The document provides an overview of the muscular system, including the three types of muscle tissue (skeletal, smooth, and cardiac), their structure and function. It discusses how muscles contract via the sliding filament model, and how motor units are recruited to produce stronger contractions. Proprioceptors like the muscle spindle and Golgi tendon organ provide feedback to regulate muscle tone and protect from injury.

1. http://www.human-body-facts.com/muscular-system.html
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2. The muscular system
The muscular system makes up nearly
half the weight of the human body, this
is why when we train we sometimes put
on weight instead of losing it. We put
on muscle weight.
The muscles provide the forces that
enable the body to move.

3. WHAT DOES THIS SYSTEM DO?
The big purpose of the muscles
found in your body is movement. We
could be talking about the movement
of your legs while you walk. We could
be talking about the beating of your
heart. We could also be talking about
the contraction of a very small blood
vessel in your brain.
http://www.biology4kids.com/files/systems_muscular.html

4. MUSCLES HELP YOU MOVE
The main parts of your voluntary
muscular system include the
muscles, and tendons. The muscle
is called the meatus. The bicep is
the meat that connect to the bones
so that you can move. Tendons
connect your muscles to your bone
at insertion points.

5. You have no control over most of the
muscular system. You do control the
voluntary muscle in your arms, legs,
neck, and torso. You have little or no
control over the heart or smooth
muscle. Those other muscles are under
the control of the autonomic nervous
system (ANS).

6. INTERACTING WITH OTHER SYSTEMS
The muscular system is closely
connected to the nervous system.
You usually have to think before
you can move. Even though
thinking is not always involved, the
neurons of the nervous system are
connected to most of the cells in
your muscular system.

7. Muscles stretch across joints to link
one bone with another and work in
groups to respond to nerve
impulses.
There are three types of muscle:

10. Muscle Structure
Our muscle structure consists
of densely packed groups of
elongated cells known as muscle
fibres.
Skeletal muscle is composed of
bundles of long striated fibres.

11. Smooth muscle which is
found in the walls of internal
organs such as intestines is
made of short spindle-shaped
fibres packed together in
layers.
Cardiac muscle found only in
the heart has short
interconnecting fibres.

12. Skeletal muscle
There are nearly 650 skeletal
muscles in the human body! Skeletal
muscles are attached to the
skeleton. They work in pairs: one
muscle moves the bone in one
direction and the other moves it
back again.

13. Skeletal muscles are voluntary
muscles - in other words we think
about what movements we want to
make (at least, usually!) and send
messages via our nervous system to
tell the appropriate muscle(s) to
contract.
Muscle contractions can be short,
single contractions or longer ones.

14. Skeletal muscle carries out
voluntary movements, and is what
we use for movement in daily life
and during exercise. The human
body has more than 650 muscles, the
body's most abundant tissue,
comprising about 23% of a woman's
body weight and about 40% of a
man's body weight.

16. Smooth muscle
Smooth muscle is found in
our internal organs: in our digestive
system, our blood vessels, our
bladder, our respiratory organs and,
in a female, the uterus.
Smooth muscle can stretch and
maintain tension over extended
periods.

17. These fibres are held together
by fibrous connective tissue.
Capillaries penetrate this tissue
to keep the muscles supplied
with oxygen and nutrients that
are needed to fuel contraction.

18. In a relaxed muscle the thick and
thin threads within a muscle fibre
overlap a little.
When a muscle contracts, the
thick filaments slide further in
between the thin filaments like
interlacing fingers. This action
shortens the entire fibre.

22. Cardiac muscle
Cardiac muscle is found only in the
heart. It can stretch, just like smooth
muscle, and contract like skeletal
muscle.
It is a twitch muscle - it only does short
single contractions.
Like smooth muscle, cardiac muscle
is involuntary.

24. Smooth muscles are
involuntary muscles - in other
words we do not have to think
about contracting them
because they are controlled
automatically by the nervous
system.

25. Smooth muscle surrounds or is part
of the internal organs. Smooth
muscle is found in the digestive
system, blood vessels, bladder,
airways and, in a female, the
uterus. It has the ability to stretch
and maintain tension for long
periods of time. Both cardiac and
smooth muscles are called
involuntary muscles, because they
cannot be consciously controlled.

26. You have smooth muscles that line
your digestive system and help
move food through your intestines.
Smooth muscle also surrounds
your circulatory system and lymph
system. Those muscle tissues are
spread throughout your body and
are even involved in controlling the
temperature of your body.

27. The stomach is an organ of the
alimentary canal, a muscular
tube that forms part of
the digestive system.
The wall of the stomach
contains smooth muscle
tissue.

28. Contractions of the smooth
muscles of the alimentary canal
serve to mix food with digestive
juices, and to move the resulting
mixture further along
(peristalsis). Smooth muscles are
called involuntary muscles, because
they cannot be consciously
controlled.

29. Skeletal muscles can do a short, single
contraction (twitch) or a long,
sustained contraction (tetanus), and
might ache after strenuous exercise. A
skeletal muscle is composed of skeletal
muscle tissue, nervous tissue, blood,
and connective tissues. Fascia covers
the surface of the muscle and also
forms the cordlike tendons which
attach the muscle to the bone.

30. Epimysium lies beneath the fascia,
and perimysium extends into the
structure of the muscle, where it
separates muscle tissue into small
compartments of bundles of skeletal
muscle fibers called fascicles.
Endomysium separates individual
muscle fibers within those fascicles.

31. Anatomy of Skeletal Muscle

32. According to the sliding filament
theory, myosin cross-bridges
attach to a binding site on the
actin filament and bend slightly,
thus pulling on the actin filament.
The filaments slide past one
another, thus shortening the
sarcomeres, thus shortening the
myofibrils, thus shortening the
muscle fiber.

33. Then the head of the myosin
cross-bridge can release,
straighten, combine with
another binding site further
down the actin filament, and
pull again, thus shortening the
sarcomere, (myofibril and
muscle fiber) more.

34. The actions of the myosin molecules are
not synchronized - at any given moment,
some myosins are attaching to the actin
filament, others are creating force
(pulling) and others are releasing the
actin filament).
This process can be repeated for as long
as the muscle fiber is stimulated, or until
the point of maximal shortening of the
sarcomere.

35. When the muscle fiber is no longer
stimulated, the cross-bridges break
down, and the muscle fiber relaxes.

36. Blood vessels and axons of nerve
cells lie within those connective
tissues. A skeletal muscle fiber is a
single, thin, long cell that may
extend the full length of the
muscle. Just beneath its cell
membrane (sarcolemma), the
cytoplasm (sarcoplasm) of the fiber
contains many threadlike
myofibrils that lie parallel to one
another.

37. Each myofibril consists of repeating
units called sarcomeres. The
characteristic dark and light
striations of a sarcomere are due to
the arrangement of two kinds
of protein filaments: thick filaments
composed of the protein myosin and
thin ones mainly composed of the
protein actin.

38. •The contraction of a muscle does not
necessarily mean that the muscle
shortens; it only means that tension has
been generated. When muscles do
cause a limb to move through the
joint's range of motion, they usually act
in the following cooperating groups:
Agonists cause the movement to
occur. They create the normal range
of movement in a joint by contracting.

39. •Agonists are also referred to
as prime movers since they are the
muscles that are primarily
responsible for generating the
movement.
•Antagonists act in opposition to
the movement generated by the
agonists and are responsible for
returning a limb to its initial
position.

40. •Synergists assist the agonist and
make its action more effective by
helping to hold the joint steady and
keeping the two bones around the
joint aligned. Synergists are also
sometimes called stabilizers.

41. Primary opposing muscle groups:
1. calves/tibialis anterior,
2. quadriceps/hamstrings,
3. hip flexors/gluteals,
4. erector spinae/abdominals,
5. pectorals/upper back,
6. latissimus dorsi/deltoids,
7. biceps/triceps.

43. A skeletal muscle fiber is a single,
thin, long cell that may extend the
full length of the muscle. Just
beneath its cell membrane
(sarcolemma), the cytoplasm
(sarcoplasm) of the fiber contains
many threadlike myofibrils
that lie parallel to one another.
Each myofibril consists of repeating
units called sarcomeres.

44. The characteristic dark and light
striations of a sarcomere are due to the
arrangement of two kinds of protein
filaments: thick filaments composed of
the protein myosin and thin ones mainly
composed of the protein actin. A
muscle fiber contraction is a complex
interaction of molecules, resulting in a
movement within the myofibrils in
which the myosin and actin filaments
slide past one another.

46. As the intensity of stimulation
increases, recruitment of motor units
continues until, finally, all possible
motor units in that muscle are
activated and the muscle contracts
with maximal tension.

47. A single stimulus of threshold
strength activates some of a muscle’s
motor units, which makes the muscle
contract and then relax. This action
lasts only a fraction of a second and is
called a twitch.

48. A whole muscle is composed of
many motor units controlled by
different motor neurons, which
respond to different thresholds
of stimulation. If only the motor
neurons with low thresholds are
stimulated, few motor units
contract, and the muscle
contracts with minimal tension.

49. At higher intensities of
stimulation, additional motor
neurons respond, and more
motor units are activated, which
produces a stronger muscle
contraction. Such an increase in
the number of motor units being
activated is called recruitment.

50. When the muscle is stretched, so is
the muscle spindle, which records
the change in length (and how fast)
and sends signals to the spine
which convey this information.

51. This triggers the stretch reflex
which attempts to resist the
change in muscle length by causing
the stretched muscle to contract.
The more sudden the change in
muscle length, the stronger the
muscle contractions will be
(plyometric, or "jump", training is
based on this fact).

52. This basic function of the muscle
spindle helps to maintain muscle
tone and to protect the body from
injury. However, ballistic stretching
may cause a muscle contraction so
strong it tears the muscle fibers or
tendons, causing injury.

53. One of the reasons for holding a
stretch for a prolonged period of
time (static stretching) is that as the
muscle is held in a stretched
position, the muscle spindle
becomes accustomed to the new
length and reduces its
signaling. Gradually, you can train
your stretch receptors to allow
greater lengthening of the muscles.

54. Physiology of Skeletal Muscle
A muscle fiber contracts only when
stimulated by its nerve, the motor
neuron. A nerve impulse from the
motor neuron translates into a muscle
impulse that affects the whole muscle
fiber at once, for as long as the
stimulation continues. A stimulated
skeletal muscle fiber responds to its
fullest extend, i.e., it has an all-or-none
response.

55. While each muscle fiber is
connected to only one axon of a
motor neuron, a motor neuron
may have many densely branched
axons, connecting to many
muscle fibers, constituting
a motor unit.

56. When muscles contract (possibly
due to the stretch reflex), they
produce tension at the point where
the muscle is connected to the
tendon, where the golgi tendon
organ is located. The Golgi tendon
organ records the change in
tension, and the rate of change of
the tension, and sends signals to
the spine to convey this
information.

57. When this tension exceeds a
certain threshold, it triggers
the lengthening reaction which
inhibits the muscles from
contracting and causes them to
relax.

58. Skeletal Muscle Action
Another reason for holding a
stretch for a prolonged period of
time is to allow this lengthening
reaction to occur, thus helping the
stretched muscles to relax. It is
easier and more beneficial to
stretch, or lengthen, a muscle when
it is not trying to contract.

59. This basic function of the golgi
tendon organ helps to protect the
muscles, tendons, and ligaments
from injury. The lengthening
reaction is possible only because
the signaling of golgi tendon organ
to the spinal cord is powerful
enough to overcome the signaling
of the muscle spindles telling the
muscle to contract.

60. The response time between
stimulation and muscle reaction
determines the classification
into fast twitch or slow
twitch fibers. Fast-twitch fibers
are capable of developing greater
forces, contracting faster to
produce bursts of power and have
greater anaerobic capacity.

61. In contrast, slow-twitch fibers
develop force slowly, can
maintain contractions longer,
have greater endurance and
higher aerobic capacity.

62. The skeletal muscles of an average
person contain about half fast
twitch and half slow twitch muscle
fibers. Certain athletic activities
promote increased percentage of
fast twitch muscle fibers (Olympic
sprinter), or slow twitch muscle
fibers (Olympic marathoner).

63. A muscle fiber exposed to a series of
stimuli of increasing frequency
reaches a point when it is unable to
completely relax before the next
stimulus in the series arrives. When
this happens, the force of individual
twitches combines, a process
called summation.

64. When the resulting forceful,
sustained contraction lacks even
partial relaxation, it is called a
tetanic contraction (tetanus).

65. As we have no control over the
smooth muscle tissue of the
stomach, we cannot consciously
contract it, or “exercise” it. Thus,
there are no “exercises to
strengthen the stomach” or “using
the stomach to move the
spine”. The term "stomach"
therefore does not belong into
Pilates class.

66. A muscle fiber contraction is a
complex interaction of molecules,
resulting in a movement within the
myofibrils in which the myosin and actin
filaments slide past one another (sliding
filament theory).
Along side (in parallel) with the regular
muscle fibers are muscle spindles or
stretch receptors, the primary
proprioceptors in the muscle.

67. They undergo the same length
changes as the rest of the muscle
and thus measure the change in
muscle length and the rate of
change in muscle length. In the
tendon of the muscle is located
the Golgi tendon organ. It is
sensitive to the change in tension
and the rate of change of the
tension, i.e., force the muscle
exerts.

68. Summation and recruitment
together can produce a sustained
contraction of increasing
strength. Although twitches may
occasionally occur in skeletal
muscles (e.g., eyelid twitch), such
contractions are of limited
use. More commonly muscular
contractions are sustained.

69. Even when a muscle appears to be
at rest, a certain amount of
sustained contraction is occurring
in a small fraction of the total
number of its fibers. This muscle
tone is important particularly in
maintaining posture, and also
enables the muscle to resist passive
elongation or stretch.

70. They undergo the same length
changes as the rest of the muscle
and thus measure the change in
muscle length and the rate of
change in muscle length. In the
tendon of the muscle is located
the Golgi tendon organ. It is
sensitive to the change in tension
and the rate of change of the
tension, i.e., force the muscle
exerts.

71. When the actin and myosin contract
in the muscles, the muscle shortens
and the bones are pulled closer
together.
Muscles called flexors force your
joints to bend.

72. Muscles called extensors cause
your limbs to straighten. A bicep is
a flexor and the triceps are
extensors. You may have also
heard of ligaments. They are
batches of connective tissue that
bind bones to each other.
Muscles, tendons, and ligaments
can been found working together
in almost all of your joints.

74. Muscles for Mastication:
• Masseter
• Temporalis
• Lateral Pterygoid
• Medial Pterygoid

75. Muscles for Facial Expression:
• Frontalis
• Orbicularis oculi (planned)
• Nasalis (planned)
• Orbicularis oris (planned)
• Levator labii superioris (planned)
• Levator anguli oris (planned)
• Zygomaticus major (planned)
• Zygomaticus minor (planned)
• Risorius (planned)
• Depressor anguli oris (planned)
• Depressor labii inferioris (planned)
• Mentalis (planned)

77. Posterior Neck Muscles :
• Splenius capiitis
• Splenius cervicis
• Semispinalis capiitis
• Semispinalis cervicis
• Semispinalis thoracis
• Trapezius
• Suboccipital muscles
Anterior Neck Muscles :
•Sternocleidomastoid
• Scalenes

78. Erector Spinal Muscles :
• Iliocostalis Thoracis
• Iliocostalis Lumborum
• Longissimus Capitis
• Longissimus Cervicis
• Longissimus Thoracis
• Spinalis Cervicis
• Spinalis Thoracis
Transversospinal Muscles:
• Multifidus
• Rotators (planned)

80. Muscles That Act On Anterior Arm:
• Deltoid (anterior & middle)
• Pectoralis major
• Biceps brachii
• Coracobrachialis
• Subscapularis
• Teres major (from the back)
• Latissimus dorsai (from the back)

81. Muscles That Act On Posterior Arm:
• Deltoid (posterior and middle)
• Supraspinatus
• Infraspinatus
• Teres minor
• Triceps brachii: long head
http://www.getbodysmart.com/ap/muscularsystem/armmuscles/menu/menu.html

84. Muscles That Act On Anterior
Shoulder:
• Serratus Anterior
• Pectoralis Minor

86. Muscle That Act On Posterior Shoulder:
• Levator Scapulae
• Trapezius
• Rhomboid Major
• Rhomboid Minor

88. Muscles That Act On Anterior Forearm:
• Biceps Brachii
• Brachialis
• Brachioradialis
• Pronator teres

89. Muscles of the Abdomen:
• External
oblique
• Internal oblique
• Transversus
abdominus
• Rectus
abdominusk

91. Muscle That Act On Posterior Forearm:
• Triceps brachii: long head
• Triceps brachii: medial head
• Triceps brachii: lateral head
• Anconeus

93. Muscles That Act On Anterior
Wrist/Hand:
• Flexor carpi radialis
• Palmaris longus
• Flexor carpi ulnaris
• Flexor digitorum superficialis

95. Muscle That Act On Posterior Wrist/Hand:
• Extensor carpi radialis longus
• Extensor carpi radialis brevis
• Extensor digitorum
• Extensor carpi ulnaris

97. Muscles of the Legs (Front)
• Iliacus
• Psoas major
• Tensor fasciae latae
• Sartorius
• Rectus femoris
• Pectineus
• Adductor longus
• Adductor brevis
• Adductor magnus
• Gracilis

99. Muscles of the Legs (Back):
• Gluteus maximus
• Gluteus medius
• Gluteus minimus
• Piriformis
• Quadratus femoris
• Biceps femoris - long head
• Semimembranosus
• Semitendinosus

101. Muscles That Act On Anterior Leg:
Rectus femoris
• Sartorius
• Gracilis
• Vastus lateralis
• Vastus medialis
• Vastus intermedius

103. Muscle That Act On Posterior Leg:
• Semimembranosus
• Semitendinosus
• Biceps femoris - long head
• Biceps femoris - short head
• Gastrocnemius
• Plantaris
• Popliteus

105. Anterior Leg Compartment Muscles:
• Tibialis anterior
• Extensor digitorum longus
• Extensor hallucis longus
• Fibularis (peroneus) tertius longus

107. Posterior Leg Compartment Muscles:
• Gastrocneumius
• Soleus
• Plantaris
• Flexor hallucis longus
• Flexor digitorum longus
• Tibialis anterior

108. Lateral Leg Compartment Muscles:
• Fibularis (peroneus) longus
• Fibularis (peroneus) brevis

109. Repetitive Strain Injury
Several Conditions are referred to as
repetitive strain injury. These are
conditions caused by the constant
repetition of a particular movement.
Irritation of the flexor and extensor
tendons in the wrist and hand is a
common injury that often affects
keyboard operators causing pain
when the fingers are moved.

110. It is also a condition suffered by
body builders and weight
trainers who constantly put strain
on the same muscles.
The symptoms of RSI include pain,
aching and tingling. Sometimes
restricted movement or weakness.
RSI can also lead to another
disorder called carpal tunnel
syndrome.

111. This is due to pressure on the
median nerve as it passes through a
gap under a ligament at the front
of the wrist. This disorder is
characterized by numbness and
pain in the thumb and middle
fingers. The condition is caused by
pressure on the median nerve.

112. Prepare a dance demo for each group
with the dance routine and music of
your choice.
This dance demo will be presented inside
the classroom on December 5, 2012.

113. http://www.human-
body-
facts.com/muscular-
system.html
http://www.biology4kids.com/files
/systems_muscular.html