nervous system 1

Question 1

Nervous system

Answer 1

The nervous system is used for communication throughout the body and communication within the brain.

Question 2

Neurons

Answer 2

Neurons process and transfer information via electrical and chemical signals. Neurons are made up of a cell body, nucleus, myelin sheath, node of ranvier, axon, dendrites, and axon terminal.

Question 3

Action potential

Answer 3

Action potential is the temporary reversal of the electrical potential along the membrane. It begins with resting potential, then enters the stimulus period, then enters depolarization, then enters repolarization, then enters the refractory period.

Question 4

Saltatory conduction

Answer 4

Saltatory conduction describes the propagation of action potentials along myelinated axons from one node of Ranvier to the next node. This process helps speed up the arrival of an impulse.

Question 5

What increases the speed of conduction along a neuron?

Answer 5

A neuron increases its speed of conduction when its axon diameter and myelination also increase. Myelination acts as an insulator and forces the impulse to “jump” along the axon from node to node.

Question 6

Synapse

Answer 6

A synapse is a connection between neurons and other neurons, glands, muscles, and receptors. A synapse consists of a presynaptic and postsynaptic neuron, which consist of a gap between them allowing for the movement of nerve signals from one neuron to another and is called the synaptic cleft.

Question 7

Neurotransmitters

Answer 7

Neurotransmitters are chemical messengers that carry signals from one neuron to the next target cell.

Question 8

Acetylcholine

Answer 8

Acetylcholine is a neurotransmitter that contains choline and an acetyl group, which are stored in vesicles. When acetylcholine is released by exocytosis, it binds to the receptors on the postsynaptic neuron, initiating depolarization. If a threshold is reached, an action potential will occur and once the neurotransmitter is released, it will be broken down into choline and acetate.

Question 9

What causes the release of neurotransmitters into the synaptic cleft?

Answer 9

The arrival of a nerve impulse at the end of an axon causes an influx of calcium ions and induces the vesicles to release their neurotransmitter into the synaptic cleft. Due to diffusion, there is a small delay of impulse transmission.

Question 10

How are neurotransmitters deactivated?

Answer 10

A neurotransmitter is deactivated by enzymes located on the membrane so it can be reabsorbed and recycled.