Ch 4: Neural Conduction And Synaptic Transmission Flashcards

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1
Q

Membrane potential

A

Difference in electron charge between inside and outside cell

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2
Q

Resting membrane potential

A

Inside neuron is negative with respect to outside

Resting membrane about -70 mV

Membrane polarized (carries a charge)

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3
Q

Ionic basis of resting potential (even distribution)

A

Factors contributing to even distribution. Of ions

  • random motion: particles move down their concent. Gradient
  • electrostatic pressure: like repels like, opposites attract
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4
Q

Ionic basis of resting potential (uneven distribution)

A

Factors contributing to uneven distribution

  • selective permeability to certain ions
  • sodium-potassium pump
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5
Q

Ionis contributing to resting potential

A

Na+
Cl-
K+
Negative charged proteins within neuron

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6
Q

Neural membrane

A

Passive and active factors that influence the dist. Of Na, K, Cl ions across neural membrane

Neuron is prepared to respond to strongly and rapidly to stimulus

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7
Q

Postsynaptic potential (psp)

A

Neurotransmitters bind at postsynaptic receptor

Depolarization: making membrane less negative

Hyperpolarization: making membrane potential more negative

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8
Q

Generation of action potential

A

One Epsp not enough to cause neuron to fire

Threshold of activation near axon hillock to generate firing

Integration of Psp and Epsp result in a potential of -65 mV to generate AP

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9
Q

Integration

A

Adding and combining a number of individual signals into one overall signal

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10
Q

Spatial summation

A

Integration of events at different places

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11
Q

Temporal summation

A

Integration of events at different times

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12
Q

Sodium and potassium channels

A

Opening and closing of voltage activated Na and K channels during the 3 phases of action potential: rising, repolarization, Hyperpolarization

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13
Q

Action potentials

A
  1. Occur in axons
  2. Any simulation beyond there’s hold = same AP
  3. In neuron all AP are equal in size and shape
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14
Q

All or none law

A

Size and shape of AP is independent of intensity of stimulus that initated it

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15
Q

Refractory periods

A

Absolute: impossible to imitate another AP

Relative: harder to imitate another AP

Limit rate of firing and prevent backward movement of AP

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16
Q

Psp

A

Decremental
Fast
Passive (energy not used)

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17
Q

AP

A

Nondecremental
More slow
Passive and active (use Atp)

18
Q

Axonal conduction of AP

A

Passive conduction along each mylin segment to next node ranvier

New AP generated at each node

Mylinated axon: instant, faster than nonmylinated

19
Q

Structure of synapse

A

Axodendrite: most common. Synapse onto dendrite spines

Directed synapse: site of release and contact are close proximity

Non directed: site of release and contact are spereated by some distance

20
Q

7 steps of NT action

A
  1. NT synthesized from enzymes
  2. NT stored in vesicles
  3. NT that leak are destroyed by Enzymes
  4. AP vesicles to fuse with presynaptic membrane and release NT into synapse
  5. released NT molecules bind with autorec.
  6. released NT bind to postsynaptic receptors
  7. released NT are deactivated by reuptake or enzymatic degradation
21
Q

Synthesis of proteins

A

Small NT are synthesized in bouton and packaged in vesicles

Large NT synthesized in cell
Body by ribosomes and transported by Microtubules

22
Q

Release of NT

A

Exocytosis: NT release
Arrival of AP at terminal opens voltage activated Ca channel

Entry of Ca causes vesicles to fuse with terminal membrane and release their contents

23
Q

Release and diffusion of NT

A

Usually 2 or 3 NT released from each neuron

24
Q

Ligand

A

Molecule that binds to another

A NT is a ligand of its receptor

25
Q

Ionotropic receptors

A

Associated with ligand activated ion channels

NT binds and an associated ion channel opens/ closes

If Na+ channels opened for example EPSP occurs

If K+ channels open for example IPsP occurs

26
Q

Metabolic receptors

A

Associated with signal

Effects slower, longer lasting, more diffuse, more varied,

  1. NT 1st messenger binds
  2. G protein subunit breaks away
  3. Ion channel open/ close or a 2nd message me
  4. 2nd messenger wide variety effects
27
Q

Postsynaptic receptors

A

On terminal at tip of an axon
2 types

  1. Autoreceptor: sensitive to the NT released by terminal bouton acts as negative feedback
  2. Hetereorecpetor: responds to chemical other than the NT released by terminal bouton
28
Q

Reuptake

A

Scoop up and recycle NT

29
Q

Enzymatic degradation

A

A NT broken down by enzymes

30
Q

Seretonin

A

Mood and temperature regulation, aggression, sleep cycles

31
Q

Glutamate

A

Main excitatory NT, participates in relay sensory info and learning

32
Q

GABA

A

Main inhibitory NT

33
Q

Norepinephrine

A

Brain arousal and other functions like mood hunger and sleep

34
Q

Anandamide

A

Pain reduction, increases in appetite

35
Q

Acetylcholine

A

Muscle contraction (PNS) cortical arousal (CNS)

36
Q

Dopamine

A

Motor function and reward

37
Q

Amino acid NT

A

Found at fast acting directed synapses in CNS

Glutamate and GABA

Aspertate and glycine

38
Q

Monoamines NT

A

Effects tend to be diffused

Atecholamines: synthesized from tyrosine (dopamine, norepinephrine, epinephrine)

Indolamines: synthesized from tryptophan (serotonin)

39
Q

Unconventional NT

A

Soluble gases: exsist only briefly (nitric acid and carbon monoxide)

Retrograde transmission: backwards communication

Endadcannabinoids: anandamine is 1 of 2 known Endo.

40
Q

Agonists

A

Increase or facilitate activity (nicotine)

Inc. synthesis of NT

Inc. # NT molecules by destroying degrading enzymes

Inc. release of NT molecules from terminal bouton

41
Q

Antagonistic

A

Decrease or inhibit activity

Blocks synthesis of NT

Cause NT to leak from vesicles and be destroyed

Blocks the release of NT from terminal bouton

Activates autoreceptors and inhibit NT release

Drug is a receptor blocker. Binds to postsynaptic receptors and blocks effect of NT