MUSCLES

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MUSCLES

• Chapter 8
• We are made wise not by the recollection of our
  past, but the responsibility for our future.
• George Bernard Shaw

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SMOOTH MUSCLES

• Smooth Hollow organs, blood vessels, and
  respiratory passages
• Involuntary
• Causes wavelike contractions peristalsis
• Look like a toothpick
• Uni-nucleate
• Triggers nerve impulse, hormonal stimulation,
  stretching and more

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CARDIAC MUSCLES

• Found only in heart
• Involuntary
• Intercalated disc
• Uni-nucleate
• Striated
• Triggers self-excitatory nerves and/or hormones
  influence rate

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SKELETAL MUSCLE

• MUSCLE FIBERS ARE CIGAR SHAPED
• MULTINUCLEATE
• LARGEST OF MUSCLE FIBER TYPES
• STRIATED
• VOLUNTARY
• MOVES SKELETAL SYSTEM
• Triggers nerve system

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MUSCLE FUNCTIONS

• PRODUCES MOVEMENT
• SKELETAL WALKING, LIFTING
• SMOOTH BLOOD FOOD MOVEMENT
• CARDIAC PUMPS BLOOD
• MAINTAINS POSTURE
• STABILIZES JOINTS
• GENERATES HEAT
• One neuron all its muscle fibers one motor
  unit

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MUSCLE COMPOSITION

• Muscle fiber has cell wall called sarcolemma
• The sarcolemma is insulated by ENDOMYSIUM
• Many groups of endomysium wrapped fibers are
  grouped together, wrapped in PERIMYSIUM and
  called a FASCICLE.
• Many fasicles are wrapped together by EPIMYSIUM
• EPIMYSIUM COVERS ENTIRE MUSCLE CONTINUES DOWN
  TO MERGE INTO A TENDON OR SPREAD INTO AN
  APONEUROSES

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NEUROMUSCULAR JUNCTION

• Impulse from nerve caused a release of
  neurotransmitter (acetylcholine ACh) via
  vesicle to exocytose to synaptic cleft.
• ACh diffuses across cleft to receptors on muscle
  sarcolemma at the motor end plate.
• Muscle must be excitable to begin the action
  potential

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MUSCLE CONTRACTION

• Must be able to shorten and change its shape
• The sarcolemma is filled with MYOFIBRILS
  (organelles of the cell)
• Each MYOFIBRIL has bands, giving it a striped
  look
• The bands are actin and myosin filaments. They
  are the contractile unit of the sarcomere.

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FROM SMALLEST TO LARGESTA REVIEW..

• ACTIN MYOSIN (MICROFILAMENTS) make up a
  sarcomere
• Many SARCOMERE make a MYOFIBRIL
• Many myofibrils are in a cell the cell wall is
  called a SARCOLEMMA
• Sarcolemma are covered by ENDOMYSIUM
• Several endomysium covered sarcolemma are wrapped
  by PERIMYSIUM to make a FASCICLE

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CONTINUED

• Many fasicles are wrapped together by EPIMYSIUM
• The epimysium wrapped package of fibers is a
  muscle biceps, triceps, spinator
• EPIMYSIUM merges into a tough cord called a
  TENDON to connect the biceps to its insertion
  site
• EPIMYSIUM may spread to become an APONEUOSIS
  (SHEET) which attaches the muscle to a bone
  surface.

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BANDING OF SARCOMERE

• BARE ZONE NO ACTIN PRESENT AT RELAXATION
• DARK AREA THICK FILAMENT CALLED MYOSIN
• THIN FILAMENT CALLED ACTIN

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HOW A CONTRACTION HAPPENS

• The presence of ACH at the muscle receptor causes
  a change in polarity. The change in Na and K
  balance causes the ACTION POTENTIAL
• Once started, the stimulus is unstoppable and
  travels the length of the sarcolemma.
• The action potential stimulates the sarcoplasmic
  reticulum to RELEASE CALCIUM into the cytoplasm
• CALCIUM triggers the opening of the myosin
  binding site on the actin filaments by binding
  to tropinin and tropomyosin.

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You Tube Assistance

• Nerve at Synapse http//www.bing.com/videos/searc
  h?qActionPotentialAnimationMcGrawHillFormVQ
  FRVPviewdetailmidBD481F1B29FC2BF8421DBD481F1B2
  9FC2BF8421D
• Muscle

http//www.bing.com/videos/search?qYouTubeMuscle
ContractionFORMRESTABviewdetailmid27DFE0C56
23BB0825B6327DFE0C5623BB0825B63
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CONTINUED

• The cross-bridge heads attach to the open site.
• The attachment and release of cross bridges to
  actin causes a rowing motion of the myosin
  heads pulling the actin filament closer together
  resulting in a contraction.
• During the muscle contraction, Acetylcholinesteras
  e breaks down ACH to stop the influx of ions
  across the sarcolemma

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CONTINUED

• THE CELL RETURNS TO RESTING STATE AS THE SODIUM-
  POTASSIUM PUMP RETURNS THE IONS TO ORIGINAL
  CONCENTRATION
• What kind of movement is this called?
• THE ACETYLCHOLINESTERASE HAS NEGATED THE NERVE
  IMPULSE UNTIL THE NEXT NEUROTRANSMITTER RELEASE
  IS ACHIEVED

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ENERGY FOR CONTRACTIONS

• MUSCLES STORE VERY LITTLE ATP
• ITS GONE IN SECONDS!!!
• NEXT, IT LOOKS FOR CREATINE PHOSPHATE IN MUSCLES
• TAKES A PHOSPHORUS MOLECULE TO RE-ENERGIZE ADP TO
  ATP
• USES ALL CP WITHIN 20 SECONDS!!!

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AEROBIC RESPIRATION

• OCCURS IN MITOCHONDRIA
• GLUCOSE BROKEN DOWN INTO H2O CO2 RELEASING
  ENERGY
• ENERGY CAPTURED AS ATP
• GET 36 ATP FOR 1 GLUCOSE
• SLOW NEEDS O2 (FROM MYOGLOBIN) NUTRIENT FUELS
  IN CONTINUOUS FLOW

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ANAEROBIC GLYCOLYSIS

• OCCURS IN CYTOSOL
• GLUCOSE BECOMES PYRUVIC ACID ENERGY
• 2 ATP FOR 1 GLUCOSE
• PYRUVIC ACID OXYGEN ENERGY
• PYRUVIC ACID NO O2 LACTIC ACID
• FASTER BUT PROMOTES MUSCLE FATIGUE SORENESS

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MUSCLE FATIGUE

• FATIGUE UNABLE TO CONTRACT EVEN THOUGH
  STIMULATED
• CONTRACTION BECOMES WEAKER UNTIL STOPS
• USUALLY DUE TO O2 DEBT OF PROLONGED MUSCLE
  ACTIVITY
• CAN HAPPEN TO MARATHON RUNNERS
• O2 DEBT MUST BE PAID BACK

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EFFECTS OF EXERCISE ON MUSCLES

• USE IT OR LOSE IT!!!!!!!
• EXERCISE INCREASES SIZE, STRENGTH ENDURANCE
• AEROBIC EXERCISE INCREASED RESISTANCE TO
  FATIGUE, IMPROVES METABOLISM DIGESTION,
  INCREASES COORDINATION, MAKES SKELETON STRONGER,
  LUNGS MORE EFFICIENT, CLEANS FAT DEPOSITS FROM
  BLOOD VESSEL WALLS

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ISOTONIC CONTRACTIONS

• SAME TONE OR TENSION
• BENDING KNEE
• SMILING
• MOVEMENT OCCURS

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ISOMETRIC CONTRACTION

• SAME MEASUREMENT
• INCREASES THE TENSION ON THE MUSCLE
• NO MOVEMENT
• MUSCLES vs IMMOVABLE OBJECT

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RESISTANCE EXERCISES

• BODY BUILDERS USE THIS
• MAKING MUSCLES CONTRACT WITH AS FORCE AS POSSIBLE
  ENLARGES THE MUSCLE CELL
• USE ISOTONIC FOR HEALTH
• USE ISOMETRIC FOR DEFINITION OF MUSCLES

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MUSCLE TONE

• SOME MUSCLE FIBERS ARE ALWAYS CONTRACTING EVEN
  WHEN WE ARE RELAXED
• MAKES MUSCLE FEEL FIRM
• CONTINUOUS PARTIAL CONTRACTIONS MUSCLE TONE

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MOVEMENT NAMES

• FLEXION DECREASE ANGLE OF JOINT
• EXTENSION ENLARGES ANGLE
• ROTATION MOVING BONE AROUND LONGITUDINAL AXIS
• ABDUCTION AWAY FROM MIDLINE
• ADDUCTION TOWARD MIDLINE
• CIRCUMDUCTION PROXIMAL END IT STABLE, DISTAL
  END MOVES IN A CIRCLE

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SPECIAL MOVEMENTS

• DORSIFLEXION STAND ON HEELS
• PLANTAR FLEXION POINT TOES
• INVERSION TURN SOLE MEDIALLY
• EVERSION TURN SOLE LATERALLY
• SUPINATION PALM FACES ANTERIORLY
• PRONATION PALM FACES DORSALLY
• OPPOSITION THUMBS TO FINGER TIPS

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INTERACTIONS of MUSCLES

• PRIME MOVER MAJOR MUSCLE CAUSING MOVEMENT
• ANTAGONIST- REVERSES MOVEMENT OF PRIME MOVER
• SYNERGISTS HELPS PRIME MOVER OR STABILIZES
  JOINT
• FIXATORS STABILIZE ORIGIN OF PRIME MOVER OR
  HOLDS BONE STILL

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NAMING MUSCLES

• DIRECTION OF THE FIBERS
• SIZE OF MUSCLE
• LOCATION
• NUMBER OF ORIGINS
• SHAPE
• ACTION
• LOCATION OF ORIGIN INSERTION

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ARRANGEMENT OF FASCICLES

• CIRCULAR SPHINCTERS
• CONVERGENT MEET IN ONE SPOT
• PARALLEL EVEN TO LONG AXIS
• FUSIFORM LIKE PARALLEL WITH WIDE CENTER
• PENNATE- FEATHERLIKE PATTERN, ENTERS THE TENDON
• UNIPENNATE, BIPENNATE, MULTIPENNATE

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FACIAL MUSCLES

• FRONTALIS
• ORBICULARIS OCULI
• ORBICULARIS ORIS
• BUCCINATOR
• ZYGOMATICUS
• CHEWING MUSCLES
• MASSETER
• TEMPORALIS

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NECK MUSCLES

• PLATYSMA SHEET OF MUSCLE FROM CHEST TO
  MANDIBLE- PULLS CORNER OF MOUTH DOWN SAG
• STERNOCLEIDOMASTOID COME FROM STERNUM AND
  CLAVICLE TO INSERT ON MASTOID

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ANTERIOR TRUNK MUSCLES

• PECTORALIS MAJOR
• INTERCOSTALS
• ABDOMINAL GIRDLE
• RECTUS ABDOMINUS STRAIGHT FROM PUBIS TO RIB
  CAGE
• EXTERNAL OBLIQUE SIDES TO CENTER DOWNWARD
• INTERNAL OBLIQUE SIDES TO CENTER UP
• TRANSVERSE ABDOMINUS LOWER RIBS AND ILIAC CREST
  ACROSS ABDOMEN

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POSTERIOR MUSCLES

• TRAPEZIUS TRIANGULAR IN UPPER BACK
• LATISSIMUS DORSI LOWER BACK
• ERECTOR SPINAE ALONG SPINE
• DELTOID TRIANGULAR IN SHOULDER/ UPPER ARM

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MUSCLES CAUSING HIP MOVEMENT

• GLUTEUS MAXIMUS FORMS BUTTOCKS, HIP EXTENSOR
• GLUTEUS MEDIUS HIP ABDUCTOR, STEADIES PELVIS
  DURING WALKING
• ILIOSPOAS HIP FLEXOR, PREVENTS HYPEREXTENSION
• ADDUCTOR MUSCLE ADDUCT HIP

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MUSCLES KNEE JOINTS

• HAMSTRING GROUP POSTERIOR THIGH, HAVE LARGE
  TENDON BY KNEE
• SARTORIUS - WEAK THIGH FLEXOR SYNERGISTICS TO
  SIT LIKE AN INDIAN
• QUADRICEPS
• RECTUS FEMORIS EXTENDS KNEE FLEX HIP
• 3 VASTUS MUSCLES HELP EXTEND KNEE

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MUSCLES AND ANKLE/ FOOT

• GASTROCNEMIUS IS MOST IDENTIFIABLE AS THE CALF
  MUSCLE
• CAUSES PLANTAR FLEXION OF FOOT AND FLEXES THE KNEE

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DEVELOPMENTAL ASPECTS OF MUSCLES

• MUSCULAR DYSTROPHY MUSCLES ENLARGE DUE TO FAT
  CONNECTIVE TISSUE DEPOSITS BUT THE MUSCLE FIBERS
  ARE DEGENERATING
• DUSCHENNES MD DX BY AGE 2-6
• W/C BY 10 -12
• DEATH IN YOUNG ADULTHOOD

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CONTINUED

• MYASTHENIA GRAVIS A SHORTAGE OF ACH RECEPTORS
  AT NEURO- MUSCULAR JUNCTION DUE TO ANTIBODIES AT
  RECEPTOR SITES. MUSCLE CELLS HAVE POOR
  STIMULATION WEAKEN. DEATH RESULTS FROM
  RESPIRATORY FAILURE.

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AGING

• LOSE MUSCLE MASS AND STRENGTH AS WE AGE UNLESS WE
  EXERCISE TO KEEP FIRM
• LOSE 50 OF STRENGTH BY AGE 80

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DISORDERS OF ASSOCIATED STRUCTURES

• BURSITIS
• TENDONITIS
• BUNIONS
• TENOSYNOVITIS
• SHINSPLINTS
• CARPAL TUNNEL SYNDROME

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MEDICAL TERMINOLOGY

• PLEASE KNOW THE TERMS ON PAGES 181 AND 182