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NEUR 2610 > Chapter 3: The Nervous System's Functional Units > Flashcards

Chapter 3: The Nervous System's Functional Units Flashcards

1
Q

where did the theory of the neuron emerge from?

A

controversy between Golgi and Ramon y Cajal

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2
Q

how did Golgi stain tissue?

A

immerse thin slice of brain tissue in solution w/ silver nitrate

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3
Q

what did Golgi’s staining suggest?

A

the nervous system is an interconnected network of fibres

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4
Q

Golgi thought information flowed around a ___, and so produced ___

A

nerve net (like water running thru pipes), behaviour

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5
Q

Ramon y Cajal used Golgi’s stain to study

A

chick embryos’ brain tissue

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6
Q

what did Cajal conclude about the nervous system?

A
  • made up of discrete cells that begin life as a rather simple structure, becomes more complex w/ age
  • when mature, each cell has a main body w/ many extensions projecting from it
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7
Q

who’s neuron theory is now accepted?

A

Cajal’s

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8
Q

the ___ neurons an animal has, the ___ complex its behaviour

A

more, more

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9
Q

we can implant tiny microscopes called ___ or ___ into the brain to view the structure and activity of its ___

A

endoscopes, microendoscopes, neurons

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10
Q

research has confirmed ___ nerve net, a covering called a ___ that forms around neurons as they mature

A

Golgi’s, perineuronal net

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11
Q

soma

A

cell body

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12
Q

what collects information from other cells?

A

dendrites

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13
Q

what would carry messages to other neurons?

A

axon

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14
Q

a neuron only has one ___, but may have many ___

A

axon, dendrites

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15
Q

dendrites ___ info, the soma ___ info, the axon ___ info

A

collect, integrates, passes

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16
Q
A

a. axon from another neuron
b. dendrites
c. soma (cell body)
d. nucleus
e. axon
f. axon collateral
g. teleodendria
h. terminal button (end foot)
i. dendrites from another neuron

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17
Q

the human nervous system contains ___ neurons and ___ glial cells

A

86 billion, 87 billion

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18
Q

neurons regulate body processes such as

A

breathing, heartbeat, body temperature

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19
Q

functional groups of neurons called ___ connect wide areas of the ___

A

neural networks, brain & spinal cord

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20
Q

in what ways are neurons “active”?

A
  • making/losing branches
  • making/losing connections w/ each other
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21
Q

the dynamic activity of the neuron underlies both the constancies and changes in our ___

A

behaviour

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22
Q

a neuron’s ___ is increased immensely by its extensions into dendrites and axon

A

surface area

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23
Q

a neuron may have up to ___ dendrites

A

20

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24
Q

juncture of soma + axon

A

axon hillock

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25
Q

branch of an axon

A

axon collaterals

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26
Q

axon collaterals may divide into multiple smaller branches called

A

telodendria

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27
Q

at the end of each telodendrion is a knob called a

A

terminal button (end foot)

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28
Q

the terminal button does not ___ a dendritic spine, this near-connection is called a

A

touch, synapse

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29
Q

a synapse includes

A
  • surface of end foot
  • surface of neighbouring dendritic spine
  • space between
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30
Q

the general shape of a neuron suggests it works in a similar way to a

A

river

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31
Q

conduct information from sensory receptors in/on the body into the spinal cord + brain

A

sensory neurons

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32
Q

associate sensory + motor activity in CNS

A

interneurons

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33
Q

carry info from brain + spinal cord out to the body’s muscles

A

motor neurons

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34
Q

sensory neurons

A
  1. bipolar neuron (retina)
  2. somatosensory neuron (skin/muscle)
    a) dendrite
    b) axon
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35
Q

interneurons

A
  1. stellate cell (thalamus)
  2. pyramidal cell (cortex)
  3. purkinje cell (cerebellum)
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36
Q
A
  1. motor neuron (spinal cord)
    a) dendrites
    b) axon
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37
Q

structurally the simplest of the 3 types of neurons

A

sensory neurons

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38
Q

a ___ has a single short dendrite one one side of its soma, and a single short axon on the other

A

bipolar neuron

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39
Q

bipolar neurons transmit ___ info from the ___ to the neurons that carry info into the brain’s ___

A

afferent/incoming sensory, retina’s light receptors, visual centres

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40
Q

brings sensory information from the body into the spinal cord

A

somatosensory neuron

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41
Q

the ___ dendrite connects directly to its axon, so the cell body sits to the side of this long pathway

A

somatosensory

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42
Q

association cells

A

interneurons

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43
Q

a small interneuron w/ many dendrites extending around the cell body

A

stellate (star-shaped) cell

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44
Q

what is one of the main reason brain sizes vary between species?

A

there are many more interneurons in larger brains than smaller, giving a correlation between interneuron # and behavioural complexity

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45
Q
  • long axon
  • pyramid-shaped cell body
  • two sets of dendrites
A

pyramidal cell

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46
Q

distinctive interneuron w/ extremely branched dendrites that form a fan shape

A

purkinje cell

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47
Q
  • extensive dendritic networks
  • large cell bodies
  • long axons that connect to muscle
A

motor neurons

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48
Q

all efferent/outgoing neural info must pass thru ___ to reach muscles

A

motor neurons

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49
Q

3 functions/features of neuronal networks

A

input, association, output

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50
Q

___ carry info to distant parts of the nervous system, while ___ are engaged in local processing

A

long extensions, short extensions

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51
Q

somatosensory neurons can send information over more than ___

A

2 metres

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52
Q

pyramidal neurons must reach from the cortex to the lower spinal cord, which can be as long as ___

A

1 metre

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53
Q

each neuron receives up to ___ of excitatory + inhibitory signals every second

A

thousands

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54
Q

how does a neuron pick which input to use?

A

it sums them all up, follows whichever input exceeds the other

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55
Q

AI is based on the principles of

A

nervous system function

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56
Q

Barbara Webb constructed a

A

cricket robot

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57
Q

___ parts are constructed to mimic parts of a human body

A

anthropomimetic robots

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58
Q

glial cells help neurons by

A
  • binding them together
  • providing support, nutrients, protection
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59
Q

5 types of glial cells

A
  1. ependymal cell
  2. astrocyte
  3. microglial cell
  4. oligodendroglial cell
  5. schwann cell
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60
Q

small ovoid, secretes CSF

A

ependymal cell

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61
Q
  • star-shaped
    contributes to
  • neuronal nutrition, support + repair
  • forming blood-brain barrier
  • healing scarring after injury
A

astrocyte

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62
Q

small, derived from blood, defensive function to remove dead tissue

A

microglial cell

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63
Q

forms myelin around CNS axons in brain + spinal cord

A

oligodendroglial cell

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64
Q

wraps around peripheral nerves to form myelin

A

schwann cell

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65
Q

errors in ___ replication are a main source of ___

A

glial cell, brain tumors/abnormal growths

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66
Q

an uncontrolled growth of new tissue that is independent of surrounding structures

A

tumor

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67
Q

incidence of brain tumors in the US is ___ according to CBTR

A

20 per 100,000

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68
Q

in adults, brain tumors grow from ___, but in infants they may grow from ___

A

glia/supporting cells, developing neurons

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69
Q

___ are not likely to recur after removal

A

benign tumors

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70
Q

___ are likely to progress + invade other tissue, and apt to recur after removal

A

malignant tumors

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71
Q

3 major types of brain tumors

A
  1. gliomas (from glial cells)
  2. meningiomas (attached to meninges)
  3. metastatic tumors (cells transfer regions)
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72
Q
  • found on the walls of ventricles
  • produce/secrete CSF
A

ependymal cells

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73
Q

functions of CSF

A
  • shock absorber for brain
  • carries away waste products
  • assist constant brain temperature
  • source of nutrients for parts of brain
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74
Q

hydrocephalus is the buildup of fluid pressure in the brain and, in infant, swelling of the head, due to the ___; can cause severe intellectual impairment

A

flow of CSF being blocked

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75
Q
  • provide structural support to CNS
  • extensions attach to blood vessels + brain’s lining, forming a scaffolding that holds neurons in place
  • provide pathways for nutrients to move between blood vessels + neurons
  • secrete chemical that keep neurons healthy + help them heal if injured
  • contribute to blood-brain barrier
A

astrocytes

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76
Q

protective partition between blood vessels + the brain formed by tight junctions between the cells that compose blood vessels in the brain, prohibits entry of certain substances like toxins into the brain

A

blood-brain barrier

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77
Q
A

a. astrocyte
b. blood vessel
c. blood vessel cells
d. astrocyte end feet
e. tight junctions
f. myelinated axon
g. neuron

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78
Q

why are brain infections difficult to treat?

A

many useful drugs cannot pass thru the blood-brain barrier

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79
Q

how do astrocytes enhance brain activity?

A

pass along signals from neurons to blood vessels to increase blood flow + fuel supply in response to a behaviour

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80
Q

how do astrocytes contribute to the healing of damaged brain tissue?

A

form a scar to seal off the damaged area

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81
Q
  • originate in the blood as an offshoot of immune system
  • migrate thru nervous system
  • make up 20% of all glial cells
A

microglia

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82
Q

how do microglia play an important role in monitoring/maintaining the health of brain tissue?

A
  • identify + attack foreign tissue
  • invade damaged areas to provide growth factors that aid in repair
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83
Q

___ engulf any foreign tissue + dead brain cells, an immune process called ___

A

microglia, phagocytosis

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84
Q

a characteristic of Alzheimer disease, a degenerative brain disorder commonly associated w/ aging, is:

A

the deposit of distinctive bodies called plaques in regions of damage

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85
Q

microglia may play a harmful role in Alzheimers by

A

consuming inflamed tissue rather than protecting it

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86
Q

___ interact w/ astrocytes in brain healing

A

microglia

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87
Q

which 2 glial cells insulate neuronal axons?

A
  1. oligodendroglia
  2. schwann cells
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88
Q

myelinated neurons send information ___ than neurons without myelin

A

much faster

89
Q

neurons that send messages over long distances quickly, like __, are ___ to increase their messaging speed

A

sensory and motor neurons, heavily myelinated

90
Q

oligodendroglia myelinate axons in the brain + spinal cord by

A

sending out large, flat branches that enclose + separate adjacent axons

91
Q

schwann cells myelinate axons in the PNS by

A

wrapping itself repeatedly around a part of an axon, forming a structure somewhat like beads on a string

92
Q

in addition to myelination, schwann cells and oligodendroglia contribute to a neuron’s nutrition + functioning by

A
  • absorbing chemicals the neuron releases
  • releasing chemicals the neuron absorbs
93
Q

multiple sclerosis (MS) is associated w/ damage to the ___ that leaves a _, rather than myelin, on neurons in nervous system pathways, resulting in ___ , producing ___

A

oligodendroglia, scar, information flow impairment, impaired movement + cognitive function

94
Q

loss of both movement + sensation

A

paralysis

95
Q

___ participate in repairing damage to the peripheral nervous system

A

microglia + schwann cells

96
Q

neuron repair

A
  1. when peripheral axon is cut, the axon dies
  2. schwann cells shrink, then divide, forming glial cells along the axon’s former path
  3. neuron sends out axon sprouts, one of which finds the schwann cell path + becomes a new axon
  4. schwann cells envelop the new axon, forming new myelin
97
Q

when the CNS is damaged, does regrowth and repair occur?

A

no

98
Q

why may regrowth/repair in CNS not occur?

A

as neural circuits mature, they become finely tuned to mediate individualized behaviour + develop chemical strategies that prevent the proliferation of new cells or regrowth of existing cells

99
Q

a cell’s ___ determine its characteristics + functions

A

proteins

100
Q

a cell’s ___ separates the cell from its surroundings + allows it to regulate what enters/leaves its domain

A

cell membrane

101
Q

nerve cell

A

a. dendrite
b. dendritic spine
c. nucleus
d. nuclear membrane
e. mitochondrion
f. endoplasmic reticulum
g. intracellular fluid
h. tubule
I. cell membrane
j. axon
k. golgi body
l. lysosomes
m. microfilaments

102
Q

very few substance can enter/leave a cell spontaneously because

A

the cell membrane is virtually impermeable

103
Q

proteins embedded in the cell membrane facilitate:

A

transport of substances in/out of the cell

104
Q

what happens inside the nucleus?

A

genetic blueprints for proteins are stored, copied, and sent to the ER

105
Q

structure that gathers, stores, and releases energy

A

mitochondrion

106
Q

folded layers of membrane where proteins are assembled

A

endoplasmic reticulum

107
Q

tiny tube that transports molecules + helps give the cell its shape

A

tubule

108
Q

membranous structure that packages protein molecules for transport

A

golgi body

109
Q

sacs containing enzymes that break down wastes

A

lysosomes

110
Q

threadlike fibres making up much of the cell’s “skeleton”

A

microfilaments

111
Q

more ___ are found in old cells vs. new ones

A

lysosomes

112
Q

the cell membrane regulates the differing concentrations of ___ on its inner/outer sides

A

salts + other chemicals

113
Q

what allows cell membranes to regulate water + salt concentrations?

A

phospholipids

114
Q

phospholipid heads are ___, and the lipid tails are ___

A

polar + hydrophilic, hydrophobic

115
Q

what can traverse a phospholipid bilayer?

A

small molecules such as
- oxygen
- CO2
- sugar glucose

116
Q

segments of DNA that encode the synthesis of particular proteins

A

genes

117
Q

genes are contained within ___, which are ___

A

chromosomes, double-helix structures that hold an organism’s DNA library

118
Q

what happens when chromosomes change shape to occupy the best location in the nucleus?

A

they expose different genes to the surrounding fluid, allowing the gene to begin the process of making a protein

119
Q

a human somatic/body cell has __ of chromosomes, or ___ in all

A

23 pairs, 46

120
Q

each chromosome is a double-stranded molecule of

A

deoxyribonucleic acid (DNA)

121
Q

4 nucleotide bases

A

(A) adenine
(T) thymine
(G) guanine
(C) cytosine

122
Q

_ always pairs with T, _ always pairs with C

A

A; G

123
Q

how are the 2 strand of the DNA helix bound together?

A

by the attraction between the 2 bases in each pair

124
Q

sequences of ___ within the chromosomes spell out the genetic code

A

hundreds of nucleotide bases

125
Q

the sequence of base pairs spell out the order in which ___ should be assembled to construct a certain ___

A

amino acids (the constituent molecules of protein); protein

126
Q

2 steps of transcription

A
  1. DNA uncoils to expose a gene, a sequence of nucleotide bases that encodes a protein
  2. 1 strand of the gene serves as a template for transcribing a molecule of mRNA
127
Q

what is different about RNA vs. DNA?

A

RNA has the base uracil (U) instead of thymine (T)

128
Q

the transcribed strand of RNA is called ___ because ___

A

messenger RNA (mRNA); it carries the protein code (message) out of the nucleus to the ER

129
Q

a distinguishing feature of the ER is that it may be studded with ___, which are ___

A

ribosomes; protein structures that act as catalysts to facilitate the building of proteins

130
Q

when mRNA reaches the ER, it passes thru a ___, where its ___

A

ribosome; genetic code is read

131
Q

2 steps of translation

A
  1. the mRNA leaves the nucleus + comes into contact w/ ribosomes in the ER
  2. as a ribosome moves along the mRNA, it translates the bases -> amino acid chain = protein
132
Q

what does transfer RNA (tRNA) do?

A

assists in translating nucelotide bases into amino acids

133
Q

___ encodes one particular amino acid

A

each group of 3 consecutive nucleotide bases along an mRNA

134
Q

what 3 bases encode the amino acid tryptophan (Trp)?

A

UGG

135
Q

what 3 bases encode the amino acid phenylalanine (Phe)?

A

UUU

136
Q

the sequence of ___ determines the sequence of the resulting amino acid chain

A

codons on the mRNA strand

137
Q
A

a. template strand
b. DNA
c. mRNA
d. codon
e. polypeptide chain
f. amino acids

138
Q

humans utilize __ different amino acids

A

20

139
Q

amino acid chemical structure

A

a central carbon (C), bound to:
- a hydrogen atom (H)
- an amino group (NH3+)
- a carboxyl group (COO-)
- a side chain (R)

140
Q

each amino group is bound to the carboxyl group (COO-) by a ___, which gives the amino acid chain the alt name of ___

A

peptide bond; polypeptide chain

141
Q

summary of info flow driven by the genetic code

A

gene transcribed into mRNA -> ribosomes translate it into a chain of amino acids (polypeptide chain) = forms a protein

142
Q

folded-up polypeptide chain that serves a particular function in the body

A

protein

143
Q

primary structure

A

amino acid chain

144
Q

secondary structure

A

pleated sheet or helix

145
Q

tertiary structure

A

protein

146
Q

quaternary structure

A

complex protein

147
Q
A

a. primary
b. secondary
c. tertiary
d. quaternary

148
Q

any one neuron contains up to ___ genes, and they can produce as many as ___ different protein molecules

A

20,000; 20,000

149
Q

the # of proteins that can ultimately be made by a neuron is far ___ than the # of its genes

A

larger

150
Q

a protein’s ___ and ___ are central to its function

A

shape; its ability to change shape/combine w/ other proteins

151
Q

2 steps of protein export

A
  1. proteins formed in ER enter Golgi bodies, then wrapped in a membrane + given a shipping address
  2. each protein package is attached to a motor molecule + moves along a microtubule to its destination
152
Q

3 membrane proteins

A
  1. channels
  2. gates
  3. pumps
153
Q

a protein’s ability to change shape is analogous to

A

a lock in a door - needs the right key

154
Q

small molecules can bind to a protein’s ___ and cause the protein to change shape

A

receptors

155
Q

changes in shape allow the proteins to ___

A

serve a new function

156
Q

how does a protein channel work?

A

an opening lets specific ions thru based on size

157
Q

how does a protein gate work?

A

it changes shape to allow the passage of substances when the gates are open, and prevents passage when they are closed

158
Q

how does a protein pump work?

A

the pump transporter changes shape to carry substances across the membrane

159
Q

whose research led to the concept of the gene?

A

Gregor Mendel

160
Q

what is the objective of epigenetics?

A

to study how the environment influences gene expression

161
Q

chromosome pairs are numbered from 1-23, according to ___, with chromosome 1 being the ___

A

size; largest

162
Q

chromosome pairs 1-22 are called ___ because ___

A

autosomes; they contain the genes that contribute most to our physical appearance + behaviour

163
Q

the 23rd pair of chromosomes are called the ___ which ___

A

sex chromosomes; contribute to our physical/behavioural sexual characteristics

164
Q

the Y chromosome contains the ___, which triggers ___

A

SRY (sex-determining region) gene; testes development

165
Q

two copies of a gene

A

alleles

166
Q

two identical nucleotide sequences in a pair of alleles

A

homozygous

167
Q

two different nucleotide sequences in a pair of alleles

A

heterozygous

168
Q

the nucleotide sequence most common in a population is called the ___, while a less frequently occurring sequence is called a ___

A

wild-type allele; mutation

169
Q

if both alleles are homozygous, they encode ___

A

the same protein

170
Q

if both alleles are heterozygous, they encode ___

A

somewhat different proteins

171
Q

3 possible outcomes from the heterozygous condition when their proteins express a physical/behavioural trait

A
  1. only the allele from mother may be expressed
  2. only the allele from father may be expressed
  3. both alleles may be expressed simultaneously
172
Q

an member of a gene pair that is routinely expressed

A

dominant allele

173
Q

an unexpressed allele

A

recessive allele

174
Q

in complete dominance, ___ is expressed in the phenotype

A

only the allele’s own trait

175
Q

in incomplete dominance, ___ expressed

A

the allele’s own trait is partially

176
Q

in codominance, ___ expressed

A

both the allele’s own train + that of the other allele is completely

177
Q

a mutation may be as small as

A

a change in 1 single nucleotide base = single nucleotide polymorphism (SNP)

178
Q

more than ___ mutations of the breast cancer gene (BRCA1) have been found

A

1000

179
Q

is a mutation always bad?

A

a mutation can be beneficial, disruptive, or both

180
Q

what is the most common genetic blood disease, affecting 80,000 US citizens

A

sickle-cell anemia

181
Q

what causes sickle-cell anemia?

A

a SNP on chromosome 11 where T is substituted for an A base in the HBB (hemoglobin) gene

182
Q

why does it make sense that neurons can get mutations?

A

most neurons are with us/are metabolically active for life!

183
Q

at 1 year of age, a neuron may have up to ___ mutations, but by 80 it may have as many as ___ mutations

A

300-900; 2000

184
Q

despite our genome being inherited from our parents, it actually ___ as we develop and age

A

gets modified a lot

185
Q

Gregor Mendel introduced dominant + recessive alleles thru the use of

A

pea plants

186
Q

what is Tay-Sachs disease?

A

inherited birth defect, appears 4-6 months after birth, results in intellectual disability, physical changes, and death by age 5

187
Q

what causes Tay-Sachs disease?

A

dysfunction in the HEXA gene on chromosome 15 = lipids accumulate in brain cells = cell damage

188
Q

to have Tay Sach’s disease, ___ must carry the mutation

A

both parents

189
Q

hereditary disease characterized by chorea (ceaseless involuntary jerky movements) and progressive dementia, ending in death

A

Huntington disease

190
Q

how does Huntington disease work?

A

buildup of an abnormal version of the huntingtin protein kills brain cells, esp in basal ganglia + cortex

191
Q

to get Huntington disease, __ must carry the allele

A

only one parent

192
Q

the HTT (huntingtin) gene is found on chromosome _, where part of the gene contains repeats of the base sequence ___

A

4; CAG

193
Q

aberrations in a part of a chromosome/an entire chromosome

A

copy number variation

194
Q

copy number variations are related to disorders such as

A
  • autism
  • schizophrenia
  • learning disabilities
195
Q

chromosomal abnormality resulting in intellectual impairment + other abnormalities, usually caused by an extra chromosome 21

A

Down syndrome

196
Q

how does one get Down syndrome?

A

one parent (usually mom) passes on 2 copies of chromosome 21 - this combined with 1 from dad = trisomy

197
Q

3 techniques of genetic engineering

A
  1. selective breeding
  2. cloning
  3. transgenics
198
Q

how has selective breeding influenced the dog brain?

A
  • made it smaller than a wolf’s
  • larger # of cortical neurons
199
Q

how do scientists clone animals like Dolly the sheep?

A
  • cell nucleus w/ DNA is placed in an egg cell that had its nucleus removed
  • egg stimulated to start dividing
  • implant new embryo in uterus of a female
200
Q

transgenic technology allows scientists to

A

introduce genes into an embryo OR remove genes from it

201
Q

___ is used when 1+ genes from one species is added to the genome of another species, passed along, and expressed in subsequent generations, creating ___

A

knock-in technology; transgenic animals

202
Q

___ is used to inactivate a gene so that a line of lab animals fail to express it

A

knockout technology

203
Q

our phenotypic plasticity is due to

A
  • the genome’s capacity to express a large # of phenotypes
  • epigenetics/the influence of environment + experience on phenotypic expression
204
Q

incidence of similar behavioural traits

A

concordance

205
Q

the concordance rate between identical twins for an array of diseases such as ___, is between ___

A

schizophrenia, Alzheimer’s, MS, Chron’s, asthma, diabetes, prostate cancer; 30-60%

206
Q

epigenetic mechanisms create ___ without ___

A

phenotypic variation; altering the base pair nucleotide sequence of the genes

207
Q

chromosomes are wrapped around supporting molecules of a protein called

A

histone

208
Q

for any gene to be transcribed into mRNA, its DNA must be ___, then the gene must be ___, then the mRNA must be ___

A

unspooled from the histone, instructed to transcribe mRNA, translated into an amino acid chain that forms the protein

209
Q

3 epigenetic mechanisms

A
  1. histone modification
  2. gene (DNA) methylation
  3. mRNA modification
210
Q

histone modification

A

a methyl group/other molecules bind to the tail of histones, either blocking them from opening or allowing them to open for transcription

211
Q

gene (DNA) methylation

A

methyl groups bind to CG base pairs to block transcription

212
Q

mRNA modification

A

ncRNA (noncoding) binds to mRNA, preventing translation

213
Q
A

a. histone modification
b. gene (DNA) methylation
c. mRNA modification

214
Q

who found that individuals’ nutritional experiences can affect their offspring’s health?

A

Lars Olov Bygren

215
Q

what was interesting about Bygren’s findings?

A

the descendants of individuals who have plenty of food had higher rates of cardiovascular disease, diabetes, and a life expectancy of 7 years shorter vs. the famine group

216
Q

what scan is used for MS?

A

MRI

217
Q

in the 1950’s, what microscope was used for synapse discovery?

A

electron microscope

218
Q

easiest tumor to remove

A

meningiomas

219
Q

Huntington vs. Parkinson disease

A

Huntington: more jerky movement + cognitive/psychological symptoms
Parkinson: rigidity/slowed movements

NEUR 2610 (8 decks)

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