Muscular SystemST 110

Muscle TissueThree typesSkeletalSmoothCardiac

Skeletal MuscleAttaches to bonesStriated (Cross stripes or striations)Voluntary

SmoothLocated in the walls of internal organsNonstriatedInvoluntaryVisceral Muscle

CardiacForms the walls of the heartStriatedInvoluntary

Role of Other Body Systems in MovementIt sometimes takes other systems of the body other than the muscular system to create movementNervous System Tells some muscles to moveThe Cerebrum generates nerve impulses for movement

Structure of Skeletal MuscleMost skeletal muscles attach to two bones that have a movable joint between themOne of the two bones is usually more stationary that the otherA body part moves with the involvement of a group of muscles. No one muscle ever works alone.

MovementInsertion portion of the muscle is what moves bonesSeveral muscles contract while others relax to produce movementPrime movers mainly responsible for producing movementSynergist help along with prime moversAntagonists move opposite of prime movers and synergists

MovementBending the armBiceps brachii prime moverBrachialis synergistsTriceps brachii antagonistsStraightening the armTriceps brachii prime moverBiceps brachii and Brachialis - antagonists

Structure of Skeletal Muscle

Fascia - fibrous connective tissue surrounding muscle groups.Tendons attach muscles to bones - Dense fibrous connective tissue. Have great strength and dont break easily. Ligaments attach bone to bone - slightly elastic and more flexible than tendons.

Microscopic StructureSarcolemmaMyofilamentsMyosinActin

Microscopic StructureSarcomere Basic functional or contractile unit of skeletal muscle. Very much like the Haversian System in bonesContraction tightening of a muscle, becomes shorter and thickerRelaxation Muscle returns to its original form, becomes longer and thinner

Muscle StimulusMuscle fibers do not contract until an applied stimulus reaches a certain level of intensity, this is called the threshold stimulusAt this time the muscle fiber contracts completely so its called all or none

Motor UnitMuscles must be stimulated by nerve impulses called motor neuronsThe area between the nerve ending and the muscle fiber is called the neuromuscular junction

Functions of Skeletal MuscleThree basic functionsMovementPosture or muscle toneHeat Production

PostureTonic ContractionSpecial type of skeletal muscle contraction that helps us maintain postureDoesnt move any body parts, it just helps us defy gravity by holding us upright

Heat ProductionMuscle fiber contractions produces heatEnergy required to produce a muscle contraction is obtained from the breakdown of ATP. Some energy is lost during these contractions and this is what helps us to maintain our body temperature

Structure of Skeletal MuscleThe muscle attachment at the more stationary bone is called its originThe muscle attachment at the more movable bone is called its insertionThe rest of the muscle is called the body

FatigueWhen muscles are stimulated repeatedly without adequate periods of rest will cause fatigue

Types of Skeletal Muscle ContractionTwitch Contraction:Jerky response to a stimulusSeen in muscles during researchPlay a minimal role in normal muscle activity

Types of Skeletal Muscle ContractionTetanic Contraction:A sustained contraction

Types of Skeletal Muscle ContractionIsotonic Contraction:Produces movement of a jointMuscle changes lengthThe insertion end moves toward the origin

Types of Skeletal Muscle ContractionIsometric Contraction:Does not always produce movementSometimes it increases the tension within a muscle but does not shorten the muscle

Effects of ExerciseProlonged inactivityMuscles shrink in mass disuse atrophyIncreased activityIncrease muscle size hypertrophyEnhanced by strength training

Effects of ExerciseEndurance training (aerobic training)Doesnt usually cause muscle hypertrophyIncreases the number of blood vessels in a muscle with increasing its sizeIncreases number of mitochondria in muscle fibers, which produces more ATP

Skeletal Muscle GroupsHead and NeckFacial ExpressionFrontal raise your eyebrow in surprise and furrow the skin of your forehead into a frown

Skeletal Muscle GroupsHead and NeckFacial ExpressionOrbicularis Oris Puckers your lips kissing muscleZygomaticus Elevates the corners of the mouth and lips smiling muscle

Skeletal Muscle GroupsHead and NeckMuscles of Mastication among the strongest groups in the bodyMasseter elevates the mandibleTemporal assists masseter in closing the jaw

Skeletal Muscle GroupsHead and NeckSternocleidomastoid rotates and flexes head and neckTrapezius Extends head and neck

Skeletal Muscle GroupsMuscles that move Upper ExtremitiesPectoralis major fan-shaped, attached to the thorax. Flexes upper arm, and helps adduct the armLatissimus dorsi Extends the upper arm, and helps adduct the upper arm

Skeletal Muscle GroupsMuscles that move Upper ExtremitiesDeltoid rounded prominence over shoulder, abducts upper arm. Shaped like an inverted triangle (Greek Letter Delta)

Skeletal Muscle GroupsMuscles that move Upper ExtremitiesBiceps brachii located on the anterior portion of the upper arm, flexes the elbow. Named for number of divisions

Skeletal Muscle GroupsMuscles that move Upper ExtremitiesTriceps brachii located on the posterior of the upper arm, extends the elbow. Also named from number of divisions

Skeletal Muscle GroupsMuscles of the trunkThree layers (anterolateral abdominal wall)External oblique outermost layer, gets its name for the oblique angle it slants away from the midline

Skeletal Muscle GroupsMuscles of the trunkThree layers (anterolateral abdominal wall)Internal oblique middle layerTransversus abdominis innermost layer, gets its name from the crosswise alignment

Skeletal Muscle GroupsMuscles of the trunkRectus abdominis runs down the midline of the abdomen from the thorax to the pubis. Helps flex the trunk. Gets name from the word rectus meaning straight

Skeletal Muscle GroupsMuscles of the trunkRespiratory MusclesIntercostal muscles located between the ribs, aid in breathing by allowing the chest to expandDiaphragm Separates the thoracic and abdominal cavities. Helps breathing again by extending the chest cavity

Skeletal Muscle GroupsMuscles that move lower extremitiesIliopsoas Flexes thigh or trunk, postural muscle that keeps the trunk from falling over backward when we stand

Skeletal Muscle GroupsMuscles that move lower extremitiesGluteus maximus outer contour and much of the substance of the buttock. Helps extend the thigh and helps support torso in the erect position. Largest muscle of the buttock

Skeletal Muscle GroupsMuscles that move lower extremitiesAdductor muscles Help adduct thighAdductor longusGracilisPectineus

Skeletal Muscle GroupsMuscles that move lower extremitiesHamstring muscles Flex the lower legBiceps femorisSemitendinosusSemimembranosus

Skeletal Muscle GroupsMuscles that move lower extremitiesQuadriceps Group Extend the kneeRectus femorisVastus lateralisVastus intermediusVastus medialis

Skeletal Muscle GroupsMuscles that move lower extremitiesTibialis Anterior - located on the anterior of the lower leg. Dorsiflexes ankle

Skeletal Muscle GroupsMuscles that move lower extremitiesGastrocnemius Calf muscle, plantar flexes ankle, known as the dancers muscleSoleus located below the calf, plantar flexes ankle

Skeletal Muscle GroupsMuscles that move lower extremitiesPeroneus Group - located along the sides of the lower leg, plantar flexion Peroneus longus

Movements of Skeletal MusclesFlexionExtensionAbductionAdductionRotationSupinationPronationDorsiflexionPlantar flexion

Movements of Skeletal MusclesFlexion - Decreasing the angle between two bonesExtension Increasing the angle between two bones

Movements of Skeletal MusclesAbduction Moves away from the midlineAdduction Moves toward the midlineRotation Turns a bone on its own axis

Movements of Skeletal MusclesSupination turns the palm of the hand upward or forwardPronation turns the palm of the hand downward or backward

Movements of Skeletal MusclesDorsiflexion bends the foot upward at the anklePlantar flexion bends the foot downward at the ankle

Medical SpecialtiesOrthopedic treats injuries and disorders of the bones, joints, muscles, and tendonsRheumatologist treat disorders that involve inflammation of connective tissues

Medical SpecialtiesNeurologist treat paralysis patients and other neuromuscular disorders

PathologyFasciitis inflammation of the fasciaTendonitis inflammation of the tendonsAdhesion fibrous tissue that holds together two structures that should be apart

PathologyAtrophy weakness or wearing away of body tissuesMyalgia muscle tenderness or painMyositis inflammation of a skeletal muscle

PathologyHernia protrusion of a part or structure through tissues normally containing itMyocele protrusion of muscle

PathologyAtaxia the inablility to coordinate muscle activity during voluntary movementDystaxia difficulty in controlling voluntary movement

PathologyBradykinesia extreme slowness in movementDyskinesia impairment of voluntary movement

PathologyHyperkinesia abnormally increased motor activityHypokinesia abnormally decreased motor activity

Repetitive Motion DisordersCarpal Tunnel Syndrome the overuse of the tendons in the carpal tunnel become swollen and inflamed. The swelling puts pressure on the median nerve and causes pain, burning, and paresthesia in the fingers and hand

Repetitive Motion DisordersEpicondylitis inflammation of the tissues surrounding the elbow.Lateral tennis elbowMedial golfers elbowPlantar Fasciitis

ParalysisMyoparesis slight paralysis or weakness of a muscleHemiparesis slight paralysis of one side of the body

ParalysisHemiplegia total paralysis of one side of the bodyCardioplegia paralysis of the muscles of the heart

ParalysisParaplegia paralysis of both legs and lower part of the bodyQuadriplegia paralysis of all four extremities

Diagnostic ProceduresElectromyography (EMG) measures the electrical activity with muscle fibers in response to nerve stimulation

Treatment ProceduresMedicationAnti-inflammatoryAnticholinergic AtropineMuscle relaxant

Treatment ProceduresPhysical TherapyTherapeutic Ultrasound

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