Muscular System

“The power system”

This is what happens without muscles

#One Function Responsibl

e for all body movement.

#Two Function Responsible for body form and shape (Posture)

Responsible for body heat and maintaining body temperature.

#Three Function

Test Your Gray Matter….

Muscles are responsible for producing most of our : White blood cells, Hormones, Protein synthesis, or Body Heat.

Types of Muscles

Skeletal Muscle

Smooth Muscle

Cardiac Muscle

Attached to bone

Visceral muscle

Found only in the heart

Voluntary Involuntary Involuntary

Skeletal Muscles

Attached to bone Striated (striped)

appearance Voluntary Sarcolemma = cell

membrane Contract quickly,

fatigue easily, can’t maintain contraction for a long period of time

Test your skeletal muscles… Open and close

your dominant hand until the teacher tells you to stop.

            

Smooth Muscle

Visceral (organ) muscle Found in the walls of

digestive system, uterus, and blood vessels

Cells small and spindle shaped

Involuntary – ANS Controlled

Act slowly, do not tire easily, can remain contracted for a long time.

Cardiac Muscle

Found in heart Striated and

branched Involuntary Cells are fused,

when one contracts, they all contract (HB)

Test your gray matter..

Which of the following muscles are considered “voluntary”

Which kind of muscle forms the walls of the heart?

Striated,cardiac, skeletal,visceral

Cardiac, Skeletal, Smooth, Visceral

Sphincter Special circular

muscles in openings of esophagus and stomach, and small intestine, anus, urethra and mouth

AKA: dilator muscles

Characteristics of MusclesCharacteristics of Muscles

ContractibilityContractibility

ExcitabilityExcitability

ExtensibilityExtensibility

ElasticityElasticity1.05 Understand the functions and disorders of the muscular system

Contractibility

Excitability

Extensibility

Elasticity

The ability of a muscle toreduce the distancebetween the parts of itscontent or the space itsurrounds.

The ability to respond tocertain stimuli by

producingimpulses.

The ability to be stretched.

Ability of muscle to return to

its original length whenrelaxing.

Muscle Characteristics

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Muscular system Muscular system structuresstructures

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Connective tissueConnective tissue

Tendons

dense bands that connect skeletal

muscle to the bone

1.04 Remember the structures of the muscular system

Structures of the Structures of the muscular systemmuscular system

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Connective Connective

tissuetissue

FasciaFasciaFibrous

connective tissue sheets that wrap around muscle bundles

Sources of heat / energy

For muscles to contract and do their work theyneed energy

ATP – adenosine triphosphate – a major source of energy found in the muscle cell.

When muscle is stimulated, ATP is released, which produces heat and energy to contract muscle.

Lactic acid – a by-product of cell metabolism

Muscle Movement

Muscle moves bones by pulling on them.

As a muscle contracts, it pulls the Insertion one closer to the Origin bone. Movement occurs at the joint between the origin and the insertion.

Rule: A muscle’s insertion bone moves toward its origin bone.

Groups of muscles usually contract to produce a single movement

muscle whose contraction is mainly responsible for producing a given movement

Prime mover

Antagonist

muscle whose actions oppose the action of prime mover in any given movement.

Synergist helps steady a movement and stabilize joint activity.

When the antagonist muscles contract, they produce a movement opposite to that of the prime movers.

Motor Unit – a motor neuron plus all the muscle fibers it stimulates.

Neuromuscular Junction – the junction between the motor neuron’s fiber which transmits the impulse – and the muscle cell membrane.

Acetylcholine

Fatigue

Oxygen Debt

Muscle chemical neurotransmitter, diffuses across the synaptic cleft (carries impulse across synaptic cleft)

caused by the accumulation of lactic acid in the muscles

after exercise, the amount of oxygen needed by the muscle to change lactic acid back to glucose.

Movement: Skeletal MuscleMovement: Skeletal 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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Movement: Digestive Movement: Digestive SystemSystem

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

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Exercise and training

Will affect the size, structure and strength of a muscle.

If injured, muscles can only regenerate a limited degree.

If severe injury, muscle tissue may be replaced with scar (connective) tissue.

Benefits of exercising

Improved muscle coordination Improved respiratory and

circulatory system to supply needs of an active muscular system

Eliminate or reduce excessive fat. Improve joint movement. Increase muscle size

Atrophy vs hypertrophy

Atrophy –wasting away of a muscle

Hypertrophy – growth of a muscle due to repetitive usage

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?

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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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Musculoskeletal disorders - Strain

a tear of the muscle resulting from excessive use

Pain and swelling occur due to bleeding in the muscle

Ice packs will help reduce swelling and stop bleeding

Rest and OTC medicines also help.

Muscle spasm

a sustained contraction of the muscle. Occurs from over usage.

Myalgia

muscle pain

Fibromyalgia

chronic disease that includes muscle pain lasting for 3 or more months

S/S: HA, fatigue, numbness, tingling, and joint pain

Tx – rest, exercise, medicines, chiropractic services, and massage.

Movement:Movement:Digestive SystemDigestive System

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

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Hernia

occurs when an organ protrudes through a weak muscle. Abdominal Inguinal Hiatal – occurs when the

stomach pushes through the diaphragm.

Tetanus (lockjaw)

infectious disease that causes continuous spasms of the voluntary muscles

Caused by toxin from the bacillus: clostridium tetani

enters the body through a wound Can be prevented by vaccine.

Muscular dystrophy

muscle cells deteriorate most common is Duchenne’s

MD:usually genetic defect Usually death occurs in late teens or

early 20’s.

Myasthenia gravis

muscle weakness and paralysis cause unknown: possible immune

system defect.

TENDONITIS

inflammation of a tendon