Download The Muscular System

THE MUSCULAR
SYSTEM
Unit 5
Unit Goals
• Describe the functions and structures of the muscular
system including muscle fibers, fascia, tendons, and the
three types of muscle
• Recognize, define, spell and pronounce the terms
related to muscle movements and explain how the
muscles are named.
• Recognize, define, pronounce and spell the terms
related to the pathology and diagnostic and treatment
procedures of the muscular system*
• Time Permitting
Enrichment Terms (see attachment)
• antagonist- muscle that acts in opposition to the action of
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another muscle, its agonist
atrophy- wasting away, decrease in size
contraction- shortening or development of tension in
muscle tissue
contracture- permanent shortening of tendons and
ligaments of a joint resulting from atrophy of muscle
dystrophy- muscle disorder resulting from defective or
faulty nutrition, abnormal development, infection
myalgia- muscle pain
paralysis- loss or impairment of motor function
posture- attitude or position of the body
Terms Cont.
• prime mover- muscle that acts directly to bring about a
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desired movement, agonist
range of motion- active or passive movement of muscle
groups to full extent possible, used to prevent contracture
sarcomere- repeating units of muscle fibers with the ability
to contract
skeletal- pertaining to the framework of the body
stimulus- any agent, act, or influence that produces a
change in the development or function of tissues
tonus- slight, continuous contraction of muscle
visceral- pertaining to any large interior organ in any one
of the cavities of the body
What is a muscle?
• Contractile Tissue
(group of cells
working together)
• Produces force and
motion
Muscle Types
• Smooth Muscle:
• Automatically
stimulated
• No striations
• Found in digestive
system, hair follicles,
and reproductive
system
Muscle Types
• Skeletal Muscle:
• Striated
• Voluntary
• Found in face, limbs,
torso
• Line all the bones in
the body
Muscle Types
• Cardiac Muscle
• Some striations
• Stimulated by the
vagus nerve in the
brain
• Found on in the heart
• Specialized to carry
and spread an
electrical charge!
Types of Muscle Review
How does movement occur?
• All of the body’s voluntary movements
are controlled by the brain
• One of the brain areas most involved in
controlling these voluntary movements
is the primary motor cortex (M1)
• Sends out nerve impulses to specific
areas of skeletal muscle
Voluntary Movement Must Be Planned
• Occurs in frontal cortex
• Relays information about
position in space from
visual
and balance info
• Movement of specific
muscles are carried out
Brain Movement Map
“Excitation”
• The site of interaction b/t
a neuron and any other
cell is known as a
synapse.
• The synapse b/t a
neuron and a muscle is
known as the
neuromuscular junction.
• Excitation causes a
reaction involving Na+,
K+, and Ca2+
Muscle Action Terms
• Flexion: decrease in joint angle from
anatomical position (ex: bicep flex)
• Extension: Return of body to anatomical
pos. after flexion
• Abduction: movement of limbs away from
body (ex: jumping jacks/ snow angels)
• Adduction: return of limbs back to
anatomical pos. after abduction
More Terms
• Inversion: turning soles of feet to face
each other (ex: common ankle sprain)
• Eversion: soles of feet turn laterally
• Protraction: horizontal movement in
anterior direction (ex: jutting jaw forward)
• Retraction: return to regular from
horizontal
More Terms
• Elevation: To move in superior
direction (ex: shoulder shrug)
• Depression: move inferiorly (ex: drop
shoulders)
Last Terms
• Supination: lateral rotation of the hand (ex:
palms down to palms up, as if holding a bowl of
soup)
• Pronation: medial rotation of the hands
(ex:palms up to palms down, dribbling position)
• Plantarflexion: increasing the angle b/t the shin
and top of foot (ex: stand on toes)
• Dorsiflexion: decreasing the angle b/t the shin
and top of foot
• REVIEW TOGETHER
Sample Movements- Hand
Muscular System
• There are over 600 muscles
• Functions include:
• Movement
• Posture Maintenance
• Generation of Heat
• Breathing/ Digestion (compression of
abdomen)
• Trapezius: Extends/abducts head,
rotates scapula
• Deltoid: Abducts arm, flexes,
extends, rotates (delts)
• Pectoralis Major: Flexes, adducts
arm (pecs)
• Latissimus Dorsi: Extends,
adducts arm (lats)
• Biceps Brachii: Flexes arm,
supinates hand (bis)
• Triceps Brachii: Extends,
adducts arm (tris)
Shoulder and Arm
Hip and Thigh
• Gluteus Maximus: Abduction of
hip, medial rotation of thigh, prevent
internal rotation of knee
• Sartorius: Flexes and Laterally
rotates thigh
• Quadriceps: (grp of 4) Extend leg,
flex thigh (Rectus Femoris, Vastus
Lateralus/Medialis)
• Hamstring Group: Extend thigh/
flex leg (Biceps femoris)
Leg and Foot
• Gastrocnemius: flex leg/ plantarflexes foot
(also known as the calf muscle)
• Soleus: Plantar flexes foot
• Tibialis anterior: inverts foot/dorsiflexes
foot
Head and Neck
• Masseter: Closes mandible, largest
mammalian mandible found on the rat
• Zygomaticus: elevates the corners of the
mouth, attached at zygomatic bone,
responsible for your smile!
• Sternocleidomastoid: cervical rotation
and flexion, raising of sternum, and assists
in forced inspiration
• (*Orbicularius oculi/oris, Frontalis, Temporalis)
Trunk Muscles
• External Oblique: Compresses abdominal wall,
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laterally rotates trunk (love handles)
Transverse Abdominis: same fxn
Rectus Abdominis: Flexes vertebral column,
compresses abdominal wall
External intercostals: Elevates ribs
(increase volume)
Internal intercostals: Depresses ribs
(decreases volume)
How Muscles Work
Which muscle is the “strongest”?
• Based on 3 factors: physiological strength (size), neuronal
strength (strong or weak the signal is), and mechanical
strength (muscle’s force angle on the lever)
• By definition of exerting force on an object: Masseter (has
a short lever, can exert 975 lbf)
• By definition of exerting force by muscle itself: (then
strength= size) Gluteus Maximus or Quadriceps
• Because muscle strength is determined by crosssectional area, then pound for pound a shorter muscle will
be stronger than a longer muscle: Myometrial Layer of
Uterus in women can exert up to 100 lbf/contraction