excitability Membrane potential/action potentials

Conductivity Propagation of action potentials

Contractility Ability to shorten & thicken (contract)

Extensibility Can be stretched

Elasticity Tends to return to its original shape after

stretching

Motor UnitsMotor Units Nerves that stimulate skeletal muscle are

called: Motor Neurons. A Motor Unit is defined as a motor neuron

and all the myofibers it innervates. Small motor units control precise, fine

movements. Eg. eye or voicebox

Large motor units control powerful, gross movements. Eg. biceps or gastrocnemius

Sliding Filament TheorySliding Filament Theory

The muscle cells is stimulated by the neuron.

Ca++ is released from the SR into the sarcoplasm.

Actin & Myosin filaments interact.Myosin pulls the thin filaments toward

the center – shortening the sarcomere.

Drug ActionsDrug Actions

BoTox (Botulinum Toxin) from the organism: clostridium botulinumBlocks exocytosis of synaptic vesicles

Curare is a poisonous resin obtained from specific types of South American trees. It is used as the poison on blow darts/arrows.Binds to and blocks Ach receptors

RelaxationRelaxation

Acetylcholinesterase (ACh E)Found in the synaptic cleftBreaks down Ach – ends stimulation by

motor neuron Ca++ is pumped back into the

sarcoplasmic reticulum (removed from the sarcoplasm)Actin and Myosin can no longer interact

Cocktail ConversationCocktail Conversation

Rigor MortisATP levels decline after deathATP required to break the actin – myosin

bondMyasthenia GravisMuscle weakness due to lack of ACh

receptorsCaused by antibody production against

the ACh receptors

Cardiac MuscleCardiac Muscle 10_table_0210_table_02

Learning ObjectivesLearning Objectives

Functions of muscle tissue Characteristics of muscle tissue Discuss the deep fascia layers in muscle Discuss fascicles Define sarcomeres and describe the

different bands, lines & zones found within them

Learning ObjectivesLearning Objectives Define and note the importance of the following

terms: sarcolemma, sarcoplasmic reticulum transverse tubules, terminal cisterna motor end plate, synaptic cleft, synaptic vesicles

Understand how nerves stimulate skeletal muscles to contract through their interaction at the NMJ

Understand the sliding filament theory of muscle contraction and the role of Ca++

Learning ObjectivesLearning Objectives

Understand motor units and the significance of their size

Discuss the structure of cardiac muscle and how it differs from skeletal muscle

Discuss smooth muscle and how it differs from both cardiac and skeletal muscle

Demonstrate and understanding of table 10.2 (general features of the 3 muscle types)