The Nervous System

Match the following

• Dendrite

• cell that carries nerve impulses throughout the body and is composed of a cell body, an axon, and dendrites

• Cell body

• nerve pathway consisting of a sensory neuron, an interneuron, and a motor neuron

• Neuron

• neuron structure that contains the nucleus and many organelles

• Axon

• neuron structure that transmits nerve impulses from the cell body to other neurons and muscle

• Reflex arc

• neuron structure that receives nerve impulses from other neurons and transmits them to the cell body

Match the following

• Node

• gap in the myelin sheath along the length of an axon; nerve impulses move from node to node

• Neurotransmitter

• nerve impulse

• Action potential

• chemical that diffuses across a synapse and binds to receptors on a neighboring neuron’s dendrite, causing channels to open on the neighboring cell and the creation of a new action potentia

• Threshold

• gap between one neuron’s axon and another neuron’s dendrite

• Synapse

• minimum stimulus needed to produce a nerve impulse

What are the gaps on the myelin sheath called?

• cell bodies

• thresholds

• nodes

• axons

What happens when an action potential is produced with a signal that is stronger than threshold?

• stronger action potential generated

• weaker action potential generated

• no action potential generated

• action potential has same strength as threshold

What would be the hypothetical result if a person lacked motor neurons?

• would be unable to feel a deep cut

• would be unable to swing hammer

• would be unable to breath

• would be unable to feel a hot plate

carries nerve impulses from the cell body to other neurons and muscles.

• axon

• nucleus

• dendrite

Explain how the myelin sheath changes the speed of an action potential.

Answer explanation

The myelin sheath insulates the axon, but it has nodes along its length where the ions can move in and out. This allows the action potential to jump from node to node and increase the speed of the impulse.