Flashcards in Chapter 2 - Neurons and Glia Deck (20):
Challenges to study of brain?
Size 0.01mm across
Development of microtome to slice
Uniform colour spawned stains
Wha tis histology?
Microscopic study of structure of tissues
What did Nissl create?
Some dyes stain nuclei of all cells plus clumps of material surrounding nuclei of neurons known as Nissl bodies are Rough ER
Nissl stain differentiates between neurons and glia, and allows study of cytoarchitecture of neurons in different parts of brain
We know now that each region performs different function
Whst did Golgi do?
Makes small number of neurons become darkly coloured in entirety
Showed neuronal body, region of neuron around nucleus, only small fraction of structure of neuron
What are names for body containing nucleus?
Soma, cell body, perikaryon
What are axons, dendrites?
What did Cajal say?
Neurons communicate by contact not continuity
What’s in soma?
Cytosol: potassium fluid with salt
How are mistakes made in DNA?
Gene copy number variations - overcopying
Single nucleotide polymorphisms - minor misspelling
1. One gene deleted
2. Genes introduced and overexpressed
3. Native gene replaced by modified gene
What distinguishes the axon from soma?
1. No rough ER extends into axon
2. Few free ribosomes in mature axons
3. Protein composition of axon membrane fundamentally different from soma membrane
4. No protein synthesis in axon. All originate in soma
What is axon collateral?
Does speed depend on diameter?
Where does axon begin? End?
How does cytoplasm of axon terminal differ from axon’s?
1. Microtubules don’t extend into terminal
2. Terminal contains numerous small bubbles of membrane called synaptic vesicles
3. Inside surface of membrane facing synapse has dense protein covering
4. Axon terminal cytoplasm has many mitochondria (high energy demand)
What moves material from soma to terminal in anterograde axoplasmic transport? Back to soma in retrograde transport?
What do dendritic spines do?
Punching bags hanging off dendrite
Believed to isolate various chemical reactions triggered by some types of synaptic activation
Unusual changes have been shown to occur in brains of individuals with cognitive impairments
How are neurons classified?
1. Number of neurites (axons and dendrites). Neurons with single neurite unipolar, two bipolar, more multipolar
2. Dendrites. In cerebral cortex are stellate and pyramidal cells. Also spiny and aspinous. Pyramids are all spiny, stellates either
3. Connections. Primary sensory neurons, motor neurons, interneurons (most)
4. Axon length. Golgi type 1 stay in brain (projection). Golgi type 2 stay local (local circuit). Pyramidal long 1, stellate short 2.
What are cholinergic cells?
Motor neurons releasing acetylcholine