Transcript Muscle Tissue - El Camino College

PowerPoint® Lecture Slides
prepared by Leslie Hendon,
University of Alabama,
Birmingham
10
HUMAN
ANATOMY
PART 2
Muscle Tissue
fifth edition
MARIEB | MALLATT | WILHELM
Copyright © 2008 Pearson Education, Inc.,
publishing as Benjamin Cummings
Types of Skeletal Muscle Fibers

Skeletal muscle fibers are categorized according
to
 How they manufacture energy (ATP)
 How quickly they contract
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Types of Skeletal Muscle Fibers

Skeletal muscle fibers
 Are divided into 3 classes
 Slow oxidative fibers (Type I)
 Red Slow twitch
 Fast glycolytic fibers (Type IIx)
 White fast-twitch
 Fast oxidative fibers (Type IIa)
 Intermediate fibers
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Types of Skeletal Muscle Fibers

Slow oxidative fibers (Type I)
 Red color due to abundant myoglobin
 Obtain energy from aerobic metabolic reactions
 Contain a large number of mitochondria
 Richly supplied with capillaries
 Contract slowly and resistant to fatigue
 Fibers are small in diameter
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Types of Skeletal Muscle Fibers

Fast glycolytic fibers (Type IIx)
 Contain little myoglobin and few mitochondria
 About twice the diameter of slow-oxidative fibers
 Contain more myofilaments and generate more
power
 Depend on anaerobic pathways
 Contract rapidly and tire quickly
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Types of Skeletal Muscle Fibers

Fast oxidative fibers (Type IIa)
 Have an intermediate diameter
 Contract quickly like fast glycolytic fibers
 Are oxygen-dependent
 Have high myoglobin content and rich supply of
capillaries
 Somewhat fatigue-resistant
 More powerful than slow oxidative fibers
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Table 10.2 (1 of 3)
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Table 10.2 (2 of 3)
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Table 10.2 (3 of 3)
Disorders of Muscle Tissue

Muscle tissues experience few disorders
 Heart muscle is the exception
 Skeletal muscle
 Remarkably resistant to infection
 Smooth muscle
 Problems stem from external irritants
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders of Muscle Tissue

Muscular dystrophy
 A group of inherited muscle destroying disease
 Affected muscles enlarge with fat and connective
tissue
 Muscles degenerate
 Types of muscular dystrophy
 Duchenne muscular dystrophy
 Myotonic dystrophy
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Disorders of Muscle Tissue

Myofascial pain syndrome
 Pain is caused by tightened bands of muscle fibers

Fibromyalgia
 A mysterious chronic-pain syndrome
 Affects mostly women
 Symptoms – fatigue, sleep abnormalities, severe
musculoskeletal pain, and headache
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Muscle Tissue Throughout Life

Muscle tissue develops from myoblasts
 Myoblasts fuse to form skeletal muscle fibers
 Skeletal muscles contract by the seventh week of
development
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Muscle Tissue Throughout Life

Cardiac muscle
 Pumps blood three weeks after fertilization

Satellite cells
 Surround skeletal muscle fibers
 Resemble undifferentiated myoblasts
 Fuse into existing muscle fibers to help them grow
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
Muscle Tissue Throughout Life

With increased age
 Amount of connective tissue increases in muscles
 Number of muscle fibers decreases

Loss of muscle mass with aging
 Decrease in muscular strength by 50% by age 80
 Sarcopenia – muscle wasting
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings