Z332 midterm 2 Flashcards
(114 cards)
1
Q
membrane permeability due to
A
number and type of channels that are open
2
Q
gated channels
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let specific ions through in respone to stimulus; change permeability to that ion, chages membrane potential
3
Q
transduction
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changing signal from one form to another ; converstion of a signal into a change of potential in a sensory neuron
4
Q
exteroreceptors
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at/near body surface, signals outside body
5
Q
interoreceptors
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signals inside body
6
Q
proprioceptors
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skeletal muscles, tendons, joints, ligaments, connective tissues
7
Q
electromagnetic energy receptors
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photoreceptors, electroreceptors, magnetoreceptors
8
Q
rods and cons
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photoreceptors
rods: gray scale
cones: red, gree, blue
9
Q
transduction of specific color info…
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activation of different receptor combinations which are then interpreted as the color in the visual association cortex of the cerebrum
10
Q
photoreception elctromagnetic to chemical messenger
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photon collides with cis retinal –> trans retinal
11
Q
photoreception chemical signal –> change in membrane potential
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trans retinal activates enzyme that effects membrane potential
12
Q
rhodopsin
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opsin + retinal
13
Q
chemoreceptors
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olfaction, gustatory, vomerolfaction
14
Q
olfaction
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odorant molecule binds to receptor portein that causes chemical cascade. causes change in membrane potential.
several chemical signlas transduced into change in potential
15
Q
mechanoreceptors
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hair cells (vestibular - acceleration, cochlear organs - sound waves)
16
Q
mechanial energy transduction
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acceleration imposed on hair cell, kinocilium shif causes mechanically gated ion channels to open and change in potential
17
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proprioception
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relative positon of body parts (mechanoreception)
18
Q
muscle stretch transduced into
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change in membrane potential
19
Q
touch, vibration, pressure sensations of skin
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meissner, merkel, hair root plexus, pacinian, ruffini
20
Q
sensory receptor adaptation
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reduction in amplitude of graded potentail of sensory receptor during maintained, constant stimulus
21
Q
rapid adaptation
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registers chaange in stimulus
meissner, hair root plexus, pacinian
22
Q
slow adaptation
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monitor stimulus, sustained response (pain, tension, chemical comp of blood)
merkel disc, ruffini
23
Q
nociceptors
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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
Q
osmoreceptors
A
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
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most important info (vision, balance, motor) carries by
lare diameter myelinated axons
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CIDP
chronic inflammatory demyelianting polyneuropathy
tingling and numbness, weakness of arms and legs, loss of deep tendon reflexes, abnormal sensations
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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
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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
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G-protein linked receptors (metabotopic)
2nd messenger system
tend to bring about widespread metabolic changes
slower, prolonges
indirect action
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antagonists
substances that inhibit a process
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agonists
substances that enhance a process
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NT classified as
excitatory (depolarize) or inhibitory (hyperpolarize)
some can be both, effect of NT is determined by receptor
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Acetylcholine
released by somatic motor neurons and some ANS neurons
cholinergic synapses
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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
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strychnine
antagonist of glycine (1904 olympics)
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Gamma AminoButyric Acid (GABA)
inhibitory NT
muscle tone, reduces anxiety
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norepinephrine
monoamine, catecholamines, biogenic amine
awaking from sleep, dreaming, reg. moods
memories of single events, adrenergic synapses
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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
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Schizophrenia
hypothesized to be due to dopamine overactivity
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cocaine and methamphetamines...
can cause psychosis and antipsychotic drugs act to block DA activity
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Positrom emission tomography (PET)
radio labeled tracer with metabolic property injected into blood stream. radiation detector can see where labeled molecules accumulate.
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Serotonin
Role in moods and attention; SSRIs = slective sertotonin reuptake inhibitors; activity blockedby LSD, enhancedby ecstacy
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nitric oxide
neurotransmitter; viagra, too unstable to be stored, produced on demand by enzymatic reaction, vasodilation, lipid soluble --\> diffusion, second messegner with cells
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neuropeptides
endorphins: natural opiates, reduce perception of pain under stressful siuations
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drug affects on synaptic transmission
stimulates release of AGO; inhibits release of ANT; stimulates AGO receptors, blocks ANT receptors; blocks AGO reuptake, inactivates AGO
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integration center
collection of neurons tht coordinates particular function
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neuronal pool
function group of neurons
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circuits
patterns of synaptic connections
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serial processing
ex: spinal relexes: chain of neurons
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parallel processing
input segregated into many pathways; one stimulus can promote many responses
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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
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epilepsy
recurrent seizures; durgs include antagonists of voltage gated sodum channels and agonists of GABA receptors, allow Cl into cell
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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
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visceral reflexes
autonomic reflexes, control systems other than muscular system; effectors: glands, smooth muscle, cardiac muscle
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monosynaptic stretch reflex
1 afferent, 1 synapse, 1 efferent, simplest and fastest
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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
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first order neuron
conduct impulses from somatic receptors to spinal cord or brain stem
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second order receptors
conduct imulses from spinal cord and brain stem to thalamus (decussate - crossover oppositeside of body, usualy at medulla)
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third order neuron
conduct impulses from thalamus to primary somatosensory area of cortex
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4 major somatosensory pathways
posterior column-lateral lemniscus pathway; spinothalamic tracts (anteror lateral); spinocerebellar (unconcious), trigeminothalamic
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motor and descending efferent pathways
pyramidal tracts - lateral and anterior corticospinal tract
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sensory and ascending afferent pathways
dorsal colmn medial lemniscus system - gracile fasciculus and cuneate fasciculus
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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
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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
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local circuit neurons
interneurons receive input from proprioceptors, maintain rhythmic activity andrefelxes without input form cerebrum; ex: cat still walks without brain
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direct somatic motor pathways
lateral corticospinal pathway: digital, precise, skilled movements; anterior : trunk and proximal parts of limbs
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direct somatic motor pathways
descend from brain to spinal cord w/o snyapsing; lateral and anterior corticospinal
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delta waves in awake adult =
brain damage
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consciousness
clinically defined on continuum: altertness, drowsiness/lethargy/ stupor, coma; involes large areas of cerebral cortex acting simultaneously
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loss of consciousness
fainting : brief, restricted blood flow to brain; coma: prolonges, oxygen use below normal, drain damage, tumors, infections , drugs ,etc
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sleep
state of partial unconciousness from which a person can be aroused, brain function continue
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carcadian rhythm
sleep/awake cycles, controlledby hypothalamus
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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
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most slow wave deep sleep occurs
in first half of night
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during REM
brain activity increases, slowed heart rate and ventilation rate, vaginal secretion and penile erection, dreaming occurs
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narcolepsy
sudden lapse into REM sleep, triggered by pleasurable event; also have cataplexy (loss of voluntary muscle control), orexins (wake up chemicals) destroyed
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insomnia
inability to get sufficient sleep, deficiency of orexins
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memory consolidation =
reinforcement due to frquent retreval of info
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influences transfer from STM to LTM
emotional state: alert and motivated, traumatic events; rehearsal, association, automatic memory: not all long term memories consciously formed
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declarative memory
facts, assiciated with contex in LTM
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nondeclarative memory
less consious/unconsious learning, acquired through experience, procedural, motor, emotional
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declarative memory circuits
temporal lobe areas important, ACh primes brain for memory formation, alzheimers = reduced ACh
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anterograde amnesia
consolidated memories retained, new inputs lost, can still learn new skills (procedural)
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retrograde amnesia
loss of memories from past
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procedural memory circuits
basal nuclei are important, dopamine is necessary (parkinson's interferes with procedural memory)
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long term potentiation
persistent strengthening of synaptic connections, essential for memory formation, binding of glutamate, results in Ca influx into postsynaptic cell
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