Lecture 4- Nerves Flashcards

1
Q

What are the valleys and ridges called

A

Gyri- ridges

Sulci- valleys

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2
Q

What are the four regions of the cerebral hemisphere

A

frontal
parietal
temporal
occipital

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3
Q

What are the three sections of the brainstem?

A

Midbrain
Pons
Medulla

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4
Q

What originates from the brain stem?

A

Cranial nerves

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5
Q

What is the role of the cerebellum?

A

Motor coordination
Balance
Posture

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6
Q

What is the role of the spinal cord?

A

Coordinates reflex actions

For nerve transmission

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7
Q

What are the 4 types of neurones and what do they look like?

A

1) Unipolar: 1 axonal projection
2) Pseudo-unipolar: single axonal projection that divides into two
3) Bipolar: 2 projections
4) Multipolar: Numerous projections

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8
Q

Name three types of Multipolar cells

A

Pyramidal cells
Purkinje cells
Golgi cells

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9
Q

Describe the structure of a neurone

A

1) Soma (cell body): contain nucleus & ribosomes
2) Axon: nerve fibre, from axon hillock on soma, branches into collaterals, covered in myelin
3) Dendrites: highly branched, not myelinated, receive signals

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10
Q

What are neurones?

A

Excitable cells of CNS

Non-dividing

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11
Q

What are the functions of astrocytes?

A
  • structural cells
  • cell repair
  • immune cells (facultative macrophages)
  • neurotransmitter release and reuptake)

CAN PROLIFERATE

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12
Q

Which two cells produce myelin? What is the difference between them two?

A

Oligoendrocytes and Schwann cells

1 Oligo–> myelinates many axons
but…
1 Schwann –> myelinates one axon segment and PNS nerves

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13
Q

What are microglial cells?

A
  • Similar to macrophages

- perform immune functions in CNS

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14
Q

What are Ependymal cells

A
  • Epithelial cells which line fluid filled ventricles

- regulate production and movement of CSF

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15
Q

What are the relative concentrations of ions at rest?

A

High EC- Na+ and Cl-
Low EC- K+
High conc gradient- K+

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16
Q

What is the RMP of neuronal cells?

A

-40mV to -90mV

17
Q

Which two channels are found in neuronal membranes and what are their states at RP?

A

Voltage gated Na+ channels (VGSCs)
Voltage gated Ca2+ channels (VGCCs)
Both are closed at RP

18
Q

What happens when membranes depolarise?

A

VGSCs open–> Na+ influx –> further depolarisation

19
Q

What happens when membranes repolarise?

A

VGKCs open–> efflux of K+ from cell –> membrane repolarisation

20
Q

What is the purpose of the Na+/ K+ ATPase pump after repolarisation?

A
  • After AP, there is an imbalance in Na+ and K+

- the pump restores the ion gradients

21
Q

Explain how the ATPase pump transports K+ and Na+

A
  • Resting configuration- Na+ enters and when channel is phosphorylated ions are transported
  • Active configuration- Na+ removed from cell–> K+ enters vestibule
  • Returns to Resting configuration- transported back into cell
22
Q

What are the characteristics of myelin which allow saltatory conduction?

A
  • high resistance

- low capacitance (ability to store electrical charge)

23
Q

What is saltatory conduction?

A

AP jumping between nodes of Ranvier

24
Q

Describe the sequence of events that allow transmission of an AP at a synapse

A

1) AP arrives at synapse
2) Causes VGCC to open
3) Ca2+ influx
4) Causes vesicles containing neurotransmitters to fuse with the presynaptic membrane
5) Neurotransmitter diffuses across synaptic cleft
6) NT binds with receptors on postsynaptic membrane, AP propagated here
7) Neurotransmitter broken down by synaptic enzymes
8) Reuptake of neurotransmitter by presynaptic knob