Z332 midterm 2 Flashcards Preview

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Flashcards in Z332 midterm 2 Deck (114)
1

membrane permeability due to 

number and type of channels that are open

2

gated channels

let specific ions through in respone to stimulus; change permeability to that ion, chages membrane potential 

3

transduction

changing signal from one form to another ; converstion of a signal into a change of potential in a sensory neuron 

4

exteroreceptors 

at/near body surface, signals outside body

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interoreceptors

signals inside body

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proprioceptors 

skeletal muscles, tendons, joints, ligaments, connective tissues 

7

electromagnetic energy receptors 

photoreceptors, electroreceptors, magnetoreceptors 

8

rods and cons

photoreceptors

rods: gray scale

cones: red, gree, blue 

9

transduction of specific color info...

activation of different receptor combinations which are then interpreted as the color in the visual association cortex of the cerebrum 

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photoreception elctromagnetic to chemical messenger 

photon collides with cis retinal --> trans retinal

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photoreception chemical signal --> change in membrane potential 

trans retinal activates enzyme that effects membrane potential

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rhodopsin

opsin + retinal

13

chemoreceptors

olfaction, gustatory, vomerolfaction

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olfaction

odorant molecule binds to receptor portein that causes chemical cascade. causes change in membrane potential.

several chemical signlas transduced into change in potential

15

mechanoreceptors

hair cells (vestibular - acceleration, cochlear organs - sound waves)

16

mechanial energy transduction

acceleration imposed on hair cell, kinocilium shif causes mechanically gated ion channels to open and change in potential 

17

proprioception 

relative positon of body parts (mechanoreception) 

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muscle stretch transduced into

change in membrane potential 

19

touch, vibration, pressure sensations of skin

meissner, merkel, hair root plexus, pacinian, ruffini

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sensory receptor adaptation 

reduction in amplitude of graded potentail of sensory receptor during maintained, constant stimulus

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rapid adaptation

registers chaange in stimulus 

meissner, hair root plexus, pacinian

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slow adaptation

monitor stimulus, sustained response (pain, tension, chemical comp of blood)

merkel disc, ruffini

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nociceptors

respond to noxious or painful stimuli, free nerve ending

chemical: cytokines released from damaged tissue

thermal: increaes frequency of nerve impulses in resposne to cold, 

mechanical: 

24

osmoreceptors

chemoreceptors that respond to osmotic pressure of body fluids (in hypothalamus)

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baroreceptors 

mechanical receptors that sense blood pressure 

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graded potential

localized, dendrites an cell bodies, decremental ,short lived, no refractory period

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excitatory postsynaptic potential 

results in depolarization 

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inhibitory postsynaptic potential 

results in hyperpolarization

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gradations

graded potentiall vary in amplitude 

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polarity (depolarization/hyperpolarization) depends on 

which ions move (depends on receptor/channel)

Cl in and/or K out = hyperpolarization/inhibitory 

Na and/or Ca in = depolarization/excitatory

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intensity depends on

strenth of stimulus (# of open channels, time channels are open)

 

summation (spatail or temporal)

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spatial summation

summing of postsynaptic potential that occur at different locations at same time

make bigger or cancle eachother out 

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temporal summation

summing of postsynaptic potential that occur at different times in same location 

more time channels are open = greater stimulus strength

more ions come in, increase amp of signal synaptic transmission, increase probabilty another stimulus will occur

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action potentail threshold

~-55mV

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graded potentail last

~10-20 sec

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3 states of voltage gated Na channels

closed, open, inactivated 

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states of K channels

closed or open

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for replarization, voltage gated Na channels are

inactivated 

39

most important info (vision, balance, motor) carries by

lare diameter myelinated axons

40

CIDP

chronic inflammatory demyelianting polyneuropathy

tingling and numbness, weakness of arms and legs, loss of deep tendon reflexes, abnormal sensations

41

chemical synapse steps 

action potential arrives at terminal

voltage gated Ca channels open and Ca enters axon terminal

Ca entry causes synaptic vesicles to release NT

NT diffuses across synaptic cleft and binds to specific receptors on postsynaptic membrane

binding of NT opens ion channels resulting in membrane potential

NT effects termianted by reuptake, enzymatic degradation, or diffuse away 

42

synaptic delay time

.3-.5ms

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excitatory

increase likelihood of action potential

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inhibitory

decrease likelihood of action potential 

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types of neurotransmitter receptors 

channel linked (ionotropic)

G-protein linked (metabotropic)

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channel linked receptors (ionotropic)

ligand binds to channel subunit, changes its shape

excitatory receptors : cation channels (Na most for depolarization)

inhibitory receptors: anion channels or K channels; hyperpolarization 

47

G-protein linked receptors (metabotopic)

2nd messenger system

tend to bring about widespread metabolic changes

slower, prolonges

indirect action

48

antagonists 

substances that inhibit a process

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agonists 

substances that enhance a process 

50

NT classified as

excitatory (depolarize) or inhibitory (hyperpolarize)

some can be both, effect of NT is determined by receptor 

51

Acetylcholine

released by somatic motor neurons and some ANS neurons

cholinergic synapses 

52

Glutamate 

excitatory amino acid NT, mot important in brain

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asparate 

excitatory NT

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glycine

inhibitory

mostly PNS- spinal cord, ganglia, motor neurons 

55

strychnine

antagonist of glycine (1904 olympics)

56

Gamma AminoButyric Acid (GABA)

inhibitory NT

muscle tone, reduces anxiety

57

norepinephrine 

monoamine, catecholamines, biogenic amine

awaking from sleep, dreaming, reg. moods

memories of single events, adrenergic synapses 

58

dopamine (DA)

emotional responses, reward, addictive behavior and pleasurable experiences 

inhibitory effects aid precise motor control 

Parkinson's disease - damaged neurons that produce DA

cocaine inhibits reuptake --> high 

59

Schizophrenia

hypothesized to be due to dopamine overactivity

60

cocaine and methamphetamines...

can cause psychosis and antipsychotic drugs act to block DA activity 

61

Positrom emission tomography (PET)

radio labeled tracer with metabolic property injected into blood stream. radiation detector can see where labeled molecules accumulate.

62

Serotonin

Role in moods and attention; SSRIs = slective sertotonin reuptake inhibitors; activity blockedby LSD, enhancedby ecstacy

63

nitric oxide

neurotransmitter; viagra, too unstable to be stored, produced on demand by enzymatic reaction, vasodilation, lipid soluble --> diffusion, second messegner with cells

64

neuropeptides

endorphins: natural opiates, reduce perception of pain under stressful siuations

65

drug affects on synaptic transmission

stimulates release of AGO; inhibits release of ANT; stimulates AGO receptors, blocks ANT receptors; blocks AGO reuptake, inactivates AGO

66

integration center

collection of neurons tht coordinates particular function

67

 neuronal pool

function group of neurons

68

circuits

patterns of synaptic connections

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serial processing

ex: spinal relexes: chain of neurons

70

parallel processing

input segregated into many pathways; one stimulus can promote many responses

71

diverging circuit

one input, many outputs; signal amplification

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converging circuit

many inputs one output; effective inhibition or stimulus; concentrating circuit

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reverberating circuit

signal travels through a chain of neurons, each feeding back to previous neurons, oscillating circuit; breathing , muscular coordination, waking up, short term memory; rhythmic activity, prolonged output

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parallel after discharge curcuit

production of multiple IPSPs and EPSPs; signal stimulates neurons arranged in parallel arrays that eventually converge on a single output cell, impulses reach output cell at different times causing burst of impulses after discharge, prolonged output

75

epilepsy

recurrent seizures; durgs include antagonists of voltage gated sodum channels and agonists of GABA receptors, allow Cl into cell

76

4 classifications of reflexes

early development: innate, acquired ; type of motor response: somatic, visceral ;  site of info integration: spinal or cranial ; complexity of neural circuit

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innate reflexes

born, basic neural reflexes, formed before birth

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acquired reflexes

learned, rapid automatic, learned motor patterns

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somatic reflexes

involuntary control of nervous system; superficial relfexes of skin, mucous membranes, stretch reflexes

80

visceral reflexes

autonomic reflexes, control systems other than muscular system; effectors: glands, smooth muscle, cardiac muscle

81

monosynaptic stretch reflex

1 afferent, 1 synapse, 1 efferent, simplest and fastest

82

gamma efferents

control sensitivity of muscle spindle by keeping tension on intrafusal fibers

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crossed extensor reflexes

contralateral reflex arc, coordinated with flexor reflex

84

first order neuron

conduct impulses from somatic receptors to spinal cord or brain stem

85

second order receptors

conduct imulses from spinal cord and brain stem to thalamus (decussate - crossover oppositeside of body, usualy at medulla) 

86

third order neuron

conduct impulses from thalamus to primary somatosensory area of cortex

87

4 major somatosensory pathways

posterior column-lateral lemniscus pathway; spinothalamic tracts (anteror lateral); spinocerebellar (unconcious), trigeminothalamic

88

motor and descending efferent pathways

pyramidal tracts - lateral and anterior corticospinal tract

89

sensory and ascending afferent pathways

dorsal colmn medial lemniscus system  - gracile fasciculus and cuneate fasciculus

90

posterior colmn-medial lemniscus pathway

somatic sensory, nerve impulses from: touch, pressure, proprioception, vibration; in limbs and trunk; lowe limbs and trunk : gracile fasciculus, upper: cuneate fasciculus; 1st 2nd and3rd order neurons

91

anterolateral (spinothalamic) pathway

nerve impulses from: pain, cold, warmth, itch; in libs, trunk, neck, and back of head; pathway: 1st order to posterior horn of spinal cord, 2nd order crossover in spinal cord; ascends via spinothalamic tract of thalamus, 3rd order to cortex

92

local circuit neurons

interneurons receive input from proprioceptors, maintain rhythmic activity andrefelxes without input form cerebrum; ex: cat still walks without brain

93

direct somatic motor pathways

lateral corticospinal pathway: digital, precise, skilled movements; anterior : trunk and proximal parts of limbs

94

direct somatic motor pathways

descend from brain to spinal cord w/o snyapsing; lateral and anterior corticospinal

95

delta waves in awake adult =

brain damage

96

consciousness

clinically defined on continuum: altertness, drowsiness/lethargy/ stupor, coma; involes large areas of cerebral cortex acting simultaneously

97

loss of consciousness

fainting : brief, restricted blood flow to brain; coma: prolonges, oxygen use below normal, drain damage, tumors, infections , drugs ,etc

98

sleep

state of partial unconciousness from which a person can be aroused, brain function continue

99

carcadian rhythm

sleep/awake cycles, controlledby hypothalamus

100

stages of sleep

awake: alpha and beta; REM: theta and beta, body paralysis, dreaming, 20-30 mins; stage 1: theta, transition phase, 15 mins. stage 2: theta and k complexes ( short bursts of neural activity), 15 mins; stage 3: 20-50% delta, stage 4: >50% delta

101

most slow wave deep sleep occurs

in first half of night

102

during REM

brain activity increases, slowed heart rate and ventilation rate, vaginal secretion and penile erection, dreaming occurs

103

narcolepsy

sudden lapse into REM sleep, triggered by pleasurable event; also have cataplexy (loss of voluntary muscle control), orexins (wake up chemicals) destroyed

104

insomnia

inability to get sufficient sleep, deficiency of orexins

105

memory consolidation =

reinforcement due to frquent retreval of info

106

influences transfer from STM to LTM

emotional state: alert and motivated, traumatic events; rehearsal, association, automatic memory: not all long term memories consciously formed

107

declarative memory

facts, assiciated with contex in LTM

108

nondeclarative memory

less consious/unconsious learning, acquired through experience, procedural, motor, emotional

109

declarative memory circuits

temporal lobe areas important, ACh primes brain for memory formation, alzheimers = reduced ACh

110

anterograde amnesia

consolidated memories retained, new inputs lost, can still learn new skills  (procedural)

111

retrograde amnesia

loss of memories from past

112

procedural memory circuits

basal nuclei are important, dopamine is necessary (parkinson's interferes with procedural memory)

113

long term potentiation

persistent strengthening of synaptic connections, essential for memory formation, binding of glutamate, results in Ca influx into postsynaptic cell

114