Exam 1 Flashcards
________are the functional units of the brain.
Neurons
______ play a supportive role in the brain.
Glial cells.
What are the two major cell types that make up the brain?
- Neurons
- Glial Cells
Cajal formulated the Neuron Theory which says_________
The cells forming the brain are not continuous with each other. Instead they are individual units
The neuron theory was proposed in opposition to the Reticular theory proposed by Golgi which postulates_______
That the brain is one big reticulum (not composed of individual cells) and thus the cytoplasm is a giant syncytium (a single cell or cytoplasmic mass containing several nuclei)
The reticular theory and the neuron theory both were supported using the _________ method
Golgi staining method. (Black reaction)
Cajal used a modified version of this method which allowed him to only color parts of the network (these parts were neurons)
What underlies the flow of information in neurons?
Polarity
How many types Neurons exist?
The number is unknown. It depends on how you classify them.
What are some different ways of classifying neurons?
Morphology
Transcription profile
Origin
Function
How many major types of glial cells are recognized?
6
Do Neurons undergo cellular division?
No. They are in a post-mitotic state
The major parts of a neuron are:
Cell body
Axon
Dendrites
Presynaptic sites
Make sure you can identify these on a diagram
Neurons are both _______ and ______ excitable
Chemically and electrically
This allows neurons to transform stimuli into electrical signals that can be transmitted over long distances
How do neurons communicate with each other?
Synapses
A neuron has both ______ and ________ sites.
Presynaptic and post synaptic sites
If neurons differentiated by the number of processes that originate from the cell body, how many types of neurons are there and what are they.
4 types:
1) unipolar neurons
2) bipolar neurons
3) pseudo-unipolar neurons
4) multipolar neurons
What are unipolar neurons?
They have only one process that bifurcates into a dendritic end and an axon an axonal end.
Most neurons in invertebrates are unipolar
What is a bipolar neuron?
The neurons have two processes that originate from the cell body:
One dendritic structure
One axonal structure
Many sensory neurons in vertebrates are bipolar
What are pseudo-unipolar neurons?
These neurons initially develop as bipolar cells, but the two cell processes fuse into a single continuous structure that emerges from a single point in the cell body
This type of neuron is found I. The somatosensory system.
What is a multipolar neuron?
These neurons usually have a single axon and multiple dendritic structures. They vary greatly in shape, especially in the extent, dimensions and intricacy of their branchings.
Most neurons in our brain are multipolar
If neurons are categorized by their function, how many types of neurons are there and what are they?
3 types:
1) sensory neurons
2) motor neurons
3) interneurons
What is a sensory neuron?
These neurons detect physical features of the outside world (e.g. a wavelength) and transform these features into electrical signals. They are mostly found in the peripheral nervous system
What are motor neurons?
These neurons transform electrical signals into behaviors- by regulating muscle tone.
What is an interneuron?
These neurons connect sensory neurons to motor neurons and integrate/process an electrical signal into a command signal.
Most of the brain is interneurons.
