The Nervous System

Match the following letters to part/location.

• Axon

• F

• Dendrites

• C

• Nodes of Ranvier

• D

• Axon Terminals

• E

• Schwann Cell

• A

Answer explanation

B is the body of the neuron.

Match the following numbers to their location:

• Presynaptic Neuron

• 3

• Synaptic Cleft

• 6

• Calcium ion (entrance)

• 4

• Ion Channel

• 2

• Synaptic vesicle

• 7

Answer explanation

The ion channels on the postsynaptic neuron are called neurotransmitter receptors. The postsynaptic neuron is number 5.

What is NOT a function of astrocytes?

• Influence neuronal functioning (info processing)

• Support & brace neurons

• Provide the defense for the CNS

• Anchor the neurons to blood vessels

• Guide the migration of young neurons

Answer explanation

Microglia provide defense for CNS. Microglia are the resident immune cells that are the first line of defense against pathogens and disease causing agents.

What happens when a neuron is depolarized? (choose ALL that are correct)

• Potassium ions move out of the cell

• The inside of the cell becomes more positive

• Sodium ions move in to the cell

• When there is a decrease in membrane potential

• The inside of the cell becomes more negative

Answer explanation

A neuron that is repolarized - the inside would become more negative, potassium would be moving out of the cell, and there would be an increase in membrane potential

Tags

NGSS.HS-PS2-5

How does the CNS determine how strong a stimulus is?

• Where the stimulus comes from

• Size of the action potentials

• The number of nodes of Ranvier

• The frequency of action potentials

Which excitatory neurotransmitter is released at the neuromuscular junction?

• GABA

• acetylcholine

• dopamine

• histamine

What characteristic DOES NOT belong to neurons?

• They have a high metabolic rate (needs lots of glucose and oxygen!)

• They have extreme longevity (100+ years!)

• They are specialized cells that conduct impulses

• They are actively mitotic

Answer explanation

They are amitotic - they DO NOT divide - which is why brain and spinal cord injuries are often more permanent.

Tags

NGSS.HS-LS1-4

What part of the neuron conducts impulses away from its cell body?

• Axon

• Dendrites

• Axon Terminals

• Nodes of Ranvier

An impulse from one nerve cell to another is communicated via the...

• Dendrites

• Axon Terminals

• Synapse

• Cell Body

What substance is released at axon terminals propagating a nerve impulse?

• Neurotransmitter

• Calcium ion

• Sodium

• Potassium