Ch 11 Nervous System

Question 1

Central Nervous System (CNS)

Answer 1

Brain, spinal cord integrates incoming information & initiates an outgoing response

Question 2

Peripheral Nervous System (PNS)

Answer 2

All other nerves, pathways going towards and away from CNS

Question 3

Nervous System

Answer 3

Functions: sensory perceptions, mental activities, stimulating muscle movement, secretions of glands

Question 4

Neuron

Answer 4

Basic unit of nervous system, nerve cell

Question 5

Dendrites

Answer 5

Extension of cell body, receives impulse

Question 6

Axon

Answer 6

Carries impulse away from the cell body

Question 7

Afferent Neurons

Answer 7

Action potentials toward the CNS; (arrives at CNS)

Question 8

Sensory Neuron

Answer 8

Receives stimuli; afferent neuron

Question 9

Efferent Neuron

Answer 9

Action potentials away from CNS; (exits CNS)

Question 10

Motor Neuron

Answer 10

Attached to a muscle or gland; efferent neuron

Question 11

Interneuron

Answer 11

Within the CNS from one neuron to another (relay, connecting impulses)

Question 12

Myelin

Answer 12

Protects and insulates axon; faster impulse (allows impulse to “jump” from node to node)

Question 13

Nodes of Ranvier

Answer 13

Not continuous on axon; spaces an impulse can jump to on a myelinated axon

Question 14

Unmyelinated Axon

Answer 14

Slower impulse

Question 15

Action Potential

Answer 15

Electrical signals; depolarization; more positive inside the cell & more negative outside cell membrane

Question 16

Ion

Answer 16

Movement across membrane allows an electrical signal to occur/result

Question 17

Resting Potential

Answer 17

Polarized and Repolarized; more negative inside cell & more positive outside cell membrane

Question 18

All or None Principle

Answer 18

Neuron will fire or won’t; sending an impulse or not

Question 19

Threshold

Answer 19

Minimum amount of stimulus needed to start an impulse

Question 20

Synapse

Answer 20

Junction or space between two cells

Question 21

Neurotransmitter

Answer 21

Chemicals that transfer electrical messages (impulse) across the synapse (crosses gap/space between neurons)

Question 22

Stimulus

Answer 22

Any change in environment; temperature, sound, smell

Question 23

Reflex

Answer 23

A predictable response to a stimulus which may or may not be conscious

Question 24

Reflex Arc

Answer 24

Includes receptor, sensory neuron, interneuron, motor neuron, effector

Question 25

What is needed to start an impulse

Answer 25

Stimulus that meets threshhold

Question 26

What causes the electrochemical signal to change from positive to negative

Answer 26

Changes in chemical concentrations

Question 27

Describe how an impulse travels

Answer 27

It is positive outside and negative inside and they flip when the impulses passes by