By: Adam Lundquist, Carmela Patriz, DeCarlo Ward

“ROTATE, FLEX, EXTENDTHE MUSCULAR SYSTEM IS YOUR FRIEND!”

The Major Functions of the muscular system:• Skeletal muscles contract which moves the body.• Skeletal muscles also maintains a person’s posture.• Production of body heat which is necessary for

homeostasis and maintaining a person’s body temperature.• Smooth muscles can move solids and liquids

through the digestive track and other secretions from organs.• Cardiac muscle makes the heart beat and propels

blood throughout the entire body. C

Muscle Structures

Skeletal Muscle Each muscle is an organ, comprised of skeletal muscle tissue, several connective tissue coverings, nervous tissue that causes it to contract and blood that nourishes it.

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• Epimysium- Under the outer layer is this layer which is around each whole muscle• Perimysium- surrounds

individual bundles of fibers called fascicles within each muscle• Endomysium- is a

fibrous connective tissue layer that covers each muscle cell (fiber)

• Fascia- Layers of fibrous tissue that surround and separate each muscle

- This type of connective tissue extends past the ends of the muscle and gives rise to cord like tendons that are fused to the periosteum of bones.

• Aponeurosis - Broad sheets of connective tissue that are sometimes connected to muscles

Connective Tissue Coverings:

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‒ Each muscle fiber is covered by a connective tissue layer called endomysium.

‒ Muscle fiber membrane is the sarcolemma which contains cytoplasm called sarcoplasm.‒ Within the sarcoplasm are many parallel

myofibrils.‒ These protein filaments are actually made up of

two types; a thicker filament which is mysosin and a thinner filament actin.

Muscle Fiber(Cell)

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Muscle Fiber(Cell)

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Relationships with the Neuromuscular Junction

The neuromuscular junction is the site where the motor neuron and muscle fiber meet.The muscle fiber membrane forms a motor end plate in which the sarcolemma is tightly folded and where nuclei and mitochondria are abundant.Acetylcholine is a neurotransmitter released from the motor of the neuron. Muscle innervation releases calcium.

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Steps:•Nerve impulse---acetylcholine is released•Muscle impulse•Calcium released--- (from sarcoplasmic reticulum)•Calcium binds to troponin, changing shape•Myosin heads attach to actin• Heads pivot, shortening• Sarcomere = Contract

Sliding Filament Theory‒Sarcomere shortens when ATP gives

energy to myosin because crossbridges of thick filaments (myosin) pull on think filaments (actin).

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ENERGYSources of Energy:Existing ATP in moleculeCreatine Phosphate(converting ADP+P to ATP)Glycolysis (without oxygen)-lactic acidCell Respiration (with oxygen)- need blood supply (hemoglobin) -interrupted=fatigueMyoglobin in muscles stores oxygen for cell respiration

A muscle cramp is an involuntarily and forcibly contracted muscle that does not relax.A cramp can involve a part of a muscle, the entire muscle, or even several muscles that usually act together.A very common reason for cramping is dehydration or low sodium.

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ENERGY(oxygen debt)

When oxygen debt gets to a certain point then muscle fatigue occurs & too much lactic acid builds up due to lack of oxygen

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Summation:

Muscular ResponsesThis is when the force of individual twitches

combines.Recruitment:

An increase inthe number ofmotor units beingactivated.

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Muscular ResponsesSustained Contraction: Muscle Tone:

‒ Summation and recruitmenttogether can produce a sustained contraction of increasing strength.

‒ Even when a muscle appears to be at rest its fibers undergo some sustained contraction. This is called muscle tone.

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Movements of Muscles

EXFLEXIONEXENTION

PRONATION SUPINATIONC

Movements of Muscles (cont.)

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Movements of Muscles (cont.)

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Diseases/Disorders • This is a group of inherited disorders

& can occur in childhood or adulthood and involve weakness in muscles and the loss of muscle tissues over a period of time that can keep getting worse and worse.

• Some of the types of muscular dystrophy are:

Becker muscular dystrophyDuchenne muscular dystrophyLimb-girdle muscular dystrophy, Myotonia congenitaMyotonic dystrophy A

Diseases/Disorders Fibromyalgia:

• Fibromyalgia is a common syndrome in which some people can have body-wide pain and some tenderness in their joints, and in muscles, tendons, and soft tissues.• It has also been linked to

loss of sleep, fatigue, depression and anxiety, and headaches.

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Diseases/Disorders Myositis:

• This is the inflammation of your skeletal muscles (called voluntary muscles)• Injuries, infections or an autoimmune

disease can cause myositis.

Inflammatory MyopathyFocal Myositis A

The EndANY QUESTONS?

Works Cited• Clencoe Hole’s Essentials of Human Anatomy & Phisiology• Gretchen Fisher• http://www.encognitive.com/node/1127