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THE MUSCULAR SYSTEM
Okoko I.E.
THE MUSCULAR SYSTEM
• Is involved in all types of body movement and
locomotion with the aid of the following
structures.
• MUSCLE FIBERS: THAT HELP THE BODY MOVE
• TENDONS: CONNECT MUSCLE TO BONE
• FASCIA:THIN SHEATH THAT COVERS MUSCLE
• BURSA:FLUID-FILLED SACK THAT ACTS AS A
CUSHION
Consist of all the muscles of the body
This system is involved in all types of
body movement and locomotion with
the aid of the following structures:
3 basic muscle types are
found in the body
–Skeletal muscle
–Cardiac muscle
–Smooth muscle
Functions of Muscles
•
•
•
•
Produce movement
Maintain posture
Stabilize joints
Generate heat
• Help in sphincter
activity
Skeletal Muscle Functions
• Provides voluntary
movement of body
–Enables breathing,
blinking, and
smiling
–Allows you to hop,
skip, jump, or do
push-ups
Functions Continued
SMOOTH MUSCLE
• Provides movement of internal
organs
– Moves food through digestive tract
– Enables bladder control
• Causes involuntary actions
– Reflex actions
– Adjusts opening of pupils
– Causes hair to stand on
end (
)
Functions Continued
Cardiac muscle
• Causes heart beat
• Directs circulation of blood
– Regulates
blood
pressure
– Sends blood to different areas
of the body
Skeletal Muscles and Body Movements
• Muscles are attached
to at least two points
–Origin –
attachment to a
moveable bone
–Insertion –
attachment to an
immovable bone
Five Golden Rules of Gross Muscle Activity
1. All muscles cross at least one joint
2. Bulk of muscles lies proximal to the joint crossed
3. All muscles have at least 2 attachments: origin &
insertion
4. Muscles only pull/never push
5. During contraction ,the muscle insertion moves
toward the origin
Types of Ordinary Body Movements
• Flexion
• Extension
• Rotation
• Abduction
• Circumduction
Body Movements
Body Movements
Naming of Skeletal Muscles
• Direction of muscle fibers
– Example: rectus (straight)
• Relative size of the muscle
– Example: maximus (largest)
• Location of the muscle
–Example: many muscles are
named for bones (e.g.,
temporalis)
Naming of Skeletal Muscles
• Number of origins
–Example: triceps (three heads)
• Location of the muscle’s origin and
insertion
–Example: sterno (on the sternum)
Naming of Skeletal Muscles
• Shape of the muscle
–Example: deltoid (triangular)
Flat muscles- have parallel fibers often
with an aponeurosis
Eg. the external oblique (broad flat
muscle).The sartorius is a narrow flat
muscle with parallel fibers.
• Fusiform muscles- are spindle
shaped with a round, thick belly
(or bellies) and tapered ends—for
example, biceps brachii.
• Convergent muscles- arise from a
broad area and converge to form a
single tendon—for example, the
pectoralis major.
• Pennate muscles- are feather-like (L.
pennatus, feather) in the arrangement of
their fascicles, and may be unipennate,
bipennate, or multi-pennate—for
example, the extensor digitorum longus
(unipennate), the rectus femoris
(bipennate), and deltoid (multi-pennate).
• Quadrate muscles-have four equal
sides (L. quadratus, square)—for
example, the rectus abdominis,
between its tendinous intersections.
• Circular or sphincteral muscles surround a body opening or orifice,
constricting it when contracted—for
example, orbicularis oculi (closes the
eyelids).
Head,Face and Neck Muscles
VERTEBRAL COLUMN (SPINE)
THORAX
EXTERNAL INTERCOSTAL
Located in b/w the ribs;runs inf. and med.
INTERNAL INTERCOSTAL
• Located deep to the
Ext.intercostals,runs
Inf. and laterally.
Innermost intercostal
is located deep to
int. intercostals;runs in
Similar direction to the
latter
SHOULDER, ABDOMEN AND ELBOW
Muscles of
the Pelvis,
Hip, and
Thigh
GLUTEAL MUSCLE
• GLUTEUS MAXIMAS ACCOUNTS LARGELY FOR THE
SHAPE AND APPEARANCE OF THE BUTTOCKS
Superficial
Muscles:
Posterior
Muscles of
the Lower
Leg
Superficial
Muscles:
Anterior
Muscles You Need to Know
•
•
•
•
•
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•
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1. brachioradialis
2. biceps brachii
3. deltoid
4. external oblique
5. frontalis
6. gastrocnemius
7. gluteus maximus
8. hamstring group
9. latissimus dorsi
10. masseter
11. pectoralis major
12. quadriceps group
13. rectus abdominis
14. tibialis anterior
15. trapezius
16. triceps brachii
A
5
F
10
15K
B
3
G
11
L16
C
2
13
H
D
4
O
9
I
1
M7
12E
P
8
14
J
N
6
MUSCLE SPASMS/CRAMPS
• Sudden, painful involuntary muscle
contractions
• Caused from overexertion, low
electrolytes or poor circulation
• Treat by applying gentle pressure and
stretching of the affected muscle
Problems from lack of movement
• Contractures
– Tightening and shortening of a muscle resulting in a
permanent flexing of a joint
• Muscle atrophy
– Muscles become weak and joints become stiff
• Mineral loss
– Especially calcium from the bones making bones brittle
and easy to be fractured
• Other problems
– Poor appetite; constipation; urinary infections;
respiratory problems; and pneumonia
• STRAIN
• Overstretching of a muscle
or tendon frequently in legs,
back or arms
• Caused by sudden muscle
exertion
• Treated by resting, muscle
relaxants, or pain
medications, elevation of
extremity and applying
hot/cold compresses
MUSCULAR DYSTROPHY
• Group of inherited diseases that cause chronic,
progressive muscle atrophy resulting in total
disability and early death
• No cure
• Treatment used to slow progression of disease
Muscular Dystrophy
• Congenital muscle-destroying disease affect specific
muscle groups
• Muscle fibers degenerate & atrophy due to an
absence of dystrophin, a protein that helps keep
muscle cells intact
• Most common & serious—Duchenne’s M.D.
– Mostly in males (diagnosed between2-6 yrs)
– Survival is rare beyond early 30’s
– X-linked recessive
Aging
• Connective Tissue increases
• Amount of Muscle tissue
decreases
• Muscles become stringier(sinewy)
• Body weight declines due to loss
of muscle mass
• By age 80, muscle strength usually
decrease by 50% without weight
training exercises