L6 (pt.2) Flashcards

1
Q

Graded potentials

A

A small change in membrane potential (depolarizing or hyperpolarizing)

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2
Q

Where do graded potentials (gp) occur?

A

Sensory receptors ➡️ receptor potential

Cell bodies/ dendrites ➡️ graded potential

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3
Q

Epsp-Ipsp cancellation

A

Excitatory and inhibitory graded potentials cancel each other out

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4
Q

Spatial summation

A

Excitatory potentials from many neurons trigger threshold potential

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5
Q

Temporal summation

A

Many excitatory potentials from one neuron triggers threshold potential

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6
Q

What are the two ways to reach threshold potential?

A

Temporal threshold ➡️ one neuron creates many graded potentials

Spatial summation ➡️ many neurons create graded potentials

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7
Q

What are graded potentials used for?

A
  1. Initiates information flow in sensory neurons
  2. Conducts information from cell bodies/ dendrites to initial segment of axon
  3. Initiate action potentials in cardiac muscle
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8
Q

What are properties of graded potentials?

A
  1. Depolarizes (epsp) or hyperpolarize (Ipsp)
  2. Amplitude modulate
  3. Amplitude delays w/ distance
  4. Can be summed ➡️ temporal or spatial
  5. Inhibited by synaptic transmission
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9
Q

Synaptic transmittion

A

Conduction across a synapse (leading to graded potential)

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10
Q

Synapse

A

Region of communication between two neurons

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11
Q

What are the two types of synapses?

A

Electrical and chemical

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12
Q

Electrical synapses function is to

A

Rapidly synchronize electrical events

  • ions pass through gap junctions b/w cells
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13
Q

Chemical synapses function is to

A

Turn post synaptic neurons on/off by creating Epsp & Ipsp

  • uses ligand gated ion channels
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14
Q

What are the 2 mechanisms for opening ion channel receptors?

A

Ligand- gated receptor & G protein receptors

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15
Q

Explain the mechanism for neurotransmitter release

A
  1. Action potential reaches axon terminal
  2. Voltage gated ca2+ channels open ➡️ca2+ diffuses down concentration gradient into cell
  3. Ca2+ binds to receptor protein (synaptotagmin) in cytoplasm
  4. Ca2+ protein complex stimulates fusion/ exocytosis of neurotransmitter
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16
Q

Nicotinic acetylcholine (ach) receptor is an example of what?

A

Ligand gated channel

17
Q

What are the two types of acetylcholine (Ach) receptor?

A

Nicotinic = Epsp

Muscarinic = Ipsp

18
Q

Where are ligand gated channel receptors found?

A

Post synaptic neuron membrane

19
Q

What three components are found in the plasma membrane of a G protein receptor?

A

G protein, effector, receptor

20
Q

Explain the process of a G protein using Ach as an example

A
  1. Ach binds to receptor
  2. G protein subunits dissociates ( alpha- beta - gamma)
  3. G protein binds to k+ channel, causing it to open
21
Q

Where are g Proteins found?

A

At the post synaptic neuron membrane

22
Q

How do you deactivate neurotransmitters?

A

By degrading ( destroying them/ breaking them apart)

Or reuptake

23
Q

The production of Ipsp/Epsp depends on the ________ of ion channels

A

Nature

24
Q

Neurotoxins

A

Disrupts normal signaling b/w neurons and muscles

25
Q

What are so,e effects of neurotoxins?

A
  • they block channels & allow for no breakdown
26
Q

Neural pathways is defines as

A

Series of communicating neurons

27
Q

What are the four neural Pathways?

A
  • simple reflex arc
  • complex reflex arc
  • sensory pathways
  • motor pathways
28
Q

What is a simple reflex arc, and give an example

A

A series of communicating neurons

Ex. Pain reflex

29
Q

Distinguish between a reflex and a reflex arc

A

Reflex = automatic, involuntary response to stimulus

Reflex arc = neural pathway

30
Q

What is an example of a complex reflex arc

A

Crossed reflex arc

  1. Flexor contracts due to synapse of Epsp & extensor relaxes drawing foot away — Ipsp
  2. IN OTHER LEG - extensor contracts & flexor relaxes to support weight
31
Q

What are sensory pathways and what are involved in Order to reach Ap consciousness?

A

Ascending tracts - arrive to the brain

  • 1 sensory neuron and 2 interneurons
32
Q

What are motor pathways and what are involved in order to reach Ap consciousness?

A

Descending tracts - deliver stimulus from brain ➡️ muscle/ gland

  • 1 motor neuron and 1 interneuron
33
Q

What factors contribute to neural complexity?

A
  1. Convergence & divergence
  2. Summation ( time and space)
  3. Synapses ( Epsp & Ipsp)
34
Q

The difference between covergence and divergence?

A

Covergence = many cells include 1 cell

Divergence = 1 cell influences many cells