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BIOH111
oCell Module
oTissue Module
oSkeletal system
o Integumentary system
oMuscle system
oNervous system
oEndocrine system
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TEXTBOOK AND
REQUIRED/RECOMMENDED READINGS
o Principles of anatomy and physiology. Tortora et al; 14th
edition: Chapter 11
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BIOH111 – MUSCLE SYSTEM MODULE
o Session 11 (Lectures 17 and 18) – Muscle
physiology: Building of muscle organ – cells,
tissue, organ and muscle contraction process and
regulation
o Session 12 (Lectures 19 and 20) - Skeletal muscle
metabolism
o Session 13 (Lectures 21 and 22) – Major muscle
groups
BIOH111
Lectures 21 and 22
Major muscle groups
Department of Bioscience
endeavour.edu.au
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PREPARATION FOR THIS SESSION
o Complete any missing concepts and linking words from
Session 12
o Write down some muscle names you know (we will learn
Latin names for these in the next session)
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OBJECTIVES
Lecture 21 and 22:
Structure of muscular system
Name major skeletal muscles
Function of muscular system: how skeletal muscles produce movement
• Describe muscle attachment sites – origin and insertion and relate to the level
systems and leverage
• Describe the effects of fascicle arrangement and co-ordination within the
muscle groups
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MUSCULAR SYSTEM
• The voluntarily controlled muscles of
the body make up the muscular
system.
• Structure: principal skeletal muscles
• Function: production of movement;
stabilization of body position;
regulation of organ volume,
movement of substances within the
body and production of heat
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COORDINATION WITHIN
MUSCLE GROUPS
o Most movement is the result of several muscle working at the
same time
o Most muscles are arranged in opposing pairs at joints
• prime mover or agonist contracts to cause the desired
action while antagonist stretches and yields to prime
mover; e.g. flexors-extensors
• synergists contract to stabilize nearby joints while prime
movers contract
• fixators stabilize the origin of the prime mover; e.g. scapula
held steady so deltoid can raise arm
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NAMING OF SKELETAL MUSCLESo The names of most of the nearly 700 skeletal muscles are
based on several types of characteristics:
• direction in which the muscle fibers run
• location
• size
• numbers of origins
• shape
• sites of origin and insertion of the muscle
• action
o Examples:
• triceps brachii - 3 sites of origin
• quadratus femoris - square shape
• serratus anterior - saw-toothed edge
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MUSCLE ATTACHMENT SITES:
ORIGIN AND INSERTION
o Skeletal muscles shorten & pull
on the bones they are attached to
o Origin: the bone that does not
move when muscle shortens
(normally proximal)
o Insertion: the movable bone
(some 2 joint muscles)
o Belly: fleshy portion of the
muscle between attachment sites
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HEAD AND NECK MUSCLESo Muscles of facial expression and muscles of mastication:
• Origin: skull; insertion point: skin
• Encircle eyes, nose & mouth
• Express emotions
• Facial Nerve (VII)
o Muscles that move mandible:
• Origin: skull; insertion point: mandible
• Cranial nerve V (trigeminal nerve)
• Protracts, elevates or retracts mandible
o Muscles that move head:• Origin: sternum & clavicle; insert point: mastoid process of skull
• Cranial nerve XI (spinal accessory)
• contraction of both flexes the cervical vertebrae & extends head
• contraction of one, laterally flexes the neck and rotates face in opposite direction
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MUSCLES OF FACIAL EXPRESSION
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MUSCLES THAT MOVE THE MANDIBLE
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MUSCLES THAT MOVE THE HEAD
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MUSCLES OF ABDOMINAL WALL
o 4 pairs of sheet like muscles
1. rectus abdominus = vertically oriented
2. external & internal obliques and transverses
abdominus
–wrap around body to form anterior body wall
– form rectus sheath and linea alba
o Inguinal ligament from anterior superior iliac spine to
upper surface of body of pubis
o Inguinal canal = passageway from pelvis through body
wall musculature opening seen as superficial inguinal ring
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MUSCLES OF ABDOMINAL WALL
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STABILIZING THE PECTORAL GIRDLE
o Muscles important for breathing:
• Pectoralis minor
• Intercostals (internal and external)
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STABILIZING THE PECTORAL GIRDLE
o Posterior thoracic muscles:
• Latissimus dorsi
• Rhomboid major
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MUSCLES THAT MOVE THE ARM
• Pectoralis major
• Latissimus dorsi
• Deltoid
• Rotator cuff muscles
(supraspinatus,
infraspinatus, teres minor
and subscapularis)
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FLEXORS OF THE FOREARM (ELBOW)o Cross anterior surface of elbow
joint & form flexor muscle
compartment
o Biceps brachii
o Brachialis
o Brachioradialis (posterior view)
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EXTENSORS OF THE FOREARM (ELBOW)
o Cross posterior surface of
elbow joint & forms extensor
muscle compartment
o Triceps brachii
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MUSCLES/TENDONS USED FOR
IDENTIFYING PULSE
o Flexor carpi
muscles/tendon
• radialis
• ulnaris
o Flexor digitorum
muscles/tendon
• profundus
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FLEXOR RETINACULUM
o Tough connective tissue band that helps hold tendons in place
o Extensor & Flexor retinaculum cross wrist region attaching from bone to bone (carpal tunnel syndrome = painful compression of median nerve due to narrowing passageway under flexor retinaculum
For interest only/clinical application
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INTRINSIC MUSCLES OF THE HAND
o Origins & insertions are within
the hand
o Help move the digits
o Thenar muscles move the thumb
o Hypothenar muscles move the
little finger
o Opposition, flexion, extension,
abduction & adduction
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MUSCLES THAT MOVE THE VERTEBRAEo Quite complex due to overlap
o Erector spinae fibers run longitudinally
• 3 groupings
– spinalis
– iliocostalis
– longissimus
• extend vertebral column
o Smaller, deeper muscles
• transversospinalis group
– semispinalis, multifidis &
rotatores
• run from transverse process to
dorsal spine of vertebrae
above & help rotate vertebrae
Non-examinable
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MUSCLES CROSSING THE HIP JOINTo Iliopsoas flexes hip joint
• arises lumbar vertebrae & ilium
• inserts on lesser trochanter
o Quadriceps femoris has 4 heads
• Rectus femoris crosses hip
• 3 heads arise from femur
• all act to extend the knee
o Adductor muscles
• bring legs together
• cross hip joint medially
• see next picture
o Pulled groin muscle
• result of quick sprint activity
• stretching or tearing of iliopsoas
or adductor muscle
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ADDUCTOR MUSCLES OF THE THIGHo Adductor group of muscle
extends from pelvis to linea
aspera on posterior surface
of femur
• pectineus
• adductor longus
• adductor brevis
• gracilis
• adductor magnus (hip
extensor)
Non-examinable
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MUSCLES OF THE HIP & THIGH
o Gluteus muscles
• maximus, medius & minimus
• maximus extends hip
• medius & minimus abduct
o Deeper muscles laterally rotate femur
o Hamstring muscles
• semimembranosus (medial)
• semitendinosus (medial)
• biceps femoris (lateral)
• extend hip & flex knee
– Pulled hamstring
– tear of origin of muscles from
ischial tuberosity
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MUSCLES OF THE CALF (POSTERIOR LEG)
o 3 muscles insert onto calcaneus
• gastrocnemius arises femur
– flexes knee and ankle
• plantaris & soleus arise from leg
– flexes ankle
o Deeper mm arise from tibia or fibula
• cross ankle joint to insert into foot
– tibialis posterior
– flexor digitorum longus
– flexor hallucis longus
• flexing ankle joint & toes
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MUSCLES OF THE LEG AND FOOTo Anterior compartment of leg
• extensors of ankle & toes– tibialis anterior
– extensor digitorum longus
– extensor hallucis longus
• tendons pass under retinaculumo Shinsplits syndrome
• pain or soreness on anterior tibia
• running on hard surfaceso Lateral compartment of leg
• peroneus mm plantarflex the foot
• tendons pass posteriorly to axis of ankle joint and into plantar foot
Non-examinable
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MUSCLES OF THE PLANTAR FOOT
o Intrinsic muscles
• arise & insert in foot
o 4 layers of muscles
• get shorter as go into
deeper layers
o Flex, adduct & abduct toes
o Digiti minimi muscles move little
toe
o Hallucis muscles move big toe
o Plantar fasciitis (painful heel
syndrome) chronic irritation of
plantar aponeurosis at calcaneus
• improper shoes &
weight gain
Non-examinable
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FUNCTION OF MUSCULAR SYSTEM
Movement
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FASCICLE (MUSCLE BUNDLE)
ARRANGEMENTS
o Contracting muscle shortens to about 70% of its length
o Fascicular arrangement correlated with the power of the
muscle and its range of motion and• muscles with longer fibers have a greater extensibility
• a short fiber can contract as forcefully as a long one
Parallel Fusiform Pennate
Circular Triangular Bipennate Multi-pennate
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RELATING MUSCLE ATTACHMENT
SITES TO MOVEMENT
Lever systems and leverage
(mechanical advantage)
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THREE TYPES OF LEVERS
o First class levers (EFL): seesaw; e.g. the head on the
vertebral column
o Second-class (FLE): wheelbarrow; e.g standing on tiptoes
o Third-class (FEL): forceps; e.g. the elbow joint
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FIRST CLASS LEVER
o Can produce mechanical advantage
or not depending on location of effort
& resistance
• if effort is further from fulcrum than
resistance, then a strong resistance
can be moved
o Head resting on vertebral column
• weight of face is the resistance or
load
• joint between skull & atlas is fulcrum
• posterior neck muscles provide effort
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SECOND CLASS LEVER
o Similar to a wheelbarrow
o Always produce mechanical
advantage
• Resistance or load is always closer
to fulcrum than the effort
o Sacrifice of speed for force
o Raising up on your toes
• resistance is body weight
• fulcrum is ball of foot
• effort is contraction of calf muscles
which pull heel up off of floor
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THIRD CLASS LEVER
o Most common levers in the body
o Always produce a mechanical
disadvantage
• effort is always closer to fulcrum
than resistance
o Favors speed and range of motion
over force
o Flexor muscles at the elbow
• resistance is weight in hand
• fulcrum is elbow joint
• effort is contraction of biceps
brachii muscle
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Recap of Session 13
Muscle groups in red boxes are examinable and needed for completing
the content in subsequent subjects (e.g. BIOE221)
Movement by muscles is accomplished using levers (first, second and
third class)
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PREPARATION FOR NEXT SESSION
o NO MISSING CONCEPTS OR LINKING WORDS from Session
13
o Review:
• animal cell components
• plasma membrane
• tissue types
o Think about cells as immature and specialised (mature) – why is
there a difference?