Download Chapter 6 Notes (muscle Tissue)

Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 6
Muscle Tissue
Pgs 162-175 and pg 194
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
What do you THINK these words mean?
• Excitability
• Contractility
• Extensibility
• Elasticity
4 characteristics of muscle tissue:
Ability of muscle to…
 Excitability - be stimulated by a motor neuron
 Contractility
- shorten when stimulated
 Extensibility
- relax when contraction is done
 Elasticity
- continually contract and relax over and
over and not change shape
3 types of
Muscle
Skeletal
Tissue
Smooth
Cardiac
Skeletal Muscle Characteristics
 Attached (by tendons) to bones
 Multinucleate, Parallel fibers,
Striated
 Movement of skeleton
 Voluntary
 Contracts quickly
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Slide 6.3
Smooth Muscle Characteristics
 Walls of hollow organs
(ex. bladder, vessels,
digestive)
Figure 6.2a
 Spindle-shaped, Single
nucleus, No striations
 Movement of materials in
organs (ex. peristalsis)
 Involuntary
 Rhythmic, self-exciting,
very slow
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.6
Cardiac Muscle Characteristics
 Only in heart
 Striations, single
nucleus, intercalated
discs, branching fibers
 Pumps blood
 Involuntary
 Self-exciting, rhythmic,
contracts as a unit
Figure 6.2b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.7
Vocabulary…You already know it 
___ Can consciously control the muscle A. Striations
___ muscle controlled subconsciously
___ contracts with a pattern
___ appears striped as a result of
filaments in the muscle tissue, needed
for strength of contraction
___ one muscle fiber is stimulated by a
neuron which then stimulates other
muscle fibers of the same type
B. Self-Exciting
C. Involuntary
D. Voluntary
E. Rythmic
Definitions
Voluntary- CAN consciously control the muscle
Involuntary- controlled subconsciously
Self exciting- one muscle fiber is stimulated by a
neuron which then stimulates other muscle fibers of
the same type
Rhythmic- contracts with a pattern
Striations- appears striped as a result of filaments in
the muscle tissue, needed for strength of contraction
Skeletal Muscle functions
 movement
 posture
 stabilize joints
 produce heat
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.8
Histology of skeletal muscle
 1. Connective tissue:
 Endomysium – wraps indiv.
Muscle fibers
 Perimysium – wraps fascicle
(which is a bundle of muscle fibers)
 Epimysium – sheaths entire
muscle (DF)
 Fascia
 Tendon/bone
 2. Skeletal muscle
tissue
 3. Nervous tissue:
motor neurons
Figure 6.1
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Slide 6.4a
POPORTUNITY!!!!! …. You’re Welcome!!!
1. ___ voluntary
A.
Ability to shorten when stimulated
2. ___ involuntary
B.
Consciously controlled
3. ___ striations
C.
Ability to relax when not stimulated
4. ___ excitability
D.
Contains intercalated disks
5. ___ contractility
E.
Subconsciously controlled
6. ___ extensibility
F.
Attached to bones
7. ___Cardiac Muscle Tissue
G.
Line organs of digestive system
8. ___ Skeletal Muscle Tissue
H.
Ability to be stimulated by a motor neuron
9. ___ Smooth Muscle Tissue
I.
Connective tissue surrounding muscle fibers
10. ___ Epimysium
J.
Connective tissue surrounding entire muscle
K.
Stripes visible under microscope due to filament
structure
L.
Ability to contract and relax repeatedly without
losing shape
Macroscopic anatomy of skeletal
muscles (largest to smallest)
3. myofiber
1. Skeletal muscle
2.
4.
5. myofilament
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Slide 6.8
Put these structures in order largest to smallest!
• Myofilaments
(actin & myosin)
• Skeletal muscle
• Fascicle
• Myofiber
• Myofibrils
Macroscopic anatomy of skeletal muscles
(largest to smallest)
Skeletal muscle- organ, made of fascicles with connective tissue
Fascicle- bundle of myofibers with connective tissue
Myofiber- muscle fiber or muscle cell; contains cytoplasm,
plasma membrane, and nuclei, made of myofibrils
Myofibrils- contractile unit of a myofiber, made of myofilaments
Myofilaments- sliding filaments made of proteins called actin
and myosin
Macroscopic anatomy of skeletal
muscles (largest to smallest)
3. myofiber
1. Skeletal muscle
2.
4.
5. myofilament
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Slide 6.8
Myofibers
-myofiber
Figure 6.1
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Slide 6.4a
Microscopic Anatomy of myofiber
 Sarcolemma –plasma membrane
 Sarcoplasm- cytoplasm
 Sarcoplasmic reticulum (SR) – specialized
smooth E.R.  job is to store and release Ca+
 Myofibrils- organelle in myofiber, have light and dark
bands
Figure 6.3a
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Slide 6.9b
Microscopic Anatomy of Myofiber
 Sarcomere - Contractile unit, “working unit”
of myofibril
Parts of Myofibrils
Figure 6.3b
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Slide 6.10b
Microscopic Anatomy of Myofiber
 Myofibril- Bundle of myofilaments
 Z lines (discs)- separate sarcomeres
 A band =
dark band
Figure 6.3b
 I band =
light band
Slide 6.10a
Microscopic Anatomy of Myofiber
 Myofilaments- found in myofibrils, 2 types:
1. Thin filaments- made of actin protein
2. Thick filaments- made of myosin protein
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 6.3c
Slide 6.11a
Microscopic Anatomy of Skeletal
Muscle
Cross bridges- part of myosin filaments
(eventually attach to actin filaments)
Figure 6.3d
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.12a
Put these structures in order largest to smallest!
• Myofilaments
(actin & myosin)
• Skeletal muscle
• Fascicle
• Myofiber
• Myofibrils
Skeletal Muscle Activity
 FYI- Skeletal
muscles are
stimulated by a
motor neuron
 Motor unit- One
motor neuron and
all the myofibers it
stimulates
Figure 6.4a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.14
1. Using the word bank, label the diagram
1
Perimysium
3 (wraps #2)
Epimysium
Tendon
Bone
Fascicle
4 (wraps bundle)
5 (wraps)
Endomysium
Myofiber
6 (entire structure)
Myofibril
Skeletal Muscle
7
2. Which structure represents a muscle
CELL.
2
8
9
(bundle…not
covering)
WARM UP
Review Synapses (neuron to neuron junctions)
Presynaptic neuron
dendrites
Postsynaptic neuron
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Slide 6.27
Skeletal Muscle Activity
Figure 6.5b
 Neuromuscular
junction – junction
of a motor neuron
and myofiber
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Slide 6.15a
Neuromuscular Junction
Motor neuron: stimulates a myofiber and causes a response
1. Dendrites
2. Cell body
3. Axon
4. Axon terminals
5. Synaptic end bulbs
Axon terminal
Cell body
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Slide 6.15a
Neuromuscular Junction
Motor neuron
6. Synaptic vesicles
7. Neurotransmitters (ACh)
in vesicles
8. Synaptic gap/cleft
Synaptic end bulb of
Slide 6.15b
Figure 6.5b
Neuromuscular junction
Myofiber
Synaptic end bulb of
 Neurotransmitter
receptors on
sarcolemma of
motor end plate
Figure 6.5b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.15b
Skeletal Muscle Activity
http://www.dnatube.com/video/1950/MuscularSystem-Neuromuscular-Junction
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.15a
Impulse from Motor Neuron to Myofiber
1. Dendrites of motor neuron are stimulated causing
polariz., depolariz., repolariz. (action potential),
Na+/K+ pump
2. Action potential causes the impulse to travel from
dendrites, cell body, axon, axon terminals,
synaptic end bulb, synaptic vesicles of a motor
neuron
3. Synaptic vesicles release neurotransmitters
(ACh)
4. ACh travels across synaptic gap to ACh receptors
on the sarcolemma of myofiber’s motor end plate
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.16a
Impulse in myofiber
5. Sarcolemma of myofiber becomes permeable to
Na+
6. Na+ enters sarcolemma & generates an action
potential in the myofiber
7. Acetylcholinesterase (AChesterase) degrades the
Ach in the receptor sites after stimulus is received
8. Action potential travels across surface of
sarcolemma to S.R. (modified smooth E.R)
9. S.R. releases Ca+ which stimulates sliding filament
theory
Slide 6.16b
Sliding filament theory
http://www.dnatube.com/video/1952/Muscular-System-SlidingFilament-Theory-2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.16b
Sliding Filament Theory of myofiber
1. Ca+ travels from S.R.
through sarcoplasm to
myofibril
2. Ca+ causes binding
sites (for myosin’s crossbridge
“heads”) on actin to open
3. Myosin (Thick filament)
heads attach to
myosin binding sites
on actin filaments
 Myosin crossbridges “grab” onto
open binding sites
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 6.7
Slide 6.17a
The Sliding Filament Theory of
Muscle Contraction
 When myosin
cross-bridges pull
on binding sites, it
causes sliding of
the actin
myofilament along
the myosin
myofilament
 Sarcomeres of
myofibril (& all of
myofiber & part of
muscle) shorten
and contract
Slide 6.17b
Energy for Muscle Contraction
 ATP released from
mitochondria of myofibers
during cellular respiration
causes cross-bridges to
detach
 Myosin cross-bridges then
reattach to the next binding
site on actin myofilament
and start over again
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Slide 6.17a
The Sliding Filament Theory
(on actin)
Figure 6.8
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Slide 6.18
Energy for Muscle Contraction
Creatine phosphate
turns into creatine to
make ATP ( only if
oxygen is present due to
RBC’s)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 6.10a
Slide 6.24
Poportunity (The # to beat is 6)
2 (zone)
1
6. One contractile unit of a muscle
is called a ________.
7. The correct name for a muscle
cell is a ___________.
4
(band)
8. What structure (inside a muscle cell) is responsible
for releasing calcium for muscle contraction?
1
3
(band)
5 (very center!)
Muscle Fatigue and Oxygen Debt
 RBC’s use hemoglobin to carry the needed
oxygen
 When a muscle is fatigued due to lack of
ATP, it is unable to contract because of
oxygen debt (too much oxygen used up)
 O2 must be “repaid” to muscle tissue …so you
breathe heavier to “try” to get more!
No O2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 6.27
All or none
 “All or None”- all of motor unit contracts
or none of it does
 But not all myofibers in a skeletal
muscle must be stimulated at same
time
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Slide 6.19
Imbalances (disorders)
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Slide 6.29
Tetanus
 Continued painful contraction of muscles = no
relaxation
 Is infection of the nervous system with the potentially
deadly bacteria Clostridium tetani (C. tetani)
 Enters body through open wound
Figure 6.9a, b
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Slide 6.20b
Muscle Cramps
Muscle cramps (due to
muscle fatigue)
 From Lactic Acid Fermentation
 break down glucose without
O2 (anaerobic)
 Produces a little ATP for
you…but lactic acid as an
unwanted byproduct
 lactic acid builds up and
causes muscle fatigue &
cramping
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Figure 6.10b
Slide 6.26a
Botulism
 Food poisoning in which bacterial TOXIN
causes paralysis
Caused by
Clostridium
botulinum
bacteria
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Bacteria may enter the
body through wounds, or
they may live in
improperly canned or
preserved food.
Slide 6.29
Botox
Botox® is a trade
name for botulinum
toxin A
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Slide 6.29
Review these from ch 6 muscular system
Charley horse
Atrophy
Hypertrophy
MD
Anabolic steroids and Creatine
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Slide 6.20a
Effects of drugs on N.M. junctions
 Stimulants
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depressants
Slide 6.27