The Nervous System Flashcards

1
Q

Neurons

A

Specialized cells capable of transmitting electrical impulses and translating them into chemical signals

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2
Q

Anatomy of Neuron: Cell Body/Soma

A

where nucleus is located

location of endoplasmic reticulum and ribosomes

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3
Q

Anatomy of Neuron: Dendrites

A

appendages coming off of the soma that receive signals

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4
Q

Anatomy of Neuron: Axon Hillock

A

info from dendrites passes through cell body and is integrated here

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5
Q

Action Potentials

A

transmission of electrical impulses down the axon

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6
Q

Signals arriving from the dendrites can be ____ or _____ , the axon hillock sums these signals and if it reaches _____ , to initiate an action potential.

A

excitatory

inhibitory

threshold

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7
Q

Anatomy of Neuron: Axon

A

long appendage that terminates in close proximity to target (muscle, gland or neuron)

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8
Q

Anatomy of Neuron: Myelin Sheath

A

insulation across nerve to prevent loss/crossing of signals and increases speed of conduction

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9
Q

Oligodendrocytes

A

CNS cells that produce myelin

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10
Q

Schwann Cells

A

PNS cells that produce myelin

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11
Q

Anatomy of Neuron: Nodes of Ranvier

A

breaks in myelin sheath on axon for rapid signal conduction

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12
Q

Anatomy of Neuron: Nerve Terminal/Synaptic Bouton

A

enlarged and flattened terminal area to maximize neurotransmission and ensure proper release of neurotransmitters

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13
Q

Anatomy of Neuron: Synaptic Cleft

A

space between neurons where axons release neurotransmitters to dendrites of next neuron

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14
Q

Anatomy of Neuron: Synapse

A

Nerve Terminal, Synaptic Cleft, Postsynaptic Membrane

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15
Q

Nerve

A

multiple neurons may be bundled together in the peripheral nervous system

can be sensory, motor or mixed

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16
Q

Cell bodies of neurons of the same type are clustered together into _____

A

ganglia

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17
Q

In the CNS, axons may be bundled together to form _____ , which cary only one type of information.

A

tracts

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18
Q

The cell bodies of neurons in the same tract are grouped into _____

A

nuclei

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19
Q

Glial Cells/Neuroglia

A

other cells that support neurons

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20
Q

Astrocytes

A

form blood/brain barrier, nourish neurons by controlling solute transport between nervous tissue and blood

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21
Q

Ependymal Cell

A

line ventricles of brain and produce cerebrospinal fluid to support brain as a shock absorber

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22
Q

Microglia

A

phagocytic cells that ingest and breakdown waste products in CNS

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23
Q

Resting Membrane Potential

A

all neurons have this, the electrical potential difference between the inside and outside of the neuron

usually -70mV

inside of neuron is negative to the outside

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24
Q

Na+ /K+ ATPase

A

channel that maintains the membrane potential of the neuron

moves 3Na+ out of cell for every 2K+ into the cell

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25
Q

Inside the neuron ____ is high and ____ is low. Outside the neuron, ____ is high and ___ is low.

A

[K+} , [Na+]

[Na+], [K+]

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26
Q

Negative resting potential is generated by both ________ within the cell and relatively greater permeability of K+ than Na+ ions into the cell allowing for passive transport out the cell.

A

negative proteins

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27
Q

ATP in transport required because_____, this is an example of ____. Each time the pump is used, it results in the inside of the cell becoming more _____

A

Na+ and K+ are moved against their gradients,

primary active transport

more negative

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28
Q

Depolarization

A

excitatory inputs to neuron raising the membrane potential, making it more likely to release an action potential

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29
Q

Hyperpolarization

A

inhibitory inputs to the neuron lowering the membrane potential to make neurons less likely to fire action potential

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30
Q

Summation

A

additive effect of multiple excitatory and inhibitory signals

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31
Q

Temporal Summation

A

multiple signals integrated during a short period of time

32
Q

Spatial Summation

A

additive effects are based on the number and location of the incoming signals

aka large number of inhibitory at action hillock effects more than small number of excitatory firing at dendrites

33
Q

1) Action Potential:When neuron is brought to threshold….

A

voltage gated sodium channels pen up leading to depolarization and let Na+ enter cell due to a strong electrochemical gradient (negative and low Na+ inside)

34
Q

2) Action Potential: When Vm reaches 35mV….

A

sodium channels are inactivated and must be brought to resting potential to deinactivate

voltage gated potassium channels open to let K+ leave the cell causing repolarization

35
Q

Three states of Sodium Channels

A

Closed (before cell reaches threshold and after inactivation is reversed)

Open ( from threshhold to 35mV)

Inactive (35mV to resting potential

36
Q

3) Action Potential: K+ ions leaving below threshold

A

hyperpolarization occurs as voltage is lower than threshold making neuron refractory(resistant) to further action potentials

37
Q

Absolute Refractory Period

A

no amount of stimulation can cause another action potential

38
Q

Relative Refractory Period

A

there must be greater than normal stimulation to cause action potential because the membrane is starting from a potential that is more negative than resting value

39
Q

4) Action Potential: Na+/K+ ATPase

A

after hyperpolarization, the Na+/K+ ATPase restores the resting potential and the gradients of each ion

40
Q

Impulse propagation

A

action potential traveling down the axon and initiating neurotransmitter release

as Na+ rushes into one segment of axon, it will depolarize subsequent segments of the axon to open Na+ channels and allow each segment to propagate action potentials to the terminal

After actin potential is fired from one segment of axon, the segment is momentarily refractory causing ONE WAY FLOW of information

41
Q

The speed at which action potentials move is dependent on ____ and _____ of an axon.

Increased _____ of axon leads to higher resistance and slower conduction.

Greater ______ allows for faster propagation due to decreased resistance

A

length , cross sectional area

length

cross sectional area

42
Q

Saltatory conduction

A

signal hoping from one node to another as membrane is only permeable at the nodes of Ranvier

43
Q

All action potentials within the same type of neuron have the same ______ during depolarization. Increased intensity of a stimulus causes an _____ of firing not _____ of the action potential.

A

potential difference

increased frequency

increased potential difference

44
Q

Presynaptic Neuron

A

neuron preceding the synaptic cleft

45
Q

Postsynaptic Neuron

A

neuron after synaptic cleft

46
Q

If a neuron signals to a gland or muscle rather than a neuron, the postsynaptic cell is termed an ______

A

effector

47
Q

When action potential reaches the nerve terminal, voltage gated _____ open allowing ____ to flow into the cell. This triggers fusion of _______ with the cell membrane at the synapse causing ___ of the neurotransmitter into synaptic cleft.

Once released into synapse, neurotransmitters ____ across the cleft and bind to ____ on post synaptic membrane.

A

calcium channels

calcium

membrane bound vesicles

exocytosis

diffuse

receptors

48
Q

Neurotransmitter receptors can be….

A

ligand gated ion channels or g protien coupled receptors

49
Q

Ligand Gated Ion Channel

A

postsynaptic cell will either be depolarized or hyperpolarized

50
Q

G Protein Coupled Receptors

A

cause changes in levels of cAMP or influx of calcium

51
Q

Breaking Down Neurotransmitter: Enzymatic

A

break down of ACh by acetylcholinesterase AChE

52
Q

Breaking Down Neurotransmitter: Reuptake carriers

A

neurotransmitters are brought back to the presynaptic carriers

ex 5-HT (serotonin), DA (dopamine) and NE (norepinephrine)

53
Q

Breaking Down Neurotransmitter: Diffuse out of Synaptic Cleft

A

nitric oxide, a gas signaling molecule

54
Q

Sensory/Afferent Neurons

A

transmit sensory information from receptors to the spinal cord/brain

55
Q

Motor/Efferent Neurons

A

transmit motor information from the brain and spinal cord to muscles/glands

56
Q

Interneurons

A

found in between other neurons and are the most occurring

located predominantly in the brain and spinal cord, reflexive behavior

57
Q

Processing of stimuli and response generation may happen at the _____ or ______/______

A

spinal cord

brainstem/cerebral cortex

58
Q

Reflexes only require processing at the level of the _____

A

spinal cord

59
Q

Supraspinal circuits

A

input from brain/brainstem

60
Q

Central Nervous System (CNS)

A

brain and spinal cord

61
Q

Brain consists of white and ____ matter.

White matter consists of _______

Grey matter consists of ______

A

grey

myelin sheath encased axons

cell bodies and dendrites

62
Q

Spinal cord can be divided into 4 sections:

A

cervical, thoracic, lumbar and sacral

63
Q

Vertebral Column

A

protects spinal cord and transmits nerves within space between adjacent vertebrae

64
Q

Spinal cord white matter is on the _____ while the grey matter is _____.

Axons of the spinal cord are _____

A

outside

deep within

within the spinal cord

65
Q

Pathway of Sensory Neurons

A

1) Sensory neuron brings info from periphery and enter the dorsal side of spinal cord
2) Cell bodies of the sensory neurons are in the dorsal root ganglia
3) motor neurons exit the spinal cord ventrally (closest to front of body)

66
Q

Peripheral Nervous System

A

made up of nerve tissue and fibers outside the brain and spinal cord including spinal nerves and 10 of the cranial nerves

connects rest of the body t the CNS

67
Q

The two pairs of cranial nerves that are part of the CNS are:

A

olfactory and optic nerves

68
Q

Somatic Nervous System

A

sensory and motor neurons throughout skin, joints muscles

Sensory: through afferent fibers

Motor: travel along efferent fibers

69
Q

Autonomic Nervous System (ANS)

A

regulates heartbeat, respiration, digestion and glandular secretion (the involuntary muscles with organs/glands) as well as temperature

automatic functions, not requiring conciousness

70
Q

One primary difference between the somatic and autonomic nervous system is that the peripheral component of ANS contains ____ neurons.

A motor neuron in the somatic nervous system goes directly from the spinal cord to the muscle without _____

In the ANS, two neurons work in series to transmit messages from the spinal cord.

The _______ is in the CNS and its axon travels to a ganglion in the PNS. Here it synapses with the cell body of the _______ which affects the target tissue.

A

two

synapsing

preganglionic neuron

postganglionic neuron

71
Q

The ANS is divided into 2 subsections. The sympathetic nervous system and the parasympathetic nervous system are _____

A

antagonistic

72
Q

Parasympathetic Nervous System

A

concerves energy

resting, sleeping, reduce heart rate, manage digestion

main neruotransmitter is actylcholine released by both the pre/postganglionic neurons

Vagus nerve(X) is responsible for parasympathetic innervation of thoracic and abdominal cavity

73
Q

Sympathetic Nervous System

A

activated by stress/ fight or flight

increase heart rate, blood to muscles, decrease digestion, relax bronchi, dialate eyes for light intake, release epinephrine

Pre releases acetylcholine
Post releases norepinephrine

74
Q

Reflex Arcs

A

neural circuits that control reflexive behavior

75
Q

Monosynaptic Reflex Arc

A

single synapse between sensory neuron that receives the stimulus and the motor neuron that responds to it.

76
Q

Knee Jerk Reflex

A

Monosynaptic Reflex Arc

When stretched…
1) info travels sensory (afferent, presynaptic) neuron to spinal cord to interface with the motor (efferent, postsynaptic) neuron to contract quadricep

77
Q

Polysynaptic Reflex Arc

A

Atleast one interneuron between the sensory and motor neuron

ex: withdrawal reflex