Muscular System Objective 1.04. 1.04 Remember the structures of the muscular system The Muscular...

Muscular SystemMuscular System

Objective 1.04Objective 1.04

1.04 Remember the structures of the muscular system

The Muscular SystemThe Muscular System

• Comprises nearly half our weight.• Over 650 muscles.• Each muscle is made up of hundreds or

thousands of muscle fibers.

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The Muscular SystemThe Muscular System::Muscle FibersMuscle Fibers

• Bundles of threadlike structures called myofibrils– Composed of:

• Myosin• Actin

– Form overlapping pattern called sarcomere

muscle muscle fiber

sarcolemma sarcomere

functional unit of muscle movement

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Structures of the muscular systemStructures of the muscular system

MusclesMuscles

Skeletal

Smooth

Cardiac

Sphincter

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Connective tissueConnective tissue

Tendons

Fascia



Types of MuscleTypes of Muscle

Skeletal musclesSkeletal muscles

Attached to boneAttached to bone

Striated (striped) appearanceStriated (striped) appearance

VoluntaryVoluntary

Multinucleated muscle cell bundlesMultinucleated muscle cell bundles

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Smooth musclesSmooth muscles

Also known as visceral muscles

Involuntary

Located in walls of digestive

system, uterus & blood vessels

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Cardiac muscleCardiac muscleFound only in the heartStriated, branchedInvoluntaryCells are fused- when one contracts, they all contract, creating the heartbeat

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Types of MuscleTypes of MuscleSphincter musclesSphincter musclesAlso called dilator musclesAlso called dilator musclesSpecial, circular musclesSpecial, circular musclesLocated in the Located in the

digestive systemdigestive system urinary systemurinary system

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Skeletal

Smooth

Cardiac

Sphincter

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Tendons

dense bands that connect skeletal muscle

to the bone



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FasciaFascia

Fibrous connective tissue sheets that wrap around muscle bundles


How do skeletal muscles get How do skeletal muscles get their names?their names?

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• However, However, not all muscles are named by not all muscles are named by the above methods!the above methods!


Head & Neck MusclesHead & Neck Muscles

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Torso/TrunkTorso/Trunk(anterior)

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Torso/TrunkTorso/Trunk(anterior)

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Torso/TrunkTorso/Trunk(posterior)

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Upper extremitiesUpper extremities

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Lower extremitiesLower extremities

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The muscular system reviewThe muscular system reviewAnterior viewAnterior view

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The muscular system reviewThe muscular system reviewPosterior viewPosterior view

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Characteristics of MusclesCharacteristics of Muscles

ContractibilityContractibility

ExcitabilityExcitability

ExtensibilityExtensibility

ElasticityElasticity

1.05 Understand the functions and disorders of the muscular

system

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Contractibility


system

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Contractibility

Myoneural stimulation

+

contraction of muscle proteins

=

movement and heat


system

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Excitability


system

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Extensibility


system

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Elasticity


system

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Contractibility

Excitability

Extensibility

Elasticity


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Contractibility


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Contractibility

Myoneural stimulation

+

contraction of muscle proteins

= movement and heat (side effect)


system

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The sodium-potassium pump of the membrane of a muscle cell.

The purpose of this slide is to illustrate the complexity of the process of movement.


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ContractibilityContractibilityNeurotransmitter at site of muscle stimulus.

Muscle ToneMuscle Tone

Discuss muscle tone.

•Atrophy: a- ________ -trophy _nourishment / development___

•Hypertrophy: hyper- _______ -trophy _nourishment / development__


system

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Muscle ToneMuscle Tone

John just got a cast off his leg. His calf muscle on the affected leg is 1” smaller in diameter than his other calf muscle.

• What happened?

• How do you explain this to him?


system

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Muscle FatigueMuscle FatigueDiscuss muscle fatigue:

– What causes muscle fatigue?

– How does the body correct muscle fatigue?

– Is muscle fatigue dangerous? Why / why not?

– Discuss aerobic and anaerobic exercise.

• Give examples of each.


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Functions of the Functions of the Muscular SystemMuscular System

What are the functions of the muscular system?


system

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Movement:Movement:Skeletal MuscleSkeletal Muscle

• Receptors in muscles provide the brain with information about body position and movement.

• The brain controls the contraction of skeletal muscle.


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MovementMovementAs your muscle contracts, one of the bones will move with the other will remain stationary.

Point of origin (end of the muscle that is attached to the stationary bone)

Point of insertion (end of muscle that is attached to the moving bone)

Prime mover or agonist

Antagonist – muscles that cause movement in the opposite direction

Synergists – assist primary mover

All movement is a result of contraction of primary movers and relaxation of opposing muscles.

Movement:Movement:Digestive SystemDigestive System

The nervous system regulates the speed at which food moves through the digestive tract.


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Movement:Movement:Circulatory SystemCirculatory System

HeartbeatHeartbeat

The nervous system and hormones regulate the speed at which the heart beats.


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PosturePosture

• How does the muscular system effect posture?


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Body HeatBody HeatWhat is the body’s response to cold? Why?

How is this response helpful?

How does the body respond to exercise? Why?


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FibromyalgiaFibromyalgia

Discuss the pictures and how they relate to fibromyalgia.

Cause - unknown

Symptoms – chronic pain, fatigue, depression

Diagnosis – location of pain

Treatment – symptom mgt

Prognosis – good…management


system

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HerniaHerniaWeakness in the muscles of the abdominal wall that allows loops of intestine to balloon outward

Causes – muscle weakness, excessive internal pressure

Locations – groin, abd

Symptoms – protrusion, pain

Diagnosis – palpation, mri

Treatment - surgery

Prevention – abd exercises

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Muscle SpasmsMuscle Spasms(Involuntary hypertonicity)(Involuntary hypertonicity)

Symptoms – severe pain

Diagnosis – hx, physical exam

Treatment – rest, stretching, exercise

Prognosis - good


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Muscular DystrophyMuscular Dystrophy

Cause – genetic defect…progressive weakness and degeneration of skeletal muscle

Symptoms – muscle weakness, drooling, falling, eyelid drooping (ptosis)

Diagnosis – physical exam, genetic test

Treatment – no treatment to stop or reverse MD…treat symptoms

Prognosis - variable

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Myasthenia GravisMyasthenia Gravis

Cause - Autoimmune attack at neuromuscular junction…affects voluntary muscles…problem with how nerves stimulate muscles to contract

Symptoms – progressive, fluctuating muscle weakness and fatigue

Diagnosis – blood tests, EMG

Treatment – steroids, immunosuppressant drugs

Prognosis – with treatment may lead a normal, active life…remission possible


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StrainStrain• Overstretching of the tendons or the muscles

themselves (“pulled muscle”).

• Treatment = RICE


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TendonitisTendonitis

• Usually from chronic injury, overuse

•Pain and inflammation are common

•Treatment = (P)RICE


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Tetanus Tetanus (Lockjaw)(Lockjaw)

Caused from a bacterial infection of clostridium tetani usually after puncture wound.

Symptoms include progressive muscle spasms, paralysis, stiffness and pain especially in jaw.

Diagnosis - physical exam, lab tests, history of wound

Treatment – wound hygiene, tetanus vaccine, pain management

Prognosis – without treatment 1 in 4 die…with treatment less than 10% infected die

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