Chapter 2 - Neurons and Glia Flashcards
Reticularism
- neurites of diff cells are fused together to form a continuous reticulum (network) like the arteries of the circulatory system
- Camillo Golgi was a big proponent of this (used golgi stain)
Neuron Doctrine
- neurites of diff neurons are not continuous with each other and communicate by contact, not continuity
- Santiago Ramon y Cajal was a big proponent of this (used Golgi stain)
- Eventually proven to be correct through EM in the 1950s
Franz Nissl
- Nissl stain - class of basic dyes that stain the nuclei and Nissl bodies (clumps of cells surrounding the nuclei)
- distinguishes btwn neurons and glia
- enabled histologist to study the cytoarchitecture of neurons, led to realization that the brain consists of many specialized regions
Camillo Golgi
- Golgi stain - silver chromate solution that makes a small percentage of neurons become darkly colored in their entirety
- showed that the portion of the Nissl bodies are only a small fraction of the total structure of the neuron
- showed that neurons have at least two distinguishable parts: cell body and neurites
Santiago Ramon y Cajal
- used golgi’s technique to visualize the circuitry of many regions of the brain
- father of neuroscience
Who coined the term neuron?
Heinrich Wilhelm Gottfried von Waldeyer-Hartz
Cell body. What is the importance or function of this part of the neuron? Which organelles does it contain
that are not present in some other parts of the neuron? How are these organelles critical for
neuron function? Are these structures found in gray matter or white matter?
- Contains the nucleus, which contains the DNA, transcription and translation occurs in the nucleus as well
- Contains RER (ribosomes conduct protein synthesis), SER (protein processing), Golgi (sorts and sends out proteins), Mitochondria (site of cellular respiration)
- found in grey matter
Dendrites. What do they look like, how do they attach to the soma, what is their function? In what
important ways are they different from axons. Are these structures found in gray matter or
white matter?
- resemble branches of a tree
- carry info towards the cell body, and mainly do short distance signaling (axons do the opp.)
- found in grey matter
What about dendritic spines - what are they and what interesting properties do
they have that make them so interesting to neuroscientists?
- dendritic spines are specialized structures that receive specific types of synaptic input, also found in grey matter
- believed to isolate various chemical reactions that are triggered by synaptic transmission
- unusual changes/underdevelopment in spines have been shown to occur in the brains of individuals with cognitive impairments
- unusual morphology is fascinating to scientists
Axons. What do they look like, how do they attach to the soma, what is their function? In what
important ways are they different from dendrites? Where are axons found? Gray matter, white
matter or both?
- long segment that is highly specialized for the transfer of info over distances in the nervous system
- attach to the soma with the axon hillock
- mainly do signaling over long distances, carries information away from the cell body
- found in white matter
What are the advantages/disadvantages of Nissl staining compared with silver chromate staining?
- Nissl stains only stains areas of a cell that produce a large amount of proteins, Golgi stains the entire cell
- distinguished btwn neurons and glia bc it doesnt stain the entire cell, golgi stains the entire neuron to become darkly colored in its entirety
How are the mechanisms of gene transcription and protein synthesis related/coordinated? What
organelles carry out these functions? Why are these processes so vital to neuron function? How does
this relate to Nissl bodies, and how can these structures be detected?
- if a gene is not transcribed in a cell, it cant be used to make a protein in that cell
- transcription occurs in the nucleus, protein synthesis occurs in the RER
- protein synthesis provides the raw materials needed to generate and differentiate new synapses
- Nissl stains stain the areas of the cell that produce the most protein (RER and free polyribosomes)
What are
some important ways we discussed that the cytoskeletal is vital to proper neuron function?
What are some types of neuropathology (disease) that involve cytoskeletal dysfunction?
- gives/helps support the neurons shape
- determines general organization of cytoplasm
- Alzheimer’s
Neuron Cytoskeleton. What are the three major cytoskeletal elements in neurons (along with all other cells).
- microtubules - long, thick, hollow, made of tubulin molecules (resemble string of pearls), assembly of microtubules is regulated by microtubule-associated proteins (MAPS)
- Microfilaments - longitudinal braid of thin polymers made of actin that are anchored to the membrane of the neuron by fibrous proteins
- neurofilaments - most closely resemble the bones and ligaments of the skeleton, made of long proteins, mechanically very strong
What are the 3 major structural classifications neurons? Can you draw them and label the
soma, dendrites, and axon? Which type of neuron is most common? What function are the
other types (motor or sensory)? What are some specific examples/locations that we discussed?
(e.g. pyramidal neurons are multipolar neurons located in the cerebral cortex).
- Unipolar, Bipolar and Multipolar, (pseudounipolar is also a classification)
- Multipolar are most common
- Multipolar is integration and, unipolar is sensory, and bipolar is sensory, (pseudounipolar is special sensory)
- Pyramidal is an ex of multipolar
- Brush cells are a type of unipolar cell
- neurons in the retina are bipolar
