CHAPTER 9: MUSCULAR SYSTEM
OBJECTIVES:
1.
Compare and contrast the types of muscle tissues in terms of structure, control, location,
and type of contraction, and function.
2.
Describe three similarities among the three muscle tissues.
3.
Identify the terms used for a muscle fiber's cell membrane and cytoplasm.
4.
Describe the functions of muscle tissue.
5.
Compare and contrast the functional characteristics of muscle tissue (i.e. excitability,
contractility, extensibility, and elasticity).
6.
Illustrate how a skeletal muscle is wrapped in four layers of connective tissue.
7.
Define the terms tendon, aponeurosis, raphe, and syncytium.
8.
Illustrate how the myofibrils that compose skeletal muscle fibers are composed of
sarcomeres. Label the thick filaments, thin filaments, A-Band, I-Band and Z-line.
9.
Compare and contrast the ultrastructure of thick and thin filaments.
10.
Explain the significance of the special membranous organelles found in skeletal muscle
tissue.
11.
Explain what happens to sarcomere structure when a muscle contracts.
12.
Explain the role that calcium plays in contraction.
13.
Name the organelle that contains a high concentration of calcium due to the action of a
calcium pump.
14.
List the sequence of events involved in the power stroke of muscle contraction.
15.
Define the terms neuromuscular junction (NMJ), motor unit, motor end plate and
neurotransmitter.
16.
Identify the neurotransmitter involved in muscle contraction.
17.
List the sequence of events involved in skeletal muscle fiber contraction beginning with
the necessary motor impulse initiated by the brain.
18.
Explain how and why a contracted muscle relaxes.
19.
Name the three pathways that regenerate energy/ATP in muscle cells.
20.
Outline a general overview of cellular respiration, denoting its two major parts and where
each occurs in the cell. Be sure to include starting products, end products, and any
additional requirements. Then discuss the significance of this pathway in skeletal muscle
contraction (don't forget that the midpoint product can take one of two pathways!!!).
21.
Explain how lactic acid is produced and what its accumulation causes.
22.
Define the term oxygen debt.
23.
Demonstrate the negative feedback mechanisms that maintain thermal homeostasis.
24.
Define the term threshold stimulus, and give the numerical value in skeletal muscle cells.
25.
A myogram measures a muscle contraction as a twitch. What does this term mean?
26.
Describe what is meant by "all or nothing" response in skeletal muscle fibers.
27.
Define the term used to describe a myogram that shows a series of twitches with
increasing strength.
28.
Name the term when a myogram illustrates a sustained contraction that lacks even slight
relaxation between twitches.
29.
Compare and contrast isometric and isotonic muscle contractions.
30.
List the differences between fast and slow muscle fibers, and explain why they are also
called white and red fibers, respectively.
31.
Distinguish between multi-unit and visceral smooth muscle and give examples of each
type.
32.
Define peristalsis.
33.
List the characteristics of cardiac muscle tissue.
34.
Define the terms origin and insertion as they relate to a skeletal muscle.
35.
Define the terms prime mover, antagonist, synergists, and fixator as they relate to muscle
actions, and use the thigh muscles as an example.
36.
For every skeletal muscle listed in this outline, be able to complete the following:
A.
locate the muscle on a
diagram or human
muscle model.
describe the
shape and/or
fascicle
arrangement
of the muscle.
B.
C.
D.
identify key origin and insertion sites.
describe the action.
I.
OVERVIEW OF MUSCLE TISSUES: Review from Chapter 5.
A.
Skeletal
B.
Similarities:
1.
All muscle cells are elongated = muscle fibers;
2.
Muscle contraction depends on two kinds of myofilaments (actin and
myosin);
3.
The cell membrane of a muscle cell is called "sarcolemma", while the
cytoplasm of a muscle cell is called "sarcoplasm".
C.
Skeletal Muscle Characteristics:
1.
long, thin and multi-nucleated fibers;
2.
striations;
3.
voluntary control;
4.
arranged into packages called muscles that attach to and cover the bony
skeleton;
5.
contracts rapidly & vigorously, but tired easily; may exert great force.
D.
Cardiac Muscle Characteristics:
1.
network of branched fibers connected by gap junctions (intercalated
disks);
2.
only in heart;
3.
striations;
4.
involuntary control;
5.
contracts at rhythmic, steady rate set by "pacemaker".
E.
Smooth Muscle Characteristics:
1.
lacks striations;
2.
walls of hollow visceral organs and blood vessels;
3.
involuntary control;
4.
contractions are slow & sustained.
F.
Functions:
1.
Movement = locomotion & manipulation, vision, facial expression
(skeletal), blood pumping (cardiac), food digesting, urination (smooth);
2.
Posture Maintenance (skeletal)
3.
Joint Stability (skeletal)
4.
Heat Generation (skeletal)
G.
II.
Muscle Types:
Smooth
Cardiac
Functional Characteristics of Muscle:
1.
Excitability = the ability to receive and respond to stimuli;
2.
Contractility = the ability to shorten forcibly when stimulated;
3.
Extensibility = the ability to be stretched or extended;
4.
Elasticity = the ability to bounce back to original length
SKELETAL MUSCLE
Introduction: Each skeletal muscle is an organ made up of skeletal muscle fibers,
connective tissue coverings, blood vessels, and nerve fibers.
A.
Structure of a Skeletal Muscle:
1. Connective Tissue Coverings: See Fig 9.2, page 280.
a.
Each muscle fiber (cell) is wrapped in a thin,
delicate layer of CT called endomysium.
b.
Many muscle fibers are bundled together
into groups called fascicles; See Fig 9.3, page 280.
o
Each fascicle is wrapped in a second layer of CT made of
collagen called perimysium.
c.
Many fascicles are bundled together to form a skeletal muscle.
o
Each skeletal muscle is covered by a third layer of dense,
fibrous CT called epimysium.
d.
Each skeletal muscle is then covered by a fourth, very
tough fibrous layer of CT called deep fascia.
o
The deep fascia may extend past the length of the muscle
(tendon or aponeurosis), and attach that muscle to a bone,
cartilage or muscle.
o
See Fig 9.1, page 279 to compare these two extensions.
B.
Skeletal Muscle Fibers
Recall that skeletal muscle tissue possesses striations: See Fig 9.7, page 282.
1.
A muscle fiber is a long, thin cell;
a.
Each muscle fiber is composed of myofibrils;
o
Each myofibril is composed of two types of protein
filaments (cytoskeletal elements): See Fig 9.4, page 281
1.
Thick filaments primarily composed of the
protein myosin;
2.
Thin filaments primarily composed of the
protein actin.
o
Striations are caused by the arrangement of thick and thin
filaments within the myofibrils:
See Fig 9.5, page 281.
1.
A-Band
=
dark area = overlapping of thick and thin filaments;
2.
I-Band = light area = thin filaments alone.
o
The length of each myofibril is divided into sarcomeres:
1.
Sarcomeres meet one another at an area
called the Z-line.
o
See Fig 9.4, Fig 9.5, Fig 9.6 page 281 and Fig 9.7, page 282
II.
SKELETAL MUSCLE
B.
Skeletal Muscle Fibers
2.
3.
Thick filaments = protein myosin.
a.
rod-like tail (axis) that terminates in two globular heads or cross
bridges;
b.
Cross bridges interact with active sites on thin filaments;
Thin filaments = protein actin.
a.
coiled helical structure (resembles twisted strands of pearls):
b.
Tropomyosin = rod-shaped protein spiraling around actin
backbone to stabilize it;
c.
Troponin = complex of polypeptides:
o
o
o
d.
Both tropomyosin and troponin help control actin's interaction with
myosin during contraction.
4.
Within the sarcoplasm of a muscle fiber, there are two
specialized membranous organelles: See Fig 9.7, page 282.
a.
Sarcoplasmic reticulum (SR)
o
Network of membranous channels that surrounds each
myofibril and runs parallel to it.
o
Same as endoplasmic reticulum in other cells.
o
SR has high concentrations of calcium ions compared to
the sarcoplasm (maintained by active transport calcium
pump).
o
When stimulated by muscle impulse, membranes become
more permeable to calcium ions and calcium diffuses out of
SR and into sarcoplasm.
b.
Transverse tubules (TT)
o set of membranous channels that extends into the
sarcoplasm as invaginations continuous with muscle cell
membrane (sarcolemma).
o TTs are filled with extracellular fluid and extend deep into
the cell.
o Each TT runs between two enlarged portions of SR called
cisternae.
 These structures form a triad near the region where
actin and myosin overlap.
c.
SR and TT are involved in activating the muscle contraction
mechanism (discussed in greater detail later).
d.
Because one TT is associated with two SR they are termed the
Triad
II.
SKELETAL MUSCLE
C.
Skeletal Muscle Contraction:
1.
Neuromuscular Junction - Stimulation of Skeletal Muscle Cell:
See Figure 9.9, page 283.
a.
b.
2.
Stimulus for Contraction
See Table 9.1, page 287.
a.
b.
c.
d.
e.
II.
Neuromuscular Junction (NMJ) = the site where a motor nerve
fiber and a skeletal muscle fiber meet; (also called a synapse or
synaptic cleft)
In order for a skeletal muscle to contract, its fibers must first be
stimulated by a motor neuron.
c.
Motor Unit = one motor neuron and many
skeletal muscle fibers; See Fig 9.9, page 283.
d.
Motor End Plate = the specific part of a
skeletal muscle fiber's sarcolemma directly beneath the NMJ.
e.
Neurotransmitter = chemical substance
released from a motor end fiber, causing stimulation of the
sarcolemma of muscle fiber; acetylcholine (ACh).
f.
Synaptic cleft – small space between
neuron and muscle
Introduction: The function of skeletal muscle is to move bones of
the skeleton under voluntary control. Contraction of a skeletal
muscle fiber is a complex interaction of several cellular and
chemical constituents. The final result is a movement whereby
actin and myosin filaments slide past one another. Accordingly,
the muscle fiber shortens and pulls on its attachments.
The process begins when a motor impulse is initiated by the brain,
travels down the spinal cord, into a motor neuron, which branches
into many motor nerve fibers/endings;
o
Each motor nerve fiber extends to the motor end-plate of a
skeletal muscle fiber forming a neuromuscular junction
(NMJ);
When the motor impulse reaches the end of the motor nerve
fiber/ending, the membrane is depolarized (-70mV to -55mV);
o
calcium ions rush into motor nerve fiber, and
o
neurotransmitter (Acetylcholine) is released into the NMJ
(via exocytosis).
Acetylcholine diffuses across the NMJ & stimulates/depolarizes
the motor end-plate (sarcolemma) of a skeletal muscle fiber from 100mV to –70mV;
The muscle impulse travels over the surface of the skeletal muscle
fiber and deep into the muscle fiber by means of the TT
SKELETAL MUSCLE
C.
Skeletal Muscle Contraction:
II.
3.
Excitation Contraction Coupling
a.
The muscle impulse reaches the sarcoplasmic reticulum, which
releases calcium ions into the sarcoplasm of the muscle fiber;
b.
Calcium binds to troponin, moving tropomyosin and exposing
myosin binding sites on actin filament;
c.
Cross-bridges (linkages) form between actin and myosin;
d.
Actin filaments are pulled inward by myosin cross-bridges;
e.
The muscle fiber shortens as contraction occurs.
4.
Sliding Filament Theory:
a.
most popular theory concerning muscle contraction;
b.
first proposed by Hugh Huxley in 1954;
c.
states that muscle contraction involves the sliding movement of
the thin filaments (actin) past the thick filaments (myosin);
d.
Sliding continues until the overlapping between the thin & thick
filaments is complete.
*Remember that in a relaxed muscle cell, overlapping of thick and thin
filaments is only slight.
e.
Changes in muscle during contraction: See Fig 9.8, page 283.
o
The distance between the Z-lines of the sarcomeres
decreases;
o
The I-Bands (light bands) shorten;
o
The A-Bands move closer together, but do not diminish in
length.
f.
The Role of Calcium in Contraction Mechanism:
o
In a resting muscle cell (i.e. in the absence of calcium
ions):

Tropomyosin blocks or inhibits the myosin
binding sites on actin.

See Fig 9.10a, page 285.
o
When calcium ions (Ca++) are present:

Ca++ binds to troponin causing a
conformational change in the troponin-complex,
which causes:
1.
Tropomyosin to move
2.
which "opens" or exposes the myosin
binding sites on actin;
3.
This results in interaction between the active
sites on actin and the heads (or cross bridges) of
myosin.

See Fig 9.10b, page 285
SKELETAL MUSCLE
C.
Skeletal Muscle Contraction:
5.
Cross-Bridge Cycling
See Fig 9.11, page 286.
When calcium ions are present, the myosin binding sites on actin are
exposed:
a.
Cross-bridge attaches.
o
ATP breakdown provides energy to “cock” myosin head.
o
“Cocked” myosin attaches to exposed actin binding site
b.
Cross-bridge (myosin head) springs from cocked position and pulls
on actin filament.
c.
Cross bridges break.
o
ATP binds to cross-bridge (but is not yet broken down)
o
Myosin heads are released from actin.
* As long as calcium ions and ATP are present, this walking continues
until the muscle fiber is fully contracted.
6.
Relaxation:
a.
Acetylcholinesterase is an enzyme present in the NMJ;
b.
It immediately destroys acetylcholine, so the motor end-plate is no
longer stimulated (i.e. it cannot cause continuous muscle
contraction).
c.
Calcium ions are transported from sarcoplasm back into
sarcoplasmic reticulum.
d.
Linkages between actin and myosin are broken.
e.
The muscle fiber relaxes.
7.
Energy Sources for Contraction:
a.
Introduction: The energy used to power the interaction between
actin and myosin comes from ATP.
b.
ATP stored in skeletal muscle lasts only about six seconds.
o
ATP must be regenerated continuously if contraction is to
continue.
o
There are three pathways in which ATP is regenerated:
1.
Coupled Reaction with Creatine Phosphate (CP)
2.
Anaerobic Cellular Respiration
3.
Aerobic Cellular Respiration
c.
Coupled Reaction with Creatine Phosphate (CP)
See Fig 9.12, page 287.
o
o
o
II.
CP + ADP <------> creatine + ATP
Muscle stores a lot of CP,
This coupling reaction allows for about 10 seconds worth
of ATP.
SKELETAL MUSCLE
C.
Skeletal Muscle Contraction:
8.
Oxygen Supply and Cellular Respiration: See Fig 9.13, page 288.
Review from Chapter 4.
a.
Anaerobic Respiration
o
Steps are called glycolysis.
o
Steps occur in the cytoplasm of the cell.
o
Results in production of pyruvic acid and 2 ATP.
b.
Aerobic Respiration
o
Steps are called citric acid cycle and electron transport
chain.
o
Oxygen is required.
o
Steps occur in the mitochondrion of the cell.
o
Results in CO2, water and 36ATP.
* Read box at the bottom of page 309, which illustrates how a runner
utilizes the sources discussed above.
9.
Muscle Fatigue
a.
Muscle fatigue is a state of physiological inability to contract;
b.
If no oxygen is available in muscle cells to complete aerobic
respiration, pyruvic acid is converted to lactic acid, which causes
muscle fatigue and soreness; See Fig 9.13 and 9.14, pages 288 +
289.
c.
Results from a relative deficit of ATP and/or accumulation of
lactic acid (which decreases pH).
10.
a.
b.
11.
II.
Oxygen Debt:
See Fig 9.14, page 289.
The oxygen debt is the amount of oxygen necessary to support the
conversion of lactic acid to glycogen.
needed to replenish spent glycogen stores.
Heat Production
a.
Almost half of the energy released during muscle contraction is
lost to heat, which helps maintain our body temperature at 37o C.
b.
Excessive heat is lost through many negative feedback
mechanisms (discussed in chapter 1) including sweating, dilation
of superficial blood vessels, increased breathing rate, and increased
heart rate.
SKELETAL MUSCLE
D.
MUSCULAR RESPONSES
1.
2.
3.
II.
Threshold Stimulus
a.
The minimal strength of stimulation required to cause contraction.
b.
A skeletal muscle fiber’s resting membrane potential must be
depolarized from –100mV to –70mv before an impulse begins;
Therefore the threshold stimulus is +30mV.
Recording a Muscle Contraction: See Fig 9.15, page 290.
a.
A myogram is a recording of a muscle contraction.
b.
A twitch is a single contraction that lasts a fraction of a second,
followed by relaxation.
c.
The delay between stimulation and contraction is called the latent
period.
d.
A muscle fiber must return to its resting state (-100mV) before it
can be stimulated again. This is called the refractory period.
e.
All-or-Nothing Response
o
If a muscle fiber is brought to threshold or above, it responds
with a complete twitch.
o
If the stimulus is sub-threshold, the muscle fiber will not
respond.
f.
Staircase Effect (treppe): See Fig 9.16a, page 291.
o
Most muscle fiber contraction is “all-or-nothing”.
o
However a muscle fiber that has been inactive can be
subjected to a series of stimuli and:

the fiber undergoes a series of twitches with
relaxation between, and

the strength of each successive contraction increases
slightly.
o
This phenomenon is small and brief and involves excess
calcium in sarcoplasm.
Summation: See Fig 9.16b, page 291.
a.
When several stimuli are delivered in succession to a muscle fiber,
it cannot completely relax between contractions.
b.
The individual twitches begin to combine and the muscle
contraction becomes sustained.

In a sustained contraction, the force of individual twitches
combines in a process called summation.

When the resulting sustained contraction lacks even slight
relaxation, it is called titanic contraction;
c.
Fig 9.16c, page 291.
SKELETAL MUSCLE
D.
MUSCULAR RESPONSES
4.
Motor Units: See Fig 9.9, page 283.
a.
Definition: A motor unit is a motor neuron and the many skeletal
5.
6.
7.
muscle fibers it stimulates.
b.
Because the motor neuron branches into several motor nerve
endings, it can stimulate many skeletal muscles fibers
simultaneously, which then contract simultaneously.
c.
The number of muscle fibers in a motor unit varies from 10hundreds.
Recruitment of Motor Units
a.
Because a whole muscle is composed of many motor units,
controlled by many different motor neurons, simultaneous
contraction of all units does not necessarily occur.
b.
As the intensity of stimulation increases, recruitment of motor
units increases, until all contract simultaneously.
Sustained Contractions
a.
Even when a muscle is at rest, a certain amount of sustained
contraction is occurring in its fibers. This is called muscle tone.
o
Muscle tone is very important in maintaining posture.
Types of Contractions: See Fig 9.18, page 295.
a.
Isotonic contractions
o
The muscle shortens and its attachment(s) move(s).
b.
Isometric contraction,
o
The muscle becomes taut, but the attachment(s) do not
move; tensing a muscle;
c.
Most muscular movements involve both isotonic and isometric
contractions.
d.
Read Clinical Application 9.2, page 293 re: use and disuse of
skeletal muscles.
8.
III.
Fast and Slow Muscle Fibers
a.
Muscle fibers vary in contraction speed (i.e. slow or fast twitch).
b.
Slow-Twitch Fibers are also called red fibers.
o
contain oxygen carrying pigment, myoglobin, receive a rich
blood supply, and contain many mitochondria
o
can generate ATP fast enough to keep up with breakdown.
o
These fibers contract for long periods without fatiguing.
c.
Fast-twitch fibers are also called white fibers.
o
contain less myoglobin, blood, and fewer mitochondria.
o
contain extensive sarcoplasmic reticulum to store and
reabsorb calcium.
o
These fibers contract rapidly, but fatigue easily due to lactic
acid accumulation.
d.
Read box at bottom of page 293 re: dark and white meat.
SMOOTH MUSCLE:
A.
Introduction: The contraction mechanism of smooth muscle is similar to that of
skeletal muscle in that interaction occurs between actin and myosin, however the
transverse tubules and sarcoplasmic reticula are greatly reduced, and troponin is
absent.
B.
Smooth Muscle Fibers - Two types:
1.
Multi-unit smooth muscle
a.
location:
o
irises of eyes
o
walls of blood vessels
b.
Contraction is rapid and vigorous (similar to skeletal muscle
tissue).
2.
C.
Visceral smooth muscle
a.
Location = the walls of hollow organs
b.
Contraction is slow and sustained.
o
Rhythmicity = pattern of repeated contractions;
o
Peristalsis = wave-like motion that helps push substances
through passageways.
c.
Structure:
o
random arrangement of actin and myosin filaments.
o
Two layers of muscle surround the passageway.
1.
inner circular layer
2.
outer longitudinal layer
Smooth Muscle Contraction:
1. A protein, calmodulin binds to calcium ions (no troponin) and activates the
contraction mechanism.
2. Most calcium diffuses in to smooth muscle cells from the extracellular fluid
(reduced SR).
3. Norepinephrine and acetylcholine are smooth muscle neurotransmitters.
4. Contraction is slow and sustained.
IV.
CARDIAC MUSCLE:
296.
See Fig 9.19, page
Will be studied in
greater detail in Chapter 15.
A.
Location:
1.
Only in heart.
B.
Anatomy:
1.
Striated uninuclear cells joined end-to-end forming a network.
a.
Cell junctions are called intercalated discs.
o
gap junctions
2.
Arrangement of actin and myosin not as organized as skeletal muscle.
3.
Contains sarcoplasmic reticula, transverse tubules, and numerous
mitochondria:
a.
Sarcoplasmic reticulum is less developed than SR in skeletal
muscle and stores much less calcium.
C.
Physiology
1.
Self-exciting tissue (i.e. “Pacemaker”);
2.
Rhythmic contractions (60-100 beats/minute);
3.
Involuntary, all-or-nothing contractions
a.
Function as a “syncytium” (all-or-nothing)
4.
Pumps blood to:
a.
Lungs for oxygenation;
b.
Body for distribution of oxygen and nutrients.
V.
SKELETAL MUSCLE ACTIONS
A.
Introduction: Skeletal muscles generate a great variety of body movements. The
action of a muscle primarily depends upon the joint associated with it and the
manner in which the muscle is attached on either side of that joint.
B.
Origin and Insertion: Recall that skeletal muscles are usually attached to a fixed
body part and a movable body part: See Fig 9.20, page 297.
1.
The origin of a muscle is its immovable (anchored) end.
2.
The insertion of a muscle is the movable end of a muscle.
*When a muscle contracts and shortens, its insertion is pulled toward its origin.
C.
Review of Skeletal Muscle Actions:
1.
Flexion = decreasing the angle between 2 bones;
a.
Dorsiflexion = decreasing the angle between the foot and shin;
b.
Plantar flexion = pointing toes;
2.
Extension = increasing the angle between 2 bones;
3.
Abduction = moving a body part away from the midline;
4.
Adduction = moving a body part toward the midline;
5.
Circumduction = movement in a circular (cone-shaped) motion;
6.
Rotation = turning movement of a bone about its long axis; (i.e.
atlas/axis);
7.
Supination = thumbs up;
8.
Pronation = thumbs down;
9.
Inversion = sole of foot in;
10.
Eversion = sole of foot out;
11.
Elevation = lifting a body part; (i.e. shoulder shrug);
12.
Depression = returning a body part to pre-elevated position.
D.
Interactions of Skeletal Muscles
1.
Prime Mover (agonist) = the primary muscle responsible for a
movement.

The biceps brachii in flexing the arm at the elbow,
2.
Antagonist(s) = the muscle(s) in opposition to the action of
the prime mover. The antagonist relaxes (or stretches) during the prime
movement.

The triceps brachii is the antagonist of the biceps brachii
when we flex the arm at the elbow.
3.
Synergist(s) = muscles that assist the prime mover.

The brachialis helps the biceps brachii during elbow flexion.
4.
Fixators = muscle groups that stabilize the origin of the
prime mover (i.e. hold it in place) so that the prime mover can act
more efficiently.

The scapula is the origin for many arm muscles, but it must
be held in place by fixator muscles in order to function in this way.
a.
serratus anterior
b.
pectoralis minor
VI.
MAJOR SKELETAL MUSCLES - Naming
CHARACTERISTIC
EXAMPLES
EXAMPLES IN HUMANS
Direction of fascicles
relative to midline
rectus = parallel
transverse = perpendicular
oblique = at 45o angle
Rectus abdominis
Transversus abdominis
External Oblique
Location (i.e. the bone or
body part that a muscle
covers)
frontal bone
tibia
Frontalis
Tibialis Anterior
Relative Size
maximus = largest
longus = longest
brevis = shortest
Gluteus maximus
Palmaris longus
Peroneus longus
Number of Origins (Heads)
biceps = 2 origins
triceps = 3 origins
Biceps brachii
Triceps brachii
Shape
deltoid = triangle
trapezius = trapezoid
serratus = saw-toothed
orbicularis = circular
Deltoid
Trapezius
Serratus anterior
Orbicularis oris
Location of Origin and/or
Insertion
origin = sternum
insertion = mastoid process
Sternocleidomastoid
Action of Muscle
flexion
extension
adduction
Flexor carpi radialis
Extensor digitorum
Adductor longus
VII.
MAJOR SKELETAL MUSCLES (Keyed at the end of this outline)
Use the figures and tables on pages 298-325 to complete the following information.
If a muscle is starred (*), please include its origin and insertion. Also see References
Plates on pages 332-336.
A.
Muscles of Facial Expression:
See Fig 9.22 on page 298, and Table 9.3 on page 299.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Epicranius
Frontalis
Occipitalis
Orbicularis oris
Zygomaticus (*)
Buccinator
Platysma
Orbicularis oculi
B.
Muscles of Mastication: See Fig 9.22 on page 298, and Table 9.4 on page 300.
NAME OF MUSCLE
Masseter(*)
Temporalis
LOCATION/
DESCRIPTION
ACTION
VII.
MAJOR SKELETAL MUSCLES (continued)
C.
Muscles that move the Head and Vertebral Column:
See Fig 9.23 on page 301, and Table 9.5 on page 302.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Sternocleidomastoid (*)
Erector Spinae
D.
Muscles that move the Pectoral Girdle:
See Fig 9.25 on page 304, Fig 9.26 on page 305, and Table 9.6 on page 304.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Trapezius (*)
Pectoralis minor
Serratus anterior
E.
Muscles that move the Arm (Humerus):
See Fig 9.25, page 304, Fig 9.26, page 305, and Table 9.7, page 306.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
Pectoralis major (*)
Latissimus dorsi
Deltoid
VII.
MAJOR SKELETAL MUSCLES (continued)
ACTION
F.
Muscles that move the Forearm (radius & ulna):
See Fig 9.28, page 307, Fig 9.29, page 309, and Table 9.8, page 308.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Biceps Brachii (*)
Brachialis
Brachioradialis
Triceps brachii
G.
Muscles that move the Hand
See Fig 9.30, page 310, Fig 9.31, page 311, and Table 9.9, page 311.
NAME OF MUSCLE
Flexor carpi radialis
Flexor carpi ulnaris
Palmaris longus
Extensor digitorum
LOCATION/
DESCRIPTION
ACTION
VII.
MAJOR SKELETAL MUSCLES (continued)
H.
Muscles of the Abdominal Wall:
See Fig 9.32, page 313, and Table 9.10, page 312.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Rectus abdominis (*)
External Oblique
Internal Oblique
Transversus abdominis
I.
Muscles of the Pelvic Outlet
See Fig 9.33 page 314 and Table 9.11 page 315.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
Levator ani
Coccygeus
Superficial transversus perinei
Bulbospongiosus
Ischiocavernosus
Sphincter urethrae
VII.
MAJOR SKELETAL MUSCLES (continued)
ACTION
J.
Muscles that move the Thigh (Femur):
See Fig 9.18, page 341, Fig 9.37, page 319, and Table 9.12, page 319.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Gluteus Maximus (*)
Gluteus Medius
Adductor Longus
K.
Muscles that move the Leg (Tibia & Fibula):
See Fig 9.35, page 317, Fig 9.37, page 319, and Table 9.13, page 320.
NAME OF MUSCLE
Rectus femoris
Vastus lateralis
Vastus Medialis
Vastus intermedius
Sartorius (*)
Biceps femoris
Semitendinosus
Semimembranosus
LOCATION/
DESCRIPTION
ACTION
VII.
MAJOR SKELETAL MUSCLES (continued)
L.
Muscles that move the Foot & Toes
See Fig 9.39, page 323, Fig 9.40, page 324, Fig 9.41, page 325, and
Table 9.14, page 348.
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Tibialis anterior
Fibularis longus
Gastrocnemius (*)
Soleus
Note the location of the Calcaneal Tendon in Fig 9.40, page 324.
VIII.
LIFE SPAN CHANGES
A.
Supplies of ATP, myoglobin, and creatine phosphate in muscle fibers begin to
decline in one’s forties.
B.
Half of one’s muscle mass has been replaced by connective and adipose tissue by
age 80, and reflexes are reduced.
C.
Exercise is the best way to maintain muscle function.
IX.
Homeostatic Imbalances/Disorders
A. Tendinitis (page 278)
B. Compartment Syndrome (page 278)
C. Muscle Strain (page 282)
D. Poliomyelitis (page 283)
E. Myasthenia Gravis (CA 9.1, page 284)
F. Duchenne Muscular Dystrophy (page 282)
G. Rigor Mortis (page 287)
H. Botulism (page 284)
I. Use and Disuse of Skeletal Muscles (CA 9.2, page 293)
J. TMJ (CA 9.3, page 300)
K. Parkinson's Disease (page 312)
X.
Innerconnections of the Muscular System: See page 326.
XI.
Clinical Terms Related to the Muscular System. See page 327.
SKELETAL MUSCLE SUMMARY TABLES
A.
Muscles of Facial Expression
NAME OF MUSCLE
LOCATION/
DESCRIPTION
Covers cranium
Epicranius
Frontalis
Occipitalis
ACTION
elevates eyebrow
over forehead
over occipital
Orbicularis oris
circular muscle around the
mouth
closes lips
(“kissing muscle”)
Zygomaticus (*)
Origin: zygomatic arch
Insertion: corners of
orbicularis oris
muscle that connects
zygomatic arch to corner of
mouth
elevates corners of mouth
(“smiling muscle”)
Buccinator
hollow of cheek
compresses cheeks
“trumpeter’s muscle”
Platysma
over lower jaw to neck
depresses mandible
Orbicularis oculi
circular muscle around eye
closes eye
B.
Muscles of Mastication
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Masseter(*)
Origin: Zygomatic Arch
Insertion: Lateral Mandible
over lateral mandible
elevates mandible
Temporalis
convergent muscle over
temporal bone
elevates mandible
SKELETAL MUSCLE SUMMARY TABLES
C.
Muscles that move the Head and Vertebral Column:
NAME OF MUSCLE
LOCATION/
DESCRIPTION
Sternocleidomastoid(*)
Origin: sternoclavicular
region
Insertion: mastoid process
of temporal
Major neck muscle
flexion of head toward chest
(both contracted)
rotation/abduction of head
(as antagonists)
Erector Spinae
Group of midline dorsum
muscles
Maintain posture
D.
ACTION
Muscles that move the Pectoral Girdle
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Trapezius (*)
Origin: occipital bone &
spines of C7-T12
Insertion: clavicle and
acromion process of
scapulae
Trapezoid shaped muscle in
posterior neck and upper
back
elevates pectoral girdle
(“shoulder shrug”)
Pectoralis minor
Muscle deep to Pectoralis
major
scapula fixator
Serratus anterior
Saw-toothed lateral thoracic
muscle
scapula fixator
E.
Muscles that move the Arm (Humerus)
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Pectoralis major (*)
Origin: clavicle, sternum, &
costal cartilages of ribs 1-6
Insertion: Greater tubercle
of humerus
Large, convergent chest
muscle
flexes arm medially (pull
arms forward and together)
Latissimus dorsi
Large, back muscle
adduction of humerus
Deltoid
Triangular shaped shoulder
muscle
abduction of humerus
SKELETAL MUSCLE SUMMARY TABLES
F.
Muscles that move the Forearm (radius & ulna)
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Biceps Brachii (*)
Origin: Coracoid process
Insertion: Radial tuberosity
fusiform, parallel, anterior
upper arm muscle (two
origins)
flexion of arm at elbow
(prime mover)
Brachialis
muscle beneath biceps
brachii
flexion of arm at elbow
(synergist)
Brachioradialis
lateral muscle between upper
and forearm
flexion of arm at elbow
(synergist)
Triceps brachii
posterior upper arm muscle
(three heads)
extension of arm at elbow
G.
Muscles that move the Hand
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Flexor carpi
Radialis
anterior, lateral forearm
muscle
flexion of wrist
Flexor carpi
Ulnaris
anterior, medial forearm
muscle
flexion of wrist
Palmaris longus
anterior forearm muscle
located between two above
flexion of wrist
Extensor digitorum
posterior forearm muscle
extension of wrist/fingers
SKELETAL MUSCLE SUMMARY TABLES
H.
Muscles of the Abdominal Wall
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Rectus abdominis (*)
Origin: pubic crest &
symphysis
Insertion: xiphoid process &
costal cartilages of 5-7th ribs
strap like muscle from costal
cartilages to ilium
tenses abdominal wall
External Oblique
superficial/lateral oblique
abdominal muscle
tenses abdominal wall
Internal Oblique
deep oblique abdominal
muscle
tenses abdominal wall
Transversus abdominis
deep abdominal muscle that
runs perpendicular to rectus
abdominis
tenses abdominal wall
I.
Muscles of the Pelvic Outlet
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Levator ani
Thin sheet surrounding anus,
urethra and vagina
Supports viscera and aids
sphincters
Coccygeus
Fan shaped, posterior to
levator ani
Same as above
Superficial transversus
perinei
Band of muscle anterior to
levator ani
Supports viscera
Bulbospongiosus
Surrounds base of penis or
vagina
Male – assists ejaculation
Female – constricts vaginal
orifice
Ischiocavernosus
Band of muscle lateral to
bulbospongiosus
Same as above
Sphincter urethrae
Surround urethra
Opens and closes urethral
orifice
SKELETAL MUSCLE SUMMARY TABLES
J.
Muscles that move the Thigh (Femur)
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Gluteus Maximus (*)
Origin: dorsal ilium,
sacrum, coccyx
Insertion: posterior femur
buttocks, largest muscle in
body
extension of hip at thigh (as
in walking or climbing
stairs)
Gluteus Medius
lateral hip muscle
abduction of femur
Adductor Longus
medial thigh muscle
adduction of femur
K.
Muscles that move the Tibia & Fibula
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Rectus femoris
anterior thigh; quadriceps
extension of leg at knee
Vastus lateralis
lateral anterior thigh;
quadriceps
extension of leg at knee
Vastus Medialis
medial anterior thigh;
quadriceps
extension of leg at knee
Vastus intermedius
deep anterior thigh;
quadriceps
extension of leg at knee
Sartorius (*)
Origin: iliac spine
Insertion: medial tibia
parallel strap-like muscle
that crosses thigh
flexion of knee forward
Biceps femoris
posterior thigh; hamstring
flexion of leg at knee
Semitendinosus
posterior thigh; hamstring
flexion of leg at knee
Semimembranosus
posterior thigh; hamstring
flexion of leg at knee
SKELETAL MUSCLE SUMMARY TABLES
L.
Muscles that move the Foot & Toes
NAME OF MUSCLE
LOCATION/
DESCRIPTION
ACTION
Tibialis anterior
anterior to tibia
dorsiflexion
Peroneus longus
lateral to fibula
eversion
Gastrocnemius (*)
Origin: condyles of femur
Insertion: calcaneus
posterior lower leg (i.e. calf
muscle); two origins
plantar flexion (prime
mover)
Soleus
deep to gastrocnemius
plantar flexion (synergist)
Shier, Butler, and Lewis: Hole’s Human Anatomy and Physiology, 10 th ed.
Chapter 9: Muscular System
I. Structure of a Skeletal Muscle
A. Introduction
1. A__________________________________ is an organ of the skeletal system.
2. A skeletal muscle is composed of ____________________________________
B. Connective Tissue Coverings
1. Fascia is ________________________________________________________
2. A tendon is ______________________________________________________
3. Tendons connect a muscle to ________________________________________
4. An aponeurosis is _________________________________________________
5. Epimysium is ____________________________________________________
6. Perimysium is____________________________________________________
7. A fascicle is _____________________________________________________
8. Endomysium is___________________________________________________
9. Deep fascia is ____________________________________________________
10. Subcutaneous fascia is ____________________________________________
11. Subserous fascia is _______________________________________________
C. Skeletal Muscle Fibers
1. A skeletal muscle fiber is a single ____________________________________
2. The sarcolemma is ________________________________________________
3. The sarcoplasm is _________________________________________________
4. The sarcoplasm contains ___________________________________________
5. Myofibrils are _________________ and are located in the ________________
6. Myofibrils play a fundamental role in _________________________________
7. Thick myofilaments are composed of _________________________________
8. Thin myofilaments are composed of __________________________________
9. The organization of myofilaments produce _____________________________
__________________________________________________________________
10. A sarcomere is __________________________________________________
11. Myofibrils may be thought of as _____________________ joined end to end.
12. I bands are composed of __________________________________________
13. Z lines are ______________________________________________________
14. A bands are composed of __________________________________________
15. The H zone is ___________________________________________________
16. The M line is ___________________________________________________
17. Titin connects ___________________________________________________
18. A sarcomere extends from one _____________________________________
19. Each myosin molecule consists of ___________________________________
__________________________________________________________________
20. Thin filaments consist of double ____________________________________
21. Actin has a binding site to which ___________________________ can attach.
22. Troponin and tropomyosin associate with _____________________________
23. Sarcoplasmic reticulum is _________________________________________
24. Transverse tubules are ____________________________________________
25. Cisternae are____________________________________________________
26. A triad is formed by ______________________________________________
II. Skeletal Muscle Contraction
A. Neuromuscular Junction
1. Each skeletal muscle is connected to ____________________________
2. A motor neuron passes out from _____________________________________
3. Normally, a skeletal muscle fiber contracts only upon ____________________
__________________________________________________________________
4. A neuromuscular junction is ________________________________________
5. A motor end plate is _______________________________________________
6. A motor unit is ___________________________________________________
7. A synaptic cleft separates___________________________________________
8. Synaptic vesicles store _____________________________________________
B. Stimulus for Contraction
1. __________________________ is the neurotrasnmitter that motor neurons use
to control skeletal muscle.
2. ACh is synthesized in the cytoplasm of ________________________________
and is stored in _____________________________________________________
3. When a nerve impulse ________________________ , acetylcholine is released
into the synaptic cleft.
4. ACh combines with ____________________________ on the motor end plate,
and stimulates ______________________________________________________
5. A muscle impulse is _______________________________________________
6. A muscle impulse changes __________________________________________
7. Ultimately the muscle impulse reaches ________________________________
C. Excitation Contraction Coupling
1. The sarcoplasmic reticulum has a high concentration of ___________________
2. In response to a muscle impulse, the membranes ________________________
___________________________, and the calcium ________________________
__________________________________________________________________
3. When a muscle fiber is at rest, ________________________ block the binding
sites on the actin molecules.
4. Calcium ions bind to ____________________, changing its _______________
and altering ________________________________________________________
5. The movement of the tropomyosin molecule exposes _____________________
__________________________, allowing________________________________
D. The Sliding Filament Theory
1. The functional unit of skeletal muscles is ______________________________
2. According to the sliding filament theory, when sarcomeres shorten, _________
__________________________________________________________________
3. As contraction occurs, ________________ and ______________ get narrower
and _____________________________________________ move closer together.
E. Cross-bridge Cycling
1. The force that shortens the sarcomeres comes from ______________________
__________________________________________________________________
2. A myosin cross-bridge attaches to actin in order to _______________________
__________________________________________________________________
3. The cross-bridge can release, straighten, and combine with ________________
__________________________________________________________________
4. Myosin cross-bridges contain the enzyme ______________________________
5. ATPase catalyzes _________________________________________________
6. The force for muscle contraction is provided by _________________________
__________________________________________________________________
7. Breaking down of ATP puts the myosin cross-bridge in a __________ position.
8. When a muscle is stimulated to contract, a ____________________ attaches to
___________________________ and pulls ______________________________ ,
shortening the ______________________________________________________
9. When another ATP binds, the ______________________________ is released,
then breaks down the ____________________to return to ___________________
10. The cross-bridge cycle may repeat over and over as long as _______________
__________________________________________________________________
F. Relaxation
1. In order for a muscle fiber to relax, acetylcholine must be decomposed by an
enzyme called ________________________________________________
2. The action of acetycholinesterase prevents _____________________________
__________________________________________________________________
3. When acetylcholine is broken down, __________________________________
____________________________________________________________ ceases.
4. The calcium pump moves calcium ___________________________________
__________________________________________________________________
5. When calcium is removed from the cytoplasm, the _______________________
break and _____________________________________ rolls back into its groove,
preventing _________________________________________________________
6. ATP is necessary for both muscle ____________________________________
and _______________________________________________________________
7. The trigger for contraction is ________________________________________
G. Energy Sources for Contraction
1. Creatine phosphate is ________________________________________
2. Creatine phosphate contains __________________________________
3. As ATP is decomposed to ADP, the energy from __________________
is transferred back to __________________________________________
4. After creatine phosphate is used, a muscle cell must depend on _______
as a source of energy
for synthesizing _______________________________________________
5. Typically a muscle stores glucose in the form of __________________
H. Oxygen Supply and Cellular Respiration
1. Glycolysis occurs _______________________ and is ____________________
2. Glycolysis releases a few ___________________________________________
3. The complete break down of glucose occurs in __________________________
and requires ________________________________________________________
4. The citric acid cycle and electron transport chain produce _________________
__________________________________________________________________
5. Oxygen is carried in the blood stream bound to _________________________
6. Myoglobin is _____________________________________________ in color.
7. Myoglobin stores ___________________________________ in muscle tissue.
I. Oxygen Debt
1. Lactic acid threshold is ____________________________________________
2. Under anaerobic conditions, glycolysis breaks down glucose into ___________
and converts it to ____________________________________________________
3. Lactic acid is carried by the blood to the _______________________________
4. Liver cells can convert lactic acid to __________________________________
5. Oxygen debt reflects ______________________________________________
__________________________________________________________________
J. Muscle Fatigue
1. Fatigue is _______________________________________________________
2. Fatigue may result from ____________________________________________
__________________________________________________________________
3. A cramp is ______________________________________________________
4. Physically fit people make less lactic acid because _______________________
__________________________________________________________________
K. Heat Production
1. Heat is a by-product of_____________________________________________
2. Blood transports heat _____________________________________________ ,
which helps ________________________________________________________
III. Muscle Responses
A. Introduction
1. One way to observe muscle contraction is to____________________________
__________________________________________________________________
2. An________________________ is usually used to produce muscle contraction.
B. Threshold Stimulus
1. Threshold stimulus is ________________________________________
2. An impulse in _______________________________ normally releases enough
______________________ to bring the muscle fibers in its __________________
to ________________________________________________________________
C. Recording a Muscle Contraction
1. A twitch is ______________________________________________________
2. A myogram is ____________________________________________________
3. Three periods of a muscle fiber contraction are__________________________
__________________________________________________________________
4. During the period of contraction, a muscle fiber is _______________________
__________________________________________________________________
5. The latent period is________________________________________________
6. The period of relaxation is __________________________________________
7. The refractory period is ____________________________________________
8. An all-or-none response is __________________________________________
__________________________________________________________________
9. The length to which a muscle is stretched before stimulation affects _________
__________________________________________________________________
10. If a muscle is stretched well beyond its normal resting length, the force will
__________________________________________________________________
11. At very short muscle lengths, the sarcomere becomes ___________________
and ___________________________________________________ is not possible.
12. In the whole muscle, the degree of tension reflects ______________________
__________________________________________________________________
D. Summation
1. Twitches in a muscle can combine to become ___________________________
2. Summation is ____________________________________________________
3. Tetanic contractions are ____________________________________________
E. Recruitment of Motor Units
1. The _______________ in the motor units, the more ________________
the movements can be produced in a particular muscle.
2. All muscle fibers in a motor unit are stimulated at __________________ time.
3. Multiple motor unit summation is ____________________________________
4. Recruitment is ___________________________________________________
5. As the intensity of stimulation increases, ______________________________
continues until all possible motor units are activated in a muscle.
F. Sustained Contractions
1. During sustained contractions, __________ tend to be recruited earlier.
2. The larger motor units respond ______________________________________
and more __________________________________________________________
3. Muscle movements are smooth because _______________________________
__________________________________________________________________
4. Muscle tone is ___________________________________________________
5. Muscle tone is important for maintaining ______________________________
G. Types of Contractions
1. An isotonic contraction is __________________________________________
2. A concentric contraction is _________________________________________
3. An eccentric contraction is__________________________________________
4. An isometric contraction is _________________________________________
5. An example of an isometric contraction is _____________________________
6. An example of an isotonic contraction is _______________________________
H. Fast and Slow Twitch Muscle Fibers
1. Type I fibers are __________________________________________________
2. Examples of type I fibers are ________________________________________
3. Type I fibers are _________________ in color because ___________________
__________________________________________________________________
4. Type I fibers are resistant to_________________________________________
5. Type IIa fibers are ________________________________________________
6. Type IIa fibers are ________________ in color because __________________
__________________________________________________________________
7. Type IIb fibers are ________________________________________________
8. A muscles contain ____________________________________ of fiber types.
IV. Smooth Muscles
A. Smooth Muscle Fibers
1. Compared to skeletal muscle fibers, smooth muscle fibers _________________
__________________________________________________________________
2. Two major types of smooth muscle are ________________________________
__________________________________________________________________
3. Multiunit smooth muscle is located ___________________________________
__________________________________________________________________
4. Visceral smooth muscle is located ____________________________________
__________________________________________________________________
5. Fibers of visceral smooth muscle are connected by_______________________
6. Rhythmicity is ___________________________________________________
7. Peristalsis is _____________________________________________________
8. Peristalsis helps force ______________________________________________
B. Smooth Muscle Contraction
1. Compared to skeletal muscle fibers, smooth muscle fibers lack _____________
and use _______________________________________ to bind calcium instead.
2. Two neurotransmitters that affect smooth muscle are _____________________
__________________________________________________________________
3. Hormones affect smooth muscle by___________________________________
__________________________________________________________________
4. Stretching of smooth muscle can trigger _______________________________
5. Smooth muscle is _________________ to contract and ___________________
to relax than skeletal muscle.
6. Unlike skeletal muscle, smooth muscle fibers can change length without
changing __________________________________________________________
V. Cardiac Muscle
A. Cardiac muscle appears only in ___________________________________________
B. Cardiac muscle is composed of _______________________________________ cells,
forming fibers that are ______________________________________________________
C. Cardiac muscle fibers can contract ___________________ then skeletal muscle fibers.
D. Intercalated discs are ____________________________________________________
E. Intercalated discs allow muscle impulses to __________________________________
F. A syncytium is _________________________________________________________
VI. Skeletal Muscle Actions
A. Introduction
1. Skeletal muscles generate __________________________________________
2. The action of each muscle mostly depends upon_________________________
__________________________________________________________________
B. Origin and Insertion
1. The origin of a muscle is ___________________________________________
2. The insertion of a muscle is _________________________________________
3. When a muscle contracts, its ________________________________________
is pulled toward its __________________________________________________
4. The head of a muscle is ____________________________________________
5. The origins of the biceps brachii are __________________________________
6. The insertion of the bicep brachii is ___________________________________
7. When the biceps brachii contracts, the __________________________ bends.
C. Interaction of Skeletal Muscles
1. A prime mover is ___________________________________________
2. A synergist is ____________________________________________________
3. An antagonist is __________________________________________________
VII. Major Skeletal Muscles
A. Introduction
1. The name of a muscle may reflect ____________________________________
__________________________________________________________________
2. An example of a muscle named for it size is ____________________________
3. An example of a muscle named for its shape is __________________________
4. An example of a muscle named for its function is________________________
5. An example of a muscle named for its number of origins is ________________
6. An example of a muscle named for its attachments site is _________________
__________________________________________________________________
7. An example of a muscle named of the direction of its muscle fibers is _______
__________________________________________________________________
B. Muscles of Facial Expression
1. As a group, muscles of facial expression connect ________________________
__________________________________________________________________
2. For the following muscles, list their origins, insertions, and actions.
Epicranius
Orbicularis oculi
Orbicularis oris
Buccinator
Zygomaticus
Platysma
C. Muscles of Mastication
1. Muscles of mastication produce______________________ movements.
2. For the following muscles, list their origins, insertions, and actions
Masseter
Temporalis
Medial pterygoid
Lateral pterygoid
D. Muscles That Move the Head and Vertebral Column
1. For the following muscles, list their origins, insertions, and actions
Sternocleidomastoid
Splenius capitis
Semispinalis capitis
Erector spinae
E. Muscles That Move the Pectoral Girdle
1. For the following muscles, list their origins, insertions, and actions
Trapezius
Rhomboideus major
Levator spinae
Serratus anterior
Pectoralis major
F. Muscles That Move the Arm
1. For the following muscles, list their origins, insertions, and actions
Coracobrachialis
Pectoralis major
Teres major
Latissimus dorsi
Supraspinatus
Deltoid
Subscapularis
Infraspinatus
Teres minor
G. Muscles That Move the Forearm
1. For the following muscles, list their origins, insertions, and actions
Biceps brachii
Brachialis
Brachioradialis
Triceps brachii
Supinator
Pronator teres
Pronator quadratus
H. Muscles That Move the Hand
1. For the following muscles, list their origins, insertions, and actions
Flexor carpi radialis longus
Flexor carpi ulnaris
Palmaris longus
Flexor digitorum profundus
Flexor digitorum superficialis
Extensor carpi radialis
Extensor carpi radialis brevic
Extensor carpi ulnaris
Extensor digitorum
I. Muscles of the Abdominal Wall
1. The linea aspera is ________________________________________________
2. For the following muscles, list their origins, insertions, and actions
External oblique
Internal oblique
Transversus abdominis
Rectus abdominis
J. Muscles of the Pelvic Outlet
1. The pelvic diaphragm forms ________________________________________
2. The urogenital diaphragm fills _______________________________________
3. For the following muscles, list their origins, insertions, and actions
Levator ani
Coccygeus
Superficial transversus perinea
Bulbospongiosus
Ischiocavernosus
Sphincter urethra
K. Muscles That Move the Thigh
1. For the following muscles, list their origins, insertions, and actions
Psoas major
Iliacus
Gluteus maximus
Gluteus medius
Gluteus minimus
Pectineus
Adductor longus
Adductor magnus
Gracilis
L. Muscles That Move the Leg
1. For the following muscles, list their origins, insertions, and actions
Biceps femoris
Semitendinosus
Semimembranosus
Sartorius
Quadriceps femoris group
M. Muscle That Move the Foot
1. For the following muscles, list their origins, insertions, and actions
Tibialis anterior
Fibularis tertius
Extensor digitorum longus
Gastrocnemius
Soleus
Flexor digitorum longus
Tibialis posterior
Fibularis longus
VIII. Life-Span Changes
A. Signs of aging of the muscular system begin to appear _________________________
B. At a microscopic level, ___________________________________________ decline.
C. _______________________________________ being to replace some muscle tissue.
D. _________________________________ can help maintain a healthy muscular system
E. According to the National Institute on Aging, exercise should include _____________
________________________________________________________________________