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Auburn University A&P I Test 3
N/A
24
Anatomy
Undergraduate 2
11/04/2011

Additional Anatomy Flashcards

 


 

Cards

Term
organelles specific to muscle fibers
Definition
multiple nuclei, sarcolemma, myofibrils, microfilaments, sarcomere, zones, bands, & lines
Term
sarcolemma
Definition
plasma membrane of muscle fiber
Term
sarcoplasm
Definition
cytoplasm of muscle fiber
Term
myofibrils
Definition
contain microfilaments; hundreds to thousands of microfilaments per muscle fiber
Term
I band
Definition
areas of no thick filaments; light space between stripes / striations; MOSTLY contains thin filaments (actin) but not completely
Term
H zone
Definition
area of thick filaments (myosin) where no thin filaments overlap
Term
A bands
Definition
thick filaments (myosin; give muscle fibers their striated appearance
Term
Z line
Definition
between thick filaments; anchor for thin filaments
Term
M line
Definition
anchor for thick filaments
Term
sarcomere***
Definition
functional unit of skeletal muscle; occurs from Z line to Z line; where action really takes place
Term
excitation-contraction coupling
Definition
stimulus reaches neuron, which sends an electrochemical signal to muscle cell; signal transduces throughout the cell, causing a contraction
Term
resting potential
Definition
electrochemical equilibrium (-85mV inside the cell)
Term
ions inside cell membrane of skeletal muscle fibers (sarcolemma)
Definition
low Na, high K, low Ca, low Cl, high Protein
Term
ions outside of sarcolemma
Definition
high Na, low K, high Ca, high Cl, low protein
Term
passive channels
Definition
ALL CELLS HAVE PASSIVE CHANNELS/ leaky channels
Term
active channels
Definition
make cells excitable. closed under normal conditions; chemically regulated channels & voltage regulated channels
Term
action potential
Definition
cell changing charge; temporarily ends resting potential
Term
chemically regulated channels
Definition
active channels (closed under normal conditions); require a specific chemical, such as a neurotransmitter, to open them: neurotransmitter binds to receptor to open gate, & charge inside of cell changes--> creates action potential // MOTOR END PLATE of motor neuron
Term
voltage regulated channels
Definition
open/close when there is a change in charge across the membrane; closed at resting potential; open when charge inside cell goes from negative to positive (from resting potential to action potential) // synaptic knob, terminal cisternae, & sarcolemma
Term
excitation
Definition
stimulus to neuron--> VR (Ca) channel on synaptic knob releases Ca into neuron--> causes sarcolemma to break (?)--> synaptic vesicles rupture & expel acetylcholine (ACH) into neuro-muscular junction--> ACH binds receptor on motor end plate--> CR Na channels open--> influx of Na into muscle fiber--> depolarization of cell; membrane potential changes to more positive--> VR channels on terminal cisternae & sarcolemma open; Ca flows into cell (20% of Ca comes from extracellular space & 80% of Ca comes from within terminal cisternae)
Term
plasma membrane of muscle fiber
Definition
sarcolemma
Term
cytoplasm of muscle fiber
Definition
sarcoplasm
Term
contains filaments
Definition
myofibrils
Term
functional unit of skeletal muscle
Definition
sarcolemma; occurs from z line to z line
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