0
What else can I help you with?
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.
What happened to the neurotransmitter release when switched from the control extracellular fluid to the extracellular fluid with no calcium?
There is no neurotransmitter release from the axon terminal when there are no calcium ions in the extracellular solution. This is because the exocytosis of the synaptic vesicles is calcium dependent.
What is the role of calcium in synaptic activity?
In a classic synapse, calcium's main role is to trigger the release of chemicals (called neurotransmitters) from the presynaptic neuron. How calcium does this is well established and is achieved through voltage-gated calcium channels located on the membrane of the presynaptic terminal. These channels open in response to membrane depolarization, the type of signal carried by an action potential. The whole process goes something like this: When an action potential arrives at the presynaptic terminal, it depolarizes the membrane sufficiently to open voltage-gated calcium channels. The calcium gradient across the membrane is such that when these channels open, an inward calcium current is produced, with calcium rapidly entering the cell. Calcium is rapidly bound by a presynaptic intracellular protein called synaptotagmin. Synaptotagmin is considered a calcium sensor that triggers a host of downstream events. Ultimately, synaptotagmin activation results in the fusion of neurotransmitter vesicles with the presynaptic membrane. These vesicles fuse with the membrane through interactions between v- and t-snares (the "v" and "t" stand for "vesicular" and "target", respectively) causing the release of neurotransmitters into the space between the pre- and postsynaptic terminal. Individual molecules of neurotransmitter diffuse across this space, called the synaptic cleft, and ultimately bind to receptors on the postsynaptic cell membrane. Since calcium triggers the conversion of an electrical signal (the action potential) into a chemical one (the release of neurotransmitters), calcium can be thought of as the trigger for electrochemical transduction (the term literally means the conversion of electrical into chemical information). Note that calcium's role is not limited to the presynaptic terminal; plenty of other synaptic phenomena rely on calcium. For example, at the specialized synapses between neurons and muscle cells (called the neuromuscular junction), binding of the neurotransmitter acetylcholine to the muscle cell triggers a rise in calcium within the muscle cell, which ultimately leads to muscle contraction. Another example occurs in the brain and involves a postsynaptic receptor called the NMDA receptor. Activation of this receptor also produces a rise in intracellular calcium in the postsynaptic cell which contributes to a number of interesting phenomena, notably learning and memory.
A mineral that contains calcium carbonate will provide a positive response to a test for .?
acid reaction
What happens if the presynaptic membrane of a motor neuron suddenly becomes permeable to calcium ion?
The motor end plate will be depolarized.If you found this answer for A&P then on the next unanswered question you come across once you find the answer type it in to help your fellow brothers out.The motor end plate will be depolarized.
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.
What ion triggers the release of a neurotransmitter at the presynaptic membrane?
Calcium ions trigger the release of neurotransmitter at the presynaptic membrane. When an action potential reaches the presynaptic terminal, it causes voltage-gated calcium channels to open, allowing calcium ions to enter the cell. The influx of calcium ions triggers the fusion of synaptic vesicles with the presynaptic membrane, leading to the release of neurotransmitter 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 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.
What most directly causes synaptic vesicles to release acetylcholine into the synaptic cleft?
The entry of calcium ions into the presynaptic terminal triggers the fusion of synaptic vesicles containing acetylcholine with the cell membrane, leading to the release of acetylcholine into the synaptic cleft. This process is known as calcium-dependent exocytosis and is a key mechanism for neurotransmitter release at synapses.
Does a stimulus traveling toward a synapse appear to open calcium ion channels in the axon terminal?
Yes, a stimulus triggers the opening of voltage-gated calcium channels in the axon terminal. When activated by an action potential, these channels allow calcium ions to enter the axon terminal, which then triggers the release of neurotransmitters into the synaptic cleft.
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 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.
Which ion causes neurotransmitters vesicles to fuse with the axons membrane during the conduction of a nerve impulse from one to the next?
Calcium ions cause the neurotransmitter vesicles to fuse with the axon terminal. When an action potential reaches the axon terminal, voltage-gated calcium ion pores are opened, allowing calcium ions into the axon terminal. These ions initiate the release of neurotransmitter vesicles stored on elements of the cytoskeleton located near the presynaptic membrane; they then travel to the presynaptic membrane, where they first dock, and then fuse with the presynaptic membrane, forming an opening or pore through which the neurotransmitters are released into the synaptic cleft.
What ion causes presynaptic vesicle to fuse to axon membrane?
The calcium ion is responsible for causing the presynaptic vesicle to fuse to the axon membrane in a process called exocytosis. When an action potential reaches the presynaptic terminal, calcium ions enter the terminal and trigger the fusion of the vesicle with the axon membrane, releasing neurotransmitters into the synaptic cleft.
What ion tiggers the release of actycholine into the synaptic cleft?
The release of acetylcholine into the synaptic cleft is triggered by an influx of calcium ions (Ca²⁺) into the presynaptic neuron. When an action potential reaches the axon terminal, voltage-gated calcium channels open, allowing Ca²⁺ to flow into the cell. This increase in intracellular calcium concentration prompts synaptic vesicles containing acetylcholine to fuse with the presynaptic membrane, leading to the release of the neurotransmitter into the synaptic cleft.
When the nerve signal reaches the axon terminal what happens next?
When a nerve signal reaches the axon terminal, it triggers the influx of calcium ions (Ca²+) into the terminal through voltage-gated calcium channels. This influx causes synaptic vesicles containing neurotransmitters to fuse with the presynaptic membrane, releasing the neurotransmitters into the synaptic cleft. The neurotransmitters then bind to receptors on the postsynaptic neuron, leading to the initiation of a new nerve signal in that neuron.
