Neuroanatomy II Flashcards

(26 cards)

1
Q

Dendrites are…

A

receiving area of a neuron

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2
Q

What happens at the axon hillock?

A

Action potentials received from dendrites are gathered and decided if there is going to be a response

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3
Q

Function of glia

A

Supports neuron

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4
Q

Sensory neuron adaptation

A

Have several dendrites but not too many in order to localise where stimulus is coming from

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5
Q

Motor neuron adaptation

A

Receive signals from many different dendrites telling it what its exact response will be and communicates this to a finite region

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6
Q

What do interneurons do?

A
  • Receive and send out information

- Process information

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7
Q

Membrane potential

A

The voltage difference across the plasma membrane

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8
Q

Resting potential

A

Membrane potential of a neuron not sending signals

  • Formed due to different ion concentrations intracellular and extracellular
  • -70mV
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9
Q

Potassium concentration

A

Intra - 140

Extra - 5

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10
Q

Sodium concentration

A

Intra - 15

Extra -150

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11
Q

Chloride

A

Intra - 10

Extra - 120

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12
Q

Large anions e.g. Proteins

A

Intra - 100

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13
Q

How is resting potential maintained

A
  • Na+/K+ pumps (ATPase)
  • For every 3 Na + out, 2 K+ into cell
  • Creates electrical gradient as well as chemical gradient
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14
Q

What happens at resting potential

A

K+ channels are open

  • Net outflow due to chemical gradient (high to low conc. K+)
  • Not all K+ flows out due to electric gradient ( positive charge of K+ attracted to negative charge inside the cell
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15
Q

Nernst equation

A

Eion = 62mV (log [inside]/[outside])

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16
Q

What does nernst equation tell you

A

There are more K+ channels than Na+ channels

17
Q

How does an action potential occur?

A
  1. ) stimulus causes change in membrane potential
  2. ) Once threshold value (-55mV) is reached, voltage-gated Na+ channels open causing an influx
  3. ) Depolarisation occurs as all voltage-gated Na+ channels are open
  4. ) At +40mV Na+ channels deactivate. Voltage-gated K+ channels open causing an efflux
  5. ) Hyperpolarisation occurs
  6. ) There is an undershoot as membrane potential gpes below resting potential as K+ channels stay open for longer
18
Q

What is the refractory period?

A

A second action potential cannot be initiated

19
Q

Adaptations of an axon

A
  • Greater the diameter, the faster the AP

- Myelinated neurons have a faster AP

20
Q

Myelinated neurons

A
  • Insulated by myelin sheath which is formed by oligodendrocytes in CNS and schwann cells in PNS
  • Voltage-gated Na+ channels are located at nodes of Ranvier
  • Action potentials jump from one node to the next
    SALTATORY CONDUCTION
21
Q

Synapses in the brain

A
  • Chemical synapses
22
Q

EPSP

A

Excitatory post synaptic potentials cause depolarisation and bring about an AP

23
Q

IPSP

A

Inhibitory postsynaptic potentials cause hyperpolarisation

24
Q

Temporal summation

A

Two EPSPs produced in rapid succession at the same synapse

25
Spatial summation
Two EPSPs produced nearly simultaneously by different synapses on the same neuron
26
Summation
AP at synapses and dendrites are summed together