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Zorluk: OrtaNervous Coordination and Sense Organs

Arrange the following physiological events of synaptic transmission across a chemical synapse in the correct sequential order from initial presynaptic stimulation to the postsynaptic response.

  1. 1Arrival of an action potential at the presynaptic axon terminal
  2. 2Influx of calcium ions (Ca2+Ca^{2+}) into the presynaptic terminal
  3. 3Fusion of synaptic vesicles with the membrane and release of neurotransmitter
  4. 4Diffusion of neurotransmitter molecules across the synaptic cleft
  5. 5Binding of neurotransmitter to specific receptors on the postsynaptic membrane

Cevap

The correct sequential order of chemical synaptic transmission is: Arrival of an action potential at the presynaptic axon terminal → Influx of calcium ions into the presynaptic terminal → Fusion of synaptic vesicles with the membrane and release of neurotransmitter → Diffusion of neurotransmitter molecules across the synaptic cleft → Binding of neurotransmitter to specific receptors on the postsynaptic membrane.
Synaptic transmission begins when an action potential depolarizes the presynaptic terminal membrane. This voltage change triggers the opening of voltage-gated calcium channels, leading to an influx of Ca2+Ca^{2+} into the presynaptic terminal. The rise in intracellular calcium causes synaptic vesicles to fuse with the presynaptic membrane and release neurotransmitters into the synaptic cleft via exocytosis. The chemical transmitter diffuses across the fluid-filled synaptic cleft and binds specifically to ligand-gated receptors on the postsynaptic membrane, generating a postsynaptic potential.

Adım Adım Çözüm

1
Identify the initial electrical signal reaching the synapse
An action potential arrives at the presynaptic terminal.
Synaptic transmission begins when an electrical wave reaches the end of the axon.
2
Determine the ion movement caused by membrane depolarization
Voltage-gated Ca2+Ca^{2+} channels open, causing calcium ions to enter the terminal.
Depolarization triggers the opening of calcium channels.
3
Trace the response of synaptic vesicles to elevated intracellular calcium
Synaptic vesicles fuse with the presynaptic membrane, releasing neurotransmitter via exocytosis.
Calcium influx activates vesicle exocytosis into the extracellular gap.
4
Trace the movement of neurotransmitters across the synaptic gap
Neurotransmitter molecules diffuse across the synaptic cleft.
Molecules move down their concentration gradient toward the postsynaptic cell.
5
Identify the final interaction leading to postsynaptic response
Neurotransmitters bind to specific receptors on the postsynaptic membrane.
Receptor binding opens ion channels, generating a electrical change in the postsynaptic cell.

Anahtar Kavram

Sequence of events in chemical synaptic transmission
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Konular

Nervous Coordination and Sense Organs

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