Download Muscle Tissue

PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
9
Muscles and
Muscle Tissue
Copyright © 2010 Pearson Education, Inc.
Figure 10.4 Anterior view of superficial
muscles of the body.
Copyright © 2010 Pearson Education, Inc.
Muscle Tissue
• Excitability
• Contractility
• Extensibility
• Elasticity
Copyright © 2010 Pearson Education, Inc.
Copyright © 2010 Pearson Education, Inc.
Table 9.3
Muscle Tissue
Copyright © 2010 Pearson Education, Inc.
.
Copyright © 2010 Pearson Education, Inc.
Figure 10.1 Patterns of fascicle arrangement in
muscles.
(a)
(b)
(f)
(a) Circular
(orbicularis oris)
(c)
(c) Parallel
(sartorius)
(d)
(e) Bipennate
(rectus femoris)
(f) Fusiform
(biceps brachii)
Copyright © 2010 Pearson Education, Inc.
(g)
(b) Convergent
(pectoralis major)
(e)
(d) Unipennate
(extensor
digitorum
longus)
(g) Multipennate
(deltoid)
Whole Muscle structure
Copyright © 2010 Pearson Education, Inc.
Epimysium
Bone Epimysium
Perimysium
Endomysium
Tendon
(b)
Perimysium Fascicle
(a)
Copyright © 2010 Pearson Education, Inc.
Muscle fiber
in middle of
a fascicle
Blood vessel
Fascicle
(wrapped by perimysium)
Endomysium
(between individual
muscle fibers)
Muscle fiber
Figure 9.1
Copyright © 2010 Pearson Education, Inc.
Table 9.1
Sarcolemma
Mitochondrion
Myofibril
Dark A band Light I band Nucleus
(b) Diagram of part of a muscle fiber showing the myofibrils. One
myofibril is extended afrom the cut end of the fiber.
Copyright © 2010 Pearson Education, Inc.
Thin (actin)
filament
Thick (myosin)
filament
Z disc
I band
H zone
A band
Sarcomere
Z disc
I band
M line
(c) Small part of one myofibril enlarged to show the myofilaments
responsible for the banding pattern. Each sarcomere extends from
one Z disc to the next.
Sarcomere
Z disc
M line
Z disc
Thin (actin)
filament
Elastic (titin)
filaments
Thick
(myosin)
filament
(d) Enlargement of one sarcomere (sectioned lengthwise). Notice the
myosin heads on the thick filaments.
Copyright © 2010 Pearson Education, Inc.
Figure 9.2c, d
Longitudinal section of filaments
within one sarcomere of a myofibril
Thick filament
Thin filament
In the center of the sarcomere, the thick
filaments lack myosin heads. Myosin heads
are present only in areas of myosin-actin overlap.
Thick filament
Thin filament
Each thick filament consists of many
A thin filament consists of two strands
myosin molecules whose heads protrude of actin subunits twisted into a helix
at opposite ends of the filament.
plus two types of regulatory proteins
(troponin and tropomyosin).
Portion of a thick filament
Portion of a thin filament
Myosin head
Tropomyosin
Troponin
Actin
Actin-binding sites
ATPbinding
site
Heads
Tail
Flexible hinge region
Myosin molecule
Copyright © 2010 Pearson Education, Inc.
Active sites
for myosin
attachment
Actin
subunits
Actin subunits
Figure 9.3
Z
Z
H
A
I
I
1 Fully relaxed sarcomere of a muscle fiber
Z
I
Z
A
I
2 Fully contracted sarcomere of a muscle fiber
Copyright © 2010 Pearson Education, Inc.
Figure 9.6
Thin filament
Actin
Ca2+
Myosin
cross bridge
ADP
Pi
Thick
filament
Myosin
Cross
bridge
formation.
1
ADP
ADP
Pi
Pi
ATP
hydrolysis
2 The power (working)
stroke.
4 Cocking of myosin head.
ATP
ATP
3 Cross bridge
detachment.
Copyright © 2010 Pearson Education, Inc.
Figure 9.12
Part of a skeletal
muscle fiber (cell)
Myofibril
I band
A band
I band
Z disc
H zone
Z disc
M line
Sarcolemma
Sarcolemma
Triad:
• T tubule
• Terminal
cisternae
of the SR (2)
Tubules of
the SR
Myofibrils
Mitochondria
Copyright © 2010 Pearson Education, Inc.
Figure 9.5
Contraction
• The generation of force
• Does not necessarily cause shortening of the
fiber – isometric contractions
• Shortening when tension generated by cross
bridges overcomes opposing forces
• Isotonic contractions when shortening occurs
as you lift a constant weight
Copyright © 2010 Pearson Education, Inc.
Action
potential (AP)
Myelinated axon
of motor neuron
Axon terminal of
neuromuscular
junction
Nucleus
Sarcolemma of
the muscle fiber
1 Action potential arrives at
axon terminal of motor neuron.
2 Voltage-gated Ca2+ channels
open and Ca2+ enters the axon
terminal.
Ca2+
Ca2+
Axon terminal
of motor neuron
Synaptic vesicle
containing ACh
Mitochondrion
Synaptic
cleft
Fusing synaptic
vesicles
Copyright © 2010 Pearson Education, Inc.
Figure 9.8
Myelinated axon
of motor neuron
Axon terminal of
neuromuscular
junction
Sarcolemma of
the muscle fiber
Action
potential (AP)
Nucleus
1 Action potential arrives at
axon terminal of motor neuron.
2 Voltage-gated
Ca2+
channels
open and Ca2+ enters the axon
terminal.
Ca2+
Ca2+
Axon terminal
of motor neuron
3 Ca2+ entry causes some
Fusing synaptic
vesicles
synaptic vesicles to release
their contents (acetylcholine)
by exocytosis.
ACh
4 Acetylcholine, a
neurotransmitter, diffuses across
the synaptic cleft and binds to
receptors in the sarcolemma.
Na+
K+
channels that allow simultaneous
passage of Na+ into the muscle
fiber and K+ out of the muscle
fiber.
by its enzymatic breakdown in
the synaptic cleft by
acetylcholinesterase.
Copyright © 2010 Pearson Education, Inc.
Junctional
folds of
sarcolemma
Sarcoplasm of
muscle fiber
5 ACh binding opens ion
6 ACh effects are terminated
Synaptic vesicle
containing ACh
Mitochondrion
Synaptic
cleft
Ach–
Degraded ACh
Na+
Acetylcholinesterase
Postsynaptic membrane
ion channel opens;
ions pass.
Postsynaptic membrane
ion channel closed;
ions cannot pass.
K+
Figure 9.8
Setting the stage
Axon terminal
of motor neuron
Action potential
Synaptic cleft
is generated
ACh
Sarcolemma
Terminal cisterna of SR
Muscle fiber Ca2+
Triad
One sarcomere
Copyright © 2010 Pearson Education, Inc.
Figure 9.11, step 1
Steps in E-C Coupling:
Sarcolemma
Voltage-sensitive
tubule protein
T tubule
1 Action potential is propagated along
the sarcolemma and down the T tubules.
Ca2+
release
channel
2 Calcium ions are released.
Terminal
cisterna
of SR
Ca2+
Actin
Troponin
Ca2+
Tropomyosin
blocking active sites
Myosin
3 Calcium binds to troponin and
removes the blocking action of
tropomyosin.
Active sites exposed and
ready for myosin binding
4 Contraction begins
Myosin
cross
bridge
The aftermath
Copyright © 2010 Pearson Education, Inc.
Figure 9.11, step 2
Thin filament
Actin
Ca2+
Myosin
cross bridge
ADP
Pi
Thick
filament
Myosin
Cross
bridge
formation.
1
ADP
ADP
Pi
Pi
ATP
hydrolysis
2 The power (working)
stroke.
4 Cocking of myosin head.
ATP
ATP
3 Cross bridge
detachment.
Copyright © 2010 Pearson Education, Inc.
Figure 9.12
Spinal cord
Motor Motor
unit 1 unit 2
Axon terminals at
neuromuscular junctions
Nerve
Motor neuron
cell body
Motor
Muscle
neuron
axon
Muscle
fibers
Axons of motor neurons extend from the spinal cord to the
muscle. There each axon divides into a number of axon
terminals that form neuromuscular junctions with muscle
fibers scattered throughout the muscle.
Copyright © 2010 Pearson Education, Inc.
Figure 9.13a
Sensory Receptors in Muscles
• Muscle spindle sensory receptor to
detect muscle stretch
and contraction
From:
http://www.partnersinfitness.com/science.htm
Copyright © 2010 Pearson Education, Inc.
Muscle Fiber Types
Copyright © 2010 Pearson Education, Inc.