Classification of Neurons (Quiz 2) Flashcards
Classification of neurons is based on function. There are 3 neuronal types. What are they?
1) motor
2) sensory
3) interneuron
note: most neurons are interneurons
Based on the number of processes, there are 4 neuronal types. What are they?
1) unipolar
2) bipolar
3) pseudounipolar
4) multipolar
note: all of these have to have a soma and axon!
also, multipolar neurons are the most common
The cylindrical process called an _________ conducts info away from the cell body
axon
The axon gives rise to a series of terminal extensions called ____________ that form synapses on other neurons
teledondria
Neuronal signaling is _______________
unidirectional (AP can only go in 1 direction)
T/F: neurons are both electrically and chemically excitable
true!
electrically through voltage gated channels
chemically through neurotransmitters
What is a multipolar neuron?
has many dendrites/branching from the cell body
What is a bipolar neuron?
-soma is in the center of 2 processes
-1 axon heading to the axon terminal, and the other process is all the dendrites uniting into 1 long process
-the teledondria have multiple synapses
What is a pseudounipolar neuron?
-dendrites unite into 1 process then the axon starts
-soma is off to the side
What is a unipolar neuron?
-only 1 process is seen
-soma is on one end
-dendrites unite in middle and then lead into an axon
What is an apolar neuron?
-an anaxonic neuron
-it appears to not have an axon but it does
The only grey matter in the PNS is called….
ganglia (its where a bunch of cell bodies are siting next to each other from pseudo-unipolar neurons)
When do unipolar neurons form?
during development but are rare in the adult brain
Unipolar neurons are typically _________ neurons with receptors located within the skin, joints, muscles, and internal organs
sensory
Where are the cell bodies found of unipolar neurons?
in spinal and cranial nerve ganglia
Bipolar neurons are in the ________, olfactory epithelium, and ganglia of the vestibulocochlear nerve (CN VIII)
test q
retina (involved in vision)
Which neurons are only known to be sensory neurons and are involved in the transmission of senses like smell, taste, sight, hearing, touch, balance, and proprioception?
bipolar neurons
The vast majority of vertebrate neurons are _________
multipolar
Which neuron class based on processes is this?
-motor neurons and interneurons
-pyramidal neurons in the cererbral cortex
-purkinje cells of the cerebellar cortex
test q
multipolar neurons
Multipolar neurons form 2 groups according to the length of their axon. What are the 2 groups?
1) long-axon multipolar neuron (Golgi type I)
2) short- axon multipolar neurons (Golgi type II)
Which type of multipolar neuron is this?
-have axons that pass from their neuronal cell body and extend for a considerable distance before ending
-form commissures, association, and projection fibers of the CNS
-also known as projection neurons (note: both multipolar and interneurons can be projection neurons- its a broad term)
-these neurons form peripheral nerves and tracts of the CNS
long axon multipolar (golgi type I) neurons
Which type of multipolar neuron is this?
-short axons that remain near the cell body of origin
-have a star like appearance
-they do not send branches out of the gray matter
-numerous in the cerebral cortex, cerebellar cortex, and retina
-works functionally as an interneuron
short axon multipolar (golgi type II) neuron
The major technique available for studying the shapes and sizes of neurons was _____________, a method that infiltrates all the processes of a small percentage of neurons with heavy metals and it reveals little about the function of an individual cell. Micropipette electrodes can be used as mini needles to inject tracers, dyes, markers, and antibodies.
golgi staining
What is immunocytochemistry?
-its genetic tags and genetic manipulation to express fluorescent markers
-used to identify neurotransmitters and enzymes
The _______ stain reveals the _________ of the arborizations of cortical neurons by completely staining a small percentage of them
test q
Golgi, shapes
The ________ method stains the ____________ of all neurons, showing their shapes and packing densities
test q
Nissl, cell bodies
The Weigert method stains _________, revealing the horizontally oriented bands of Baillarger and the vertically oriented collections of cortical afferents and efferents
myelin
