Lecture 2 - Nerve Cell Structure and General Anatomy (Neurons and Glia) Flashcards
What type of macroglia are developmentally transient (last for a short period of time)? Are there any exceptions to this transientness?
The radial glia are developmentally transient with the exception of the Muller glia in the retina and the Bergmann glia in the cerebellum.
What words are the term “synapse” derived from?
Syn (together) and Haptein (clasp)
Both dendrites and axons have a microtubule network, but axons have more filamentous actin than dendrites (though dendritic spines are highly enriched in actin).
True
What type of neuron is pictured below?
Pseudounipolar Cell
If you pick up a hot coffee cup, why do you feel that you’ve picked up the cup long before you’ve realized how hot it is?
Large-diameter sensory neurons tend to be myelinated while small-diameter pain fibers tend to not be myelinated. As such, the sensory neuron that tells you you’ve picked up the cup transmits its signal much faster than the pain fiber that tells you how hot it is.
What are the 3 components of the tripartite synapse?
- Presynaptic Axon
- Postsynaptic Dendrite
- Associated Glial Astrocyte Process
What is block face electron microscopy?
Rather than sectioning the brain, you take a chunk of tissue and put it on the EM. You take a scan of the surface of the chunk, burn off a layer (just a few molecules thick), and then repeat.
What are the 4 compartments in neurons?
- Input Compartment
- Integrative Compartment
- Conductile Compartment
- Output Compartment
What 3 things do astrocytes do at synapses?
- Neurotransmitter Uptake, Processing, & Recycling: Pump excess glutamate into glia and away from synapses to improve temporal and spatial resolution of chemical neurotransmissions and prevent excitotoxicity.
- Responding to Neural Activity: Use their own neurotransmitter receptors (for glutamate, GABA, and ATP) to increase increase [Ca2+] in response to neural activity.
- Releasing Neuromodulatory Factors: Release gliotransmitters (D-serine, ATP, and glutamate) to modulate neuronal responses and influence synaptic plasticity.
True or False?:
Neurons with small, simple dendritic arbors can integrate large amount of information, such as for learning associations or storing memories.
False
Neurons with large, complex dendritic arbors can integrate large amount of information, such as for learning associations or storing memories.
True or False:?
Cajal proposed the Reticular Theory.
False
Golgi proposed the reticular theory.
What theory did Golgi propose and what did it dictate?
Golgi proposed the reticular theory which stated that the nervous system is made up of a network of fibres which are all fused into an interconnected mesh that function as a single unit.
True or False?:
Bipolar and unipolar cells tend to transmit information with high fidelity, such as in sensory transmission.
True
What are microtubules composed of?
Microtubules consist of helices of 13 tubulin dimers (alpha & beta). The end with beta-tubulin exposed is the end that can add more dimers and is called the (+) end.
True or False?:
Microglia are derived from ectoderm rather than yolk sac.
False
Microglia are derived from yolk sac rather than ectoderm.
Is glycine an excitatory or inhibitory neurotransmitter?
Inhibitory
What part of the neuron is the conductile compartment?
Axon
What disease is a result of CNS demyelination?
Multiple Sclerosis
What is the role of non-myelinating Schwann cells?
Non-myelinating Schwann cells bundle small-diameter (C-fibers) axons into Remak bundles and help maintain peripheral synapses.
True or False?:
Spine synapses are often times inhibitory and shaft synapses are excitatory.
False
Spine synapses are excitatory and shaft synapses are often times inhibitory.
What are the four main classes of microglia?
- Oligodendrocytes
- Astrocytes
- Ependymal Cells
- Radial Glia
What cells serve as dedicated immune cells in the CNS?
Microglia
What happens at the conductile compartment?
Action potentials are conducted.
What method of staining did Golgi use and how was it discovered?
Golgi used a silver impregnation stain. It was discovered by accident when he threw out a chunk of leftover brain along with chemicals used for photo reactions. The next day when he went to throw out his trash, he noticed the silver stain.
What cells myelinate in the CNS?
Oligodendrocytes
What theory did Cajal propose?
Cajal proposed the Neuron Doctrine.
What are dendritic spines?
Spines are filopodial protuberances that are studded along dendrites. At the tip of each spine is a postsynaptic density. Each of these can act as postsynaptic sites for a neuron as they are innervated with presynaptic cells.
What happens at the input compartment?
Excitatory (dendrites/spines) and inhibitory (soma) inputs are received.
True or False?:
Spines are the primary sites for excitatory synapses onto pyramidal neurons.
True
Where do microglia originate?
Microglia are born in the yolk sac during development and migrate into the brain early on.
True or False?:
One Schwann cell wraps many axons, but one axon is wrapped by just one Schwann cell.
False
One Schwann cell wraps jut one axon, but one axon is wrapped by many Schwann cells.
Where are ependymocytes found?
Ependymocytes line the ventricle are are foudn in the choroid plexus (which makes CSF).
What happens at the output compartment?
Action potentials cause the release of chemical neurotransmitters.
Is serotonin an excitatory or inhibitory neurotransmitter?
Excitatory
What are located at the postsynaptic density?
Neurotransmitter Receptors
What is the main role of ependymocytes?
The main role of epdenymocytes is to cirulate cerebrospinal fluid through beating their cilia.
What is pictured below?
Dendritic Spines
What do astrocytes look like?
They look like stars (hence astro-).
What is an action potential from a presynaptic cell converted into in a postsynaptic cell?
An EPSP or IPSP