1. Small intestine (a) Skeletal Cardiac Smooth Functions:
Figure 9.26a Arrangement of smooth muscle in the walls of hollow organs.
Skeletal
Cardiac
Smooth
Small intestine
(a)
Functions:
Support (jts. & organs)
Movement
Heat Production (75%)
Pg 306

2. Figure 9.2b Microscopic anatomy of a skeletal muscle fiber.
Muscle fiber = Muscle cell
Long
Densely packed
Nucleus
Light I band
Dark A band
Sarcolemma
Mitochondrion
(b) Diagram of part of a muscle fiber showing the myofibrils. One myofibril is extended afrom the cut end of the fiber.
Myofibril
cytoskeleton
Pg 280

3. Figure 4.10a Muscle tissues.
(a) Skeletal muscle
Description: Long, cylindrical,
multinucleate cells; obvious
striations.
Striations
Function: Voluntary movement;
locomotion; manipulation of the
environment; facial expression;
voluntary control.
Nuclei
Location: In skeletal muscles
attached to bones or
occasionally to skin.
Part of
muscle
fiber (cell)
Photomicrograph: Skeletal muscle (approx. 460x).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.
-nicotonic receptors
-Myoglobin
Pg 138

4. Figure 4.10b Muscle tissues.
(b) Cardiac muscle
Description: Branching, short
striated, generally uninucleate
cells that interdigitate at
specialized junctions
(intercalated discs).
Striations
Lots of mitochondria
Intercalated
discs
Function: As it contracts, it
propels blood into the
circulation; involuntary control.
Location: The walls of the
heart.
Nucleus
Photomicrograph: Cardiac muscle (500X);
notice the striations, branching of cells, and
the intercalated discs.
-Muscarinic & Beta receptors
-Lots of myoglobin & good blood supply
Pg 139

5. Figure 4.10c Muscle tissues.
(c) Smooth muscle
Description: Spindle-shaped
cells with central nuclei; no
striations; cells arranged
closely to form sheets.
Smooth
muscle
cell
Function: Propels substances
or objects (foodstuffs, urine,
a baby) along internal passage-
ways; involuntary control.
Location: Mostly in the walls
of hollow organs.
Nuclei
Photomicrograph: Sheet of smooth muscle (200x).
-Muscarinic & alpha or beta receptors
-No myoglobin
Pg 139

6. 307

7. Myofilaments (sarcomeres)
Figure 9.5 Relationship of the sarcoplasmic reticulum and T tubules to myofibrils of skeletal muscle.
Myofilaments (sarcomeres)
Myofibril
Myofibrils
Sarcotubular Sys.
Tubules of
the SR
Sarcolemma
A.P.
Mitochondria
I band
A band
H zone
Z disc
Part of a skeletal
muscle fiber (cell) •
T tubule
Sarcoplasmic
Reticulum (Ca)
M line
Pg 284

8. Figure 9.2b Microscopic anatomy of a skeletal muscle fiber.
Nucleus
Light I band
Dark A band
Sarcolemma
Mitochondrion
(b) Diagram of part of a muscle fiber showing the myofibrils. One myofibril is extended afrom the cut end of the fiber.
Myofibril
Pg 280

9. Figure 9.2c Microscopic anatomy of a skeletal muscle fiber.
I band
A band
Sarcomere
H zone
Thin (actin)
filament
Thick (myosin)
Z disc
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.
Pg 280

10. Figure 9.3 Composition of thick and thin filaments.
Flexible hinge region
Tail
Tropomyosin
Troponin
Actin
Myosin head
ATP-
binding
site
Heads
Active sites
for myosin
attachment
subunits
Actin-binding sites
Thick filament
Each thick filament consists of many
myosin molecules whose heads protrude
at opposite ends of the filament.
Thin filament
A thin filament consists of two strands
of actin subunits twisted into a helix
plus two types of regulatory proteins
(troponin and tropomyosin).
In the center of the sarcomere, the thick
filaments lack myosin heads. Myosin heads
are present only in areas of myosin-actin overlap.
Longitudinal section of filaments
within one sarcomere of a myofibril
Portion of a thick filament
Portion of a thin filament
Myosin molecule
Actin subunits
200
ATPase
Pg 282

12. Figure 9.2d Microscopic anatomy of a skeletal muscle fiber.
Z disc
M line
Sarcomere
Thin (actin)
filament
Thick
(myosin)
Elastic (titin)
filaments
(d)
Enlargement of one sarcomere (sectioned lengthwise). Notice the
myosin heads on the thick filaments.
pg 280

13. All or nothing 4 100 fibers Polio Pg 294
Figure A motor unit consists of a motor neuron and all the muscle fibers it innervates.
Spinal cord
Motor neuron
cell body
Muscle
Branching axon
to motor unit
Nerve
Motor
unit 1
unit 2
fibers
axon
Axon terminals at
neuromuscular junctions
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.
terminals form
neuromuscular
junctions, one per
muscle fiber (photo-
micrograph 330x).
(b)
(a)
All or nothing
Polio
fibers
Pg 294

14. (wrapped by perimysium) Epimysium
Figure 9.1a Connective tissue sheaths of skeletal muscle: epimysium, perimysium, and endomysium.
Bone
Perimysium
Endomysium
(between individual
muscle fibers)
Muscle fiber
Fascicle
(wrapped by perimysium)
Epimysium
Tendon
Dense Reg.
Blood vessel
Tendon vs. Aponeurosis
Pg 279

15. Figure 10.6 Lateral view of muscles of the scalp, face, and neck.
Epicranius
Galea
aponeurotica
Corrugator
supercilii
Frontal belly
Orbicularis oculi
Occipital
belly
Levator labii
superioris
Zygomaticus
minor and major
Temporalis
Buccinator
Masseter
Risorius
Sternocleidomastoid
Orbicularis oris
Trapezius
Mentalis
Splenius capitis
Depressor
labii inferioris
Depressor anguli oris
Platysma
Pg 331

16. Long head Biceps brachii Short head O = origin I = insertion (c)
Figure 10.14c Muscles crossing the shoulder and elbow joint, causing movements of the arm and forearm, respectively.
Long head
Biceps
brachii
Short head
O = origin
I = insertion
Extrinsic vs. Intrinsic
Prime mover
Synergist
Antagonist
(c)
Pg 352

17. Figure 9.8 Events at the Neuromuscular Junction
Nucleus
Action
potential (AP)
Myelinated axon
of motor neuron
Axon terminal of
neuromuscular
junction
Sarcolemma of
the muscle fiber
Ca2+
Axon terminal
Synaptic vesicle
containing ACh
Mitochondrion
Synaptic
cleft
Junctional
folds of
sarcolemma
Fusing synaptic
vesicles
ACh
Sarcoplasm of
muscle fiber
Postsynaptic membrane
ion channel opens;
ions pass.
Na+ K+
Ach–
Degraded ACh
Acetyl-
cholinesterase
ion channel closed;
ions cannot pass. 1
Action potential arrives at
axon terminal of motor neuron. 2
Voltage-gated Ca2+ channels
open and Ca2+ enters the axon
terminal. 3
Ca2+ entry causes some
synaptic vesicles to release
their contents (acetylcholine)
by exocytosis. 4
Acetylcholine, a
neurotransmitter, diffuses across
the synaptic cleft and binds to
receptors in the sarcolemma. 5
ACh binding opens ion
channels that allow simultaneous
passage of Na+ into the muscle
fiber and K+ out of the muscle
fiber. 6
ACh effects are terminated
by its enzymatic breakdown in
the synaptic cleft by
acetylcholinesterase.
Motor End Plate
-1/cell
-Middle of cell
-Location of receptors
Pg 287

19. Figure 9.11 Excitation-Contraction Coupling (1 of 4)
Axon terminal
of motor neuron
Muscle fiber
Triad
One sarcomere
Synaptic cleft
Setting the stage
Sarcolemma
Action potential
is generated
Terminal cisterna of SR
ACh
Ca2+
Pg 290

20. Figure 9.11 Excitation-Contraction Coupling (2 of 4)
ECC Clip
Steps in E-C Coupling:
Sarcolemma
Voltage-sensitive
tubule protein
T tubule
Action potential is propagated
along the sarcolemma and down
the T tubules. 1
Ca2+
release
channel
Calcium ions are released. 2
Terminal
cisterna
of SR
Ca2+
Actin
Tropomyosin
blocking active sites
Ca2+
Troponin
Myosin
Calcium binds to troponin and
removes the blocking action of
tropomyosin. 3
Active sites exposed and
ready for myosin binding
Contraction begins 4
Myosin
cross
bridge
The aftermath
Pg 291

21. Figure 9.12 Cross Bridge Cycle
CBC clip
Actin
Cross bridge formation.
Cocking of myosin head.
The power (working)
stroke.
Cross bridge
detachment.
Ca2+ 1 2 3 4
Myosin
head
Thick
filament
Thin filament
ADP P i
ATP
hydrolysis
charged
Rigor mortis
Cramps
Pg 292

22. Figure 9.6 Sliding filament model of contraction.
Fully relaxed sarcomere of a muscle fiber
Fully contracted sarcomere of a muscle fiber A Z H 1 2
Pg 285

23. (a) Concentric isotonic contraction
Figure 9.18a Isotonic (concentric) and isometric contractions (1 of 2).
(a) Concentric isotonic contraction
On stimulation, muscle develops enough tension (force) to lift
the load (weight). Once the resistance is overcome, the muscle
shortens, and the tension remains constant for the rest of the
contraction.
3 kg
Muscle
contracts
(isotonic
contraction)
Tendon
Muscle shortens
Same tension
Pg 297

24. (b) Isometric contraction
Figure 9.18b Isotonic (concentric) and isometric contractions (1 of 2).
(b) Isometric contraction
Muscle is attached to a weight that exceeds the muscle’s peak
tension-developing capabilities. When stimulated, the tension
increases to the muscle’s peak tension-developing capability,
but the muscle does not shorten.
6 kg
Muscle
contracts
(isometric contraction)
No Shortening
Increasing Tension
Maintains Posture
Pg 297

25. Figure 9.19 Pathways for regenerating ATP during muscle activity.
Coupled reaction of creatine
phosphate (CP) and ADP
Energy source: CP
Energy source: glucose
Energy source: glucose; pyruvic acid;
free fatty acids from adipose tissue;
amino acids from protein catabolism
Glycolysis and lactic acid formation
(a) Direct phosphorylation
(b) Anaerobic pathway
(c) Aerobic pathway
Aerobic cellular respiration
Oxygen use: None
Products: 1 ATP per CP, creatine
Duration of energy provision:
15 seconds
Products: 2 ATP per glucose, lactic acid
60 seconds, or slightly more
Oxygen use: Required
Products: 32 ATP per glucose, CO2, H2O
Duration of energy provision: Hours
Creatine
kinase
ADP CP
Glucose (from
glycogen breakdown or
delivered from blood)
Glycolysis
in cytosol
Pyruvic acid
Released
to blood
net gain 2 32
Lactic acid O2 O
H2O
CO2
Fatty
acids
Amino
Aerobic respiration
in mitochondria
ATP
net gain per
glucose
60-70%
Rapid ATP Production
Pg 299

26. Lactic Acid Byproduct 70% max muscle activity Pg 300
Figure Comparison of energy sources used during short-duration exercise and prolonged-duration exercise.
Short-duration exercise
Prolonged-duration
exercise
ATP stored in
muscles is
used first.
ATP is formed
from creatine
Phosphate
and ADP.
Glycogen stored in muscles is broken
down to glucose, which is oxidized to
generate ATP.
ATP is generated by
breakdown of several
nutrient energy fuels by
aerobic pathway. This
pathway uses oxygen
released from myoglobin
or delivered in the blood
by hemoglobin. When it
ends, the oxygen deficit is
paid back.
Lactic Acid Byproduct
70% max muscle activity
Pg 300

28. Twitch The contraction of a muscle in response to a brief, single stimulus. Example: Blinking Consists of 3 distinct phases

29. Figure 9.14a The muscle twitch.
Latent
period
Single
stimulus
Period of
contraction
relaxation
(a) Myogram showing the three phases of an isometric twitch
Refractory period
Pg 295

31. Increasing # of motor units
No recruitment
Piggy-backing twitches
Partial relaxation
Twitches fusing

32. Figure 9.15c Muscle response to changes in stimulation frequency.
ONLY Skeletal Muscle
Stimuli
High stimulation frequency
fused (complete) tetanus
(c) At higher stimulus frequencies, there is no relaxation
at all between stimuli. This is fused (complete) tetanus.
-Stimulate at peak of twitch
-No relaxation
-Normal
Rotation
Muscle Tone
Pg 295

33. Sarcomeres excessively
Figure Length-tension relationships of sarcomeres in skeletal muscles.
Congestive heart failure
Sarcomeres
greatly
shortened
Sarcomeres at
resting length
Sarcomeres excessively
stretched
170%
Optimal sarcomere
operating length
(80%–120% of
resting length)
100%
75%
Smooth Muscle
-Accommodation
-Bladder, Uterus
Pg 302

34. Temperature Too cool -Decreases enzyme functioning Too warm -Decreases enzyme functioning -May even denature enzymes and muscle proteins ( degrees F) -Heat rigor

35. Fatigue 1. Build up of waste products 2. Decreased energy stores 3
Fatigue 1. Build up of waste products 2. Decreased energy stores 3. Increased temperature 4. Synaptic fatigue

36. 312

37. Exercise and Training Aerobic Continuous, prolonged
Cellular respiration
Increases mitochondrion
Usage of fat as fuel
Improves endurance
Improves muscle tone
(red)
Anaerobic Bursts of activity Cellular respiration & anaerobic glycolysis Increases size of muscles (hypertrophy) Increases strength (white)

38. Muscle fiber types Red Fibers (Slow Oxidative)
White Fibers (Fast Glycolytic)
Increased Mitochondrion
Lots of myoglobin
Highly vascular
Slow to fatigue
Use for endurance activities
Slow contraction time
Efficiency vs. Endurance
Less mitochondrion
Decreased myoglobin
High levels of ATPase
Use for anaerobic activity
Increase in size
Fast contraction time
? Fast Oxidative Glycolytic