| Term 
 
        | Critical functions of the muscular system |  | Definition 
 
        | -movement -thermoregulation
 -posture, body and organ support
 -cardiovascular pump
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        | Term 
 | Definition 
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        | Term 
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        | this tissue is striated and under voluntary nervous control |  | 
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        | Term 
 | Definition 
 
        | this tissue is striated and under involuntary nervous control |  | 
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        | Term 
 | Definition 
 
        | this tissue is non-striated and under involuntary nervous control |  | 
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        | Term 
 
        | Basic characteristics of muscle tissue |  | Definition 
 
        | -Irritability -Contractility
 -Extensibility
 -Elasticity
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        | Term 
 | Definition 
 
        | the ability to respond to a nervous stimulus |  | 
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        | Term 
 | Definition 
 
        | the ability to respond by shortening |  | 
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        | Term 
 | Definition 
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        | Term 
 | Definition 
 
        | the ability to return to the original shape |  | 
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        | Term 
 
        | Groups of muscles classified by shape |  | Definition 
 
        | -Parallel -Convergent
 -Pennate
 -Circular
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        | Term 
 | Definition 
 
        | -Origin tendon -Insertion tendon
 -body
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        | Term 
 | Definition 
 
        | always attaches to a bone; it is also the most proximal and/or least mobile portion of the muscle. |  | 
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        | Term 
 | Definition 
 
        | usually attaches to a bone or may attach to the skin or an organ; it is usually the most distal and/or most mobile protion of a muscle |  | 
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        | Term 
 | Definition 
 
        | the region of contraction as it consists of muscle tissue; it is the only portion of the muscle that does contract. |  | 
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        | Term 
 
        | -epimysium -perimysium
 -endomysium
 |  | Definition 
 
        | increasingly smaller portions of loose connective tissue that ensheath the components of skeletal muscles |  | 
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        | Term 
 | Definition 
 
        | Outer sheath of connective tissue. Consists of two distinct portions:
 -fascia
 -epimysium proper
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        | Term 
 | Definition 
 
        | Outer portion of epimysium. Consists of dense irregular connective tissue and helps to separate individual muscles within a group and from other structures. |  | 
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        | Term 
 | Definition 
 
        | Inner portion of epimysium. This layer consists of loose connective tissue and helps to provide a means of holding the entire muscle together.
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        | Term 
 | Definition 
 
        | Middle sheath of skeletal muscle. Ensheathes the muscle bundles known as muscle fasciculi and is composed of loose connective tissue |  | 
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        | Term 
 | Definition 
 
        | Inner sheath of skeletal muscle tissue. Ensheathes specific muscle cells also known as muscle fibers and is composed of loose connective tissue.
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        | Term 
 
        | Skeletal muscle cells (fibers) |  | Definition 
 
        | Somewhat spindle-shaped and striated. Each fiber is surrounded by a sheath of endomysium. These groups of fibers are arranged as bundles and the bundles comprise an entire muscle.
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        | Term 
 | Definition 
 
        | hundreds to thousands of long protein fibers that traverse the long axis of the cell |  | 
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        | Term 
 | Definition 
 
        | Form the basic structural and functional unit of contraction in a skeletal muscle cell. Each myofibril consists of thousands of these repeating protein units |  | 
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        | Term 
 | Definition 
 
        | Sarcomeres are composed of these structural protein filaments that are arranged in a specific alignment |  | 
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        | Term 
 | Definition 
 
        | Long, thin filaments that are directly attached to the Z line myofilament. Composed of a series of globular proteins that are twisted around each other to form a double helical structure. |  | 
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        | Term 
 | Definition 
 
        | Thick filaments that occur between successive actin filaments. Consists of a series of rod-like proteins that form a tail-like structure and a globular head-like structure that forms a hinge onto the tail. |  | 
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        | Term 
 | Definition 
 
        | Composed of a fibrous protein called actinin that directly attach the actin filaments. Every two successive lines form a single sarcomere. |  | 
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        | Term 
 | Definition 
 
        | the interface of two plasma membranes of a nerve terminus and a skeletal muscle cells |  | 
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        | Term 
 | Definition 
 
        | depressed into the cell membrane near the middle of the muscle cell and anchored by the endomysium. |  | 
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        | Term 
 | Definition 
 
        | The muscle cell membrane. Serves as the post-synaptic membrane.
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        | neurotransmitter molecules that are held in the synaptic vesicles |  | 
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        | Term 
 | Definition 
 
        | Located on the sarcolemma. When neurotransmitter molecules diffuse across synaptic cleft and attach, this action opens channels for sodium ions that result in an action potential (i.e. an electrical impulse) in the muscle cell that eventually results in its contraction. |  | 
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        | Term 
 
        | acetylcholinesterase (AChase) |  | Definition 
 
        | Enzyme that breaks down the ACh for re-uptake into the bouton so that ACh is recycled. Found in the motor end plate.
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        | Term 
 | Definition 
 
        | The space between the motor end plate and the nerve terminus |  | 
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        | Term 
 | Definition 
 
        | The post-synaptic memebrane is known as this at the place where the terminal bouton occurs. It is invaginated and the membrane folded to increase the surface area. |  | 
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        | Term 
 | Definition 
 
        | Consists of a pre-synaptic membrane, synaptic cleft, and post-synaptic membrane. |  | 
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        | Term 
 
        | Sliding Filament Model of Contraction |  | Definition 
 
        | Thick and think filaments slide over one another. Length of each sarcomere shortens, muscle contracts. |  | 
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