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Chapter 6: Muscular System. Anatomy & Physiology Kasprowicz. The essential function of muscle is contraction – making it responsible for almost all body movement. Types of Muscle Skeletal Cardiac Smooth . Types of Muscle . muscle cells are elongated =

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Chapter 6 muscular system

Chapter 6: Muscular System

Anatomy & Physiology

Kasprowicz


The essential function of muscle is contraction making it responsible for almost all body movement

The essential function of muscle is contraction – making it responsible for almost all body movement.


Types of muscle

Types of Muscle

Skeletal

Cardiac

Smooth

Types of Muscle


General muscle characteristics

  • muscle cells are elongated =

  • muscle fibers (smooth, skeletal)

  • contain myofilaments (ability

  • to contract)

  • terminology:

  • myo-, mys- = muscle

  • sarco- = flesh

General Muscle Characteristics


Skeletal muscle

  • Very large, multinucleated cells

  • Striated (visible stripes or banding pattern)

  • Voluntary (conscious) control; can be reflexive too

  • muscle fibers (cells) are bundled together by strong connective tissues 

    exert great force, but tire easily

Skeletal Muscle


Connective tissues in skeletal muscle

Deep fascia

Connective Tissues in Skeletal Muscle


Connective tissues in skeletal muscles

  • Endomysium – around single muscle fiber

  • Perimysium – around a fascicle (bundle) of fibers

  • Epimysium – covers the entire skeletal muscle

  • Deep Fascia – on the outside of the epimysium

Connective Tissues in Skeletal Muscles


Connective tissues in skeletal muscle1

Connective Tissues in Skeletal Muscle


Connective tissues in skeletal muscles1

  • tendon – dense connective tissue attaching muscle to bone (cord-like)

  • aponeuroses – attach muscles indirectly to bone,cartilages or connective tissue coverings (sheet-like)

  • Epimysium blends into a connective tissue attachment

Connective Tissues in Skeletal Muscles


Connective tissues in skeletal muscles2

Connective Tissues in Skeletal Muscles


Connective tissues in skeletal muscles3

Aponeurosis of the

external oblique

Connective Tissues in Skeletal Muscles


Connective tissues in skeletal muscles4

Refer to pg. 272 in your textbook

Connective Tissues in Skeletal Muscles


Smooth muscle

  • Spindle-shaped cells with one nucleus

  • no striations

  • Involuntary (no conscious control)

  • Found in hollow visceralorgans

  • Have small amount of endomysium

Smooth Muscle


Smooth muscle1

  • slow, sustained, tireless movement

  • often layers in

    opposite

    directions

Smooth Muscle


Smooth muscle stomach wall

Smooth Muscle: Stomach Wall


Cardiac muscle

  • Branching cells with one nucleus

    connected by intercalated discs

    2) Striated

    3) Involuntary (no conscious control)

  • small amounts of endomysium

Cardiac Muscle


Cardiac muscle1

  • Cardiac fibers

    are arranged in

    spiral or 8-shaped bundles

Cardiac Muscle


Muscle functions

  • Producing movement

  • Maintaining posture

  • Stabilizing joints

  • Support soft tissues

  • Generating heat

  • Guard entrances and exits

Muscle Functions


Muscle functions1

Muscle Functions


Skeletal muscle fiber cell formation

Skeletal Muscle Fiber (Cell) Formation


Skeletal muscle fiber cell formation1

Skeletal Muscle Fiber (Cell) Formation


Microscopic anatomy of muscle

  • Cells are multinucleate

  • Nuclei are just beneath the sarcolemma

    (1) sarcolemma - specialized plasma

    membrane of muscle cells

Microscopic Anatomy of Muscle


Microscopic anatomy of muscle1

(2) Cytoplasm filled with myofibrils

myofibrils – perfectly aligned, ribbon-

like organelles; give muscle

fiber its striped appearance

Microscopic Anatomy of Muscle


Microscopic anatomy of muscle2

(2) Cytoplasm filled with myofibrils

A closer look at the myofibril

Light (I) bands

Dark (A) bands

Microscopic Anatomy of Muscle


Microscopic anatomy of muscle3

(2) Cytoplasm filled with myofibrils

Banding Pattern:

Light (I) bands contain the Z disc

Dark (A) bands contain the H zone

M line - holds

adjacent

filaments

together;

center of

H zone

Microscopic Anatomy of Muscle


Microscopic anatomy of muscle4

An even closer look at the myofibril…

  • Sarcomere

    - contractile unit of the myofibril

    - Z disc to Z disc

Microscopic Anatomy of Muscle


Microscopic anatomy of muscle5

An even closer look at the myofibril…

  • Sarcomere

Microscopic Anatomy of Muscle


Microscopic anatomy of muscle6

Zooming in on the sarcomere…

  • Myofilaments- special proteins

    that cause muscle to contract

    Two Types:

    a) myosin (thick filament)

    b) actin (thin filament)

Microscopic Anatomy of Muscle


Microscopic anatomy of muscle7

Two Types:

a) myosin (thick filament)

  • protein with heads that form

    cross bridges b/t thick & thin

    filaments during muscle

    contraction

  • Contain ATPase enzymes

  • Microscopic Anatomy of Muscle


    Microscopic anatomy of muscle8

    Two Types:

    b) actin (thin filament)

    • Made of the contractile protein actin & some other regulatory proteins

    Microscopic Anatomy of Muscle


    Microscopic anatomy of muscle9

    Zooming in around the H zone….

    Microscopic Anatomy of Muscle


    Microscopic anatomy of muscle10

    (5) Sarcoplasmic reticulum (SR)

    specialized smooth ER surrounding

    each myofibril

    stores calcium which is released

    when muscle is stimulated to

    contract

    Microscopic Anatomy of Muscle


    Microscopic anatomy of muscle11

    Sarcoplasmic reticulum (SR)

    Microscopic Anatomy of Muscle


    Microscopic anatomy of muscle12

    Sarcoplasmic reticulum (SR)

    Microscopic Anatomy of Muscle


    Let s put this all together

    Microscopic Organization of Muscle:

    Level 1 (refer to Fig. 10-6, pg. 278)

    Let’s put this all together….


    Let s put this all together1

    Microscopic Organization of Muscle:

    Level 2

    Let’s put this all together….


    Let s put this all together2

    Microscopic Organization of Muscle:

    Level 3

    Let’s put this all together….


    Let s put this all together3

    Microscopic Organization of Muscle:

    Level 4

    Let’s put this all together….


    Let s put this all together4

    Microscopic Organization of Muscle:

    Level 5

    Let’s put this all together….


    Skeletal muscle activity initiating the contraction

    Skeletal Muscle Activity: Initiating the Contraction


    Special functional properties of muscle

    • Irritability – ability to receive and respond to a stimulus

    • (a property shared with neurons)

    • Contractility – ability to shorten when an adequate stimulus is received

    Special Functional Properties of Muscle


    Skeletal muscles must be stimulated by a nerve to contract motor neuron

    Skeletal muscles must bestimulated by a nerve to contract (motor neuron).


    Quick review of neurons synapses

    Quick Review of Neurons & Synapses


    Quick review of neurons synapses1

    Quick Review of Neurons & Synapses


    Quick review of neurons synapses2

    Quick Review of Neurons & Synapses


    Nerve stimulus to muscle

    Motor unit:

    One neuron & the muscle cells stimulated

    by that neuron

    Nerve Stimulus to Muscle


    Nerve stimulus to muscle1

    Neuromuscular junctions

    • the neuron & muscle fibers do NOT touch

    • separated by a gap

      called the synaptic

      cleftwhich is filled

      w/ interstitial fluid

    Nerve Stimulus to Muscle


    Nerve stimulus to muscle2

    Neuromuscular junctions

    Nerve Stimulus to Muscle


    Transmission of nerve impulse to muscle

    Neurotransmitters

    • chemical released by neurons used to

      “carry” the impulse across the

      synaptic cleft

      Acetylcholine (ACh) is the

      neurotransmitter used at the

      neuromuscular junction of skeletal

      muscle

    Transmission of Nerve Impulse to Muscle


    Transmission of nerve impulse to muscle1

    Steps in Impulse Transmission

    • ACh is released by the pre-synaptic axon terminal of the motor neuron

    • ACh crosses the synaptic cleft & attaches to receptors on the sarcolemma

    • Sarcolemma becomes permeable to sodium (Na+)

    Transmission of Nerve Impulse to Muscle


    Transmission of nerve impulse to muscle2

    Steps in Impulse Transmission

    • Sodium floods into the cell generating an action potential (electrical current)

    • Once started, muscle contraction cannot be stopped !!

    • ACh is broken down by the enzyme acetylcholinesterase

      Thisprevents continued contraction of the muscle cell in the absence of additional nerve impulses.

    Transmission of Nerve Impulse to Muscle


    Transmission of nerve impulse to muscle3

    Steps in Impulse Transmission

    • When an action potential

      sweeps along the sarcolemma

      and a muscle cell is excited,

      calcium ions are released from

      the sarcoplasmic reticulum

    Transmission of Nerve Impulse to Muscle


    Transmission of nerve impulse to muscle4

    Steps in Impulse Transmission

    • The flood of Ca+ ions is the final

      trigger for the contraction of the

      muscle

    Transmission of Nerve Impulse to Muscle


    Skeletal muscle activity sliding filament theory of muscle contraction

    Skeletal Muscle Activity: Sliding Filament Theory of Muscle Contraction


    Mechanism of muscle contraction

    Sliding Filament

    Theory: Overview

    • Myosin heads form

    • cross bridges with

    • binding sites on

    • actin

    • Myosin heads detach &

    • then bind to the next

    • site on actin

    Resting Sarcomere

    Mechanism of Muscle Contraction

    Sarcomere Contracts


    Mechanism of muscle contraction1

    Sliding Filament

    Theory: Overview

    • This action continues,

      causing the myosin &

      actin to slide past

      each other

    Resting Sarcomere

    Mechanism of Muscle Contraction

    Sarcomere Contracts


    Mechanism of muscle contraction2

    Sliding Filament

    Theory: Overview

    • Collective shortening of

      the muscle cell

      sarcomeres =

      muscle contraction

    Resting Sarcomere

    Mechanism of Muscle Contraction

    Sarcomere Contracts


    The contraction cycle the nitty gritty

    Step 1:

    • Ca+ ions released from the SR

      attach to the troponin-

      tropomyosin complex

    • Binding sites on the actin

      filament are exposed

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty1

    Step 1:

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty2

    Step 2:

    • myosin heads attach to actin binding

      sites, forming cross bridges

    • ATP was required to prep the

      myosin head (ATP  ADP + P)

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty3

    Step 2:

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty4

    Step 3:

    • ADP + P released from myosin

      head

    • myosin head flexes/pivots =

      “power stroke”

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty5

    Step 3:

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty6

    Step 4:

    • ATP binds to myosin head,

      causing it to

      detach from

      the actin

      filament

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty7

    Step 5:

    • myosin head re-energized

      (ATP  ADP + P)

      Step 6:

    • Ca+ ions pumped back into the SR

    • troponin-tropomyosin complex

      moves back to its original position

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty8

    The Contraction Cycle : The Nitty Gritty


    The contraction cycle the nitty gritty9

    The Contraction Cycle : The Nitty Gritty


    Chapter 6 muscular system

    Muscle Contraction Animations

    http://www.mhhe.com/biosci/bio_animations/09_MH_MuscleContraction_Web/index.html

    Muscle Contraction 3-D Animation

    http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__action_potentials_and_muscle_contraction.html

    Action Potentials & Muscle Contraction

    https://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_atp_and_crossbridge_movement_during_muscle_contraction.html

    Break Down of ATP & Cross Bridge Attachment

    https://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__sarcomere_contraction.html

    Sarcomere Contraction


    Contraction of the whole muscle

    • The “all-or-none” response of muscle

      contraction refers to the muscle cell,

      NOT the whole muscle

    • Whole muscle reacts with a graded

      response (different degrees of

      shortening)

    Contraction of the Whole Muscle


    Contraction of the whole muscle1

    Graded responses are produced in 2 ways:

    • Change the frequency of stimulation

    • Change the # of muscle cells

      stimulated/time

      - more activated muscle cells

      stronger FORCE of contraction

    Contraction of the Whole Muscle


    Contraction of the whole muscle2

    Changing Stimulation Frequency

    Muscle Twitch – 1 stimulus;

    single, brief, jerky contraction

    1

    Contraction of the Whole Muscle


    Contraction of the whole muscle3

    Changing Stimulation Frequency

    2

    Wave Summation– frequency of stimulus increases; less time to relax; contraction strength “summed”

    Contraction of the Whole Muscle


    Contraction of the whole muscle4

    Changing Stimulation Frequency

    3

    Incomplete Tetanus – frequency of stimulation increases even more

    Contraction of the Whole Muscle


    Contraction of the whole muscle5

    Changing Stimulation Frequency

    4

    Tetanus – frequency of stimulation very rapid; no evidence of relaxation; smooth, sustained contraction

    Contraction of the Whole Muscle


    Energy for muscle contraction

    • Initially, muscles used stored ATP for energy

      • ATP is hydrolyzed into ADP + P

      • Only 4-6 seconds worth of ATP is stored

        by muscles

    • After this, other metabolic pathways must be used to produce ATP

    Energy for Muscle Contraction


    Energy for muscle contraction1

    Pathway 1: Direct Phosphorylation

    • Muscle cells contain creatine phosphate (CP)

      • CP is a high-energy molecule that transfers energy to ADP, regenerating ATP

  • CP supplies are exhausted in about 20 seconds

  • Energy for Muscle Contraction


    Energy for muscle contraction2

    Pathway 1:

    Direct

    Phosphorylation

    Energy for Muscle Contraction


    Energy for muscle contraction3

    Pathway 2: Anaerobic Respiration

    (a.k.a. lactic acid fermentation)

    • breaks down glucose without oxygen

    • Glucose is broken down to pyruvic acid;2 ATP are produced

    • Pyruvic acid lactic acid

    Energy for Muscle Contraction


    Energy for muscle contraction4

    Pathway 2:

    Anaerobic Respiration

    (lactic acid fermentation)

    Energy for Muscle Contraction


    Energy for muscle contraction5

    Pathway 2: Anaerobic Respiration

    • This reaction is not as efficient,

      but it is fast

      • Huge amounts of glucose are needed

      • Lactic acid produces muscle fatigue

  • Duration: 30-60 seconds

  • Energy for Muscle Contraction


    Energy for muscle contraction6

    Pathway 3: Aerobic Respiration

    • Series of metabolic pathways that occur in the mitochondria & require oxygen

    • Glucose is broken down to carbon dioxide and water releasing energy

    • This is a slower reaction that requires continuous oxygen

    • High energy pay-off: 36 ATP

    Energy for Muscle Contraction


    Energy for muscle contraction7

    Pathway 3:

    Aerobic Respiration

    Energy for Muscle Contraction


    Muscle fatigue oxygen debt

    • When a muscle is fatigued, it is unable to contract

    • The common reason for muscle fatigue is oxygen debt

      • Oxygen must be “repaid” to tissue to remove oxygen debt

      • Oxygen is required to get rid of accumulated lactic acid

    • Increasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less

    Muscle Fatigue & Oxygen Debt


    Types of muscle contraction

    Isotonic Muscle Contraction

    • The myofilaments slide past

      each other  muscle shortens

       movement occurs

      Examples: bending knee,

      rotating the arms,

      smiling

    Types of Muscle Contraction


    Types of muscle contraction1

    Isometric Muscle Contraction

    • muscle is not able to shorten

    • muscle tension keeps increasing

      Examples:

      lifting a 1000 lb. object alone;

      pushing against an object that

      doesn‘t move

    Types of Muscle Contraction


    Muscle tone

    • state of continuous partial contractions

      • Different fibers contract at different times to provide muscle tone

  • muscle remains firm, healthy & ready for action

  • Increasing muscle tone increases metabolic energy used, even at rest

  • Muscle Tone


    Muscle tone1

    Muscle Tone


    Muscle tone2

    If the nerve supply to a muscle is

    destroyed, the muscle is no

    longer stimulated in this manner,

    and it loses tone and becomes

    paralyzed. Soon after, it becomes

    flaccid (soft and flabby) and

    begins to atrophy (waste away).

    Muscle Tone


    Muscle tone3

    Muscle Tone


    Effects of exercise

    “use it or lose it”

    Aerobic (Endurance) Exercise

    • Examples: jogging, biking, swimming

    • stronger, more flexible muscles w/

      greater resistance to fatigue

    Effects of Exercise


    Effects of exercise1

    Aerobic (Endurance) Exercise

    • Physiological Effects

      1) increased blood supply to muscles

      2) more mitochondria

      3) increased metabolism

      4) keeps bones strong

      5) improves neuromuscular coordination

    Effects of Exercise


    Effects of exercise2

    “use it or lose it”

    Resistance (Isometric) Exercise

    • Examples: weight training

    • increased muscle

      size and strength

    Effects of Exercise


    Effects of exercise3

    Aerobic (Endurance) Exercise

    • Physiological Effects

      1) increased # of myofilaments

      increased size of muscle fibers

      2) more connective tissue

      3) keeps bone strong

    Effects of Exercise


    Golden rules of skeletal muscle activity

    • All (almost ) skeletal muscle cross a least one joint

    • Most of a skeletal muscle lies proximal to the joint crossed

    • All skeletal muscles have at least 2 attachments: the origin and the insertion

    • Skeletal muscles can only PULL (create tension)

    • When a muscle contracts, the insertion moves toward the origin

    “Golden Rules” of Skeletal Muscle Activity


    Types of body movements

    • Movement occurs when a muscle contracts and moves an attached bone

    • Muscles are attached to at least two points

      • Origin – attachment to a immoveable bone

      • Insertion – attachment to an movable bone

    Types of Body Movements


    Types of body movements1

    When a

    skeletal muscle

    contracts, its

    insertion

    moves toward

    its origin

    Types of Body Movements


    Body movements muscle interactions

    • prime mover – muscle primarily responsible for a certain movement

      • Example: biceps, hamstrings

      • (a.k.a. agonist)

    • Antagonist – muscle that opposes or reverses a prime mover

      • Triceps when biceps flexes; quads when hamstrings flex

    Body Movements: Muscle Interactions


    Chapter 6 muscular system

    Prime Mover – biceps

    Antagonist – triceps

    Prime Mover – triceps

    Antagonist – biceps


    Body movements muscle interactions1

    • Synergist – muscle that aids a prime mover in a movement and helps prevent rotation

      • Example: finger flexor muscles

      • brachioradiulus & brachialis in the forelimb

    Body Movements: Muscle Interactions


    Types of body movements2

    Flexion

    decreases angle of joint, bringing 2 bones closer together

    common in hinge, ball & socket joints

    Extension

    increases the angle of a joint, moving the bones apart

    hyperextension >180° angle

    Types of Body Movements


    Chapter 6 muscular system

    Hyperextension

    Flexion & Extension


    Chapter 6 muscular system

    Flexion & Extension


    Types of body movements3

    3) Rotation

    movement of a bone around its longitudinal axis

    common in ball & socket joints

    atlas (C1) around the axis (C2)

    Types of Body Movements


    Chapter 6 muscular system

    Rotation


    Types of body movements4

    4) Abduction

    movement of a limb away from the medial plane

    also used to refer to fanning of finger or toes

    5) Adduction

    movement of a limb toward the midline

    Types of Body Movements


    Chapter 6 muscular system

    Abduction & Adduction


    Chapter 6 muscular system

    Abduction & Adduction


    Types of body movements5

    6) Circumduction

    proximal end is stationary; distal end moves in a circle

    limb moves in a cone shape

    common in ball & socket joint

    combo of flexion, extension, abduction &

    adduction

    Types of Body Movements


    Chapter 6 muscular system

    Circumduction


    Special body movements

    1) Dorsiflexion(point toes up towards shin) & Plantar Flexion (pointing the toes)

    Special Body Movements


    Special body movements1

    2) Inversion (turn sole of foot medially) & Eversion(turn sole of foot laterally)

    Special Body Movements


    Special body movements2

    Supination & Pronation

    movements of the radius around the ulna

    supination: palm forward; radius & ulna are parallel (anatomical position); thumb lateral

    pronation: palm facing back; radius crosses ulna; thumb medial

    Special Body Movements


    Special body movements3

    Supination & Pronation

    Special Body Movements


    Special body movements4

    Opposition

    movement of thumb across palm to touch fingertips

    Special Body Movements


    Chapter 6 muscular system

    Elevation & Depression


    Chapter 6 muscular system

    Protraction &

    Retraction


    Naming skeletal muscles

    Direction of muscle fibers

    in reference to an imaginary line (midline of body, long axis of limb)

    ie. Rectus(fibers parallel to line)

    Oblique(fibers at a slant to line)

    Naming Skeletal Muscles


    Naming skeletal muscles1

    2) Relative Size

    Longus= long

    Longissimus = longest

    Teres = long and round

    Brevis = short

    Magnus = large

    Major = larger

    Maximus = largest

    Minor = small

    Minimus = smallest

    Naming Skeletal Muscles


    Naming skeletal muscles2

    3) Location of the Muscle

    in reference to the associated bone

    ie. temporalis(temporal bone)

    frontalis(frontal bone)

    Naming Skeletal Muscles


    Naming skeletal muscles3

    4) Number of origins

    ie. biceps, triceps, quadriceps

    Location of the muscle’s origin and insertion

    ie. Sternocleidomastoid muscle

    Naming Skeletal Muscles


    Naming skeletal muscles4

    6) Shape of the muscle

    ie. Deltoid(triangular)

    7) Action of the muscle

    ie. adductor muscle, extensor muscle

    Naming Skeletal Muscles


    Head neck muscles

    Head & Neck Muscles


    Head and neck muscles

    • Facial Muscles

    • Frontalis

    • raises eyebrows and wrinkles the

    • forehead

    • OrbicularisOculi

    • close, squint, blink and wink the eyes

    • OrbicularisOris

    • closes the mouth and protrudes the lips;

    • the “kissing” muscle

    Head and Neck Muscles


    Head and neck muscles1

    • Buccinator

    • flattens the cheek (whistling or playing

    • a trumpet); also a chewing muscle

    • Zygomaticus

    • “smiling” muscle; raises the corners of

    • the mouth upward

    Head and Neck Muscles


    Head and neck muscles2

    Chewing Muscles

    • Buccinator

    • Masseter

    • closes the jaw by elevating the mandible

    • (prime mover)

    • Temporalis

    • helps masseter close the jaw (synergist)

    Head and Neck Muscles


    Chapter 6 muscular system

    Frontalis

    Temporalis

    Orbicularisoculi

    Zygomaticus

    Masseter

    Orbicularisoris

    Buccinator


    Chapter 6 muscular system

    Temporalis

    Frontalis

    Orbicularisoculi

    Orbicularisoris

    Masseter

    Buccinator

    Zygomaticus


    Chapter 6 muscular system

    Frontalis

    Orbicularis

    oculi

    Temporalis

    Zygomaticus

    Buccinator

    Orbicularisoris

    Masseter


    Head and neck muscles3

    Neck Muscles

    • Platysma

    • pulls down corners of the mouth,

    • downward sag of the mouth

    • Sternocleidomastoid

    • two-headed muscle;

    • flex your neck (bowing of head); tilt

    • head to side

    Head and Neck Muscles


    Chapter 6 muscular system

    Frontalis

    Temporalis

    Orbicularisoculi

    Zygomaticus

    Masseter

    Orbicularisoris

    Buccinator

    Sternocleido-mastoid

    Platysma


    Chapter 6 muscular system

    Temporalis

    Frontalis

    Orbicularisoculi

    Orbicularisoris

    Masseter

    Zygomaticus

    Buccinator

    Sternocleidomastoid

    Plastysma


    Chapter 6 muscular system

    Frontalis

    Orbicularis

    oculi

    Temporalis

    Zygomaticus

    Buccinator

    Orbicularisoris

    Masseter

    platysma

    Sternocleido-mastoid


    Trunk muscles

    Trunk Muscles

    • move the vertebral column (mostly

    • posterior, anti-gravity muscles)

    • anterior thorax muscles (move ribs,

    • head & arms)

    • muscles of the abdominal wall (help

    • move vertebral column & form the

    • “girdle” holding internal organs in place)

    Trunk Muscles


    Trunk muscles1

    Anterior Muscles: Thorax

    • Pectoralis Major

    • - fan-shaped muscle

    • - origin: sternum, pectoral girdle, ribs

    • - insertion: humerus

    • - adduct & flex the arm

    Trunk Muscles


    Chapter 6 muscular system

    Pectoralis

    minor

    Pectoralis

    major


    Trunk muscles2

    Anterior Muscles: Thorax

    • Intercostal Muscles

    • - deep muscles between the ribs

    • - aid in breathing

    • (external – inhale, internal – forcible

    • exhale)

    Trunk Muscles


    Chapter 6 muscular system

    Internal

    intercostals

    External intercostals


    Trunk muscles3

    Anterior Muscles: Abdominal Girdle

    • Rectus abdominus

    • - pubis to rib cage

    • - flex the vertebral column

    • - compression of abdominal contents

    Trunk Muscles


    Trunk muscles4

    Anterior Muscles: Abdominal Girdle

    • External Oblique

    • - lateral walls of abdomen

    • - origin: ribs insertion: illium

    • - flex the vertebral column, rotate/bend

    • trunk

    Trunk Muscles


    Trunk muscles5

    Anterior Muscles: Abdominal Girdle

    • Internal Oblique

    • - origin: iliac crest insertion: ribs

    • - function same as external oblique

    • Transversusabdominis

    • - deepest muscle in abdomen

    • - fibers run horizontally

    • - compresses the abdominal contents

    Trunk Muscles


    Trunk muscles6

    Posterior Muscles

    • Trapezius

    • - kite-shaped muscle

    • - origin: occipital bone to last thoracic

    • vertebrae

    • insertion: scapula & clavicle

    • - head extension & movement of

    • scapula

    Trunk Muscles


    Trunk muscles7

    Posterior Muscles

    • LatissimusDorsi

    • - 2 large, flat muscles in the lower

    • back

    • - origin: lower spine & ilium

    • insertion: proximal end of humerus

    • - arm extension & adduction

    • (“power stroke”)

    Trunk Muscles


    Trunk muscles8

    Posterior Muscles

    • Erector Spinae

    • - prime mover of back extension

    • (keep your body “erect”); control

    • bending at the waist

    • - paired; deep in the back

    • - span vertebral column

    Trunk Muscles


    Trunk muscles9

    Posterior Muscles

    • Qudratuslumborum

    • - posterior abdominal wall

    • - flex spine laterally, extend vertebral

    • column

    • - origin: iliac crest

    • insertion: upper lumbar vertebrae

    Trunk Muscles


    Trunk muscles10

    Posterior Muscles

    • Deltoids

    • - triangular muscle forming shoulder

    • - origin: spine of scapula to clavicle

    • insertion: proximal humerus

    • - prime mover of arm abduction

    Trunk Muscles


    Muscles of the upper limb

    • The anterior arm muscles cause elbow

    • flexion

    • strongest: brachialis

    • biceps brachii

    • “weakest”: brachioradialis

    • posterior arm: triceps brachii

    Muscles of the Upper Limb


    Muscles of the upper limb1

    Anterior Arm Muscles

    • Biceps brachii

    • - origin: 2 heads in pectoral girdle

    • insertion: radius

    • - prime mover of forearm flexion &

    • supination

    Muscles of the Upper Limb


    Muscles of the upper limb2

    Anterior Arm Muscles

    • Brachialis

    • - origin: humerus insertion: ulna

    • - forearm flexion

    • Brachioradialis

    • - origin: humerus

    • insertion: distal forearm

    Muscles of the Upper Limb


    Muscles of the upper limb3

    Posterior Arm Muscles

    • Triceps brachii

    • - origin: 3 heads in pectoral girdle

    • insertion: olecranon process of ulna

    • - prime mover of elbow extension

    • - biceps brachii antagonist

    Muscles of the Upper Limb


    Muscles of the lower limb

    • cause movement of hip, knee &

    • foot joints

    • some of the largest, strongest

    • muscles in the body

    • specialized for walking & balance

    • many of the muscles cross 2 joints

    • and can cause movement at both

    Muscles of the Lower Limb


    Muscles of the lower limb1

    Muscles that Move the Hip Joint

    • Gluteus Maximus

    • - forms most of the flesh of the buttock

    • - origin: sacrum & illiac

    • insertion: femur & iliotibial tract

    • - hip extensor (important when

    • climbing and jumping)

    Muscles of the Lower Limb


    Muscles of the lower limb2

    Muscles that Move the Hip Joint

    • Gluteus Medius

    • - beneath gluteus maximus

    • - hip abductor; steadies pelvis when

    • walking

    • Iliopsoas(two, fused muscles)

    • - prime mover of hip flexion; keeps

    • upper body from falling backward

    • when standing

    Muscles of the Lower Limb


    Muscles of the lower limb3

    Muscles that Move the Hip Joint

    • Adductor Muscles

    • - group of muscles; medial thigh

    • - adduct, or press, thighs together

    • - origin: pelvis insertion: femur

    • - tend to get flabby

    Muscles of the Lower Limb


    Chapter 6 muscular system

    Iliopsoas

    Adductor muscles

    Anterior

    View


    Chapter 6 muscular system

    Gluteus medius

    Gluteus maximus

    Adductor magnus

    Iliotibial tract

    Posterior

    View


    Muscles of the lower limb4

    Muscles that Move the Knee Joint

    • Hamstring Group

    • - group of muscles; posterior thigh

    • - biceps femoris, semimembranosus,

    • semitendinosus

    • - origin: ischium insertion: tibia

    • - prime movers of thigh extension &

    • knee flexion

    Muscles of the Lower Limb


    Muscles of the lower limb5

    Muscles that Move the Knee Joint

    • Sartorius

    • - thin, strap-like, relatively weak flexor

    • - most superficial thigh muscle

    • - synergist in sitting

    • “criss cross

    • applesauce”

    Muscles of the Lower Limb


    Muscles of the lower limb6

    Muscles that Move the Knee Joint

    • Quadriceps Group

    • - group of muscles; anterior thigh

    • - rectus femoris & 3 vastus muscles

    • - origin: pelvis & thigh

    • insertion: tibia via patellar ligament

    • - prime movers of knee extension; hip

    • flexion

    Muscles of the Lower Limb


    Chapter 6 muscular system

    Iliopsoas

    Sartorius

    Iliopsoas

    QUADS

    Adductor muscles

    Rectus femoris

    Vastuslateralis

    Vastusmedialis

    Anterior

    View


    Chapter 6 muscular system

    Posterior

    View


    Muscles of the lower limb7

    Muscles that Move the Ankle & Foot

    • Tibialis Anterior

    • - superficial muscle of anterior leg (shin)

    • - origin: tibia insertion: tarsals

    • - dorsiflex & invert the foot

    • Fibularis Muscles

    • - plantar flexion and eversion

    • - origin: fibula insertion: metatarsals

    Muscles of the Lower Limb


    Muscles of the lower limb8

    Muscles that Move the Ankle & Foot

    • Gastrocnemius

    • - forms curved calf; 2 parts

    • - origin: femur

    • insertion: heel using Achille’s tendon

    • - prime mover of plantar flexion

    Muscles of the Lower Limb


    Muscles of the lower limb9

    Muscles that Move the Ankle & Foot

    • Soleus

    • - deep to gastrocnemius

    • - origin: tibia & fibula (no effect on knee)

    • insertion: heel using Achille’s tendon

    • - plantar flexion

    Muscles of the Lower Limb


    Chapter 6 muscular system

    Posterior

    View

    Anterior

    View


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