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MUSCULAR SYSTEMKaitlyn SkidmoreQuaShaya HammonCamille TorresThe Functions of the Muscular SystemThe Muscular System:Provides StructureAids in MovementProduction of HeatStability of Joints

SKELETAL MUSCLE STRUCTURE

MUSCLE FIBER STRUCTURE

Neuromuscular junction- Connection between the motor neuron and the muscle fiber

Motor End Plate- The flattened end of a motor neuron that transmits neural impulses to a muscle

Neurotransmitter- Cytoplasm at the distal ends of these motor neuron axons; rich in mitochondria and contains many tiny vesicles that stores chemicals.

Muscle Contraction- A complex interaction of organelles and molecules in which myosin binds to actin and exerts pulling action.

ACTIN AND MYOSINActin:A protein involved in cell movement: a protein present in all cells and in muscle tissue where it plays a role in contraction.

Myosin:A muscle protein: a protein in muscles that helps them contract when connected with the protein actin.

SLIDING FILAMENT THEORY

The process of contraction begins with:The stimulation of a motor neuron, which releasesacetylcholine, causing the chemical, calcium (Ca++) to bereleased.

This calcium molecule will shift a troponin, making a siteavailable for the myosin heads to connect to the actinmolecule creating the contraction.

Once the myosin filament attaches to the actin, ATP releasesthe bond between the two, then a chemical,acetylcholinesterase, is released to digest the acetylcholine,so that it may be recycled and used once again forcontraction.

Muscle Fatigue: a muscle exercised strenuously for a prolonged period may lose its ability to contract.

Cramps: is a painful condition in which a muscle undergoes a sustained involuntary contraction.

Skeletal Muscle Contraction TypesSustained ContractionsEven when a muscle is at rest, a certain amount of sustained contraction is occurring in its fibers. This is called muscle tone.Isometric contractionThe muscle becomes taut, but the attachment(s) do not move; tensing a muscleIsotonic contractions The muscle shortens and its attachment(s) move(s).

SMOOTH MUSCLE CONTRACTIONA protein, calmodulin binds to calcium ions (no troponin) and activates the contraction mechanism.

Most calcium diffuses in to smooth muscle cells from the extracellular fluid (reduced SR).

Norepinephrine and acetylcholine are smooth muscle neurotransmitters.

4.Contraction is slow and sustained.

Prime Mover (agonist) = the primary muscle responsible for a movement.The biceps brachii in flexing the arm at the elbow

Antagonist(s) = the muscle(s) in opposition to the action of the prime mover. The antagonist relaxes (or stretches) during the prime movement.The triceps brachii is the antagonist of the biceps brachii when we flex the arm at the elbow.

Synergist(s) = muscles that assist the prime mover. The brachialis helps the biceps brachii during elbow flexion.

Origin = the attachment site of the muscles tendon to a more stationary bone. It has very less movement and normally a muscle contracts towards it.Some muscles have more than one origin, for example, biceps brachii.

Insertion = the attachment site of the muscles tendon to a more movable bone is known as the muscles insertion. It has the greatest motion when the muscle contracts and it tends to be more distal.radius/ulnaInsertion is the attachment site of the muscles tendon to a more movable bone is known as the muscles insertion. It has the greatest motion when the muscle contracts and it tends to be more distal.Origin is the attachment site of the muscles tendon to a more stationary bone. It has very less movement and normally a muscle contracts towards it. Some muscles have more than one origin, for example, biceps brachii.

ORIGIN AND INSERTION

An antagonist muscle is one that works in opposition to the movement initiated by an agonist muscle. The antagonist muscle in a muscle set brings a limb or other anatomical part back to its initial position of rest.A synergist muscle is a muscle which works in concert with another muscle to generate movement. These muscles can work with the agonists or prime movers which surround a joint, or the antagonistic muscles, which move in the opposite direction.

ANTAGONIST AND SYNERGISTMuscular dystrophy is a group of inherited disorders that involve muscle weakness and loss of muscle tissue, which get worse over time.

MUSCULAR DYSTROPHYCAUSES AND SYMPTOMSMuscular dystrophies, or MD, are a group of inherited conditions, which means they are passed down through families. They may occur in childhood or adulthood. Symptoms include:

Intellectual disability (only present in some types of the condition)Muscle weakness that slowly gets worse Delayed development of muscle motor skillsDifficulty using one or more muscle groupsDroolingEyelid drooping (ptosis)Frequent fallsLoss of strength in a muscle or group of muscles as an adultLoss in muscle sizeProblems walking (delayed walking)

TEST/TREATMENTSThe doctor's exam may show:

Abnormally curved spine (scoliosis)Joint contractures (clubfoot, clawhand, or others)Low muscle tone (hypotonia) And Heart testing - electrocardiography (ECG)

Nerve testing - electromyography (EMG)

Blood testing - including CPK level

Genetic testing for some forms of muscular dystrophyThere are no known cures for the various muscular dystrophies. The goal of treatment is to control symptoms

Summation- Occurs in the neuromuscular junction; it is the additive effect of several electrical impulses.

Recruitment- contraction of one motor unit and all muscle fibers at the same time

Sustained contraction- also called a tetanic contraction, occurs when there is an accumulation of acetylcholine in the neuromuscular junction. -It occurs rapidly, giving no time for the muscle to relax between stimuli-Remains constant in a steady state; maximal muscle contraction

Muscle Tone- continuous and partial contraction of muscles-recruitment and summation combined

20http://www.nytimes.com/imagepages/2008/02/11/science/20080212_MUSC_GRAPHIC.htmlhttp://www.livestrong.com/article/259009-muscles-that-are-prime-movers/http://www.differencebetween.com/difference-between-origin-and-vs-insertion/http://www.wisegeek.org/what-is-a-synergist-muscle.htmhttp://topics.wisegeek.org/topics.htm?antagonist-muscle#a=65221&t=default&k=Antagonist%20Muscle&b=1&p=5&s=RelatedTopicsSorterDefault&r=0http://homepages.ius.edu/KEDMONDS/muscles.htmWORKS CITED http://quizlet.com/3513668/skeletal-muscle-parts-flash-cards/http://faculty.stcc.edu/AandP/AP/AP1pages/Units5to9/unit9/summatio.htmhttp://www.sci.sdsu.edu/movies/actin_myosin_gif.htmlhttp://washhouseanatomy.wikispaces.com/Tyesha+Robinsonhttp://gifsoup.com/view/4447671/muscle-origin-insertion.html