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Physiology 2: neuro > Neurons and Glia > Flashcards

Flashcards in Neurons and Glia Deck (37)
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1
Q

Anterograde transport

A

A cellular process responsible for the movement of substance from the cell body to the distal parts of a cell

2
Q

Aspinous neuron

A

A neuron lacking dendritic spines

3
Q

Astrocyte

A

A star-shaped glial cell of the central nervous system

4
Q

Axon

A

The long thread-like part of a neuron along which impulses are conducted from the cell body to other cells

5
Q

Axon collateral

A

Branches off a neuron’s main axon

6
Q

Axon hillock

A

The site in the soma where membrane potentials propagated from synaptic inputs are summated before being transmitted to the axon

7
Q

Axon terminal (bouton)

A

The enlarged club-shaped endings by which axons make synaptic connections with other neurons or effector cells

8
Q

Axoplasmic transport

A

A cellular process responsible for the movement of substances from the soma down the axon

9
Q

Bipolar neuron

A

A neuron with two neurites extending from the soma

10
Q

(“Reticular theory”) by Camillo Golgi (1843-1926)

A

Golgi proposed that neurons were fused together to form a continuous reticulum (or network)

11
Q

(“Neuron doctrine”) by Santiago Ramon y Cajal (1852-1934)

A

Cajal proposed that neurons were not continuous but communicated by neuron-neuron contact

12
Q

Nissl stain

A

comprised of a basic dye (e.g. cresyl violet) – stains the nuclei and Nissl bodies of neurons

13
Q

Golgi stain

A

comprised of a silver chromate solution – stains neurons and their projections

14
Q

Light microscopy

A
  • Standard light microscopy has a limit of resolution of 0.1 𝝻M
  • Space between neurons approximately 0.02 𝝻M (or 20 nM)
15
Q

Electron microscopy

A
  • Electron microscopy has a limit of resolution of 0.1 nM

* Our insights into the fine structure of neurons have come from electron microscopy

16
Q

Structure of simple prototypical neuron

A
  1. Cell body (soma)
  2. Axon
  3. Dendrites
17
Q

Cell body organelles

A
  • Nucleus
  • Rough endoplasmic reticulum (RER)
  • Smooth endoplasmic reticulum (SER)
  • Golgi apparatus
  • Mitochondrion
18
Q

Microtubules

A

• A polymer of the protein tubulin – located in axons and dendrites and important in axoplasmic transport

19
Q

Microfilaments

A

• A polymer of the protein actin – found throughout the neuron but particularly abundant in axons and dendrites

20
Q

Neurofilaments

A
  • A type of intermediate filament – particularly abundant in axons and important in regulating axonal shape
  • Promising biomarker for neurodegenerative disorders (e.g. Alzheimer’s)
21
Q

What are axons?

A

Axons are highly specialised neuronal projections that conduct nerve impulses (or action potentials) within the nervous system

22
Q

What are axons comprised of?

A
  • Axon hillock – tapers away from the soma to form the initial segment of the axon
  • Axon ‘proper’ – axon can branch to form axon collaterals (and recurrent collaterals)
  • Axon terminal – site at which the axon meets other neurons at a synapse
23
Q

Glial cells

A
  • Myelin is a membranous sheath that wraps around and insulates axons
  • Gaps in myelin sheath are Nodes of Ranvier – highly enriched in voltage-gated Na+ ion channels
24
Q

What are dendrites?

A
  • Dendrites are highly specialised neuronal projections that receive synaptic inputs from other neurons
  • Dendritic spine structure is sensitive to type and amount of synaptic activity
25
Q

Different dendrites?

A

Stellate

Pyramidal

26
Q

Neuron projects

A

Unipolar
Bipolar
Multipolar

27
Q

Connections

A

Sensory
Motor
Interneurons

28
Q

Axon length

A

Golgi type I and Golgi type II

29
Q

What are astrocytes

A

Astrocytes are star-shaped glial cells that function to regulate – in a number of ways – the extracellular environment of the brain.

30
Q

Astrocytes

A

• Astrocytes regulate the extracellular environment in the brain by, for example, enclosing synaptic junctions and actively removing neurotransmitters from the synaptic cleft

31
Q

Microglia

A

Phagocytosis of neuronal and glial debris (e.g. sites of injury)
• Synaptic connection remodelling
• Directing neuronal migration during brain development

32
Q

Ependymal cells

A
  • Osmotic regulation of cerebrospinal fluid
  • Flow of cerebrospinal fluid
  • Directing cell migration during brain development
33
Q

What are ependymal cells?

A

Ependymal cells are a type of glial cell that provides the lining of the ventricular system of both the brain and spinal cord.
Ependymal cells line the ventricular system and act as a physical barrier separating brain tissue from cerebrospinal fluid (CSF)

34
Q

What are microglia?

A

Microglia are a type of glial cell that function as phagocytes within the nervous system to remove neuronal and glial debris.
Microglia – which account for approximately 5-15% of total CNS cell number depending on anatomical region – are broadly distributed in the brain and spinal cord

35
Q

4 types of glial cells

A
Astrocytes 
Microglia 
Ependymal cells 
Oligodendrocytes/Schwann cells 
Glial cells are the “support cells” within the nervous system and can be classified into four categories based on structure and function.
36
Q

Oligodendrocytes

A

Oligodendrocytes (pictured) are situated in the central nervous system (CNS)

37
Q

Schwann cells

A

Schwann cells are situated in the peripheral nervous system (PNS)