What most directly causes the release of neurotransmitter?
The arrival of the nerve impulse at the presynaptic terminal stimulates the release of neurotransmitter into the synaptic gap. The binding of the neurotransmitter to receptors on the postsynaptic membrane stimulates the regeneration of the action potential in the postsynaptic neuron.
Which cellular event is indicated by a?
What cellular event is indicated by A? >exocytosis. Neurotransmitters stored in synaptic vesicles are released into the synaptic cleft by exocytosis.
What event most directly triggers the release of calcium from the terminal Cisternae?
What event most directly triggers the release of calcium from the terminal cisternae? The action potential propagating down the T tubule causes voltage sensitive tubule proteins to change shape, which opens calcium release channels in the terminal cisternae.
What event that most directly triggers contraction of a heart cell?
What specific event initiates the contraction? Calcium release from the sarcoplasmic reticulum initiates the contraction. After a power stroke, the myosin head must detach from actin before another power stroke can occur.
What directly causes the release of neurotransmitter from a neuron?
Neurons talk to each other across synapses. When an action potential reaches the presynaptic terminal, it causes neurotransmitter to be released from the neuron into the synaptic cleft, a 20–40nm gap between the presynaptic axon terminal and the postsynaptic dendrite (often a spine).
What releases neurotransmitters quizlet?
A neuron is the only type of presynaptic cell. Neurons release neurotransmitters, effectively changing an electrical signal or action potential into a chemical signal that can communicate across the synaptic cleft to the postsynaptic cell.
Which of the following events triggers the subsequent steps of excitation contraction coupling?
Which of the following events triggers the subsequent steps of excitation-contraction coupling? release of acetylcholine from axon terminals at the neuromuscular junction.
What causes the direct release of the myosin head from the actin active site?
Calcium binds to myosin, causing the myosin head to release from the actin myofilament. Calcium binds to troponin, exposing the active site on troponin.
What triggers the release of calcium from the sarcoplasmic reticulum?
In other words, nervous stimulation leads to depolarization of the sarcolemma (muscle membrane) that triggers calcium ions' release from the sarcoplasmic reticulum.
What most directly causes synaptic vesicles to release acetylcholine into the synaptic cleft?
What most directly causes synaptic vesicles to release acetylcholine into the synaptic cleft? rationale: Calcium entry causes synaptic vesicles to release acetylcholine into the synaptic cleft.
Which element is important in directly triggering contraction?
As the muscle membrane depolarizes, another set of ion channels called voltage-gated sodium channels are triggered to open. Sodium ions enter the muscle fiber, and an action potential rapidly spreads (or “fires”) along the entire membrane to initiate excitation-contraction coupling.
What event initiates the contraction cycle?
What specific event initiates the contraction? Calcium release from the sarcoplasmic reticulum initiates the contraction.
What is the process of neurotransmitter release?
Neurotransmitter release from the presynaptic terminal consists of a series of intricate steps: 1) depolarization of the terminal membrane, 2) activation of voltage-gated Ca2+ channels, 3) Ca2+ entry, 4) a change in the conformation of docking proteins, 5) fusion of the vesicle to the plasma membrane, with subsequent …
What triggers the release of neurotransmitters from the sending neuron?
When an action potential reaches the presynaptic terminal, it causes neurotransmitter to be released from the neuron into the synaptic cleft, a 20–40nm gap between the presynaptic axon terminal and the postsynaptic dendrite (often a spine).
Where are neurotransmitter released from?
synaptic vesicles Neurotransmitters are released from synaptic vesicles in presynaptic neurons in response to neural activity, diffuse across the synaptic cleft, and bind specific receptors in order to bring about changes in postsynaptic neurons.
What specific event initiates the contraction?
What specific event initiates the contraction? Calcium release from the sarcoplasmic reticulum initiates the contraction.
What triggers the release of acetylcholine from the sarcoplasmic reticulum?
The neurotransmitter acetylcholine diffuses across the synaptic cleft, causing the depolarization of the sarcolemma. The depolarization of the sarcolemma stimulates the sarcoplasmic reticulum to release Ca2+, which causes the muscle to contract.
Which of the following events is the direct result of an action potential in the membrane of a muscle cell?
Which of the following events is the direct result of an action potential in the membrane of a muscle cell? The muscle cell's endoplasmic reticulum (ER) releases calcium ions.
What stimulates the release of the myosin head from the active site on actin during relaxation?
ATP binding ATP binding causes the myosin head to detach from the actin ((Figure)d). After this occurs, ATP is converted to ADP and Pi by the intrinsic ATPase activity of myosin. The energy released during ATP hydrolysis changes the angle of the myosin head into a cocked position ((Figure)e).
What triggers the release of calcium?
Skeletal muscles release calcium and contract when they receive signals from neurons, or nerve cells, that control muscle movement. Your brain sends electrical signals through neurons to your skeletal muscle.
What triggers the release of calcium ions from the sarcoplasmic reticulum quizlet?
Acetylcholine. Calcium ions. rationale: Action potentials propagating down the T-tubule cause a voltage-sensitive protein to change shape. This shape change opens calcium release channels in the sarcoplasmic reticulum, allowing calcium ions to flood the sarcoplasm.
What triggers the release of acetylcholine from a synaptic terminal quizlet?
Calcium enters the presynaptic cell and causes the release of ACh. As a presynaptic action potential reaches the synaptic terminal, voltage-gated calcium channels open.
What triggers the release of acetylcholine from a synaptic terminal?
The release of acetylcholine occurs when an action potential is relayed and reaches the axon terminus in which depolarization causes voltage-gated calcium channels to open and conduct an influx of calcium, which will allow the vesicles containing acetylcholine for release into the synaptic cleft.
Which of the following receptors is directly involved in causing skeletal muscle contraction?
– Acetylcholine receptor : a type of chemically-gated ion channel located on the junctional folds of the muscle fiber. – Acetylcholine : neurotransmitter that stimulates skeletal muscle contraction.
Which is the neurotransmitter that causes the release of calcium ions and initiates the steps of skeletal muscle fiber contraction?
ACh ACh is the neurotransmitter that binds at the neuromuscular junction (NMJ) to trigger depolarization, and an action potential travels along the sarcolemma to trigger calcium release from SR.
How are neurotransmitters activated?
They undergo a change in shape when neurotransmitter binds, causing the channel to open. This may have either an excitatory or an inhibitory effect, depending on the ions that can pass through the channel and their concentrations inside and outside the cell.
What neurotransmitter is needed to initiate a muscle contraction?
When the nervous system signal reaches the neuromuscular junction a chemical message is released by the motor neuron. The chemical message, a neurotransmitter called acetylcholine, binds to receptors on the outside of the muscle fiber. That starts a chemical reaction within the muscle.
What triggers the process to release acetylcholine?
The release of acetylcholine occurs when an action potential is relayed and reaches the axon terminus in which depolarization causes voltage-gated calcium channels to open and conduct an influx of calcium, which will allow the vesicles containing acetylcholine for release into the synaptic cleft.
What event triggers the generation of an action potential?
So, an action potential is generated when a stimulus changes the membrane potential to the values of threshold potential. The threshold potential is usually around -50 to -55 mV.
Which of the following events is the direct result of an action potential in the membrane of a muscle cell quizlet?
Which of the following events is the direct result of an action potential in the membrane of a muscle cell? The muscle cell's endoplasmic reticulum (ER) releases calcium ions.