Question: When voltage-gated k+ channels open on the conductive segment of a neuron,?

What is the conductive segment of a neuron?

The axon or conductive segment conducts the impulse that is generated from the dendritic zone to the terminal portion of the axon referred to as the telodendron or transmissive segment. This will be at a synapse with another neuron in the CNS or with an effector organ in the PNS.

When transmission occurs at a synapse neurotransmitter is released by?

At a chemical synapse, one neuron releases neurotransmitter molecules into a small space (the synaptic cleft) that is adjacent to another neuron. The neurotransmitters are contained within small sacs called synaptic vesicles, and are released into the synaptic cleft by exocytosis.

Where is the synaptic knob located?

Synaptic knobs are located on a neuron’s axon. The axon can be very long and have many synaptic knobs.

Which is true regarding the action of a Neurolemmocyte?

Which is true regarding the action of a neurolemmocyte? Each neurolemmocyte can form a myelin sheath around many axons simultaneously. Each neurolemmocyte can wrap only a 1 mm portion of a single axon. Each neurolemmocyte can wrap only a 1 mm portion of a single axon.

What is the initial segment of a neuron?

At the base of axons sits a unique compartment called the axon initial segment (AIS). The AIS generates and shapes the action potential before it is propagated along the axon. Neuronal excitability thus depends crucially on the AIS composition and position, and these adapt to developmental and physiological conditions.

What happens when a nerve impulse reaches the transmissive segment of a neuron?

When a nerve impulse reaches the transmissive segment of a neuron: calcium diffuses into the neuron and neurotransmitter is released by exocytosis. Arrival of an action potential at the synaptic knob results in: opening of voltage-gated calcium channels and diffusion of calcium into the synaptic knob.

What are the 3 types of synapses?

Different Types of Synapses [back to top]

• Excitatory Ion Channel Synapses. These synapses have neuroreceptors that are sodium channels.
• Inhibitory Ion Channel Synapses. These synapses have neuroreceptors that are chloride channels.
• Non Channel Synapses.
• Neuromuscular Junctions.
• Electrical Synapses.

What are the steps 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 happens at the synapse between two neurons?

Transmission of nerve impulses between two neurons takes plave through the synapse. The axon terminal of a neuron releases specialized chemicals called neurotransmitters. These chemicals travel through the synapse and reach the dendrites of the successive neuron.

What does a synaptic knob do?

Axons often have thousands of terminal branches, each ending as a bulbous enlargement, the synaptic knob or synaptic terminal. At the synaptic knob, the action potential is converted into a chemical message which, in turn, interacts with the recipient neuron or effector. This process is synaptic transmission.

When a nerve fiber is polarized Where is the concentration of sodium ions higher?

A resting nerve fiber is “polarized” partly because the concentration of: Na+ is higher on the outside and K+ is higher on the inside.

What is synapse and its function?

In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to the transmission of nervous impulses from one neuron to another.

Why are the nodes of Ranvier important?

Node of Ranvier, periodic gap in the insulating sheath (myelin) on the axon of certain neurons that serves to facilitate the rapid conduction of nerve impulses. In a myelinated axon, the myelin sheath prevents the local current (small black arrows) from flowing across the membrane.

What is the first step in Wallerian degeneration?

What are the steps of Wallerian degeneration? 1. Distal to the injury site the axon and myelin degenerate and fragment. 2.

Which is the most common structural type of synapse?

The most common type of synapse is an axodendritic synapse, where the axon of the presynaptic neuron synapses with a dendrite of the postsynaptic neuron.