Chapter 12 Vocabulary

Question 1

The membrane potential at which an action potential begins

Answer 1

Threshold (-60 to -55 mV)

Question 3

A graded hyperpolarization of the postsynaptic membrane

Answer 3

Inhibitory Postsynaptic Potentials

Question 4

In communication between two cells, the axon terminal of the presynaptic cell most commonly releases these chemicals into the synaptic cleft

Answer 4

Neurotransmitters

Question 5

All the voltage-gated sodium channels either are already open or are inactivated, and another action potential cannot be propagated

Answer 5

Absolute refractory period

Question 6

The addition of stimuli occurring in rapid succession at a single synapse that is active repeatedly

Answer 6

Temporal summation (tempus = time)

Question 10

The sodium channels have regained their normal resting condition, but the membrane potential has not yet stabilized

Answer 10

Relative refractory period

Question 11

Cause depolarization and promote the generation of action potentials

Answer 11

Excitatory neurotransmitters

Question 12

Consists of the brain and spinal cord

Answer 12

Central nervous system

Question 13

Synapses that release norepinephrine

Answer 13

Adrenergic synapses

Question 14

Changes in the membrane potential that cannot spread far from the site of stimulation

Answer 14

Graded potentials

Question 19

A graded depolarization caused by the arrival of a neurotransmitter at the postsynaptic membrane

Answer 19

Excitatory Postsynaptic Potentials

Question 20

This is how an action potential travels along unmyelinated axons

Answer 20

Continuous propagation

Question 21

Occurs when simultaneous stimuli applied at different locations have a cumulative effect on the membrane potential

Answer 21

Spatial summation

Question 22

This division of the PNS brings sensory information from the PNS to the CNS

Answer 22

Afferent division

Question 24

Typical resting membrane potential

Answer 24

-70 mV

Question 25

Controls skeletal muscle contractions

Answer 25

Somatic nervous system

Question 26

How an action potential travels over a myelinated axon

Answer 26

Saltatory propagation

Question 27

Neurons which form the efferent division of the PNS

Answer 27

Motor neurons

Question 28

States that the properties of an action potential are independent of the relative strength of the depolarizing stimulus, as long as that stimulus exceeds the threshold

Answer 28

All-or-none principle

Question 31

Propagated changes in the membrane potential that, once initiated, affect an entire excitable membrane. These electrical events are also known as nerve impulses.

Answer 31

Action potential

Question 32

Activity at an axoaxonic synapse increases the amount of neurotransmitter released when an action potential arrives at the axon terminal

Answer 32

Presynaptic facilitation

Question 34

A compound, released by the axon terminal, which alters the rate of neurotransmitter release by the presynaptic neuron or changes the postsynaptic cell’s response to neurotransmitters

Answer 34

Neuromodulators

Question 35

The release of GABA inhibits the opening of voltage-gated calcium channels in the axon terminal

Answer 35

Presynaptic inhibition

Question 38

The process of restoring the resting membrane potential after depolarization

Answer 38

Repolarization

Question 39

Synapses that release ACh

Answer 39

Cholinergic synapses

Question 40

Bundles of axons which carry sensory information and motor commands, along with their associated blood vessels and connective tissues

Answer 40

Nerves

Question 42

Cause hyperpolarization and suppress the generation of action potentials

Answer 42

Inhibitory neurotransmitters

Question 43

Any shift from the resting membrane potential towards a more positive potential

Answer 43

Depolarization

Question 44

Open or close when they bind specific chemicals

Answer 44

Chemically gated channels

Question 51

Open or close in response to the membrane potential

Answer 51

Voltage gated channels

Question 52

During repolarization, the inside of the cell becomes more negative than the resting membrane potential

Answer 52

Hyperpolarization

Question 53

Automatically regulates smooth muscle, cardiac muscle, glandular secretions, and adipose tissue at the subconscious level

Answer 53

Autonomic nervous system

Question 54

Neurons which form the afferent division of the PNS

Answer 54

Sensory neurons

Question 55

This division of the PNS brings motor commands from the CNS to muscles, glands, and adipose tissue

Answer 55

Efferent division

Question 60

These are always open, however, their permeability can vary from moment to moment as the proteins that make up the channel change shape in response to local conditions

Answer 60

Leak channels

Question 61

Consists of all neural tissue outside of the brain and spinal cord

Answer 61

Peripheral nervous system