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What is the stimulus for Acetylcholine release?
The stimulus for acetylcholine release is the action potential traveling down the axon of the presynaptic neuron. This depolarization causes calcium channels to open, allowing calcium ions to enter the axon terminal and trigger the release of acetylcholine into the synaptic cleft.
What triggers the release of acetylcholine from a synaptic terminal?
The release of acetylcholine from a synaptic terminal is triggered by the arrival of an action potential at the terminal. This depolarization causes voltage-gated calcium channels to open, leading to an influx of calcium ions into the terminal. The increased calcium levels then trigger the release of acetylcholine vesicles into the synaptic cleft.
What effect do calcium slow channels have on shortening or lengthening the contraction of the heart muscle?
Calcium slow channels, also known as L-type calcium channels, play a crucial role in regulating the duration of cardiac muscle contraction. Activation of these channels leads to an influx of calcium ions into the cardiac muscle cells, which triggers contraction. Inhibition of these channels can result in decreased contractility and lengthening of the contraction phase of the heart muscle.
What effects do calcium slow channels have on shortening or lengthening the contraction time of the heart muscle?
Calcium slow channels play a crucial role in regulating the entry of calcium into cardiac muscle cells. Activation of these channels during the action potential leads to an influx of calcium, ultimately prolonging the duration of contraction in the heart muscle. Inhibition of these channels can lead to a decrease in contraction time by reducing the amount of calcium available for muscle contraction.
What effect do calcium slow channels haveon shortening or lengthing the contraction time of the heart?
Calcium slow channels play a crucial role in cardiac muscle contraction by allowing calcium ions to enter the cell. Activation of these channels leads to an increase in intracellular calcium levels, which ultimately shortens the contraction time of the heart by promoting cross-bridge formation between actin and myosin. In contrast, inhibition of calcium slow channels would lead to a lengthening of contraction time due to reduced calcium availability for muscle contraction.
What is the stimulus for Acetylcholine release?
The stimulus for acetylcholine release is the action potential traveling down the axon of the presynaptic neuron. This depolarization causes calcium channels to open, allowing calcium ions to enter the axon terminal and trigger the release of acetylcholine into the synaptic cleft.
What type of ion channels does an actions potential in the axon terminal of a motor neuron open?
Voltage-gated calcium channels are the ion channels that open during an action potential in the axon terminal of a motor neuron. These channels allow calcium ions to flow into the terminal, triggering the release of neurotransmitters into the synaptic cleft.
When an action potential arrives at the axon terminal of motor neuron which ion channels open?
voltage-gated calcium channels
What ion enters the axon nerve terminal to cause exocytosis of the neurotransmitter is called?
The ion that enters the axon nerve terminal to trigger neurotransmitter release is calcium (Ca2+). When an action potential reaches the nerve terminal, voltage-gated calcium channels open, allowing calcium ions to flow into the cell and initiate the process of exocytosis of neurotransmitter-containing vesicles.
In a neuron where are voltage-gated calcium channels located?
Voltage-gated calcium channels in neurons are mainly located in the axon terminals, where they play a key role in mediating calcium entry upon depolarization. This influx of calcium triggers neurotransmitter release at the synapse, allowing for communication between neurons.
What does the long refractory period observed in cardiac muscle mean?
it means that no matter what stimulus is applied the cardiac muscle will not be able to contract
What sequence of events occurs when an action potential arrives at the presynaptic terminal?
When an action potential arrives at the presynaptic terminal, voltage-gated calcium channels open, allowing calcium ions to enter the cell. The influx of calcium triggers the release of neurotransmitter vesicles from the presynaptic terminal into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic membrane, leading to changes in the postsynaptic cell's membrane potential.
What triggers the release of acetylcholine from a synaptic terminal?
The release of acetylcholine from a synaptic terminal is triggered by the arrival of an action potential at the terminal. This depolarization causes voltage-gated calcium channels to open, leading to an influx of calcium ions into the terminal. The increased calcium levels then trigger the release of acetylcholine vesicles into the synaptic cleft.
What is the process of a neurotransmitter being absorbed into the axon terminal?
When an action potential reaches the axon terminal, it triggers the opening of voltage-gated calcium channels. Calcium ions enter the axon terminal, leading to the fusion of neurotransmitter-containing vesicles with the synaptic membrane. The neurotransmitter is then released into the synaptic cleft where it can bind to receptors on the postsynaptic neuron.
Which of these is a humoral stimulus for hormone release?
calcium
What is stored in the terminal cisternae?
calcium
What causes calcium ions to enter the synaptic bulb?
The nerve signal arrives at a synaptic knob and causes calcium channels to open. This allows the calcium ions to enter the synaptic knob. Calcium ions entry into the synaptic knob triggers exocytosis of synaptic vesicles, which release acetylcholine into the synaptic cleft.
