The Nervous System

Front 1

highly specialized cells responsible for the conduction of impulses

Back 1

neurons

Front 2

what are the 2 forms of communication neurons use?

Back 2

chemical and electrical

Front 3

this type of communication between neurons occurs via ion exchange and the generation of membrane potentials down the length of the axon

Back 3

electrical communication

Front 4

this type of communication between neurons occurs via neurotransmitter release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell

Back 4

chemical communication

Front 5

where is the nucleus of a neuron found?

Back 5

in the soma or cell body

Front 6

the soma is the location of the nucleus as well as what other 2 things?

Back 6

ribosomes and ER

Front 7

appendages emanating directly from the soma that receive incoming messages from other cells

Back 7

dendrites

Front 8

information received from the dendrites is transmitted through the cell body before it reaches this structure that integrates incoming signals

Back 8

axon hillock

Front 9

the transmission of electrical impulses down the axon

Back 9

action potentials

Front 10

a long appendage that terminates in close proximity to a target structure like a muscle, gland, or another neuron

Back 10

axon

Front 11

most mammalian nerve fibers are insulated by this to prevent signal loss or crossing of signals

Back 11

myelin

Front 12

this maintains the electrical signal within one neuron

Back 12

myelin sheath

Front 13

what is myelin produced by in the CNS?

Back 13

oligodendrocytes

Front 14

what is myelin produced by in the PNS?

Back 14

Schwann cells

Front 15

small breaks in the myelin shear with exposed areas of axon membrane that are critical for rapid signal conduction

Back 15

nodes of Ranvier

Front 16

this is at the end of an axon

Back 16

nerve terminal or synaptic bouton

Front 17

the chemicals that transmit information between neurons

Back 17

neurotransmitters

Front 18

the small space into which the terminal portion of the axon releases neurotransmitters

Back 18

synaptic cleft

Front 19

together the nerve terminal, synaptic cleft, and postsynaptic neuron are known as what?

Back 19

synapse

Front 20

multiple neurons bound together in the PNS

Back 20

nerve

Front 21

cell bodies of neurons of the same type in the PNS clustered together

Back 21

ganglia

Front 22

multiple neurons bound together in the CNS

Back 22

tracts

Front 23

cell bodies of neurons clustered together in the CNS

Back 23

nuclei

Front 24

cells that support neurons in the nervous system

Back 24

glial cells or neuroglia

Front 25

these cells nourish neurons and form the blood brain barrier

Back 25

astrocytes

Front 26

this controls the transmission of solutes from the blood stream into nervous tissue

Back 26

blood brain barrier

Front 27

these cells line the ventricles of the brain and produce CSF

Back 27

ependymal cells

Front 28

phagocytic cells that ingest and breakdown waste products and pathogens in the CNS

Back 28

microglia

Front 29

neurons use these all or nothing messages to relay electrical impulses down the axon to the synaptic terminal

Back 29

action potentials

Front 30

a single __________ may carry multiple types of information including sensory, motor, or both while _____________ only contain one type of information

Back 30

nerve, tracts

Front 31

all neurons exhibit a resting membrane potential of approximately what?

Back 31

-70 mV

Front 32

What two things help maintain resting potential?

Back 32

selective permeability of ions and the Na+/K+ ATPase

Front 33

the Na+/K+ ATPase pumps __ ions of ___________ out of the cell for every ___ ions of ____________ pumped into the cell.

Back 33

3 Na+, 2 K+

Front 34

these type of signals cause depolarization of the neuron

Back 34

excitatory

Front 35

these type of signals cause hyperpolarization of the neuron

Back 35

inhibitory

Front 36

this refers to the addition of multiple signals near each other in time

Back 36

temporal summation

Front 37

this refers to the addition of multiple signals near each other in space

Back 37

spatial summation

Front 38

when enough excitatory stimulation occurs the cell is depolarized to what?

Back 38

threshold voltage

Front 39

when the cell reaches threshold voltage what happens?

Back 39

voltage gated sodium channels open

Front 40

sodium flows into the ion due to its strong what?

Back 40

electrochemical gradient

Front 41

what is the peak of the action potential?

Back 41

35 mV

Front 42

at about 35 mV sodium channels are inactivated and what happens?

Back 42

potassium channels open

Front 43

does potassium flow into or out of the neuron due to its strong electrochemical gradient?

Back 43

out of

Front 44

potassium channels stay open long enough to overshoot the action potential resulting in a ______________________ neuron

Back 44

hyperpolarized

Front 45

while the axon is hyperpolarized it is said to be in what?

Back 45

its refractory period

Front 46

in this refractory period, the cell is unable to fire another action potential

Back 46

absolute refractory period

Front 47

in this refractory period the cell requires a larger than normal stimulus to fire an action potential

Back 47

relative refractory period

Front 48

at the nerve terminal, neurotransmitters are released into what?

Back 48

synapse

Front 49

when the action potential arrives at the nerve terminal what opens?

Back 49

calcium channels

Front 50

the influx of calcium causes fusion of vesicles filled with neurotransmitters with the presynaptic membrane resulting in what?

Back 50

exocytosis of the neurotransmitter

Front 51

what 2 types of receptors can neurotransmitters bind to on the postsynaptic cell

Back 51

ligand gated ion channels or G protein coupled receptors

Front 52

a neurotransmitter can be broken down by what?

Back 52

enzymes

Front 53

a neurotransmitter can be absorbed back into the presynaptic cell by what?

Back 53

reuptake channels

Front 54

a neurotransmitter can diffuse out of what?

Back 54

synaptic cleft

Front 55

what are the 3 types of neurons in the nervous system?

Back 55

sensory, motor and interneurons

Front 56

the brain and spinal cord

Back 56

central nervous system

Front 57

the cranial and spinal nerves

Back 57

peripheral nervous system

Front 58

these nerve cells are often linked to reflexive behavior

Back 58

interneurons

Front 59

what 2 cranial nerves are technically not a part of the PNS

Back 59

optic and olfactory

Front 60

in the CNS what does white matter consist of?

Back 60

myelinated axons

Front 61

in the CNS what does grey matter consist of?

Back 61

unmyelinated cell bodies and dendrites

Front 62

in the brain is white matter or grey matter deeper?

Back 62

white matter

Front 63

in the spinal cord is white matter or grey matter deeper?

Back 63

grey matter

Front 64

what are the 2 divisions of the PNS?

Back 64

somatic and autonomic

Front 65

what are the 2 divisions of the autonomic nervous system?

Back 65

sympathetic and parasympathetic

Front 66

these use the ability of interneurons in the spinal cord to relay information to the source of a stimulus while simultaneously routing it to the brain

Back 66

reflex arcs

Front 67

in this type of reflex arc, the presynaptic neuron fires directly on to the postsynaptic neuron

Back 67

monosynaptic reflex arc

Front 68

in this type of reflex arc, the presynaptic neuron may fire onto a motor neuron as well as interneurons that fire onto other motor neurons

Back 68

polysynaptic reflex arc

Front 69

the additive effect of multiple signals

Back 69

summation