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1
Q

two systems responsible for maintaining homestasis

A

nervous and endocrine

2
Q

regulates body activities by responding rapidly using nerve impulses

A

nervous system

3
Q

system responds more slowly by use of hormones

A

endocrine system

4
Q

the branch of medical science that deals with the normal functioning and disorders of the nervous system

A

neurology

5
Q

brain and spinal cord

A

CNS

6
Q

12 cranial nerves, spinal nerves (31 pairs), peripheral nerves

A

PNS

7
Q

The nervous system comprises:

A

brain, spinal cord, spinal nerves, ganglia, enteric plexuses, and sensory receptors

8
Q

functions of the nervous system

A

sensory, integrative, motor

9
Q

detect changes in internal / external environment
carry info to brain and spinal cord
afferent neurons

A

sensory

10
Q

afferent neurons

A

sensory receptors

11
Q

analyze and store info
make decisions
many are interneurons, relatively short in brain, spinal cord, and ganglia that connect nearby neurons

A

Integrative

12
Q

responds to decisions
motor neurons carry info from brain to spinal cord to effectors (muscles or glands)
efferent neurons

A

Motor

13
Q

efferent neurons

A

motor neurons

14
Q

general organization of the nervous system

A

somatic
autonomic
enteric

15
Q

sensation from body wall, limbs, head, special senses (sight, hearing, taste, balance, smell)

A

somatic

16
Q

motor control of skeletal muscle

A

somatic (voluntary control)

17
Q

sensation from internal organs like heart, lungs, bladder

A

autonomic

18
Q

motor control of smooth and cardiac muscle (i.e. involuntary muscle), glands (involuntary control)

A

autonomic

19
Q

sensation from gastrointestinal tract

A

enteric

20
Q

motor control of smooth muscle and glands of the GI (involuntary control)

A

enteric

21
Q

consists of all nervous tissue outside the CNS

A

PNS

22
Q

made up of Somatic, Autonomic, and Enteric Nervous Systems

A

PNS

23
Q

has both sensory and motor neurons

A

PNS

24
Q

The motor part of the ANS has which two branches?

A

sympathetic and parasympathetic

25
Q

an association (a bundle) of neuronal axons in the PNS

A

nerve

26
Q

a group of neuronal cell bodies in the PNS

A

ganglion

27
Q

an association (a bundle) of neuronal axons in the CNS

A

tract

28
Q

an association (a bundle) of (unmyelinated) nerve cell bodies in the CNS

A

Nucleus

29
Q

an extensive network of nerves found within the PNS

A

Plexus

30
Q

cells that have the property of electrical excitability, and are specially adapted to produce and transmit AP’s

A

Neurons

31
Q

cells of the NS that support, flourish, and protect the neurons

A

Neuroglia

32
Q

are there more neuroglia or neurons? Why?

A

neuroglia stupid!

neurons do not replace themselves via mitosis like neuroglia

33
Q

what are the basic parts of the neuron

A

cell body and nerve fibers comprising of an axon and dendrites

34
Q

name adaptions for neurons

A

axoplasm (the cytoplasm of an axon)

axolemma (the plasmalemma of axon)

35
Q

axoplasm

A

(the cytoplasm of an axon)

36
Q

axolemma

A

(the plasmalemma of axon)

37
Q

like most cell neurons have nucleus, cytoplasm, typical organelles

what are the specialized forms of organelles?

A

Nissl bodies (prominent clusters of rough ER)

38
Q

prominent clusters of rough ER in a neuron

A

Nissl bodies

39
Q

little trees

A

dendrites

40
Q

typically short, tapering, highly branched

A

dendrites

41
Q

propagates impulses to another neuron, muscle, or nerve

A

axon

42
Q

can approximate three feet in humans

A

axon

43
Q

almost always a single axon per nueron, T or F

A

True

44
Q

typically arises from an elevation in the cell body called the axon hillock

A

axon

45
Q

small hill of the neuron

A

axon hillock

46
Q

first part of the axon

A

intial segment

47
Q

impulses i.e. AP’s generally arise in the

A

trigger zone

48
Q

the junction of the hillock an initial segment

A

trigger zone

49
Q

if an axon is cut what happens

A

distal fragment dies

50
Q

does axon contain RER?

A

No… protein synthesis does not occur in axon

51
Q

axon contains?

A

Mitochondira
Microtubules
Neurofibrils

52
Q

may branch of main axon

A

axon collaterals

53
Q

end of axons and collaterals

A

axon terminal (telodendria)

54
Q

telodendria

A

end of axons and collaterals

55
Q

telodendria end in either

A

synaptic bulbs

varicosities

56
Q

synaptic bulbs are

A

bulb-shaped structures at end of telodendria

57
Q

varicosities are

A

string of swollen bulbs at end of telodendria

58
Q

cytoskeleton of typical neuron comprised of

A

neurofibrils

microtubules

59
Q

neurofibrils of typical neuron

A

intermediate filaments which provide structure and support

60
Q

microtubules of typical neuron are made of and do what?

A

tubulin

moving material between the cell body and axon

61
Q

what does synthesis of new proteins, vessicles, etc take place in the neuron?

A

cell body not axon

62
Q

how far apart can cell body and axon terminals be?

A

over a meter

63
Q

one way only, cell body to axon terminals

transports axoplasm to growing or generating axons

A

slow axonal transport

64
Q

two way transport, both toward and away from cell body

uses microtubules as “tracks” and “motors”

transports organelles and materials that are used to form axolemma membranes, synaptic end bulbs, and synaptic vessicles

A

fast axonal transport

65
Q

Look at slide 21 of ppt… before you do imagine the three structural classifications of neurons

A

multipolar
bipolar
pseudounipolar

66
Q

special senses think

A

bipolar neuron

67
Q

sensory neurons think

A

pseudounipolar neuron

68
Q

structural classification of neurons is based on…

A

processes (axons or dendrites) extending from the cell body

69
Q

key takeaway from structural classification?

A

trigger zone of each neuron location

70
Q

the vast majority of the neurons in the human body are

A

multipolar neurons

71
Q

have several dendrites and only one axon and are located throughout the brain and spinal cord

A

multipolar neurons

72
Q

have one main dendrite and one axon

A

bipolar neurons

73
Q

are used to convey the special senses of sight, smell, hearing, and balance and are found where?

A

bipolar neurons

found in retina of eye, inner ear, and olfactory area of the brain

74
Q

contain one process which extends from the body and divides into a central branch that functions as an axon and as a dendritic root

A

unipolar neurons (psuedounipolar)

75
Q

often employed for sensory neurons that convey touch and stretching info from extremities

A

unipolar neurons (psuedounipolar)

76
Q

not excitable cells

small, more numerous than neurons

A

neuroglia

77
Q

play a supporting role (nourishment)

make up half the volume of the CNS

A

neuroglia

78
Q

in cases of injury or disease, multiply to fill in spaces formerly occupied by neurons

A

neuroglia

79
Q

not excitable cells

small, more numerous than neurons

play a supporting role (nourishment)

make up half the volume of the CNS

in cases of injury or disease, multiply to fill in spaces formerly occupied by neurons

A

neuroglia

80
Q

astrocytes
microglia
oligodendrocytes
ependymal cells

AMOE

A

Neuroglia of the CNS

81
Q

Neuroglia of the CNS

A

astrocytes
microglia
oligodendrocytes
ependymal cells

82
Q

Neuroglia of the PNS

A
Schwann cells (neurolemmoytes)
Satellite cells
83
Q
Schwann cells (neurolemmoytes)
Satellite cells
A

Neuroglia of the PNS

84
Q

regulate the composition of the extracellular fluid in the CNS

help form the BBB

take up excess neurotransmitters

may influence formation of neuronal synapses

A

Astrocytes (star shaped)

85
Q

phagocytes of the CNS

A

Microglia

86
Q

line the ventricles of the brain; produce, monitor, and aid in circulation of CSF; help form the blood CSF barrier

A

Ependymal cells (of CNS)

87
Q

myelinate axons in the PNS

A

Schwann cells

88
Q

neuroglia of the CNS completely surround ___ and ___ of neurons

A

axons and cell bodies of neurons

89
Q

do not typically undergo mitosis, meaning if a neuron dies there is no reservoir of cells to replace it

A

neurons

90
Q

do undergo mitosis (can be highly malignant and grow rapidly i.e. brain tumors – can be highly malignant and grow rapidly, and include astrocytomas, oligodendrogliomas, and schwannomas

A

neuroglial cells

91
Q

No mitosis

A

nuerons

92
Q

yes mitosis

A

neuroglial cells

93
Q

myelination is produced by ___ of the CNS and ____ of the PNS

A

Oligodendrocytes (CNS)

Schwann cells (PNS)

94
Q

a multi-layered complex of lipids and proteins, i.e. player of plasma membranes

insulates axons (prevents loss of electrical signal speeding up conduction of nerve impulses)

A

myelin

95
Q

a ___ or ___ can be associated with a neuron, yet the neuron may be unmeylinated. Myelination requires

A

Schwann cell (neurolemmocyte) or oligodendrocyte

requires the glial cell to have wrapped its plasma membrane around the axon many times

96
Q

schwann cell in the

A

PNS

97
Q

oligodendrocytes in the

A

CNS

98
Q

the outer nucleated cytoplasmic layer of the schwann cell, which encloses the myelin sheath is the ____

A

neurolemma

99
Q

unmyelinated cells w/ Schwann cells means axons lay in grooves on the surface of schwann cells but there is no

A

myelin sheath and no neurolemma

100
Q

neurolemmocyte

A

schwann cell

101
Q

schwann cell inner portion encircles the axon, forming many layers that comprise the

A

myelin sheath

102
Q

resides in the neurolemma (outer nucleated cytoplasmic layer of the schwann cell)

A

nucleus of the neurolemmocyte

103
Q

outer lay of a myelinating Schwann cell

A

neurolemma

104
Q

contains the nucleus and virtually all the cytoplasm of Schwann cells, not to be confused with Axolemma

which NS?

A

Neurolemma

in the PNS

105
Q

only on nerve fibers supplied by potentially nerve-producing cells

gaps between myelinating cells (where there is no myelin)

A

nodes of ranvier (found in CNS and PNS)

106
Q

a nerve fiber consists of

A

axon plus myelin sheath

107
Q

the ___ surrounds the nerve fiber

A

endoneurium

108
Q

the endoneurium overlies the

A

Schwann cells

109
Q

have multiple processes

each process can form a myelinated segment where they can myelinate several segments of ONE axon OR several axons

A

oligodendrocytes

110
Q

are neurolemmas present in the CNS?

why?

A

NO; oligodendrocyte cell body and nucleus do not envelope the axon

111
Q

one oligodendrocyte can myelinate multiple times

there is no?

there are?

A

no neurolemma

are nodes of Ranvier

112
Q

color of myelin and type of matter

A

white; white matter of the CNS

113
Q

matter or region with neuronal cell bodies and no myelin

what makes it gray?

A

gray matter; Nissl bodies make it gray

114
Q

Virtually all cells in the body exhibit a
membrane potential, which is an electrical
voltage difference across the membrane

T or F

A

True

115
Q

Nerve cells are highly adapted for using
membrane potentials, and changes in
membrane potentials, to initiate and
transmit nerve impulses

T or F

A

T

116
Q

Neurons communicate with one another by using which two types of electrical signals?

A
Action potentials (nerve impulses), for both short and
long distance communication within the body.  This is “all-or-none” 

Graded potentials, for short-distance (localized) communication only. The physiological role of graded potentials is to affect (and effect) the generation of action potentials. This is NOT “all-or-none”

117
Q

Neuronal signals: Both types of signal depend on which two features of the plasma membrane of excitable cells?

A

– Existence of a resting membrane potential

– Presence of specific ion channels

118
Q

Are there more specific leakage channels for K+ or for Na+

A

K+

119
Q

Is the resting membrane is
more permeable to K+ or to
Na+

A

K+

120
Q

The resting membrane potential is due to a small buildup of anions in the cytosol just inside the membrane, and an equal buildup of cations in the extracellular fluid just outside the membrane

A

Equal numbers, but on opposite the membrane, sides!

121
Q

higher sodium and Cl where

A

ECF

122
Q

Higher K, organic phosphates, amino acids, proteins where?

A

ICF

123
Q

The resting membrane is 50 to 100 times more

permeable to ___ than to ____

A

K+ than to Na+

124
Q

Cl- permeability is in between that of Na+ and K+

A

True dat

125
Q

The membrane is impermeable to nearly all of the negatively charged intracellular molecules

A

True dat times two

126
Q

▪ K+ diffuses down its concentration gradient out of the cell

▪The intracellular negatively charged ions are left behind
because they can’t get through the membrane

▪The interior of the membrane becomes negatively
charged; the exterior becomes positively charged; net
diffusion of K+ stops (electrochemical equilibrium)

▪Na+ diffuses into the cell but at a much lower rate than
K+ diffuses out because the membrane is less permeable
to Na+

▪A little Cl - diffuses into the cell, also making the interior
more negative

▪Net result: the resting membrane potential

A

ESTABLISHING THE RESTING MEMBRANE POTENTIAL

127
Q

▪___ or ____ gated ion channels produce graded potentials in response to stimuli

▪_____ means the size of the change in the membrane potential varies in proportion to the strength of the stimulus (not all-or-none)

▪Local effects only: channels open, current flows through the membrane and along the membrane, and travels only a short distance before diminishing to zero

A

GRADED POTENTIALS

▪Ligand-gated or mechanically gated ion channels produce graded potentials in response to stimuli

▪“Graded” means the size of the change in the membrane potential varies in proportion to the strength of the stimulus (not all-or-none)

▪Local effects only: channels open, current flows through the membrane and along the membrane, and travels only a short distance before diminishing to zero

128
Q

A graded potential can either ____ the membrane or ____the membrane

A

depolarize

hyperpolarize

129
Q

membrane becomes more polarized (more negative)

A

hyperpolarization

130
Q

membrane becomes less polarized (less negative or more positive)

A

–Depolarization:

131
Q

difference between graded potentials and action potentials?

A

▪graded potentials are a localized phenomenon, and do not travel far before being attenuated, once an action potential is generated it travels the length of the neuron and can initiate an action potential in subsequent neurons, muscles, or glands

▪Action potentials are all-or-none

132
Q

▪_____ accompanies opening of voltage-gated Na+ channels. Stimulus causes depolarization to threshold (-55 mV)

▪_____ accompanies opening of voltage-gated K+ channels and closure of Na+ channels

A

Depolarization

Repolarization

133
Q

– ___ has both Na+ and K+ voltage- gated channels closed

– ____ has Na+ gates open

– ______ accompanied by K+ gates open and Na+
gates closed or closing

– Resting state restored finds K+ gates closed

A

Resting state

Depolarization

Repolarization

134
Q

▪The _____ progresses sequentially down the
length of the axon

▪The _____ measured at a fixed point on the axon varies with time as the action potential transits the point

A

action potential

voltage

135
Q

CALCIUM ION DEFICIT

▪______ appear to bind to the exterior surfaces of the sodium channel protein molecule.

▪The _____ charges of the calcium ions alter the electrical state of the channel protein, increasing the voltage level required to open the gate.

▪Absent the bound calcium ions, ____ than normal voltages are required for gate activation.

A

Calcium ions

positive

smaller

136
Q

CALCIUM ION DEFICIT

▪Calcium ion concentration in the _____ therefore has an effect on the voltage level at which sodium channels become activated.

▪When there is a deficit of calcium ions, the sodium channels become ______ by very little change of the membrane potential from its normal resting level.

▪The nerve fiber then becomes ___ ____, sometimes discharging repetitively without provocation, rather than remaining in the resting state.

A

extracellular fluid

activated (open)

highly excitable

137
Q

_____ is associated with muscle contraction, cramps, and even tetany, which can be lethal because of tetanic contraction of the respiratory muscles

A

low blood calcium

138
Q

Propagation of nerve impulses

▪Nerve impulses must travel from where they arise at a trigger zone (typically the axon hillock) down the neuron to the axon terminals.

▪That movement is called _________

▪Propagation depends on ______ feedback

A

propagation, or conduction

positive

139
Q

Positive feedback of propagation

▪The inflow of _____ ions causes depolarization that opens voltage-gated Na+ channels in adjacent segments of the membrane

▪Those in turn allow in sodium ions, causing that segment to _____, and so on down the axon

A

sodium

depolarize

140
Q

Explain the function of dendrites:

A

Receive stimuli through activation of ligand-gated or mechanically-gated ion channels. In sensory neurons produces generator or receptor potential. In motor neurons and interneurons produces excitatory and inhibitory postsynaptic potentials

141
Q

Explain the function of the cell body:

A

Receives stimuli and produces EPSPs and IPSPs through activation of ligand-gated or mechanically gated ion channels

142
Q

Explain the function of the Junction of the axon hillock and initial segment of axon:

A

Trigger zone in many neurons

integrates ESPSs and IPSPs— if sum is depolarization that reaches threshold, initiates action potential (nerve impulse)

143
Q

Explain the function of the axon:

A

Propagates (conducts) nerve impulses to axon terminals in a self- reinforcing manner. Impulse amplitude does not change as it propagates along the axon

144
Q

Explain the function of the axon terminals and synaptic end bulbs (varicosities):

A

Inflow of Ca2+ caused by depolarizing phase of nerve impulse triggers exocytosis of neurotransmitters from synaptic vesicles

145
Q

Types of conduction

▪Step-by-step depolarization and repolarization of adjacent segments is termed ______.

▪______ is a special mode of impulse propagation that occurs along myelinated axons

A

continuous conduction.

Saltatory conduction

146
Q

Saltatory conduction

▪Only in ______

▪Voltage-gated channels are concentrated at _______, with few in regions where the myelin sheath covers the ______

▪______ is carried by extracellular and intracellular ions from one node to the next, and the nodes depolarize and repolarize as previously discussed

A

myelinated axons

nodes of Ranvier; axolemma

Electric current

147
Q

▪ Saltatory conduction is much ____ than continuous conduction

▪ It is also more energy efficient, requiring less ____ to repolarize

A

faster

ATP

148
Q

Metabolism

▪Neurons produce virtually all their ATP via _____ of glucose

▪This process requires large amounts of ____, so the nervous system requires a high blood flow, and is consequently highly vascularized

▪Alternative—and very minor—sources of energy for neurons are ______, ____, and ____.

A

aerobic metabolism

oxygen

ketones, medium chain fatty acids, and possibly amino acids

149
Q

Metabolism

▪Most of the brain’s energy consumption goes into
sustaining the __________

▪The majority of vertebrate species devote between 2% and 8% of basal metabolism to the brain. It is higher in primates, and in humans it rises to 20% to 25%

A

electric charge of neurons

150
Q

The greater the diameter of the axon, the faster the conduction will be (less resistance to the flow of ions through the axoplasm)

▪ __ fibers
– Large diameter
– Myelinated
– Conduct at about 100 meters/second (around 200 miles per hour)

▪__ fibers
– Medium diameter
– Myelinated
– Conduct at about 15 meters/second (around 32 miles per hour)

▪__ fibers
– Small diameter
– Unmyelinated
– Conduct at about 1 meter/second (around 3 miles per hour)

A

▪ A fibers
– Large diameter
– Myelinated
– Conduct at about 100 meters/second (around 200 miles per hour)

▪B fibers
– Medium diameter
– Myelinated
– Conduct at about 15 meters/second (around 32 miles per hour)

▪C fibers
– Small diameter
– Unmyelinated
– Conduct at about 1 meter/second (around 3 miles per hour)

151
Q

Perceiving stimulus intensity

▪Since all nerve impulses are the same size, there would not seem to be a way to distinguish between stimuli of different magnitudes

▪Two mechanisms enable stimuli of differing intensities to be registered as such ________

A

– Frequency of impulses

– Number of sensory neurons activated (recruited)

152
Q

Example of intensity perception (using touch)

▪Frequency of impulses
– A light touch generates a _____ of widely spaced nerve impulses
– A firm pressure causes nerve impulses to go down the axon closer together (i.e. at a higher frequency)

▪Number of sensory neurons recruited
– A light touch stimulates only a few pressure sensitive neurons
– A firm pressure stimulates more pressure sensitive neurons

A

low frequency

153
Q

Stimulus strength and generation of action potential

▪No action potential is generated by a ___ stimulus.

▪Several action potentials result from a ____
stimulus, yet each has the same amplitude. This is perceived as a stronger stimulus.

A

subthreshold

suprathreshold