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Chapter 10
Muscle Tissue
Lecture Presentation by
Lee Ann Frederick
University of Texas at Arlington
(heavily modified by GJC)
© 2015 Pearson Education, Inc.
An Introduction to Muscle Tissue
• Review (from Chapter 4):
• What are the 3 types of muscle tissue and what
are the differences among them?
10-1 Functions of Skeletal Muscle Tissue
• Functions of Skeletal Muscle Tissue
SKELETAL MUSCLE (organ)
FASCICLE (bundle of fibers)
MUSCLE FIBER (cell)
10th Martini, Figure 10-1
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Figure 10-2a The Formation of a Multinucleate Skeletal Muscle Fiber.
Muscle fibers develop through the fusion of
embryonic cells called myoblasts.
Myoblast
Myosatellite cell
Immature
muscle
fiber
Myosatellite cell
Mature muscle fiber
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Why (some) muscles look striated (striped)
http://en.wikipedia.org/wiki/Sarcomere
Figure 10-5 Sarcomere Structure, Superficial and Cross-Sectional Views.
Sarcomere
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How muscles contract: a multi-step overview
1.
A motor neuron transmits A-C-h;
A-C-h opens sodium channels;
2.
Sodium causes depolarization;
Depolarization triggers the SR….
3.
And the SR releases calcium ions,
And the calcium ions bind to troponin,
4.
And troponin gives tropomyosin a tug,
And tropomyosin accommodates myosin,
5.
And myosin pulls on the actin, child --
The myosin pulls on the actin.
http://www.noteflight.com/scores/view/5a4cd6a620007ba4b24b5e15d5c58196e238927a
The neuromuscular junction (Figure 10-9)
Arriving action
potential
Na+
1
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2
Na+
ACh
3 receptor
Na+
Figure 10-10 Excitation-Contraction Coupling.
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[Space to take notes on previous figure]
The contraction cycle (Figure 10-11)
1
2
white ovals = ADP + Pi (breakdown products of ATP)
3
The contraction cycle (Figure 10-11)
4
5
yellow ovals = ATP
6
Where in the contraction cycle will a “fresh”
dead person’s muscles stop?
Figure 10-12 Shortening during a Contraction.
a When both ends are free to move, the ends of a contracting
muscle fiber move toward the center of the muscle fiber.
b When only one end of a myofibril is fixed in position,
the free end is pulled toward the fixed end.
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How does a muscle contraction END?
The effect of
sarcomere length
on muscle force
(like Figure 10-14)
Figure: Principles of Physiology by Cindy L. Stanfield
Figure 10-17a The Arrangement and Activity of Motor Units in a Skeletal Muscle.
Axons of
motor neurons
Motor
nerve
KEY
Motor unit 1
Motor unit 2
Motor unit 3
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SPINAL CORD
Muscle fibers
How do we adjust a muscle’s level of force?
(2 basic ways)
Figure 10-18 Concentric, Eccentric, and Isometric Contractions.
Tendon
2 kg
2 kg
6 kg
6 kg
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Why are eccentric contractions clinically
interesting?
Figure 10-20 Muscle Metabolism.
Fatty acids
O2
Glucose
Glycogen
ADP
ATP
Pyruvate
ADP
ATP
CO2
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To myofibrils to support
muscle contraction
3 key components of muscle
Component
Contractile
proteins
(actin/myosin)
Sarcoplasmic
Reticulum (SR)
Mitochondria
Function
Effect of
Effect of
strength training endurance
training
Changes in SR? Look at evolution…
P.J. Schaeffer et
al., Journal of
Experimental
Biology (1996)