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BMS 521 > Exam 3 > Flashcards

Exam 3 Flashcards

1
Q

What binds to start signal transduction by RTKs?

A

a protein with SH2 domain to a tyrosine on the receptor

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2
Q

What is the Ras family composed of?

A

small G-protiens

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3
Q

What drives over 30% of all human cancers?

A

Ras genes

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4
Q

How do signals pass from activated Ras?

A

Ras to Raf to MEK to MAPK

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5
Q

What regulates the activity of many transcription factors that control early response genes?

A

MAP kinase (MAPK)

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6
Q

In unstimulated cells, where is PKB?

A

cytosol

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7
Q

In unstimulated cells, what inhibits PKB activity?

A

catalytic kinase domain bound to pH domain of PKB

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8
Q

What leads to the activation of PI-2 kinase & PKB?

A

hormone stimulation

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9
Q

Disrupted JAK/STAT signaling can lead to what diseases?

A

skin conditions, cancer, immune system disorders

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10
Q

What are cytokines important in?

A

cell signaling

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11
Q

Examples of cytokines?

A

chemokines
interferons
interleukins
lymphokines
tumor necrosis factors
transforming growth factor

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12
Q

How can the same signal induce different responses in different cells?

A

different types of cells have different collections of proteins that lead to different cellular events
ex. epinephrine simulates liver for breakdown of glycogen but stimulates heart to contract faster

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13
Q

What causes termination of the cell signal?

A
  1. concentration of signal decreases
  2. G-protein hydrolyzes
  3. cAMP to AMP
  4. phosphorylated kinases inactivated
  5. GRK desensitizes receptors
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14
Q

4 phases of the cell cycle

A
  1. G1 (gap stage 1)
  2. S (synthesis)
  3. G2 (gap stage 2)
  4. M (mitosis)
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15
Q

What drives cell cycle progression and initiates centrosome splitting?

A

CDK

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16
Q

What drives CDK activity?

A

positive & negative feedback loops

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17
Q

What guarantees each cell cycle step is completed correctly before going to the next step?

A

checkpoint pathway surveillance mechanisms

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18
Q

How do cells reproduce?

A

cell division

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19
Q

How do cells produced from mitosis look?

A

identical to their parent

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20
Q

How do cells produced from meiosis look?

A

have half the genetic content of the parent

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21
Q

3 main features of cell cycle

A
  1. cell growth & DNA replication
  2. chromosome segregation
  3. cell division
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22
Q

What cells lack the ability to divide?

A

nerve, muscle & red blood cells

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23
Q

What cells have a high level of mitotic activity?

A

stem cells

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24
Q

What cells can be induced to begin DNA synthesis?

A

liver cells & lymphocytes

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25
Q

Which cell cycle phase is the shortest?

A

mitotic

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26
Q

What is cytokinesis & when does it happen?

A

formation of 2 daughter cells; in M phase

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27
Q

What is the interphase?

A

period between M phases
includes G1 & G2 and S-phase

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28
Q

What are G0 cells & where do they exist?

A

cells with no ability to receive signals to initiate division; G1 stage

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29
Q

G1 phase

A

first stage within interphase
runs from M phase until the beginning of DNA synthesis

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30
Q

S phase

A

second stage within interphase
DNA synthesis & chromosome/centrosome replication

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31
Q

G2 phase

A

third stage within interphase
lasts until cell enters mitosis

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32
Q

M phase

A

duplicated chromosomes separate into 2 nuclei, cytokinesis happens

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33
Q

What is a centrosome?

A

move to opposite ends of the cells during division
work with microtubules to assemble a spindle

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34
Q

What are kinetochores?

A

near the centromere of the chromosome, where the spindle attaches

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35
Q

What aligns sister chromatid pairs in the spindle?

A

kinetochore-associated tension-sensing mechanism

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36
Q

What are the stages of mitosis

A

interphase
prophase
prometaphase
metaphase
anaphase
telophase
cytokinesis

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37
Q

What happens during interphase?

A

chromosome/centrosome duplication & cohesion

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38
Q

What happens during prophase?

A

chromosomes condense, nuclear envelope breaks down, formation of mitotic spindle apparatus, kinetochore assembles

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39
Q

What happens during prometaphase?

A

spindle microtubules attache to kinetochores and center the sister chromatid pairs

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40
Q

What happens during metaphase?

A

chromosomes align at the metaphase plate

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41
Q

What happens during anaphase?

A

spindle microtubules shorten, sister chromatids pulled towards opposite sides

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42
Q

What happens during telophase?

A

each daughter cell reassembles a nuclear membrane

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43
Q

What happens during cytokinesis?

A

cells fully separate
contractile ring forms cleavage furrow to split the cell

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44
Q

3 classes of microtubules

A
  1. astral (project towards cortex/outside)
  2. kinetochore (connected to chromosomes)
  3. polar (project towards center)
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45
Q

What are the model organisms for studying cell cycle?

A

saccharomyces cervisiae
schizosaccharomyces pombe
xenopus laevis
drosophila melanogaster

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46
Q

Where are the major checkpoints?

A
  1. G1 checkpoint
  2. G2 checkpoint
  3. mitotic checkpoint
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47
Q

What are the checkpoint proteins?

A

CDK
protein phosphatases
ubiquitin-protein ligases

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48
Q

What does the activity of CDK depend on?

A

cyclins

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49
Q

What cyclin-CDK complexes promote entry into cell cycle?

A

G1 cyclin-CDK
G1/S phase cyclin-CDK

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50
Q

What cyclin-CDK complex triggers S phase

A

S phase cyclin-CDK

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51
Q

What cyclin-CDK complex initiates mitosis?

A

mitotic cyclin-CDK

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52
Q

How can you regulate CDKs?

A
  1. cyclin binding
  2. CDK phosphorylation
  3. CDK inhibitors
  4. controlled proteolysis
  5. sub cellular localization
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53
Q

What cyclins can CDK1 act on?

A

cyclins A & B
for mitosis

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54
Q

What cyclins can CDK2 act on?

A

cyclins E & A
for entry into cell cycle & S phase

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55
Q

What cyclin can CDK4 act on?

A

cyclin D
for G1 entry into cell cycle

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56
Q

What cyclin can CDK6 act on?

A

cyclin D
for G1 entry into cell cycle

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57
Q

What dephosphorylates CDK1?

A

Cdc25

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58
Q

What phosphorylates CDK1?

A

Wee1

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59
Q

What inhibits the S phase CDK complex & prevents the cell from entering the S phase?

A

Sic1

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60
Q

In order for the cell to enter the next phase what must be done?

A

everything must be done correctly & the cyclin that blocks it must be degraded

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61
Q

5 basic steps of genome replication

A
  1. recognition of replicate origins
  2. assembling replication initiation factors
  3. recruitment of helicase cofactors
  4. activation of helicase
  5. DNA polymerase copies each strand
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62
Q

What CDKs get phosphorylated to then phosphorylate MCM helicases to make them active?

A

S phase CDKs

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63
Q

What glue sister chromatids together?

A

cohesive molecules

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64
Q

What do aurora proteins do?

A

stop mitotic process until the correct tension is formed

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65
Q

What does chromosome condensation result in?

A

dramatic reduction in chromosome length

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66
Q

What is sister chromatid resolution & what is is mediated by?

A

untangling of sister chromatids; topoisomerase II

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67
Q

What triggers chromosome condensation?

A

CDK1

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68
Q

What inhibits separase?

A

binding of securin or by phosphorylation

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69
Q

What are some steps checked at each checkpoint?

A

damage to chromosomal DNA
incomplete DNA replication
incomplete chromosomal alignment

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70
Q

What are the 2 categories of surveillance genes?

A

genes promoting cell proliferation genes (encode of proteins that promote division)
anti proliferation genes (encode for checkpoint proteins)

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71
Q

Daughter cells for mitosis

A

2 that are diploid (genetically identical)

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72
Q

Daughter cells for meiosis

A

4 that are haploid (genetically different)

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73
Q

Which cells does mitosis happen in?

A

somatic cells

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74
Q

Which cells does meiosis happen in?

A

germline cells

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75
Q

What hormone stimulates red blood cell formation?

A

erythropoietin (Epo)

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76
Q

When & where is erythropoietin synthesized?

A

synthesized in the liver & kidney in response to low OXYGEN levels

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77
Q

What transcription factor coordinates many cellular responses to low O2?

A

Hif-1alpha

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78
Q

When is Hif-1alpha protein present?

A

only at low O2 levels
(gets degraded at high O2 levels)

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79
Q

Defime chronobiology

A

the study of the biology of circadian rhythms

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80
Q

What organisms exhibit circadian rhythms?

A

all eukaryotes & some prokaryotes

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81
Q

What is the most powerful external cue for the circadian rhythm?

A

dark-light cycle

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82
Q

What are other cues that impact circadian rhythms?

A

medication
temp
social interactions
exercise
eating / drinking
weather

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83
Q

In mammals, what functions as the master clock or pacemaker for circadian rhythms?

A

suprachiasmatic nucleus (SCN)

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84
Q

Melatonin production is inhibited by what?

A

light

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85
Q

Melatonin production is stimulated by what?

A

darkness

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86
Q

What secretes melatonin?

A

pineal gland

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87
Q

When is cortisol hormone the highest?

A

during daytime

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88
Q

What is the primary disease of circadian rhythms?

A

narcolepsy

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89
Q

What are some other diseases accompanied by alterations to circadian rhythms?

A

alzheimers & autism spectrum

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90
Q

Cells respond to tension across what?

A

intercellular adherents junctions

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91
Q

What modulates cell growth & differentiation?

A

hippo pathway

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92
Q

How does hippo signaling & YAP-TAZ look when there are actin stress fibers?

A

hippo signaling is off
YAP-TAZ is ACTIVE in nucleus

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93
Q

How does hippo signaling & YAP-TAZ look when there are NO actin stress fibers?

A

hippo signaling is on
YAP-TAZ is INACTIVE in cytosol

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94
Q

What is required for YAP nuclear localization?

A

actin stress fibers

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95
Q

Where is YAP-TAZ in the outer cells of morula?

A

in nucleus because cells are dividing (hippo pathway is off)

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96
Q

Where is YAP-TAZ in the inner cells of morula?

A

in cytoplasm because cells are not dividing

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97
Q

What 2 systems make up the nervous system?

A

central & peripheral nervous system
(CNS & PNS)

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98
Q

What 4 areas make up the CNS?

A

spinal cord, brain stem, cerebellum, cerebrum

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99
Q

What does the spinal cord do?

A

relays sensory & motor info

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100
Q

What does the brainstem do?

A

controls basic functions such as breathing & HR

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101
Q

What does the cerebellum do?

A

coordinates movements

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102
Q

What does the cerebrum do?

A

controls higher functions like language, learning, memory, & emotion

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103
Q

What do glial cells do?

A

provide support to nerve cells
theres more of them than neurons in the brain

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104
Q

How much of the total body energy does the brain consume?

A

20%

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105
Q

What 4 lobes make up the cerebrum (brain)?

A

frontal, temporal, parietal, occipital

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106
Q

What does the frontal lobe do?

A

involved in analytical stuff such as problem solving, language, & impulse-control

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107
Q

What does the temporal lobe do?

A

involved in auditory processing, memory, & emotion

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108
Q

What does the parietal lobe do?

A

involved in sensations such as touch, taste, temp, & movement

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109
Q

What does the occipital lobe do?

A

involved in vision

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110
Q

What does the PNS consist of?

A

somatic & autonomic systems

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111
Q

What does the somatic system do?

A

involved with the conscious control of the body

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112
Q

What does the autonomic system do?

A

controls body functions that happen without us thinking about it

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113
Q

What are the two types of the autonomic nervous system?

A

sympathetic & parasympathetic nervous system

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114
Q

What does the sympathetic nervous system do?

A

stimulates the fight or flight response
regulates HR, respiration rate, & pupillary response

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115
Q

What does the parasympathetic nervous system do?

A

stimulates the rest & digest response

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116
Q

Where is the sympathetic nervous system located?

A

near the thoracic & lumbar regions

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117
Q

Where is the parasympathetic nervous system located?

A

between the spinal cord & the medulla

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118
Q

What 2 cells make up the nervous system?

A

neurons & glia

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119
Q

Types of glial cells in CNS

A

astrocytes
oligodendrocytes
microglia
ependymal glial cells

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120
Q

Types of glial cells in PNS

A

Schwann cells
satellite cells

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121
Q

What glial cells produce myelin sheaths in CNS

A

oligodendrocytes

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122
Q

What glial cells produce myelin sheaths in PNS

A

Schwann cells

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123
Q

What are the 3 functional classes of neurons

A

sensory (afferent) neurons
interneurons
motor (efferent) neurons

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124
Q

Describe sensory (afferent) neurons

A

detect stimuli & conduct signals TOWARDS the CNS

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125
Q

Describe interneurons

A

lie within the CNS
receives signals & decides where it goes

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126
Q

What class are the majority of neurons?

A

interneurons

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127
Q

Describe motor (efferent) neurons

A

lead to muscle cells
sends signals from CNS to the muscle or gland

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128
Q

Describe multipolar neurons

A

have 1 axon & multiple dendrites

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129
Q

What is the most common type of neuron?

A

multipolar

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130
Q

Describe bipolar neurons

A

have 1 axon & 1 dendrite

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131
Q

Examples of bipolar neurons

A

olfactory cells
sensory neurons
retina neurons

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132
Q

Describe unipolar (pseudounipolar) neurons

A

have a SINGLE process leading away from the soma
gets divided into dendrites later

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133
Q

Describe anaxonic neurons

A

have NO axon but multiple dendrites
do NOT produce action potentials

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134
Q

Where are anoxic neurons found?

A

brain
retina
adrenal medulla

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135
Q

What cells secrete & circulate CSF in the CNS?

A

ependymal cells

136
Q

What cells engulf things & destroy them in the CNS?

A

microglia

137
Q

What cells provide nutrients to cells in the CNS?

A

astrocytes

138
Q

What cells provide electrical insulation in the PNS?

A

satellite cells

139
Q

What is the myelin sheath?

A

insulation around a nerve fiber that aids in fast movement of APs

140
Q

What is the neurilemma of the Schwann cell?

A

the thick outermost coil (bulging body) that contains the nucleus of the Schwann cell

141
Q

What is the endonceurium of the Schwann cell?

A

a basal lamia & a thin sleeve of fibrous connective tissue

142
Q

What is a node of Ranvier?

A

gap between segments of the myelin sheath

143
Q

What are internodes?

A

myelin covered segments of the nerve

144
Q

What is the initial segment?

A

the short section of nerve between the axon hillock & the first glial cell

145
Q

What makes up the trigger zone?

A

axon hillock & initial segment

146
Q

What are unmyelinated fibers enveloped in in the PNS?

A

enveloped in Schwann cells

147
Q

The speed that the signal travels along a nerve fiber depends on what 2 factors?

A

diameter of the fiber
presence or absence of myelin

148
Q

Commands to the skeletal muscle or signals for vision & balance use what kind of fibers?

A

fast myelinated fibers

149
Q

Dilating the pupil & secreting stomach acid use what kind of fibers?

A

slow unmyelinated fibers

150
Q

What are diseases of the myelin sheath & what do they cause?

A

multiple sclerosis (MS) & tay-sachs disease
cause a disruption of nerve conduction

151
Q

Describe multiple sclerosis (MS)

A

oligodendrocytes & myelin sheaths of the CNS deteriorate & are replaced by scare tissue

152
Q

Describe tay-sachs disease

A

there is an abnormal accumulation of ganglioside in the myelin sheath

153
Q

What does the blood brain barrier do?

A

prevents free flow of substances
is the sight of a lot of signal transduction

154
Q

Brain tumors (gliomas) are composed of what?

A

a mass of glial cells

155
Q

What does a tumor consist of?

A

a mass of rapidly dividing cells

156
Q

What are the 3 main components of the cytoskeleton?

A

microtubules
intermediate filaments
microfilaments

157
Q

Describe microtubules

A

longitudinal structures that give neuritis their structure

158
Q

Describe intermediate filaments

A

strong structures that consist of long proteins

159
Q

Describe microfilaments

A

thin structures that are important for motility

160
Q

When Tau proteins over phosphorylate, what does it cause neurons to form?

A

NFTs (neuron fiber tangles)

161
Q

Describe axoplasmic transport

A

transport along the INTERIOR of the axon

162
Q

What direction is anterograde axonal transport

A

from cell body (soma) to nerve ends

163
Q

What direction is retrograde axonal transport

A

from nerve ends to cell body (soma)

164
Q

What proteins are involved in transport along neurons-tubules?

A

kinesin & dynein

165
Q

Fast axonal transport occurs in what direction?

A

both anterograde & retrograde

166
Q

What transport moves organelles, synaptic vesicles, & small molecules?

A

fast ANTEROGRADE transport
(soma to nerve ending)

167
Q

What transport returns uses synaptic vesicles to the soma & is used by pathogens?

A

fast RETROGRADE transport
(nerve endings to soma)

168
Q

Slow axonal transport occurs in what direction?

A

anterograde (soma to nerve ending)

169
Q

What transport moves enzymes & cytoskeletal components & renews worn-out axoplasmic components?

A

slow axonal transport

170
Q

What is a disorder of peripheral nerves?

A

tetanus

171
Q

During a tetanus infection, what transmitters get blocked & what does that cause?

A

blocks GABA & glycine (muscle contraction inhibitors)
causes uncontrollable muscle contractions

172
Q

What is risus sardonicus?

A

face has a fixed smile
early sign of tetanus

173
Q

What is opisthotonus?

A

muscle spasms

174
Q

What is tetany?

A

prolonged muscular action that causes painful contractions, fractures, & muscle tears

175
Q

What happens during early nerve regeneration?

A

a regeneration tube forms

176
Q

What happens during late nerve regeneration?

A

the regeneration tube guides the growing sprout back to the original target cells, reforming synaptic contact; soma shrinks & muscle fibers regrow

177
Q

Nerve regeneration can only happen if what is still intact?

A

the soma (cell body)

178
Q

What maintains intracellular Na+ & K+ concentrations?

A

Na/K pump (ATPase)

179
Q

E1 conformation of Na/K ATPase

A

releases K+
high affinity for Na+

180
Q

E2 conformation of Na/K ATPase

A

releases Na+
high affinity for K+

181
Q

How does Na/K ATPase go from E1 to E2 conformation?

A

conformational change

182
Q

What does the K+ channel use to push K+ out?

A

the electrochemical gradient made from the Na/K pump

183
Q

The Na/K pump sends how many Na+ out & brings how many K+ in?

A

3 Na+ out, 2 K+ in

184
Q

What is the resting membrane potential?

A

-70 mV

185
Q

What are the 4 properties of a local (graded) potential?

A
  1. graded: vary in magnitude bases on stimulus strength
  2. decremental: get weaker the further they travel
  3. reversible: returns to RMP when stimulus stops
  4. can be excitatory OR inhibitory
186
Q

Excitatory local potentials do what?

A

depolarize the cell (more Na+ in) thus producing an action potential
ex. acetylcholine

187
Q

Inhibitory local potentials do what?

A

hyperpolarize the cell (makes it more negative)
ex. glycine

188
Q

What causes depolarization?

A

stimulus open Na+ channels allowing Na+ into the cell thus depolarizing it

189
Q

Local potentials are produced by what?

A

LIGAND GATED channels

190
Q

Action potentials are produced by what?

A

VOLTAGE GATED channels

191
Q

Steps of an action potential

A
  1. local stimulus depolarizes membrane
  2. Voltage gated Na+ channels open at threshold (-55mV)
  3. Na+ enters cell, depolarizing it
  4. At 0 mV, Na+ channels close
  5. At +35 mV, K+ channels open
  6. K+ channels repolarize cell
  7. K+ channels remain open hyperpolarizing the cell
  8. RMP is restored
192
Q

Characteristics of an action potential

A
  1. not graded: strong stimulus does not produce a stronger action potential
  2. non-decremental: do not get weaker with distance
  3. irreversible: once fired goes to completion
193
Q

Why aren’t all nerve fibers large, myelinated, & fast?

A

it would make the nervous system very bulky & inefficient

194
Q

A nerve signal is what?

A

a chain reaction of action potentials

195
Q

Refractory membrane ensures what?

A

that the action potential travels in ONE direction

196
Q

Unmyelinated nerve fibers have what kind of conduction?

A

continuous conduction

197
Q

Myelinated nerve fibers have what kind of conduction?

A

saltatory conduction
signal “jumps” from node to node

198
Q

On myelinated nerve fibers, where can action potentials occur?

A

only at nodes of Ranvier
this is what gives the appearance of the signal “jumping”

199
Q

How does myelin speed up signal conduction?

A

by minimizing leakage of Na+ out of the cells & separating the inner positive ions from attraction of outside negative ions

200
Q

What is a synapse?

A

where pre & post synaptic neurons meet

201
Q

A presynaptic neuron can synapse with what 3 things?

A

dendrites
the soma of a postsynaptic neuron
the axon of a postsynaptic neuron

202
Q

What are the types of synapses based by site of contact?

A

axodendritic synapse
axosomatic synapse
axoaxonic synapse

203
Q

What are the types of synapses based by transmission mechanisms?

A

electrical & chemical synapses

204
Q

What do electrical synapses have that chemical synapses do not?

A

gap junctions

205
Q

Define electrical synapses

A

has gap junctions between pre & postsynaptic membranes that allow direct flow of current

206
Q

Define chemical synapses

A

has no direct flow of current
rely on neurotransmitters

207
Q

What is a synaptic cleft?

A

a gap between pre & post synaptic cells

208
Q

How are neurotransmitters released into the cleft?

A

via exocytosis

209
Q

Define neurotransmitters

A

molecules that are released when a signal reaches a synaptic cleft that binds to a receptor on another cell & alters its physiology

210
Q

What are the major chemical categories of neurotransmitters?

A

acetylcholine
monoamines
amino acid neurotransmitters
purines

211
Q

What do neuromodulators do?

A

modulate the activity to neuron groups in various ways

212
Q

How can neuromodulators modulate the activity of neuron groups?

A
  1. increasing release by presynaptic neurons
  2. adjusting sensitivity of postsynaptic neurons
  3. altering rate of breakdown
213
Q

What are 2 neuromodulators?

A

gases (nitric oxide)
neuropeptides (endorphins)

214
Q

Who was awarded the Nobel prize in 1936?

A

Loewi & Dale

215
Q

What does an excitatory cholinergic synapse use as its neurotransmitter?

A

acetylcholine

216
Q

Describe the process of an excitatory cholinergic synapse

A
  1. signal arrives & opens voltage gated Ca2+ channels
  2. Ca2+ enders cell
  3. ACh released & binds to postsynaptic receptors
  4. Na+ & K+ diffuse into cell
  5. action potential generated
217
Q

What proteins are involved in neurotransmitter release?

A

v-SNARE & t-SNARE (SNARE complex when bound together)

218
Q

Influx of what triggers the release of neurotransmitters?

A

Ca2+

219
Q

What prevents membrane fusion?

A

complexin protein & synaptotagmin without bound Ca2+ binding to the SNARE complex

220
Q

What does an inhibitory GABA-ergic synapse use as its neurotransmitter?

A

game-aminobutyric acid

221
Q

GABA receptors are what kind of channels?

A

chloride channels

222
Q

An excitatory adrenergic synapse uses what as its neurotransmitter?

A

norepinephrine
acts through second messengers like cAMP

223
Q

For an adrenergic synapse, what is the receptors?

A

GPCR
(G-protein coupled receptor)

224
Q

Describe the process of an excitatory adrenergic synapse

A
  1. norepinephrine binds to G-protein
  2. G-protein dissociates & binds to adenylate cyclase
  3. cAMP is released
  4. ligand-gated channels open
  5. cell depolarizes
225
Q

Define neural integration

A

the ability of neurons to process info, store & recall it, & make decisions

226
Q

Define excitatory postsynaptic potential (EPSP)

A

any voltage change above resting membrane potential that makes a neuron more likely to fire

227
Q

EPSPs usually result from what?

A

Na+ flowing INTO the cell

228
Q

What excitatory brain neurotransmitters produce EPSPs?

A

glutamate & aspartate

229
Q

Define inhibitory postsynaptic potential (IPSP)

A

when a neurotransmitters hyperpolarizes the postsynaptic cell & makes it less likely to fire

230
Q

IPSPs usually result from what?

A

chloride flowing INTO the cell or K+ flowing OUT

231
Q

What are inhibitory brain neurotransmitters that produce IPSPs?

A

glycine & GABA

232
Q

Where does summation occur?

A

in the trigger zone

233
Q

Describe summation

A

the process of adding up postsynaptic potentials & responding to their net effect

234
Q

Describe temporal summation

A

a SINGLE synapse generates EPSPs so fast that the one before has not finished

235
Q

Describe spatial summation

A

EPSPs from MULTIPLE synapses add up

236
Q

Define neural coding

A

nervous system converts QUALITATIVE info to a meaningful pattern of APs

237
Q

What is the most important mechanism for transmitting qualitative info?

A

labeled line code
(brain interprets based on the labeled neuron that the signal comes from)

238
Q

In neural coding, qualitative info is..

A

where the stimulus is coming from

239
Q

In neural coding, quantitative info is..

A

how strong the stimulus is

240
Q

What are the 4 types of neural circuits

A

diverging
converging
reverberating
parallel after-discharge

241
Q

Describe a diverging circuit

A

ONE neuron sends signals to multiple neurons
signals going OUT of the brain

242
Q

Describe a converging circuit

A

signals from MULTIPLE neurons all come together at one point
signals coming back to the brain

243
Q

Describe reverberating circuit

A

neurons stimulate each other in a linear sequence but some send signals back to neurons earlier in the path
is a loop (positive feedback) stopped by inhibitory signal

244
Q

What neural circuit can play a role in seizures?

A

reverberating circuit

245
Q

Describe parallel after-discharge circuit

A

ONE neuron stimulates several CHAINS

246
Q

Describe mechanoreceptors

A

sensory structures that respond to touch, pain, & temp
are Na+/Ca2+ channels

247
Q

What organism is used for research of mechanoreceptors?

A

C. elegans & heier MEC proteins

248
Q

What receptor is used for salty & sour tastes?

A

channel proteins

249
Q

What receptor is used for sweetness & bitterness?

A

GPCR

250
Q

Describe the structure of an olfactory receptor neuron

A

have 1 dendrite that ends in a dendritic knob that has cilia extending into the nasal mucus

251
Q

What catalyzes cAMP from ATP?

A

adenylyl cyclase

252
Q

What hydrolyzes cAMP?

A

cAMP phosphodiesterase

253
Q

Describe memory trace

A

memory pathway where new synapses form or existing synapses are modified

254
Q

The ability of synapses to change is called what?

A

synaptic plasticity

255
Q

Define immediate memory

A

ability to hold a memory in mind for a few seconds

256
Q

What circuit is immediate memory based on?

A

reverberating

257
Q

Define working memory

A

a form of short term memory that allows you to hold an idea long enough to perform an action

258
Q

Define post-tetanic potentiation

A

memories lasting for a few hours

259
Q

How long does short term memory last?

A

few seconds to a few hours

260
Q

What taste can directly depolarize the membrane?

A

salt taste

261
Q

What taste uses H+ to block K+ channels to depolarize the membrane?

A

sour taste

262
Q

What tastes use GPCRs to elevate Ca2+ levels that open Na+ channels to depolarize the cell?

A

sweet, bitter, umami tastes

263
Q

Describe the signal transduction from olfactory GPCRs

A
  1. odorant binds & releases active Galpha-GTP
  2. AC3 produces cAMP
  3. influx of Na+ & Ca2+
  4. cell depolarizes
264
Q

What are the 2 forms of long term memory?

A

explicit & implicit

265
Q

Describe explicit memory

A

retention of events that you can put into words
“physical memories”

266
Q

Describe implicit memory

A

retention of emotions or motor skills
“emotional & procedural memories”

267
Q

What is long term potentiation?

A

a process involving persistent strengthening of synapses
involves NMDA receptors

268
Q

What blocks NMDA receptors?

A

magnesium ions

269
Q

What is the model organism for studying synaptic plasticity & memory?

A

Aplysia californica
(sea slug)

270
Q

Sensitization is accompanied by what?

A

the growth of new connections between the sensory & motor neurons

271
Q

Habituation is accompanied by what?

A

a decrease in the number of connections between the sensory & motor neurons

272
Q

What erases long term memories?

A

long term depression (LTD)

273
Q

What is required for memory formation?

A

the hippocampus

274
Q

How does long term depression affect receptors in the post synaptic?

A

decreases the number of receptors, decreasing the response
(long term potentiation does the opposite)

275
Q

Mutation in FMRP (proteins) causes what mental disorder?

A

fragile X syndrome

276
Q

Mutation in FMRI gene causes what?

A

autism

277
Q

What are the 2 types of immunity?

A

innate & adaptive

278
Q

Describe innate immunity

A

body recognizes any pathogen
dos not require previous exposure

279
Q

Describe adaptive immunity

A

immune system specifically targets CERTAIN pathogens
has specific recognition of antigens

280
Q

Describe plasma

A

blood without cells

281
Q

Describe serum

A

blood without cells or proteins

282
Q

What are platelets?

A

cell-like bodies that clump to prevent blood from leaking out when vessels are damaged

283
Q

Describe erythrocytes

A

RBCs
have no nucleus & carry O2

284
Q

All white blood cells (leukocytes) start as what & where?

A

start in bone marrow as stem cells

285
Q

3 classes of leukocytes

A

granulocytes (neutrophils, eosinophils, basophils)
monocytes (macrophages, dendritic cells)
lymphocytes (B & T cells)

286
Q

What is lymph?

A

fluid with WBCs that bathes tissues

287
Q

What are the primary lymphoid organs?

A

bone marrow & thymus

288
Q

What are the secondary lymphoid organs?

A

lymph nodes, spleen, MALT

289
Q

What are the functions of the lymphatic system?

A

absorption of fat & excess fluid, immunity

290
Q

Where do B cells mature?

A

in bone marrow

291
Q

Where do T cells mature?

A

in thymus gland

292
Q

What are lymph nodes & what do they do?

A

nodules in lymphatic veins
function to filter & purify lymph fluid

293
Q

What is the function of the spleen?

A

to filter blood

294
Q

What mediates innate immunity?

A

physical & chemical barriers
phagocytes
cytokines

295
Q

Describe cell mediated immunity (CMI)

A

LYMPHOCYTES recognize specific antigens

296
Q

Describe humoral immunity

A

ANTIBODIES recognize the antigen

297
Q

What are the 2 types of cells involved in innate immunity?

A
  1. neutrophils
  2. monocytes & macrophages
298
Q

How do neutrophils work for innate immunity?

A

they circulate through the blood & bone marrow & migrate to sites of infection causing an inflammatory response

299
Q

How do monocytes & macrophages work for innate immunity?

A

monocytes circulate through the blood & lymph & have macrophages on their surface to present the antigen

300
Q

What are PAMPs?

A

pathogen-associated molecular patterns
structural components on a particular PAHTOGEN

301
Q

What are PRRs?

A

pattern recognition receptors
HOST proteins that interact with PAMPs on pathogens

302
Q

What is an example of PRR?

A

TLR

303
Q

During innate immunity, what are released by host cells in response to PRR binding to PAMP?

A

interferons which activate immune cells

304
Q

How do macrophages & phagocytes take action during innate immunity?

A
  1. recognition & engulfment of pathogen
  2. produce antigen
  3. antigen presented on macrophage cell surface
  4. antigen presented to T & B cells
  5. immune response
305
Q

How can phagocytes kill bacteria?

A

acid attack
phagocyte stimulation
toxic oxygen

306
Q

How can pathogens fight against phagocytes?

A

production of anti-oxidants (to give resistance)
production of leucocidins (to kill phagocytes)
capsules (to block adherence of phagocyte)

307
Q

What are the 3 fundamental characteristics of adaptive (specific) immune response?

A

specificity
memory
tolerance (protects host cells from immune response)

308
Q

What do T-cells have that allow them to recognize a specific antigen?

A

antigen specific T cell receptors (TCRs)

309
Q

What part of a TCR binds to the antigen?

A

variable region

310
Q

What part of a TCR is integrated in the membrane & very specific?

A

constant region

311
Q

What cells are responsible for producing antibodies?

A

B cells

312
Q

What do antigens (from pathogens) interact with?

A

antibodies or TCRs

313
Q

Antigens are what?

A

immumnogens

314
Q

What are immunogens?

A

substances that induce an immune response

315
Q

What are haptens?

A

antigens that bind to antibodies but cannot induce an immune response unless bound to a large carrier

316
Q

What INTRINSIC factors affect the ability of an antigen to induce an immune response?

A

molecular size
complexity
form (more insoluble, better immunogen)

317
Q

What EXTRINSIC factors affect the ability of an antigen to induce an immune response?

A

dose size
route of entry
foreign nature (more foreign better response)

318
Q

What are ineffective immunogens?

A

small molecules
sugars
nucleic acids

319
Q

What are effective immunogens?

A

proteins

320
Q

What are epitopes?

A

the part of the antigen that directly binds to the antibody or TCR

321
Q

What is a homologous antigen?

A

epitope that antibody recognizes to stimulate an immune response

322
Q

What is a heterologous antigen?

A

epitope where the antibody ACCIDENTALLY binds
interaction is a cross reaction

323
Q

What are the 2 kinds of adaptive immunity?

A

cell mediated
antibody mediated

324
Q

What is cell mediated immunity?

A

pathogen infected host cells are immediately killed after recognized

325
Q

What is antibody mediated immunity?

A

pathogen is recognized & antibodies are developed
effective against bacteria & extracellular pathogens

326
Q

What cells process antigens?

A

antigen presenting cells

327
Q

What do antigen presenting cells have to have on their surface to present the antigen?

A

major histocompatibility complex (MHC)

328
Q

What do cytotoxic T cells (TC cells) do?

A

invade infected cells & destroy them

329
Q

What do T helper cells (TH cells) do?

A

interact with the antigen & secrete cytokines that activate host defense OR stimulate B cells to produce antibodies

330
Q

Antigen presentation requires what 2 things?

A

T cell receptors (TCRs)
MHC (on antigens)

331
Q

What class of MHC proteins presents antigens to cytotoxic T cells?

A

class I

332
Q

What class of MHC proteins presents antigens to helper T cells?

A

class II

333
Q

Cytotoxic T cells have what kind of receptors?

A

CD8+

334
Q

Helper T cells have what kind of receptors?

A

CD4+

335
Q

What transporter delivers degraded pathogens to the interior of the ER to get loaded onto MHC protein?

A

TAP

336
Q

Successful recognition of an antigenic peptide-MHC complex by a T cell receptor requires what?

A

a good fit among the receptor, antigen, & MHC molecule

337
Q

What do class II MHC proteins have that prevent it from binding cellular peptides?

A

invariant chain

BMS 521 (3 decks)

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