voltage-gated calcium channels
When an action potential arrives at the axon terminal of a motor neuron, which ion channels open?
chemically gated sodium
Binding of the neurotransmitter causes ________ _____ ________ channels to open in the motor end plate
Release of acetylcholine from axon terminals at the neuromuscular junction is an event that _________ excitation-contraction coupling, which begins with "excitation" of the T-tubules.
A muscle that is lengthening while it produces tension is performing a(an) ________ contraction.
to lower objects (such as lowering a book from the shelf, or lowering the barbell during a bench press).
When do we use eccentric contractions?
During _________ contractions muscle lengthens as is generates tension, but not enough force to overcome the load.
The ___________ _________ functions in the storage, release, and reuptake of calcium ions.
A ______ is composed of a T-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum.
Voltage-gated sodium channels play a role in the generation and propagation of _________ _________.
Potassium leak channels are important to the _________ ________ potential of neurons.
A series of proteins that control calcium release.
A triad is composed of a T-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum. How are these components connected?
what ion is most directly responsible for the coupling of excitation to contraction of skeletal muscle fibers?
Cross bridge cycling _____ when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin.
The second, more forceful contraction that occurs before the muscle has completely relaxed is an example of wave __________.
__________ refers to the increased force generated by the activation of increasing numbers of motor units.
load placed on the muscle
Which of the following factors influence the velocity and duration of muscle contraction?
Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine.
Calcium entry into the axon terminal triggers which of the following events?
Acetylcholine binds to its receptor in the sarcolemma and triggers the opening of ________-______ ______ channels.
diffusion of Na+ into the muscle fiber
what event is most significant in initiating the "wave of depolarization?"
diffusion of Ca2+ into the axonal terminus
What event directly triggers the exocytosis of neurotransmitter?
so they don't get crushed when the muscle contracts.
why are the nuclei of skeletal muscle on the outside?
a thick fascia that connects two muscle bellies like that of the occipitalis and frontalis making the occipitofrontalis.
________ is composed of a bunch of glucose. EX. multiple beads make necklace. Pop off a bead as needed.
the __ disc is a sheet of proteins that anchors the thin filaments and connects myofibrils to one another.
light polypeptide chains
myosin heads contain 2 smaller, ______ _____________ _______ that act as cross bridges during contraction.
TRUE or FALSE: the SR is in contact with every myofibril so it is present when the muscle needs to contract.
axon terminal and muscle fiber are separated by a gel-filled space called the ________ _____.
TRUE or FALSE: in the generation of an action potential Na+ moves into the cell until it reaches the threshold. At that point the muscle contracts. It is all or none--like firing a gun. It only takes 1 force.