the muscular system muscle system functions 1. provides voluntary movement of body enables...

The Muscular SystemThe Muscular System

Muscle System FunctionsMuscle System Functions

1. Provides voluntary 1. Provides voluntary movement of bodymovement of body Enables breathing, Enables breathing,

blinking, and smilingblinking, and smiling Allows you to hop, Allows you to hop,

skip, jump, or do skip, jump, or do push-ups push-ups

2. Maintains posture2. Maintains posture3. Produces heat3. Produces heat

Functions ContinuedFunctions Continued

4. Causes heart beat4. Causes heart beat5. Directs circulation 5. Directs circulation

of blood of blood RegulatesRegulates

blood blood pressurepressure

Sends blood to Sends blood to different areas of different areas of the bodythe body

Functions ContinuedFunctions Continued6. Provides movement of internal 6. Provides movement of internal

organsorgans Moves food through digestive Moves food through digestive

tracttract Enables bladder controlEnables bladder control

7. Causes involuntary actions7. Causes involuntary actions Reflex actions Reflex actions Adjusts opening of pupilsAdjusts opening of pupils Causes hair to stand on Causes hair to stand on

end ( ). With which end ( ). With which

muscle????muscle????

Types of Muscle TissueTypes of Muscle Tissue

There are There are three main three main types of types of muscle tissuemuscle tissue SkeletalSkeletal

(striated)(striated) CardiacCardiac

(heart)(heart) SmoothSmooth

(visceral)(visceral)

Comparison of Muscle TypesComparison of Muscle Types

Muscle TypeMuscle Type CardiacCardiac

FunctionFunctionMovement of Movement of

bonebone

Walls of internal Walls of internal organs + in skinorgans + in skinLocationLocation

Attached to Attached to bonebone

HeartHeart

SmoothSmoothSkeletalSkeletal

Striated- light Striated- light and dark bandsand dark bands

Many nucleiMany nuclei

StriatedStriatedOne or two One or two

nucleinuclei

CharacteristicsCharacteristicsNon-striatedNon-striatedOne nucleusOne nucleus

(visceral)(visceral)

Long + slenderLong + slender BranchingBranchingShapeShape Spindle shapeSpindle shape

Control ModeControl Mode

Beating of heartBeating of heart

InvoluntaryInvoluntary InvoluntaryInvoluntary

Movement of Movement of internal organsinternal organs

VoluntaryVoluntary

Location Location of of

MusclesMuscles SkeletalSkeletal

MusclesMuscles Anterior Anterior

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Quadriceps Quadriceps groupgroup

Rectus abdominisRectus abdominis

Quadriceps GroupQuadriceps Group

External ObliquesExternal Obliques

FrontalisFrontalis

MasseterMasseter

Tibialis AnteriorTibialis Anterior

DeltoidDeltoidPectoralis MajorPectoralis Majorbiceps brachiibiceps brachii

BrachioradialisBrachioradialis

LocationLocationof Musclesof Muscles SkeletalSkeletal

MusclesMuscles PosteriorPosterior

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Hamstring group

TrapeziusTrapezius

Hamstring Hamstring groupgroup

GastrocnemiusGastrocnemius

Latissimus dorsiLatissimus dorsi

Gluteus Gluteus maximusmaximus

Triceps brachiiTriceps brachii

FF

AA

DD

CC

BB

EE

LL

KK

JJ

HH

GG

PP

OO

NN

MM

II

Skeletal Muscles You Need to Skeletal Muscles You Need to KnowKnow

1. brachioradialis1. brachioradialis 2. biceps brachii2. biceps brachii 3. deltoid3. deltoid 4. external oblique4. external oblique 5. frontalis5. frontalis 6. gastrocnemius6. gastrocnemius 7. gluteus maximus7. gluteus maximus 8. hamstring group8. hamstring group 9. latissimus dorsi9. latissimus dorsi 10. masseter10. masseter 11. pectoralis major11. pectoralis major 12. quadriceps group12. quadriceps group 13. rectus abdominis13. rectus abdominis 14. tibialis anterior14. tibialis anterior 15. trapezius15. trapezius 16. triceps brachii16. triceps brachii

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11

22

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1212

1313

1414

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Muscles Day 2Muscles Day 2

Muscle Tissue AnatomyMuscle Tissue Anatomy

bundle of muscle bundle of muscle fibers – fasciclefibers – fascicle

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MuscleMuscle

FilamentsFilaments

MyofibrilsMyofibrils

Muscle FibersMuscle Fibers

FascicleFascicle

Muscles are made up of bundlesof muscle fibers, called fascicles Fascicle is a bundle of muscle

fibers A muscle fiber is a muscle

cell….made up of many small myofibrils

Myofibrils contain two types ofprotein filaments

SarcomereSarcomere

MyofibrilMyofibril Contain two types Contain two types

of protein filamentsof protein filaments ActinActin- thin- thin

proteinproteinfilamentsfilaments

MyosinMyosin- thick- thickprotein filamentsprotein filaments

Z lineZ line- point of - point of anchor of actinanchor of actin

SarcomereSarcomere- - functional unit of functional unit of a myofibril, a myofibril, region between region between Z discs Z discs

Thin FilamentsThin Filaments

ActinActinMoleculeMolecule

Thick FilamentsThick Filaments

Myosin MoleculeMyosin Molecule

Z DiscZ Disc

SarcomereSarcomere

DD

CC

BBAA

Muscle TissueMuscle TissueAnatomyAnatomy

What parts do you What parts do you remember?remember?

1. Muscle1. Muscle

2. Fascicle 2. Fascicle (bundle of fibers) (bundle of fibers)

3. Muscle fiber 3. Muscle fiber (muscle cell) (muscle cell)

4. Myofibrils4. Myofibrils33

44

22

11

Muscle MovementMuscle Movement ______-______- Muscle that bends the joint when Muscle that bends the joint when

contracted.contracted. ________-________- Muscle that straightens the joint Muscle that straightens the joint

when contracted.when contracted. __________ muscle__________ muscle

is short, firm, tight is short, firm, tight and thicker around.and thicker around.

_______ muscle is _______ muscle is stretched, long, loose stretched, long, loose and thinner around.and thinner around.

FlexorFlexor

ExtensorExtensor

RelaxedRelaxed

ContractedContracted

Closer look at a Closer look at a SarcomereSarcomere

Mechanics of a Muscle Mechanics of a Muscle ContractionContraction

What stimulates a muscle to What stimulates a muscle to contract?contract? Your nervous systemYour nervous system

What cells are involved?What cells are involved? Muscle cells and a motor neuronMuscle cells and a motor neuron Motor neuron sends Motor neuron sends

impulse to muscle cellsimpulse to muscle cells One neuron will form One neuron will form

synapses with many synapses with many muscle cellsmuscle cells

What is this called?What is this called? A motor unitA motor unit Let’s take a look under Let’s take a look under

the microscope.…the microscope.…A motor unitA motor unit

Steps of a muscle Steps of a muscle contractioncontraction

1.1. Message from brainMessage from brain

2.2. Message (in the form of an electrical Message (in the form of an electrical impulse called an impulse called an action-potential)action-potential) travels down the motor travels down the motor neuronneuron..

3.3. Impulse reaches neuromuscular junction Impulse reaches neuromuscular junction and neuron releases and neuron releases neurotransmitterneurotransmitter (chemical message)(chemical message)

Steps of a muscle Steps of a muscle contractioncontraction

4. Neurotransmitter causes muscle to 4. Neurotransmitter causes muscle to release calcium ions.release calcium ions.

5. Calcium ions cause myosin crossbridges 5. Calcium ions cause myosin crossbridges to formto form

6. Myosin head pivot to pull actin filaments 6. Myosin head pivot to pull actin filaments closer togethercloser together

7. Myosin head releases and reattaches to 7. Myosin head releases and reattaches to pull actin even closer.pull actin even closer.


When each sarcomere becomes shorter it When each sarcomere becomes shorter it causes each myofibril to become shorter.causes each myofibril to become shorter.

When each When each myofibril becomesmyofibril becomesshorter it causes shorter it causes the muscle fibers the muscle fibers to become shorterto become shorter

When each When each muscle fiber muscle fiber shortens the shortens the overall muscle overall muscle contracts.contracts.

SarcomereSarcomere

Control of a Muscle Control of a Muscle ContractionContraction

How strongly does a muscle fiber contract?How strongly does a muscle fiber contract? To it’s fullest extent.To it’s fullest extent. All-or-none responseAll-or-none response

So what controls the So what controls the strength of a contraction?strength of a contraction? Number of muscle cells recruitedNumber of muscle cells recruited To get a stronger contraction, more To get a stronger contraction, more

cells are stimulatedcells are stimulated A single cell can’t contract harderA single cell can’t contract harder

Muscle + Bone Muscle + Bone InteractionInteraction

Let’s review the structures involved in Let’s review the structures involved in movement at a joint. movement at a joint.

LigamentLigament TendonTendon CartilageCartilage Body (Belly)Body (Belly) OriginOrigin InsertionInsertion Contracted muscleContracted muscle Relaxed muscleRelaxed muscle FlexorFlexor ExtensorExtensor

BB

CC

FF FF

BB

FF

BB

CC

DDEE

GG

DD CC

AA


Where does stimulation occur?Where does stimulation occur? Neuromuscular junctionNeuromuscular junction

How do motor neurons How do motor neurons communicate with communicate with muscle cells?muscle cells? Neurotransmitters Neurotransmitters (chemicals) carry(chemicals) carry

impulse signal across the gapimpulse signal across the gap What happens when a What happens when a

muscle cell is stimulated?muscle cell is stimulated? Calcium ions are released into the muscle cellCalcium ions are released into the muscle cell

Myofibrils are surrounded by

calcium-containing

sarcoplasmic reticulum.

NeurotransmittersNeurotransmitters


What do calcium ions do?What do calcium ions do? Cause interaction between actin and myosinCause interaction between actin and myosin

How do actin and myosin interact?How do actin and myosin interact? Actin filaments slide over the myosin filaments.Actin filaments slide over the myosin filaments.

What model explains this?What model explains this? Sliding Filament ModelSliding Filament Model

Mechanics of a Muscle Mechanics of a Muscle ContractionContraction What causes actin to What causes actin to

slide over myosin?slide over myosin? The head of myosin The head of myosin

connects to actin connects to actin and pivots.and pivots.

What is this What is this connection called?connection called?

crossbridgecrossbridge

Some myosin heads Some myosin heads are binding while other are binding while other heads are releasing heads are releasing the actin filaments. the actin filaments.

A Closer Look at Muscle ContractionA Closer Look at Muscle Contraction

Deltoid Deltoid musclemuscle

MuscleMuscleFiberFiber

MyofibrilMyofibril

sarcomeresarcomere

ActinActin

MyosinMyosin

Muscle DisordersMuscle Disorders

A strain is an injury to a muscle or tendon, and A strain is an injury to a muscle or tendon, and is often caused by overuse, force, or stretching.is often caused by overuse, force, or stretching.

Injured area Injured area experiences: experiences: pain and sorenesspain and soreness swelling swelling warmth, bruising, warmth, bruising,

or redness or redness difficulty using or difficulty using or

moving the injured moving the injured area in a normal area in a normal mannermanner

StrainStrain


R.I.C.E.R.I.C.E. Rest:Rest: Stop all activities which Stop all activities which

cause pain. cause pain. Ice:Ice: Helps reduce swelling. Helps reduce swelling.

Never ice more than 10-15 min. Never ice more than 10-15 min. at a time. Protect the skin. at a time. Protect the skin.

Compression:Compression: Wrap the strained Wrap the strained area to reduce swelling. area to reduce swelling.

Elevation:Elevation: Keep the strained area as Keep the strained area as close to the level of the heart as is close to the level of the heart as is conveniently possible to keep blood conveniently possible to keep blood from pooling in the injured area.from pooling in the injured area.

Treatment for Muscle InjuriesTreatment for Muscle Injuries


Muscle spasm- when a muscle (or even a few Muscle spasm- when a muscle (or even a few fibers of a muscle) involuntarily contract fibers of a muscle) involuntarily contract

Muscle cramp- involuntarily + forcibly Muscle cramp- involuntarily + forcibly contracted muscle that does not relaxcontracted muscle that does not relax A forceful + sustained spasmA forceful + sustained spasm Nick named charley horseNick named charley horse

CrampsCrampsSpasmsSpasms

Can last anywhere from a few Can last anywhere from a few seconds to a quarter of an hour seconds to a quarter of an hour

Caused by strain, injury, Caused by strain, injury, dehydration, or fatiguedehydration, or fatigue

Muscle feels tied up in knotsMuscle feels tied up in knots


Tetanus is a preventable disease through vaccination Tetanus is a preventable disease through vaccination Caused by bacteria that enters the body Caused by bacteria that enters the body

through the skin through the skin Found in soil, dust and manure Found in soil, dust and manure Toxin bacteria produces interferes with nerve Toxin bacteria produces interferes with nerve

transmission to your muscles and causes transmission to your muscles and causes them to seize up in painful spasms.them to seize up in painful spasms.

““Lockjaw”Lockjaw” Difficulty swallowing Difficulty swallowing Intestines often seize upIntestines often seize up Bladder fails to emptyBladder fails to empty Asphyxiation Asphyxiation Cardiac arrest Cardiac arrest

TetanusTetanus


Produced naturally by the body to support such functions as Produced naturally by the body to support such functions as fighting stress and promoting growth and developmentfighting stress and promoting growth and development

People use steroid pills, gels, creams, or injections to improve their People use steroid pills, gels, creams, or injections to improve their sports performance or the way they look. sports performance or the way they look.

Anabolic steroids cause many different types of problemsAnabolic steroids cause many different types of problems

types of problems types of problems premature balding or hair loss premature balding or hair loss dizziness dizziness mood swingsmood swings problems sleeping problems sleeping nausea and vomiting nausea and vomiting high blood pressurehigh blood pressure aching joints aching joints urinary problems urinary problems shortening of final adult height shortening of final adult height increased risk of heart disease,increased risk of heart disease,

stroke, and some cancers stroke, and some cancers

Anabolic SteroidsAnabolic Steroids


Cerebral palsy is a group of disorders that affect a Cerebral palsy is a group of disorders that affect a person's ability to move and to maintain balance andperson's ability to move and to maintain balance and posture. posture.

The disorders appear in theThe disorders appear in thefirst few years of life, and first few years of life, and usually don’t get worse over time. usually don’t get worse over time.

People with cerebral palsy People with cerebral palsy may have difficulty walking. They may also may have difficulty walking. They may also have trouble with tasks such as writing or have trouble with tasks such as writing or using scissors. using scissors.

Some people with cerebral palsy have other Some people with cerebral palsy have other medical conditions, including seizure medical conditions, including seizure disorders or mental impairment. disorders or mental impairment.

Cerebral palsy happens when the areas of Cerebral palsy happens when the areas of the brain that control movement and posture the brain that control movement and posture do not develop correctly or get damaged.do not develop correctly or get damaged.

Cerebral PalsyCerebral Palsy


Muscular DystrophyMuscular Dystrophy- most well known of - most well known of hereditary diseaseshereditary diseases

A genetic condition that describes over 20 A genetic condition that describes over 20 genetic and hereditary muscle diseases.genetic and hereditary muscle diseases.

Characterized by progressive skeletal muscle Characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the weakness, defects in muscle proteins, and the death of muscle cells and tissue.death of muscle cells and tissue.

In some cases, cardiac and smooth muscles In some cases, cardiac and smooth muscles are affected. are affected.

Progressive Muscular Wasting (weakness) Progressive Muscular Wasting (weakness) Poor Balance and FPoor Balance and Frequent Falls requent Falls Walking Difficulty + Waddling Gait Walking Difficulty + Waddling Gait Limited Range of Movement Limited Range of Movement Scoliosis (curvature of the spine) Scoliosis (curvature of the spine) Inability to Walk Inability to Walk Muscle Atrophy and Drooping EyelidsMuscle Atrophy and Drooping Eyelids

Muscular DystrophyMuscular Dystrophy

Principal symptoms: Principal symptoms:


The characteristic symptom of myasthenia gravis is fatigability, which The characteristic symptom of myasthenia gravis is fatigability, which means that a muscle that is used repeatedly starts to become weak. means that a muscle that is used repeatedly starts to become weak.

The symptoms usually start in the face and spread to the other parts of The symptoms usually start in the face and spread to the other parts of the body as the disease progresses. the body as the disease progresses.

Certain muscles such as those that control eye and eyelid movement, Certain muscles such as those that control eye and eyelid movement, facial expression, chewing, talking, and swallowing are often involvedfacial expression, chewing, talking, and swallowing are often involved

The muscles that control breathing and neck and limb movements may The muscles that control breathing and neck and limb movements may also be affected. also be affected.

Patients initially complain of drooping eye lids that get worst as the Patients initially complain of drooping eye lids that get worst as the day goes on; they develop double vision, difficulty talking, and difficulty day goes on; they develop double vision, difficulty talking, and difficulty chewing. chewing.

Muscle weakness increases during periods of activity and improves Muscle weakness increases during periods of activity and improves after periods of rest. after periods of rest.

Myasthenia gravis-Myasthenia gravis- chronic chronic autoimmune neuromuscular disease autoimmune neuromuscular disease characterized by varying degrees of characterized by varying degrees of weakness of the skeletal musclesweakness of the skeletal muscles

Caused by a defect in the Caused by a defect in the transmission of nerve impulses at transmission of nerve impulses at the neuromuscular junctionthe neuromuscular junction

Myasthenia GravisMyasthenia Gravis


PoliomyelitisPoliomyelitis, often called , often called poliopolio is an acute is an acuteviral infectious disease which is spread fromviral infectious disease which is spread fromperson-to-person via the fecal-oral route. person-to-person via the fecal-oral route.

Within the CNS, poliovirus infects and Within the CNS, poliovirus infects and destroys motor destroys motor neurons. neurons.

PolioPolio

Old PolioAsymmetric atrophy & weaknessAtrophic right leg (arrow) in patient with paralytic polio 70 years in past

The destruction of The destruction of motor neurons causes motor neurons causes muscle weakness and muscle weakness and paralysisparalysis

Vaccination created Vaccination created by Jonas Salk in 1955 by Jonas Salk in 1955 has eliminated has eliminated the diseasethe disease

the muscular system muscle system functions 1. provides voluntary movement of body enables...

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