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30 Cards in this Set
- Front
- Back
functions of muscles
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internal and skeletal movement, thermal regulation, protection, stabilize body positions, 40%-50% of body weight
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3 different kinds of muscles in the body
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skeletal, cardiac, and smooth
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3 ways muscles differ from each other
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microscopic anatomy, location, and how they are controlled (what tells them to contract)
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Skeletal muscles
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striated, voluntary, attach to moving bones of the skeleton, uniform formation
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cardiac muscles
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striated, auto rhythmic, involuntary, branched formation, found in heart
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smooth muscles
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non-striated, mostly involuntary, make up walls of the organs (except heart) and walls of blood vessels
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membrane potential
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difference in charge across membrane of cell (polorized)
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electricity
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movement of charged particles
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what does it mean when a cell has potential
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has the potential to make energy
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when Na+ enters a cell, what does it create
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energy
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action potential
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rolling open of Na+ channels around the muscle cell membrane, an electrical current flying around the cell
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what is needed for a muscle cell to start a contraction
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action potential
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what opens the first Na+ channel (3 ways)
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Nerve - skeletal & some smooth muscles
Endocrine - adrenalin (some smooth muscles) Auto rhythmic - cardiac & some smooth |
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interclated disc
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A connection between two cells bridged by connexons, membrane thickens between cardiac cells
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Right atrium has what special group of muscles cells that form a natural pacemaker
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SA Node
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what is the funcion of the SA Node
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runs an action potential, electrial current runs through gap junctions of each of the cells, and stimulate at same time
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muscles cells have 4 important properties
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electrically excitable, contractility, extensibility, elasticity
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contractility
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a muscle cell will contract forcefully when stimulated by an action potential
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2 types of muscle contractions
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isotonic & isometric contractions
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isotonic contraction
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muscle shortens when contracted
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isometric contraction
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muscle contracted, but not shortened
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extensibility of a muscle cell
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muscle cell stretches without damage to the cell
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elasticity of a muscle cell
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after stretched, muscle cell will return to original shape and size
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CT wrapping for each individual muscle cell
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Endomysium - made of areolar CT
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CT wrapping for each bundle of muscle fibers
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Perimysium - made of dense irrecular CT
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CT wrapping for the entire muscle
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Epimysium - dense irredular
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each bundle of muscle fibers is called this _____
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fasicle
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mesoderm cells innitially differentiate into small cells called _______
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myoblast cells
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um-teen thousand myocells form 1 _____ ______ _____
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skeletal muscle cell
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sarcolemma
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the plasma membrane of a muscle cell
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