Download Chapter 7 Notes - Aurora City Schools

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prepared by
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Austin Community College
CHAPTER
7
The
Muscular
System
© 2013 Pearson Education, Inc.
Chapter 7 Learning Outcomes
•
7-1: Specify the functions of skeletal muscle tissue.
•
7-2: Describe the organization of muscle at the tissue level.
•
7-3: Identify the structural components of a sarcomere.
•
7-4: Explain the key steps involved in the contraction of a skeletal
muscle fiber beginning at the neuromuscular junction.
•
7-5: Compare the different types of muscle contractions.
•
7-6: Describe the mechanisms by which muscles obtain the energy to
power contractions.
•
7-7: Relate the types of muscle fibers to muscle performance, and
distinguish between aerobic and anaerobic endurance.
•
7-8: Contrast the structures and functions of skeletal, cardiac, and
smooth muscle tissues.
•
7-9: Explain how the name of a muscle can help identify its location,
appearance, or function.
© 2013 Pearson Education, Inc.
Chapter 7 Learning Outcomes
•
7-10: Identify the main axial muscles of the body together with their
origins, insertions, and actions.
•
7-11: Identify the main appendicular muscles of the body together with
their origins, insertions, and actions.
•
7-12: Describe the effects of aging on muscle tissue.
•
7-13: Discuss the functional relationships between the muscular
system and other organ systems.
© 2013 Pearson Education, Inc.
Review Muscle Types
• Elongated muscle cells or fibers that are highly
specialized for contraction
3 types:
a. Skeletal- most abundant, striated, large
multinucleated, voluntary, cant divide
b. Cardiac- only in heart, striated, single nucleus,
intercalated discs, involuntary, cant divide
c. Smooth- line organs, non striated, single
nucleus, can divide, involuntary
© 2013 Pearson Education, Inc.
Five Skeletal Muscle Functions (7-1)
1. Produce movement of the skeleton
• By pulling on tendons that then move bones
2. Maintain posture and body position
3. Support soft tissues
• With the muscles of the abdominal wall and the pelvic floor
4. Guard entrances and exits
• In the form of sphincters
5. Maintain body temperature
• When contraction occurs, energy is used and converted to
heat
© 2013 Pearson Education, Inc.
Checkpoint (7-1)
1. Identify the five primary functions of skeletal
muscle.
1. Produce movement of the skeleton
2. Maintain posture and body position
3. Support soft tissues
4. Guard entrances and exits
5. Maintain body temperature
© 2013 Pearson Education, Inc.
Organization of Skeletal Muscle Tissue (7-2)
Skeletal muscles – approximately 700,
•Single skeletal muscle cells or muscle fibers
Are organs that contain:
1. Skeletal muscle tissue (primary)
2. Connective tissue
3. Blood vessels
4. Nerves
© 2013 Pearson Education, Inc.
A. Three Layers of Connective Tissue (7-2)
1. Epimysium (ep-i-MIZ-e-um muscle)
• Covers the entire muscle
2. Perimysium (per-i-MIZ-e-um around)
• Divides the muscle into bundles called fascicles (FASi-kl)
• Blood vessels and nerves are contained in the
perimysium
3. Endomysium (en-do-MIZ-e-um- inside)
• Covers each muscle fiber and ties fibers together
• Contains capillaries and nerve tissue
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B. Tendons (7-2)Where the ends of all three layers of connective
tissue come together and attach the muscle to a
bone
Aponeurosis (ap-o-noo-RO-sis)
• A broad sheet of collagen fibers that connects muscles to
each other, Similar to tendons, but do not connect to a bone
© 2013 Pearson Education, Inc.
C. Blood Vessels (7-2)
• Extensive network of blood vessels in skeletal
muscle provides high amounts of nutrients and
oxygen to skeletal muscles which have high
metabolic needs
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D. Nerves -Control of Skeletal Muscle (7-2)
Mostly under voluntary control, Must be stimulated by the central
nervous system; To control individual muscle fibers
• Axons (nerve fibers)
a) Push through the epimysium
b) Branch through the perimysium
c) And enter the endomysium
© 2013 Pearson Education, Inc.
Figure 7-1 The Organization of Skeletal Muscles.
Skeletal Muscle (organ)
Epimysium Perimysium Endomysium Nerve
Muscle Muscle Blood
fascicle fibers vessels
Muscle Fascicle (bundle of fibers)
Perimysium
Epimysium
Blood vessels
and nerves
Muscle fiber
Endomysium
Tendon
Endomysium
Muscle Fiber (cell)
Capillary Myofibril Endomysium
Sarcoplasm
Perimysium
Mitochondrion
Stem cell
Sarcolemma
Nucleus
Axon of neuron
© 2013 Pearson Education, Inc.
Checkpoint (7-2)
2. Describe the connective tissue layers associated
with a skeletal muscle.
A. epimysium is a dense layer of collagen fibers th at surrounds the
entire muscle
B. Perimuysium divides the skeletal muscle into a series of
compartments, each containing a bundle of muscle fibers called a
fascile
C. Endomysium surrounds individual skeletal muscle cells (fibers)
http://www.youtube.com/watch?v=f_tZne9ON7c
© 2013 Pearson Education, Inc.
Checkpoint (7-2)
3. How would severing the tendon attached to a
muscle affect the muscle's ability to move a body
part?
Would prevent the muscle from moving the body
part because the muscle would no longer be
connected to the bone.
© 2013 Pearson Education, Inc.
Features of Skeletal Muscle Fibers/ cells(7-3)
• Are specifically organized to produce contraction
and have specific names for general cell
structures
• Can be very long and are multinucleated
• Composed of highly organized structures, giving
them a striped or striated appearance
© 2013 Pearson Education, Inc.
Features of Skeletal Muscle Fibers/ cells(7-3)
1. Sarcolemma
2. Transverse Tubules
3. Myofibrils
4. Sarcoplasmic Reticulum
5. Sarcomeres
6. Think and Thin Filaments
© 2013 Pearson Education, Inc.
The Sarcolemma and Transverse Tubules (7-3)
The sarcolemma(Flesh, husk)
• Specific name of muscle fiber plasma membrane
• Has openings across the surface that lead into a network of
transverse tubules, or T tubules
• T tubules allow for electrical stimuli to reach deep into each
fiber, coordinate contractions
The sarcoplasm- Specific name for muscle fiber cytoplasm
http://www.youtube.com/watch?v=F3ISlvNGTEg
© 2013 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
Myofibrils in Muscle Fiber (7-3)
• Hundreds to thousands in each fiber
• Are encircled by T tubules and are as long as the
entire muscle fiber
• Are bundles of thick and thin myofilaments
• Actin molecules are found in thin filaments
• Myosin molecules are found in thick filaments
• Are the contractile proteins that shorten and are
responsible for contraction
•
http://www.youtube.com/watch?v=DA7iOW7T-G4
© 2013 Pearson Education, Inc.
The Sarcoplasmic Reticulum (SR) (7-3)
• Specialized smooth endoplasmic reticulum
• Expanded end that is next to the T tubule is the
terminal cisternae, Contain high concentrations of
calcium ions
• Triad- A combination of two terminal cisternae and
one T tubule
© 2013 Pearson Education, Inc.
Sarcomeres (7-3)
• Smallest functional unit of skeletal muscle fiber
• Formed by repeating myofilament arrangements
• Each myofibril has about 10,000 sarcomeres
• Thick and thin filament arrangements are what
produce the striated appearance of the fiber
• Overlapping filaments define lines and bands
• http://www.youtube.com/watch?v=-9DmO-SRY3E
© 2013 Pearson Education, Inc.
Sarcomere Lines (7-3) x
• Z lines
• Thin filaments at both ends of the sarcomere
• Another protein connects the Z lines to the thick filament to
maintain alignment
• M line
• Made of connections between the thick filaments
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Sarcomere Bands (7-3)x
• A band
• Contains the thick filaments (dArk)
• I band
• Contains the thin filaments, including the Z line (Light)
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Figure 7-2 The Organization of a Skeletal Muscle Fiber.
Terminal Sarcoplasmic
T tubules cisterna
reticulum Triad
Sarcolemma
Mitochondria
Thick
filament
Thin
filament
Myofilaments
MYOFIBRIL
The structure of a skeletal
muscle fiber.
SARCOMERE
Z line
Zone of overlap
M line
Myofibril
H band
I band
Zone of overlap
A band
The organization of a sarcomere, part of a single myofibril.
M line
Z line
Z line
A stretched out
sarcomere.
M line
Z line
Z line and thin
filaments
Myosin
head
Thick filaments
Active site Actin molecules
Myosin tail
ACTIN
STRAND
Tropomyosin
Thin filament
The structure of a thin filament.
Troponin
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Hinge
MYOSIN MOLECULE
The structure of a thick filament.
Figure 7-2a The Organization of a Skeletal Muscle Fiber.
Terminal Sarcoplasmic
Triad Sarcolemma
T tubules cisterna
reticulum
Mitochondria
Thick
filament
Thin
filament
Myofilaments
MYOFIBRIL
The structure of a skeletal
muscle fiber.
© 2013 Pearson Education, Inc.
Figure 7-2b The Organization of a Skeletal Muscle Fiber.
SARCOMERE
Z line Zone of overlap M line
Myofibril
I band
H band
A band
The organization of a sarcomere, part of a single myofibril.
© 2013 Pearson Education, Inc.
Zone of overlap
Figure 7-2c The Organization of a Skeletal Muscle Fiber.
Z line
M line
Z line
A stretched out
sarcomere.
Z line
Z line and thin
filaments
© 2013 Pearson Education, Inc.
M line
Thick filaments
Figure 7-2d The Organization of a Skeletal Muscle Fiber.
Active site
Actin molecules
ACTIN
STRAND
Troponin
Tropomyosin
Thin filament
The structure of a thin filament.
© 2013 Pearson Education, Inc.
Figure 7-2e The Organization of a Skeletal Muscle Fiber.
Myosin
head
Myosin tail
MYOSIN MOLECULE Hinge
The structure of a thick filament.
© 2013 Pearson Education, Inc.
Thin and Thick Filaments (7-3)
1. Actin
• A thin twisted protein, with specific active sites for myosin to
bind to
• At rest, active sites are covered by strands of tropomyosin,
held in position by troponin
2. Myosin
• A thick filament with tail and globular head that attaches to
actin active sites during contraction
© 2013 Pearson Education, Inc.
Steps of Contraction (7-3)- calcium is the key
1. Calcium released from SR
2. Calcium binds to troponin
3. Change of troponin shape causes tropomyosin to
move away from active sites
4. Myosin heads bind to active site, creating cross-
bridges, rotate and cause actin to slide over
myosin
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Sliding Filament Theory (7-3)
• Based on observed changes in sarcomere
• I bands get smaller
• Z lines move closer together
• H bands decrease
• A bands don't change, indicating that the thin filaments are
sliding toward the center
• http://www.youtube.com/watch?v=Ct8AbZn_A8A
• http://www.youtube.com/watch?v=sJZm2YsBwMY
• http://www.youtube.com/watch?v=9BFvBRLDaQY
© 2013 Pearson Education, Inc.
Figure 7-3 Changes in the Appearance of a Sarcomere during Contraction of a Skeletal Muscle Fiber.
I band
Z line
A band
H band
Z line
A relaxed sarcomere showing
locations of the A band, Z lines,
and I band.
© 2013 Pearson Education, Inc.
I band
A band
H band
Z line
Z line
During a contraction, the A band stays the
same width, but the Z lines move closer
together and the I band gets smaller.
Checkpoint (7-3)
4. Describe the basic structure of a sarcomere.
• The smallest contractile units of a skeletal muscle cell, are
segments of myofibrils.
• Have a Dark A Band and Light I Band.
• Band A contains the M line, H band, and the zone of
overlap. Each I Band contains thin filaments, but not thick
filaments. Z lines mark the boundaries between adjacent
sarcomeres
© 2013 Pearson Education, Inc.
Checkpoint (7-3)
5. Why do skeletal muscle fibers appear striated
when viewed through a light microscope?
The arrangement of the actin and myosin
myofilaments within myofibrils produces a
banded appearance
© 2013 Pearson Education, Inc.
Checkpoint (7-3)
6. Where would you expect the greatest
concentration of calcium ions to be in a resting
skeletal muscle fiber?
In the terminal cisternae of the sarcoplasmic
reticulum of a resting skeletal muscle fiber.
© 2013 Pearson Education, Inc.
The Neuromuscular Junction (7-4)
http://www.youtube.com/watch?v=y7X7IZ_ubg4 (
Where a motor neuron communicates with a skeletal
muscle fiber
• Axon terminal of the neuron, An enlarged end that contains
vesicles of the neurotransmitter
• Acetylcholine (ACh) – chemical released by the neuron to
communicate with other cells it is a neurotransmitter that will
cross the synaptic cleft, space between axon terminal and
sarcolemma
Drawing video
http://www.bing.com/videos/search?q=neuromuscular+junction&FORM=HDRSC3#view=detail&mid=A474BC69B34FDD
© 2013 Pearson
Education, Inc.
6752ADA474BC69B34FDD6752AD
The Neuromuscular Junction (7-4)
• ACh binds to the receptor on the motor end plate
• Cleft and the motor end plate contain
acetylcholinesterase (AChE), enzyme breaks
down ACh
• Neurons stimulate sarcolemma by generating an
action potential, An electrical impulse
© 2013 Pearson Education, Inc.
Figure 7-8 Motor Units.
Axons of
motor neurons
Motor
nerve
KEY
Motor unit 1
Motor unit 2
Motor unit 3
© 2013 Pearson Education, Inc.
SPINAL CORD
Muscle fibers
Figure 7-4 Skeletal Muscle Innervation.
The cytoplasm of the axon
terminal contains vesicles
filled with molecules of acetylcholine, or ACh. Acetylcholine is a neurotransmitter, a
chemical released by a
neuron to change the permeability or other properties of
another cell’s plasma membrane. The synaptic cleft and
the motor end plate contain
molecules of the enzyme
acetylcholinesterase (AChE),
which breaks down ACh.
Vesicles
ACh
Synaptic cleft
Motor
end plate
© 2013 Pearson Education, Inc.
AChE
Slide 1
Figure 7-4 Skeletal Muscle Innervation.
Slide 2
The stimulus for ACh
release is the arrival of an
electrical impulse, or
action potential, at the
axon terminal. The action
potential arrives at the
NMJ after traveling along
the length of the axon.
Arriving action
potential
© 2013 Pearson Education, Inc.
Figure 7-4 Skeletal Muscle Innervation.
When the action
potential reaches the
neuron’s axon terminal,
permeability changes in
the membrane trigger the
exocytosis of ACh into the
synaptic cleft. Exocytosis
occurs as vesicles fuse
with the neuron’s plasma
membrane.
Motor
end plate
© 2013 Pearson Education, Inc.
Slide 3
Figure 7-4 Skeletal Muscle Innervation.
Slide 4
ACh molecules diffuse
across the synaptic cleft
and bind to ACh receptors
on the surface of the motor
end plate. ACh binding
alters the membrane’s
permeability to sodium
ions. Because the extracellular fluid contains a high
concentration of sodium
ions, and sodium ion
concentration inside the cell
is very low, sodium ions
rush into the sarcoplasm.
ACh receptor site
© 2013 Pearson Education, Inc.
Figure 7-4 Skeletal Muscle Innervation.
Slide 5
The sudden inrush of
sodium ions results in
the generation
of an action potential
in the sarcolemma.
AChE quickly breaks
down the ACh on the
motor end plate and in
the synaptic cleft, thus
inactivating the ACh
receptor sites.
Action
potential
AChE
© 2013 Pearson Education, Inc.
Interference  Paralysis
• Botulism- bacterial toxin often found in canned or
smoked foods, prevents the release of Ach at that
axon terminals, leading to a potentially fatal
muscular paralysis
• Myasthenia gravis- progressive muscular
paralysis, loss of Ach receptors at the motor end
plate. Immune system attacks the receptors due to
genetic factors.
© 2013 Pearson Education, Inc.
Rigor Mortis- body becoming stiff as a board
• After a few hours ATP runs out
• Muscle fibers are unable to remove calcium ions
causing a sustained contraction
• With out ATP the cross-bridges cannot detach
from the active sites
• Will last until the lysosomal enzymes released by
autolysis break down the myofilaments, about 710 hours of death and end 1-6 days or during
decomposition (environmental factors influence
rate)
© 2013 Pearson Education, Inc.
The Contraction Cycle (7-4)- Key is Calcium
• Involves the triads
• Action potential travels over the sarcolemma,
down into the T tubules
• Causes release of calcium from the SR
• Calcium binds to troponin and the contraction
cycle starts
© 2013 Pearson Education, Inc.
Figure 7-5 The Contraction Cycle
Slide 1
Contraction Cycle
Begins
Myosin head
Troponin
Tropomyosin
© 2013 Pearson Education, Inc.
Actin
Figure 7-5 The Contraction Cycle
Slide 2
Active-Site Exposure
Sarcoplasm
Active
site
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Figure 7-5 The Contraction Cycle
Slide 3
Cross-Bridge Formation
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Figure 7-5 The Contraction Cycle
Slide 4
Myosin Head Pivoting
© 2013 Pearson Education, Inc.
Figure 7-5 The Contraction Cycle
Slide 5
Cross-Bridge
Detachment
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Figure 7-5 The Contraction Cycle
Slide 6
Myosin Reactivation
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Table 7-1 Steps Involved in Skeletal Muscle Contraction and Relaxation
© 2013 Pearson Education, Inc.
Checkpoint (7-4)
7. Describe the neuromuscular junction.
The link between a motor neuron and a muscle cell-
allows for communication between the nervous
system and skeletal muscle fiber.
© 2013 Pearson Education, Inc.
Checkpoint (7-4)
8. How would a drug that blocks acetylcholine
release affect muscle contraction?
It prevents muscle contraction
© 2013 Pearson Education, Inc.
Checkpoint (7-4)
9. What would you expect to happen to a resting
skeletal muscle if the sarcolemma suddenly became
very permeable to calcium ions?
The muscles would contract and may not relax
completely
© 2013 Pearson Education, Inc.
Contraction Produces Tension (7-5)
• Individual fibers (cells) surround by connective
tissue, Are either contracted or relaxed, "On" or
"off"
• Tension is a product of the number of cross-bridges a fiber
contains, pulling towards, active force
Variation in tension can occur based on:
1. The amount of overlap of the myofilaments
2. The frequency of stimulation, The more frequent the
stimulus, the more Ca2+ builds up, resulting in greater
contractions
© 2013 Pearson Education, Inc.
Contraction Produces Tension (7-5)
Resistance- passive force, opposed movement
Depends on:
1.Objects weight
2.Shape
3.Friction
4.Other
Compression- push applied to object, tends to force the object
away fro the source of compression
(muscle cells can only contract- shorten and generate tension) they
cannot actively lengthen and generate compression)
© 2013 Pearson Education, Inc.
Contraction Produces Tension (7-5)
Whole skeletal muscle organ
Contracts with varying tensions based on:
1. Frequency of muscle fiber stimulation
2. Number of fibers activated
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A Muscle Twitch (7-5)
• A single stimulus-contraction-relaxation cycle in a
muscle fiber or whole muscle
• Represented by a myogram
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Three Phases of a Muscle Twitch (7-5)
1. Latent period
• Starts at the point of stimulus and includes the action
potential, release of Ca2+, and the activation of
troponin/tropomyosin
2. Contraction phase
• Is the development of tension because of the cross-bridge
cycle
3. Relaxation phase
• Occurs when tension decreases due to the re-storage of
Ca2+ and covering of actin active sites
© 2013 Pearson Education, Inc.
Figure 7-6 The Twitch and Development of Tension.
Tension
Maximum tension
development
Stimulus
Time (msec) 0
5
10
Resting Latent Contraction
phase period
phase
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20
30
Relaxation
phase
40
Summation and Tetanus (7-5)
• Summation
• Occurs with repeated, frequent stimuli that trigger a response
before full relaxation has occurred
• Incomplete tetanus
• Near peak tension with little relaxation
• Complete tetanus
• Stimuli are so frequent that relaxation does not occur
PLAY
ANIMATION Frog Wave Summation
© 2013 Pearson Education, Inc.
Figure 7-7 Effects of Repeated Stimulations.
Maximum tension
(in tetanus)
Tension
= Stimulus
Time
Summation. Summation
of twitches occurs when
successive stimuli arrive
before the relaxation phase
has been completed.
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Time
Incomplete tetanus.
Incomplete tetanus occurs
if the stimulus frequency
increases further. Tension
production rises to a peak,
and the periods of
relaxation are very brief.
Time
Complete tetanus.
During complete tetanus,
the stimulus frequency is
so high that the relaxation
phase is eliminated;
tension plateaus at
maximal levels.
Varying Numbers of Fibers Activated (7-5)
• Allows for smooth contraction and a lot of control
• Most motor neurons control a number of fibers
through multiple, branching axon terminals
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Motor Unit (7-5)
• A single motor neuron and all the muscle fibers it
innervates
• Motor units are dispersed throughout the muscle
• Fine control movements
• Use motor units with very few fibers per neuron
• Gross movements
• Motor units have a high fiber-to-neuron ratio
© 2013 Pearson Education, Inc.
Recruitment (7-5)
• A mechanism for increasing tension to create
more movement
• A graded addition of more and more motor units to
produce adequate tension
© 2013 Pearson Education, Inc.
Figure 7-8 Motor Units.
Axons of
motor neurons
Motor
nerve
KEY
Motor unit 1
Motor unit 2
Motor unit 3
© 2013 Pearson Education, Inc.
SPINAL CORD
Muscle fibers
Tetanus- Clostridium tetani
• Bacteria that can be found everywhere
• Thrive in low O2
• Powerful toxin that is released will affect the CNS
• Inhibits motor neuron activity causing a sustained powerful
contraction of the skeletal muscles through out the body
• Incubation period is less than 2 weeks
• Headache, muscle stiffness and difficulty swaloling,
lockjaw
• 40-60% mortality
• Immunization and booster shots every 10 yrs , antitoxins
can be administered if detected early, but will not reduce
symptoms if have already appeared.
© 2013 Pearson Education, Inc.
Muscle Tone and Atrophy (7-5)
Muscle tone- muscle that is firm and solid
• Some muscles at rest will still have a little tension
• Primary function is stabilization of joints and posture
Atrophy – loss of muscle tone
• Occurs in a muscle that is not regularly stimulated
• Muscle becomes small and weak
• Can be observed after a cast comes off a fracture
© 2013 Pearson Education, Inc.
Types of Contraction (7-5)
1. Isotonic contraction
• When the length of the muscle changes, but the tension
remains the same until relaxation
• For example, lifting a book
2. Isometric contraction
• When the whole muscle length stays the same, the tension
produced does not exceed the load
• For example, pushing against a wall
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Elongation of Muscle after Contraction (7-5)
• No active mechanism for returning a muscle to a
pre-contracted, elongated state
Passively uses a combination of:
1. Gravity
2. Elastic forces
3. Opposing muscle movement
© 2013 Pearson Education, Inc.
Checkpoint (7-5)
10. What factors are responsible for the amount of
tension a skeletal muscle develops?
a. The frequency of muscle fiber stimulation
b. Number of muscle fibers activated
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Checkpoint (7-5)
11. A motor unit from a skeletal muscle contains
1500 muscle fibers. Would this muscle be involved
in fine, delicate movements or in powerful, gross
movements? Explain.
powerful, gross movements such as moving
your leg would require large amounts of muscle
fibers.
© 2013 Pearson Education, Inc.
Checkpoint (7-5)
12. Can a skeletal muscle contract without
shortening? Explain.
Yes in an isometric contraction. The muscle does
not shorten even thought tension increases.
(isotonic shortens)
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ATP and CP Reserves (7-6)
• At rest, muscle cells generate ATP, some of which
will be held in reserve
• Some is used to transfer high energy to creatine
forming creatine phosphate (CP)
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ATP and CP Reserves (7-6)
• During contraction each cross-bridge breaks down
ATP into ADP and a phosphate group
• CP is then used to recharge ATP
• The enzyme creatine phosphokinase (CPK or
CK) regulates this reaction
• It lasts for about 15 seconds
• ATP must then be generated in a different way
© 2013 Pearson Education, Inc.
Aerobic Metabolism (7-6)- provides 95% ATP/
Cellular Respiration
• Occurs in the mitochondria
• Using ADP, oxygen, phosphate ions, and organic substrates
from carbohydrates, lipids, or proteins
• Substrates go through the citric acid cycle
• A series of chemical reactions that result in energy to make
ATP, water, and carbon dioxide
• Oxygen supply decides ATP aerobic production
© 2013 Pearson Education, Inc.
Glycolysis (7-6)- alone is insufficient
• Breaks glucose down to pyruvate in the cytoplasm
of the
• If pyruvate can go through the citric acid cycle with
oxygen, it is very efficient
• Forming about 34 ATP
• With insufficient oxygen, pyruvate yields only 2
ATP
• Pyruvate is converted to lactic acid
• Potentially causing a pH problem in cells causing fatigue
© 2013 Pearson Education, Inc.
Muscle Fatigue (7-6)
• Caused by depletion of energy reserves or a
lowering of pH, Muscle will no longer contract
even if stimulated
• Endurance athletes, using aerobic metabolism,
can draw on stored glycogen and lipids (carb
loading)
• Sprinters, functioning anaerobically, deplete CP
and ATP rapidly, and build up lactic acid
•
PLAY
ANIMATION Frog Fatigue
© 2013 Pearson Education, Inc.
The Recovery Period (7-6)
• Requires "repaying" the oxygen debt by continuing to
breathe faster, Even after the end of exercise, and recycling lactic
acid
• Heat production occurs during exercise, Raising the body
temperature
• Blood vessels in skin will dilate; sweat covers the skin and
evaporates, Promoting heat loss
© 2013 Pearson Education, Inc.
Checkpoint (7-6)
13. How do muscle cells continuously synthesize
ATP?
By utilizing creatine phosphate (CP) and
metabolizing glycogen and fatty acids. Most cells
generate ATP through aerobic metabolism.
(cellular respiration/ aerobic respiration)
© 2013 Pearson Education, Inc.
Checkpoint (7-6)
14 What is muscle fatigue?
Reduced ability to contract due to low ATP
levels, low pH (lactic acid buildup and
dissociation)
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Checkpoint (7-6)
15. Define oxygen debt.
Amount of oxygen required to restore normal, preexertion conditions in muscles
© 2013 Pearson Education, Inc.
Muscle Performance (7-7)
Measured in force
• The maximum amount of tension produced by a muscle or
muscle group
Measured in endurance
• The amount of time a particular activity can be performed
Two keys to performance:
1. Types of fibers in muscle
2. Physical conditioning or training
http://www.youtube.com/watch?v=HpyRkoL42w0
© 2013 Pearson Education, Inc.
Fast Fibers (7-7)
• The majority of muscle fibers in the body
• Large in diameter
• Large glycogen reserves
• Few mitochondria
• Rely on glycolysis
• Are rapidly fatigued
© 2013 Pearson Education, Inc.
Slow Fibers (7-7)
• About half the diameter of, and three times slower
than, fast fibers
Are fatigue resistant because of three factors:
1. Oxygen supply is greater due to more perfusion(network
capillaries)
2. Myoglobin stores oxygen in the fibers
3. Oxygen use is efficient due to large numbers of mitochondria
© 2013 Pearson Education, Inc.
Percentages of Muscle Types Vary (7-7)
• Fast fibers appear pale and are called white muscles
(chicken breast, wings short burst energy/ anaerobic
process)
• Extensive vasculature and myoglobin in slow fibers cause
them to appear reddish and are called red muscles (legs
dark meat, chickens walk around all day/ aerobic)
• Human muscles are a mixture of fiber types and appear
pink
• Hands and eyes only have white(quick movement), calf is
red (standing)
© 2013 Pearson Education, Inc.
Muscle Conditioning and Performance (7-7)
Physical conditioning and training Can increase
power and endurance
1. Anaerobic endurance
• Is increased by brief, intense workouts
• Hypertrophy of muscles results (enlargement)
2. Aerobic endurance
• Is increased by sustained, low levels of activity
© 2013 Pearson Education, Inc.
Checkpoint (7-7)
16. Why would a sprinter experience muscle fatigue
before a marathon runner would?
Sprinters require large amounts of energy for a relatively short burst of
activity. To supply this energy , the sprinter’s muscles switch to anaerobic
metabolism. Anaerobic metabolism is less efficient in producing energy
than aerobic metabolism and produces acidic waste products; this
combination contributes to muscle fatigue.
Marathon runners derive most of their energy from aerobic metabolism,
which is more efficient and produces fewer waste products than anaerobic
metabolism.
© 2013 Pearson Education, Inc.
Checkpoint (7-7)
17. Which activity would be more likely to create an
oxygen debt in an individual who regularly exercises:
swimming laps or lifting weights?
Activities that require short periods of strenuous
activity produce a greater oxygen debt, because
such activities rely heavily on energy production by
anaerobic metabolism.
Weight lifting
© 2013 Pearson Education, Inc.
Checkpoint (7-7)
18. Which type of muscle fibers would you expect to
predominate in the large leg muscles of someone
who excels at endurance activities such as cycling or
long-distance running?
They would have a higher than normal
percentage of slow muscle fibers.
© 2013 Pearson Education, Inc.
Cardiac Muscle Tissue (7-8)
• Found only in heart
• Cardiac muscle cells
• Relatively small with usually only one central nucleus
• Striated and branched
• Intercalated discs, which connect cells to other cells
• Communicate through gap junctions, allowing all the fibers to
work together
© 2013 Pearson Education, Inc.
1. Cardiac Pacemaker Cells (7-8)
• Exhibit automaticity
• Make up only 1 percent of myocardium
• Establish rate of contraction
© 2013 Pearson Education, Inc.
2. Cardiac Contractile Cells (7-8)
• 99 percent of myocardium
• Contract for longer period than skeletal muscle
fibers
• Unique sarcolemmas make tetanus impossible
• Are permeable to calcium
• Rely on aerobic metabolism
© 2013 Pearson Education, Inc.
Smooth Muscle Tissue (7-8)
• Found in the walls of most organs, in the form of
sheets, bundles, or sheaths
• Lacks myofibrils, sarcomeres, or striations
• Smooth muscle cells
• Also smaller than skeletal fibers
• Spindle-shaped and have a single nucleus
© 2013 Pearson Education, Inc.
Smooth Muscle Tissue (7-8)
• Thick filaments are scattered throughout
sarcoplasm
• Thin filaments are anchored to the sarcolemma
• Causing contraction to be like a twisting corkscrew
• Cells are bound together
• Resulting in forces being transmitted throughout the tissue
© 2013 Pearson Education, Inc.
Smooth Muscle Tissue (7-8)
• Different from other muscle types
• Calcium ions from the extracellular fluid are needed to trigger
a contraction mechanism that is different from other muscle
tissues
• Function involuntarily
• Can respond to hormones or pacesetter cells
© 2013 Pearson Education, Inc.
Figure 7-10 Cardiac and Smooth Muscle Tissues.
Cardiac
muscle cell
Intercalated
discs
Cardiac muscle tissue
LM x 575
A light micrograph of cardiac muscle tissue.
T
L
Circular
muscle layer
Longitudinal
muscle layer
Smooth muscle tissue LM x 100
© 2013 Pearson Education, Inc.
Many visceral organs contain several layers of smooth
muscle tissue oriented in different directions. Here, a
single sectional view shows smooth muscle cells in
both longitudinal (L) and transverse (T) sections.
Table 7-2 A Comparison of Skeletal, Cardiac, and Smooth Muscle Tissues
© 2013 Pearson Education, Inc.
Checkpoint (7-8)
19. How do intercalated discs enhance the
functioning of cardiac muscle tissue?
© 2013 Pearson Education, Inc.
Checkpoint (7-8)
20. Extracellular calcium ions are important for the
contraction of what type(s) of muscle tissue?
© 2013 Pearson Education, Inc.
Checkpoint (7-8)
21. Why can smooth muscle contract over a wider
range of resting lengths than skeletal muscle?
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Skeletal Muscle System Names (7-9)
• Based on:
• Action
• What they do
• Origin
• The end that stays stationary
• Insertion
• The end that moves
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Actions (7-9)
• Described as relative to the bone that is moved
• Example, "flexion of the forearm"
• Described as the joint that is involved
• Example, "flexion at the elbow"
© 2013 Pearson Education, Inc.
Primary Actions of Muscles (7-9)
• Prime mover, or agonist
• The muscle that is chiefly responsible for producing a
movement
• Antagonist
• A muscle that opposes another muscle
• Synergist
• A muscle that helps the prime mover
• Example, flexion of the elbow
• The biceps brachii is the prime mover, the triceps brachii is
the antagonist, and the brachialis is the synergist
© 2013 Pearson Education, Inc.
Table 7-3 Muscle Terminology (1 of 2)
© 2013 Pearson Education, Inc.
Table 7-3 Muscle Terminology (2 of 2)
© 2013 Pearson Education, Inc.
Muscle Terminology (7-9)
•
Combining the various terms in Table 7-3,
anatomists name the muscles using:
•
Location, direction of fibers, number of origins, and/or
function
•
Muscles are organized into two groups
1. Axial muscles (mostly stabilizers)
2. Appendicular muscles (stabilizers or movers of the limbs)
© 2013 Pearson Education, Inc.
Figure 7-11a An Overview of the Major Skeletal Muscles.
Frontalis
Temporalis
Trapezius
Clavicle
Deltoid
Masseter
Sternocleidomastoid
Pectoralis major
Sternum
Latissimus dorsi
Serratus anterior
External oblique
Rectus abdominis
Extensor carpi radialis
Brachioradialis
Flexor carpi ulnaris
Biceps brachii
Triceps brachii
Brachialis
Pronator teres
Palmaris longus
Flexor carpi radialis
Flexor digitorum
Tensor fasciae
latae
Vastus lateralis
Rectus femoris
Patella
Tibia
Tibialis anterior
Extensor digitorum
Gluteus
medius
Iliopsoas
Adductor longus
Gracilis
Sartorius
Vastus medialis
Fibularis
Gastrocnemius
Soleus
Anterior view
© 2013 Pearson Education, Inc.
Figure 7-11b An Overview of the Major Skeletal Muscles.
Sternocleidomastoid
Trapezius
Deltoid
Infraspinatus
Teres minor
Teres major
Latissimus dorsi
Brachioradialis
Extensor carpi
radialis
Tensor fasciae
latae
Semitendinosus
Biceps femoris
Gastrocnemius
Occipitalis
Triceps brachii
Rhomboid major
Flexor carpi ulnaris
External oblique
Extensor digitorum
Extensor carpi ulnaris
Gluteus medius
Gluteus maximus
Adductor magnus
Semimembranosus
Gracilis
Sartorius
Soleus
Calcaneal
tendon
© 2013 Pearson Education, Inc.
Calcaneus
Posterior view
Checkpoint (7-9)
22. Identify the kinds of descriptive information used
to name skeletal muscles.
© 2013 Pearson Education, Inc.
Checkpoint (7-9)
23. Which muscle is the antagonist of the biceps
brachii?
© 2013 Pearson Education, Inc.
Checkpoint (7-9)
24.What does the name flexor carpi radialis longus
tell you about this muscle?
© 2013 Pearson Education, Inc.
Axial Muscles (7-10)
• Muscles of the head and neck
• Muscles of the spine
• Muscles of the trunk
• Muscles of the pelvic floor
© 2013 Pearson Education, Inc.
Checkpoint (7-10)
25. If you were contracting and relaxing your
masseter muscle, what would you probably be
doing?
© 2013 Pearson Education, Inc.
Checkpoint (7-10)
26. Which facial muscle would you expect to be well
developed in a trumpet player?
© 2013 Pearson Education, Inc.
Checkpoint (7-10)
27. Damage to the external intercostal muscles
would interfere with what important process?
© 2013 Pearson Education, Inc.
Checkpoint (7-10)
28. If someone were to hit you in your rectus
abdominis, how would your body position change?
© 2013 Pearson Education, Inc.
Appendicular Muscles (7-11)
• Muscles that position the pectoral girdle
• Muscles that move the arm, forearm, and wrist
• Muscles that move the hand and fingers
• Muscles of the pelvic girdle
• Muscles that move the thigh and leg
• Muscles that move the foot and toes
© 2013 Pearson Education, Inc.
Muscles That Position Pectoral Girdle (7-11)
• Trapezius
• Diamond-shaped muscle, has many actions depending on the
region
• Rhomboid
• Adducts and rotates scapula laterally
• Levator scapulae
• Adducts and elevates scapula
• Serratus anterior
• Abducts and rotates scapula
• Pectoralis minor and subclavius
• Depress and abduct shoulder
© 2013 Pearson Education, Inc.
Figure 7-17 Muscles That Position the Pectoral Girdle.
Superficial Dissection
Deep Dissection
Muscles That Position
the Pectoral Girdle
Trapezius
Muscles That Position
the Pectoral Girdle
Levator scapulae
Rhomboid muscles
Scapula
Serratus anterior
Triceps
brachii
Posterior view
Muscles That Position
the Pectoral Girdle
Trapezius
Levator scapulae
Subclavius
Pectoralis minor
Muscles That Position
the Pectoral Girdle
Pectoralis minor
(cut)
Serratus anterior
Pectoralis major
(cut and reflected)
Internal intercostals
Biceps brachii
External intercostals
Anterior view
© 2013 Pearson Education, Inc.
T12 vertebra
Table 7-8 Muscles That Position the Pectoral Girdle
© 2013 Pearson Education, Inc.
Muscles That Move the Arm (7-11)
• Deltoid
• Abducts arm, supraspinatus assists
• Subscapularis, teres major, infraspinatus, and
teres minor
• Form the rotator cuff
• Pectoralis major
• Flexes the arm at the shoulder
• Latissimus dorsi
• Extends the arm at the shoulder
PLAY
A&P FLIX™ Rotator cuff muscles: An overview (a)
PLAY
A&P FLIX™ Rotator cuff muscles: An overview (b)
© 2013 Pearson Education, Inc.
Figure 7-18 Muscles That Move the Arm.
Deep Dissection
Superficial Dissection
Sternum
Clavicle
Ribs (cut)
Muscles That
Move the Arm
Deltoid
Pectoralis major
Muscles That
Move the Arm
Subscapularis
Coracobrachialis
Teres major
Biceps brachii
Vertebra T12
Anterior view
Deep Dissection
Superficial Dissection
Muscles That
Move the Arm
Supraspinatus
Deltoid
Latissimus dorsi
Vertebra T1
Muscles That
Move the Arm
Supraspinatus
Infraspinatus
Teres minor
Teres major
Triceps brachii
Posterior view
© 2013 Pearson Education, Inc.
Table 7-9 Muscles That Move the Arm
© 2013 Pearson Education, Inc.
Muscles That Move the Forearm and Wrist
(7-11)
• Biceps brachii
• Flexes the elbow and supinates forearm
• Triceps brachii
• Extends elbow
• Brachialis and brachioradialis
• Flex elbow
• Flexor carpi ulnaris, flexor carpi radialis, and palmaris
longus
• Flex wrist
• Extensor carpi radialis and extensor carpi ulnaris
• Extend wrist
• Pronators and supinators
• Rotate radius
© 2013 Pearson Education, Inc.
Muscles That Move the Hand (7-11)
• Extensor digitorum
• Extends fingers
• Flexor digitorum
• Flexes fingers
• Abductor pollicis
• Abducts thumb
• Extensor pollicis
• Extends thumb
PLAY
A&P FLIX™ The elbow joint and forearm: An overview
© 2013 Pearson Education, Inc.
Figure 7-19 Muscles That Move the Forearm and Wrist.
Humerus
Coracobrachialis
Triceps brachii
Biceps brachii
Brachioradialis
Extensor
carpi radialis
Brachialis
Flexor carpi
Extensor
radialis
carpi ulnaris
Flexor
Extensor
digitorum
digitorum
superficialis
Abductor
pollicis
Flexor
Extensor
retinaculum
pollicis
Extensor
retinaculum
Flexor
carpi
ulnaris
Ulna
Pronator teres
Brachioradialis
Palmaris longus
Flexor carpi
ulnaris
Pronator
quadratus
Supinator
Pronator
teres
Ulna
Radius
Posterior view of
right upper limb
© 2013 Pearson Education, Inc.
Anterior view of
right upper limb
Anterior view of the
muscles of pronation
and supination when
the limb is supinated
Table 7-10 Muscles That Move the Forearm, Wrist, and Hand (1 of 2)
© 2013 Pearson Education, Inc.
Table 7-10 Muscles That Move the Forearm, Wrist, and Hand (2 of 2)
© 2013 Pearson Education, Inc.
Checkpoint (7-11)
29. Which muscle do you use to shrug your
shoulders?
© 2013 Pearson Education, Inc.
Checkpoint (7-11)
30. Sometimes baseball pitchers suffer rotator cuff
injuries. Which muscles are involved in this type of
injury?
© 2013 Pearson Education, Inc.
Checkpoint (7-11)
31.Injury to the flexor carpi ulnaris would impair
which two movements?
© 2013 Pearson Education, Inc.
Muscles That Move the Thigh (7-11)
• Gluteal group
• Includes gluteus maximus, the largest and most posterior;
is a hip extensor
• Adductors
• Include the adductor magnus, adductor brevis, adductor
longus, the pectineus, and the gracilis
• Largest hip flexor is the iliopsoas
• Made up of the psoas major and the iliacus
PLAY
A&P FLIX™ Anterior muscles that cross the hip joint
© 2013 Pearson Education, Inc.
Figure 7-20 Muscles That Move the Thigh.
Iliac crest
Gluteus
medius (cut)
Gluteus
maximus
(cut)
Sacrum
Gluteal region, posterior
view
Gluteal Group
Gluteus medius
Gluteus maximus
Gluteus minimus
Tensor fasciae
latae
Iliotibial tract
Vastus lateralis
Sartorius
Rectus
femoris
Biceps femoris
Semimembranosus
Plantaris
Head of fibula
L5
Patella
Patellar
Lateral ligament
view
Iliopsoas Group
Psoas major
Iliacus
Adductor Group
Pectineus
Adductor brevis
Adductor longus
Adductor magnus
Gracilis
Anterior view of the
iliopsoas muscle and
the adductor group
© 2013 Pearson Education, Inc.
Table 7-11 Muscles That Move the Thigh (1 of 3)
© 2013 Pearson Education, Inc.
Table 7-11 Muscles That Move the Thigh (2 of 3)
© 2013 Pearson Education, Inc.
Table 7-11 Muscles That Move the Thigh (3 of 3)
© 2013 Pearson Education, Inc.
Muscles That Move the Leg (7-11)
• Knee flexors are the hamstrings
• Biceps femoris, semimembranosus, semitendinosus,
and the sartorius
• Knee extensors are the quadriceps femoris
• Which include the rectus femoris and the three vastus
muscles
• Popliteus muscle
• Unlocks the knee joint
© 2013 Pearson Education, Inc.
Figure 7-21 Muscles That Move the Leg.
Iliac crest
Gluteus medius
Tensor fasciae
latae
Gluteus maximus
Iliacus
Psoas major
Iliopsoas
Tensor fasciae
latae
Pectineus
Adductor longus
Gracilis
Adductor magnus
Sartorius
Gracilis
Iliotibial tract
Flexors of the Knee
Extensors of the Knee
(Quadriceps muscles)
Rectus femoris
Biceps femoris
Vastus lateralis
Semitendinosus
Vastus medialis
Vastus intermedius
(deep to above muscles)
Semimembranosus
Quadriceps tendon
Sartorius
Patella
Popliteus
Patellar ligament
Hip and thigh, posterior view
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Quadriceps and thigh muscles, anterior view
Table 7-12 Muscles That Move the Leg
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Muscles That Move the Foot and Toes (7-11)
• The gastrocnemius of the calf is assisted by the
underlying soleus
• They share a common calcaneal tendon, and are both
plantar flexors
• Fibularis muscles
• Produce eversion and plantar flexion
• Tibialis
• Cause inversion of the foot
• Tibialis anterior is largest and produces dorsiflexion
© 2013 Pearson Education, Inc.
Figure 7-22a Muscles That Move the Foot and Toes.
Superficial Dissection
Deep Dissection
Ankle Extensors
Plantaris
Head of fibula
Gastrocnemius
Soleus
Popliteus
Ankle Extensors
(Deep)
Tibialis posterior
Fibularis longus
Fibularis brevis
Digital Flexors
Gastrocnemius
(cut and removed)
Flexor digitorum
longus
Flexor hallucis
longus
Calcaneal
tendon
Tendon of flexor
hallucis longus
Calcaneus
Tendons of fibularis
muscles
Posterior views
© 2013 Pearson Education, Inc.
Tendon of flexor digitorum
longus
Figure 7-22b Muscles That Move the Foot and Toes.
Iliotibial tract
Head of fibula
Ankle Extensors
Gastrocnemius
Ankle Flexors
Fibularis longus
Tibialis anterior
Soleus
Fibularis brevis
Digital Extensors
Extensor digitorum
longus
Tendon of extensor
hallucis longus
Calcaneal tendon
Retinacula
Lateral view
© 2013 Pearson Education, Inc.
Figure 7-22c Muscles That Move the Foot and Toes.
Patella
Medial surface
of tibial shaft
Patellar
ligament
Ankle Flexors
Ankle Extensors
Tibialis anterior
Gastrocnemius
Soleus
Digital Extensors
Tibialis posterior
Tendon of extensor
hallucis longus
Calcaneal tendon
Retinacula
Tendon of
tibialis anterior
Medial view
© 2013 Pearson Education, Inc.
Table 7-13 Muscles That Move the Foot and Toes (1 of 2)
© 2013 Pearson Education, Inc.
Table 7-13 Muscles That Move the Foot and Toes (2 of 2)
© 2013 Pearson Education, Inc.
Checkpoint (7-11)
32. You often hear of athletes suffering a "pulled
hamstring." To what does this phrase refer?
© 2013 Pearson Education, Inc.
Checkpoint (7-11)
33. How would you expect a torn calcaneal tendon
to affect movement of the foot?
© 2013 Pearson Education, Inc.
Four Effects of Aging on Skeletal Muscle (7-12)
1. Muscle fibers become smaller in diameter
2. Muscles become less elastic and more fibrous
3. Tolerance for exercise decreases due to a
decrease in thermoregulation
4. Ability to recover from injury is decreased
© 2013 Pearson Education, Inc.
Checkpoint (7-12)
34. Describe general age-related effects on skeletal
muscle tissue.
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Exercise Engages Multiple Systems (7-13)
• Cardiovascular system
• Increases heart rate and speeds up delivery of oxygen
• Respiratory system
• Increases rate and depth of respiration
• Integumentary system
• Dilation of blood vessels and sweating combine to increase
cooling
• Nervous and endocrine systems
• Control of heart rate, respiratory rate, and release of stored
energy
© 2013 Pearson Education, Inc.
SYSTEM INTEGRATOR
Skeletal
Removes excess body heat;
synthesizes vitamin D3 for calcium
and phosphate absorption; protects
underlying muscles
Provides mineral reserve for maintaining
normal calcium and phosphate levels in
body fluids; supports skeletal muscles;
provides sites of attachment
Muscular System
Body System
Skeletal muscles pulling on skin of
face produce facial expressions
Provides movement and support;
stresses exerted by tendons maintain
bone mass; stabilizes bones and
joints
(Page 138)
Muscular System
Integumentary
Integumentary
Body System
Skeletal
(Page 188)
Figure 7-23
Endocrine
(Page 376)
Reproductive
(Page 671)
Urinary
(Page 637)
Digestive
(Page 572)
Respiratory
(Page 532)
Lymphatic
(Page 500)
Cardiovascular
(Page 467)
The muscular system performs five
primary functions for the human
body. It produces skeletal
movement, helps maintain
posture and body position,
supports soft tissues, guards
entrances and exits to the body,
and helps maintain body
temperature.
Nervous
(Page 302)
The MUSCULAR System
© 2013 Pearson Education, Inc.
Checkpoint (7-13)
35. What major function does the muscular system
perform for the body as a whole?
© 2013 Pearson Education, Inc.
Checkpoint (7-13)
36. Identify the physiological effects of exercise on
the cardiovascular, respiratory, and integumentary
systems, and indicate the relationship between
these physiological effects and the nervous and
endocrine systems.
© 2013 Pearson Education, Inc.