chap 2 key terms

Question 1

action potential

Answer 1

o Action potential- the electrical charge that travels down the axon of a neuron during transmission of a neural impulse, occurring as the result of the rapid depolarization of the neurons membrane and prompting the release of neurotransmitters.

Question 2

agonists

Answer 2

o Agonists-in neural communication, a substance that binds to a neuroreceptor to produce a similar effect to that of a neurotransmitter in either exciting or inhibiting a postsynaptic neuron, e.g. benzodiazepine drugs are GABA receptor agonists that have sedative effects similar to GABA.

Question 3

antagonists

Answer 3

o Antagonists- in neural communication, a substance that suppresses the release of a neurotransmitter or blocks the receptor sites, making the postsynaptic neuron less likely to fire.

Question 4

autonomic nervous system (ANS)

Answer 4

o Autonomic nervous system (ANS)- the component of the peripheral NS (PNS) that intervates involuntary muscles and glands, including the organs of the circulatory, digestive, respiratory and reproductive systems; transmits information from the brain to organs and glands, and from these systems back to the brain.

Question 5

axon

Answer 5

o Axon- the long, thin fibre of the neuron through which action potentials are transmitted.

Question 6

axon terminals

Answer 6

o Axon terminals- the swollen tip of a presynaptic neurons axon, containing the synaptic vesicles from which neurotransmitters are released, that forms a synapse with the dendrite of the postsynaptic neuron.

Question 7

brain

Answer 7

o Brain- the master organ of the CNS, responsible for receiving and processing information from the rest of the body and generating responses to it.

Question 8

central nervous system (CNS)

Answer 8

o Central nervous system (CNS)- a major division of the nervous system consisting of all the nerves in the brain and spinal cord.

Question 9

Consciousness

Answer 9

o Consciousness- an organisms awareness of internal or external events, including awareness of sensations, perceptions, emotions and thoughts.

Question 10

dendrites

Answer 10

o Dendrites- the thread line branches that extend from the cell body (soma) of the neuron and receive signals from other neurons.

Question 11

dopamine

Answer 11

o Dopamine- a modulatory neurotransmitter produced in the midbrain and adrenal glands that plays a major role in the coordination of movement and in the regulation of reward; dopamine imbalance is associated with many neurological disorders and with many mental health problems, including addictive behaviours.

Question 12

enteric nervous system (ENS)

Answer 12

o Enteric nervous system (ENS)- largest component of the autonomic NS, which manages the functions of the digestive system; can function independently of the CNS and so is sometimes called the ‘second brain’; the extensive two-way neural connections between the ENS and the CNS, particularly via the vagus nerve, form the gut-brain axis.

Question 13

excitatory neurotransmitter

Answer 13

o Excitatory neurotransmitter- neurotransmitters that increase the likelihood that a receiving neuron will dire an action potential.

Question 14

GABA

Answer 14

o Gamma-amino butyric acid (GABA)- the primary inhibitory neurotransmitter; its overall effects are to calm or slow neural transmission and therefore the body’s response.

Question 15

glutamate

Answer 15

o Glutamate- the primary excitatory neurotransmitter in the brain responsible for the fast transmission of neural messages and involves in cognitive functions.

Question 16

inhibitory neurotransmitter

Answer 16

o Inhibitory neurotransmitter- any neurotransmitter that decreases the likelihood that a receiving neuron will fire an action potential.

Question 17

Long term depression (LTD)

Answer 17

o Long-term depression (LTD)- a form of neural plasticity that results in a long-lasting reduction in the strength of a neural impulse due to persistent weak stimulation.

Question 18

motor neurons

Answer 18

o Motor neurons- specialised efferent neurons within the CNS that carry motor commands from the brain and spinal cord to muscles, organs and glands to control voluntary and involuntary movements; upper motor neurons carry info from brain to spinal cord; lower motor neurons form connections between spinal cord and muscles, organs and glands.

Question 19

Nervous system

Answer 19

o Nervous system- the integrated network of neurons, nerves, nerve tracts and associated organs and tissues, including the brain, that together coordinate a persons functioning, behaviours and responses adaptively as they interact with and adapt to their external environment.

Question 20

neuromodulator

Answer 20

o Neuromodulator- any of a group of neurotransmitters that can affect a large number of neurons at the same time; they are slow acting but bring about long lasting change to affected neurons and synapses; responsible for a range of human behaviour related to sleep, pain, motivation and voluntary movements.

Question 21

neurotransmitter

Answer 21

o Neurotransmitter- any chemical released from the axon terminal buttons of a presynaptic neuron into the synaptic cleft following an action potential that either excites or inhibits the postsynaptic neuron.

Question 22

parasympathetic NS

Answer 22

o Parasympathetic nervous system- the branch of the autonomic NS that controls unconscious processes related to rest, repair and enjoyment, such as digestion, sleep, slowed heat rate, pupil constriction, sexual arousal; it calms the effects of the sympathetic NS.

Question 23

parkinsons disease (PD)

Answer 23

o Parkinsons disease (PD)- a disease that causes tremors, muscular rigidity, slowness of movement and difficulty in initiating voluntary movement; believed to be caused by a lack of dopamine.

Question 24

peripheral NS (PNS)

Answer 24

o Peripheral Nervous system (PNS)- the division of the NS that comprises all of the nerves outside the CNS, through which motor info is communicated from the CNS to muscles and organs of the body, and sensory info is communicated back to the CNS.

Question 25

postsynaptic neuron

Answer 25

o Postsynaptic neuron- the neuron with a synapse that releases a neurotransmitter signal from a presynaptic neuron.

Question 26

presynaptic neuron

Answer 26

o Presynaptic neuron- the neuron within a synapse that releases a neurotransmitter into the synaptic cleft to transmit a signal to postsynaptic neurons.

Question 27

receptor cells

Answer 27

o Receptor sites- tiny areas on the membrane of a neuron that are sensitive to particular neurotransmitters, located mainly on dendrites but can be anywhere on the neuron.

Question 28

rerouting

Answer 28

o Rerouting- neurons near damaged area seek new active connections with healthy neurons.

Question 29

reward system

Answer 29

o Reward system- an area of the brain that responds to the release of dopamine to produce a state of motivation.

Question 30

sensory neurons

Answer 30

o Sensory neurons- specialised afferent neurons (sensory receptors) located in sense organs that detect and respond to info (physical energy) from the environment and transmit it to the CNS.

Question 31

serotonin

Answer 31

o Serotonin- A major neuromodulator that’s involved in pain, sleep and mood regulation.

Question 32

soma

Answer 32

o Soma- the main cell body of a neuron that contains the nucleus and other organelles.

Question 33

somatic NS (SNS)

Answer 33

o Somatic nervous system (SNS)- the part of the peripheral NS (PNS) that transmits sensory info received from sensory receptors to the CNS and motor messages from the CNS to skeletal muscles.

Question 34

spinal cord

Answer 34

o Spinal cord- part of the CNS consisting of a cable of sensory and motor nerve fibres that extend from the brainstem through a canal in the centre of the spine to the lumbar region of the spine; transmits sensory info from the PNS to the brain, and motor messages from the brain to the PNS.

Question 35

spinal reflex

Answer 35

o Spinal reflex- the simplest kind of automatic, unlearned responses to stimuli (reflec) controlled by simple sensory-motor circuits in the spinal cord (bypassing the brain); includes reflexes comprising a sensory and motor neuron connected by an interneuron (e.g. withdrawal reflex) and reflexes in which there is a direct connection between a sensory and motor neuron (e.g. patellar knee-jerk response); also called simple reflex arcs.

Question 36

sprouting

Answer 36

o Sprouting- the growth of new dendritic spines and/or axon terminals on a neuron, allowing stronger and more numerous connections with other neurons.

Question 37

sympathetic NS

Answer 37

o Sympathetic Nervous System- the branch of the autonomic NS that alters the activity level of internal muscles, organs and glands to physically prepare our body for increased activity during times of high emotional or physical arousal.

Question 38

synapse

Answer 38

o Synapse- the specialised junction between a presynaptic and postsynaptic neuron, separated by a small gap called the synaptic cleft; enables neural signals to be transmitted when an action potential causes the presynaptic neuron to release neurotransmitters into the synaptic cleft, where they can bind to receptors on the postsynaptic neuron.

Question 39

synaptic cleft

Answer 39

o Synaptic cleft- the 20-40 nanometre gap between the axon terminals of the presynaptic neuron and receptors on the dendrites of the postsynaptic neuron in the synapse.

Question 40

synaptic plasticity

Answer 40

o Synaptic plasticity- describes Changes that occur to the synaptic connection between 2 or more neurons.

Question 41

synaptic pruning

Answer 41

o Synaptic pruning- a process of removing extra, weak or unused synaptic connections so that neural transmission is as efficient as possible.

Question 42

synaptic vesicles

Answer 42

o Synaptic vesicles- small spherical sacs within the axon terminals of presynaptic neurons that contain molecules of neurotransmitters; an action potential causes the vesicles to fuse with the cell membrane and release neurotransmitters into the synaptic cleft.

Question 43

unconscious

Answer 43

o Unconscious- describes the self-regulating, constant responses, controlled by the autonomic NS, that aren’t normally under our conscious control.