Neuroanatomy II Flashcards Preview

PY5030 CNS and Mental health > Neuroanatomy II > Flashcards

Flashcards in Neuroanatomy II Deck (26)
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1
Q

Dendrites are…

A

receiving area of a neuron

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

3
Q

Function of glia

A

Supports neuron

4
Q

Sensory neuron adaptation

A

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

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

6
Q

What do interneurons do?

A
  • Receive and send out information

- Process information

7
Q

Membrane potential

A

The voltage difference across the plasma membrane

8
Q

Resting potential

A

Membrane potential of a neuron not sending signals

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

Potassium concentration

A

Intra - 140

Extra - 5

10
Q

Sodium concentration

A

Intra - 15

Extra -150

11
Q

Chloride

A

Intra - 10

Extra - 120

12
Q

Large anions e.g. Proteins

A

Intra - 100

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
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
15
Q

Nernst equation

A

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

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
Q

Spatial summation

A

Two EPSPs produced nearly simultaneously by different synapses on the same neuron

26
Q

Summation

A

AP at synapses and dendrites are summed together