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The *ENTIRE* Skeletal Muscle Contraction Process

Terms in this set (26)

This set was made from that fill-in paragraph worksheet we did in class. I left the numbers in case you wanted to check if I did something wrong. Good luck!
:)
The contraction of a skeletal muscle begins when an action potential (electrical impulse)
travels down the axon of a __2__ _____ to its axon terminal.
motor neuron
The __1__ _____ is where a motor neuron synapses with a muscle fiber.
Neuromuscular junction
terminal. At the axon terminal, the
action potential stimulates the opening of _____-_____ __3__ _____ _____.
voltage gated calcium ion channel
The opening of these ion channels allows __4__ ions to diffuse across the axon
terminal membrane (presynaptic membrane).
calcium
Calcium ions bind to __5__ _____, filled
with __6__, a neurotransmitter, causing them to fuse to the axon terminal membrane.
synaptic vesicles, acetylochine
Fusion to the axon terminal membrane causes the synaptic vesicles to release acetylcholine into the __7__ _____, which is a gap between the axon terminal membrane and sarcolemma.
synaptic cleft
Once in the synaptic cleft, acetylcholine binds to a _____-_____ ____8____ _____, causing it to open and allowing _9___ ions to diffuse across the
the __10__ or post-synaptic membrane.
chemical gated sodium ion channel, sodium, sarcolemma
Diffusion of sodium ions across the
sarcolemma creates another ____ ___11__.
action potential
The newly formed action potential travels down the __12__ _____, which is a bundle of myofibrils, via the sarcolemma and into an invagination called the __13__ _____.
muscle fiber, transverse tubule
Once inside the transverse tubule, the action potential is passed to the terminal
cisternae, which is the enlarged part of the __14__ _____.
sarcoplasmic reticulum
The function of the sarcoplasmic reticulum is to store __14__ ions.
calcium
The action potential causes _____-_____ __16__ _____ _____, located on the membrane of the terminal cisternae to open allowing __17__ ions to move from the sarcoplasmic reticulum, diffuse out of the terminal cisternae and into the __18__, which is composed of individual contractile units of muscle called __19__. It's at the level of the sarcomere where calcium ions interact with the microstructures of a muscle to elicit a muscle contraction.
voltage-gated chemical ion channel, calcium, sarcomere, myofilaments,
The sarcomere is composed of two myofilaments. The thin myofilament is called
__20__ and the thick myofilament is called __21__.
action, myosin
The actin myofilament has three parts, __22__, __23__, and __-__24__.
tropomyosin, troponin, g-actin
The first part, called __25__, binds to calcium and to tropomyosin.
troponin
The second part, tropomyosin, covers the _____
__26__ _____ _____ of the third part of actin, which is called __27__-_____.
active binding site, g-actin
The myosin myofilament is composed of two parts, the rod and the __28__ _____, whose
function is to bind to the active binding site of G-actin.
myosin head
Once calcium diffuses into the sarcomere it binds to __29__.
troponin
The binding of calcium to troponin, causes troponin to pull on __30__, thus exposing the active binding site of __31__-_____.
tropomyosin, g-actin
Exposure of the active binding site allows the __32__ _____ of myosin to bind to actin creating a __33__-_____.
myosin head, cross-bridge
Attached to the myosin head are two molecules called __34__ (abbreviated) and __35__, which keeps the myosin head in an upward
high-energy configuration.
ADP, phosphate
When ADP and phosphate are released from the myosin head, the myosin head bends and pulls on actin. This is called the __36__ _____.
working stroke
Once the head is bent, it must detach from the active binding site and return to an upward high-energy configuration in order to perform another cross-bridge. Detachment of the myosin head occurs when the high-energy
molecule, __37__ (abbreviated) binds to the myosin head.
ATP
To return the myosin head to an upward high-energy configuration state, ATP must be split
into ADP and phosphate by a process called __38__ _____.
ATP Hydrolysis
Once the myosin head has returned to an upward high-energy configuration, it can
perform another __39__-_____ with the G-actin. The interacting movements between myosin and actin is known as the _____ __40__ _____.
cross-bridge, sliding filament
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