7.4 skeletal muscle fiber physiology Flashcards
two components of muscle fiber contraction
mechanical and electrical
what travel form the brain or spinal cord along the axons to muscle fibers and cause them to contract?
action potentials
electrically excitable cells are _______
polarized
what does it mean when a cell is polarized
inside of most cell membranes is negatively charged compared with the outside. thus, a voltage/electrical charge difference exists across each cell membrane
the ability of a cell or tissue to respond to a stimulus by generating an electrical signal
excitability
the charge difference across each cell membrane of an unstimulated cell is called the
resting membrane potential
what layer is a hydrophobic environment, which inhibits the movement of charged particles, particularly ions, across the cell membrane
the phospholipid bilayer
the basis of the electrical properties of skeletal muscle cells is the ______ of ions across a cell _____.
movement, membrane
ions an move across the cell membrane through
ion channels
two types of ion channels that contribute to the electrical properties of both a resting cell and stimulated cell
leaked and gated
what channel governs the production of action potentials ?
gated ion channels
the electrical charge difference in an unstimulated cell, ready to respond at a moments notice
resting membrane potential
the resting membrane is the result of the concentration of K+ ______ the cell membrane is higher than _____ the cell membrane
inside, outside
the resting membrane is the result of the concentration of Na+ _______ the cell membrane is higher than _____ the cell membrane
the resting membrane is the result of the cell membrane being more permeable o K+ than to Na+
the concentration of K+ ______ the cell is higher than ______ the cell membrane.
inside, outside
the concentration of Na+ ______ the cell is higher than ______ the cell membrane.
outside, inside
______ charged proteins are trapped inside the cells because the cell membrane is impermeable to them
negatively
the ______ _____ for an ion determines whether it will enter or leave the cell
concentration gradient
most ____ cells have many more ____+ leak ion channels than ____+ leak channels, so the cell membrane is more permeable to ____+ than to____+
excitable, K, Na
K, Na
____+ leaks out of the cell ___ than ____+ leaks out of the cell
K, faster, Na
because K+ is positively charged, its movement from inside the cell to outside causes the inside of the cell membrane to become more ___ charged than the outside
negatively
active transport of Na+ and K+ by the sodium-potassium _____ that maintains the uneven distribution of Na+ and K+ across the cell membrane
pump
in a resting cell, the Na-K pump transports K+ from ___ the cell to the ___
inside, outside
___ _____ occurs when the excitable cell is stimulated
action potential
2 phases of action potential
depolarization and depolarization
