Lesson 4, Chapter 4

Question 1

Reflex arc

Answer 1

The simplest of movements; often occurs due to a sudden painful stimulus.

Question 2

Sensory receptors, sensory neurons, interneurons, motor neurons, effectors

Answer 2

The five components to a reflex arc in the correct order.

Question 3

Sensory receptors

Answer 3

Structures that activate sensory neurons.

Question 4

Sensory neurons

Answer 4

Neurons that send nervous impulses into the central nervous system.

Question 5

Interneurons

Answer 5

Neurons that stay inside the structures of the central nervous system.

Question 6

Motor neurons

Answer 6

Neurons that send action potentials (nervous impulses) to muscles or glands.

Question 7

Effectors

Answer 7

Structures that act in response to neurotransmitters secreted by a motor neuron.

Question 8

Presynaptic terminals

Answer 8

The ends of the branches of an axon.

Question 9

Axon hillock

Answer 9

The structure that connects the axon to the cell body.

Question 10

Synaptic vesicles

Answer 10

Vesicles inside the ends of an axon that contain a neurotransmitter.

Question 11

Neurotransmitter

Answer 11

A chemical that is released by a neuron which has an effect on another neuron or a muscle fiber.

Question 12

Presynaptic membrane

Answer 12

The membrane at the end of the branches of an axon.

Question 13

Synaptic cleft

Answer 13

The space between the end of a branch of a neuron and either the dendrite of another neuron or a muscle fiber.

Question 14

Neuromuscular junction

Answer 14

An area consisting of a presynaptic terminal, a synaptic cleft, and the area of a muscle fiber directly affected by a neurotransmitter.

Question 15

Polarized

Answer 15

A term reflecting the difference in charge between the outside of an axon’s membrane and the inside of the axon’s membrane when the neuron is at rest.

Question 16

Sodium ions

Answer 16

Ions with a positive charge that are more concentrated outside the membrane of a neuron’s axon when the neuron is at rest.

Question 17

Potassium ions

Answer 17

Ions with a positive charge that are more concentrated inside the membrane of a neuron’s axon when the neuron is at rest.

Question 18

Action potential

Answer 18

The nervous impulse that occurs when sodium ions rush into the axon of a neuron.

Question 19

Depolarization

Answer 19

A term reflecting a reduction of the difference in charge between outside and inside the membrane of a neuron’s axon; it occurs when an action potential (nervous impulse) is generated.