Introduction to Neuroanatomy Flashcards
What are the four basic morphological types of neurons?
Which is most common?
Which is associated with dorsal root ganglia?
•1 Unipolar
•2 Bipolar
•3 Multipolar
–Most neurons
•4 Pseudounipolar
–Dorsal root ganglia
Identify the types of neurons shown.
- 1 Unipolar
- 2 Bipolar
- 3 Multipolar
- 4 Pseudounipolar
What does myelin do? How?
Insulates the axon, by blocking ion channels. Enabling saltatory conduction.
A unipolary neuron has how many dendrites?
Zero
Do humans have many unipolar neurons?
No, they are mostly in invertebrates
How are the branches of neurons classified?
Primary, secondary, tertiary, etc
How many dendrites do pseudounipolar neurons have?
Zero, but one end of the axon works essentially as a dendrite.
What is the myelinating cell of the CNS?
Oligodendrocyte
How do Schwann cells do their thing?
Kool-aid man style. Sacrifices self to myelinate target
What role does an astrocyte have in the tri-partite synapse?
Essential…
enables the synapse to exist, provides nutrients, mediates neurotransmitter levels, vasculature, etc.
What is a quanta of NT?
What ever amount of NT that is released by a neuron in response to an action potential.
What is the most prevelant excitatory NT?
Glutamate
What are the two main ways glutamate serves as an NT?
Ionotropic
Metabotropic
Glutamate is ionotropic for what three receptors?
–AMPA—Na+ influx
–Kainate
–NMDA—Requires depolarization, some Mg2+ and then Na+ and Ca2+ influx in addition to glutamate binding
What receptors is glutamate metabotropic for?
MGLURS
What is an important clinical correlate for glutamate?
It can be excitotoxic
NMDA receptors are currently a hot topic for what two things?
Memory formation and epilepsy
What is the most prevalent inhibitory NT?
GABA
What happens due to long term use of antiepileptics?
Retardation
GABA can act ionotropically or metabotropically. What are the receptors it associates with in each way?
•Ionotropic
–GABA A—Cl- influx
•Metabotropic
–GABA B—GPCR and 2nd messengers
–GIRK channels trigger IPSPs by expelling K+
What are two examples of agonists of Ionotropic GABA A receptors?
Benzos
Alcohol
Glycine is a NT found all throughout the body, where is it particularly active?
Spinal cord
Ach is synthesized from coA and choline with the CHAT enzyme, and degraded by acetyl cholinesterase. What are the ionotropic and metabotropic receptors?
Ionotropic - Nicotinic (skeletal muscle, primarily found in PNS)
Metabotropic - Muscarinic (mostly in CNS)
Where are GABA receptors concentrated on the neuron?
The axon hillock
Is glycine inhibitory or excitatory?
Inhibitory
All motoneurons use what NT?
Ach
Myasthenia gravis is an autoimmune disorder, what is it against?
Nicotinic receptors
What is a treatment target for myastheia gravis?
Acetyl cholinesterase inhibitors
Dopamine receptors are metabotropic. What are the excitatory and inhibitory receptors?
»D1 (Excitatory) and D2 (Inhibitory) receptors
Dopamine works in two major areas: SUBSTANTIA NIGRA and VENTRAL TEGMENTAL AREA (VTA).
What do each of these do?
»Substantia nigra is involved with basal ganglia circuit and loss of dopamine here is cause of Parkinson’s Disease (Mostly motor component)
»VTA involved with both addiction and schizophrenia (Mostly mental part)