Overview of the Nervous System

Question 1

Nervous system

Answer 1

body’s speedy, electrochemical communication network, consisting of all nerve cells of the peripheral & central nervous systems - Made up of nerves that communicate via chemical messengers called neurotransmitters

Question 2

Central nervous system (CNS)

Answer 2

brain & spinal cord

Question 3

Peripheral nervous system (PNS)

Answer 3

sensory & motor neurons that connect CNS to the rest of the body

Question 4

Nerves

Answer 4

bundles axons that form neural cables connecting the CNS with muscles, glands, & sensory organs
■ I.e. the optic nerve carries messages from the eye to the brain

Question 5

Sensory (afferent) neurons

Answer 5

carry incoming information from body’s tissues & sensory
receptors to the brain & spinal cord

Question 6

Motor (efferent) neurons

Answer 6

carry outgoing information from brain & spinal cord to
muscles & glands (motor = muscle movement)

Question 7

Interneurons

Answer 7

neurons within the brain & spinal cord; communicate internally & process
information between sensory inputs & motor outputs (in between sensory & motor neurons)

Question 8

Somatic nervous system

Answer 8

controls the body’s skeletal muscles & enables voluntary
movement

Question 9

Autonomic nervous system (ANS)

Answer 9

controls involuntary systems like glands &
muscles of internal organs (such as the heart); made up of sympathetic & parasympathetic nervous systems

Question 10

Sympathetic nervous system

Answer 10

arouses the body, mobilizing its energy
○ Our “fight or flight” system - accelerates heart rate, raises blood pressure, slows
digestion, cools you with perspiration, dilates pupils

Question 11

Parasympathetic nervous system

Answer 11

calms the body, conserving energy
○ Our “rest & digest” or “feed & breed” system - slows down heart rate, lowers blood pressure, speeds up digestion, constricts pupils

Question 12

Brain

Answer 12

enables our humanity & conscious awareness - contains some 128 billion neurons
■ Brain’s neurons cluster into working groups called neural networks - allows for short, fast connections with other neurons that are doing similar tasks
● Neurons that fire together wire together

Question 13

Spinal cord

Answer 13

two-way information highway connecting the PNS & the brain
■ Ascending neural fibers send up sensory information; descending neural fibers send back motor-control information

Question 14

Reflex

Answer 14

simple, automatic response to a sensory stimulus, such as the knee-jerk response
● No brain involvement with reflexes - all in spinal cord

Question 15

Neuron

Answer 15

nerve cell; building blocks of the brain/nervous system
○ Receive, process, & transmit information between body & brain