Exam #1: Histology Review--Self Study Flashcards
What is the Perikaryon?
Cell body of a neuron, also known as the some
List the histological characteristics the perikaryon.
- Prominent round to oval euchromatic nucleus (protein synthesis is constant)
- Rich in free ribosomes & rER–> contains nissil bodies
- Dark nucleolus
- Rich in mitochondria to meet high energy requirements
*Remember that euchromatic= loosely packed & active
What are nissil bodies?
Stacks of rER that stain dark blue with acidophilic stains
What are microtubules? What is the function of microtubules?
- Long, rigid, & flexible structures that form the skeleton of the neuron
- Also aid in transport of materials to & from the soma
What are neurofilaments?
- Intermediate filaments of neurons
- “Muscles” of the neuron b/c of contractile properties
What is the axon hillock?
- Proximal end of the axon
- Funnel-shaped
- Pale staining b/c lacking rER
- Contains microtubules & microfilaments
What is lipofuscin?
- Old degenerated plasma membrane that cannot be fully degraded by lysosomes & accumulates in the cytoplasm
- Accumulates with age; thus, commonly called the “age pigment”
What is neuromelanin?
Byproduct of DA synthesis that commonly accumulates in the Substantia Nigra
What is the function of dendrites?
Increase the receptive surface area of the neuron
What is the initial segment of a neuron?
Part of the axon where the nerve terminal is generated (proximal)
What are the function of myelin?
- Increases conduction velocity
- Insulates axons
Does the axon contain rER?
NO!
What is Anterograde Transport? What facilitates anterograde transport?
- Flow of substances away from the cell body
- Kinesin micotubule motor protein
- Slow= No ATP
- Fast= ATP
What substances are transported via slow anterograde transport?
- Tubulin
- Actin
- Neurofilament proteins
What is Retrograde Transport? What facilitates retrograde transport?
- Flow of substances from the axon terminal to the cell body
- Dynein mitrotubule motor protein
- Fast Transport only (ATP)
- Viruses & toxins
What substances are transported via fast retorgrade transport?
- sER
- Vesicles
- Mitochondria
- Amino Acids
- Sugars
- Nucleotides
- Ca++
List the characteristics of bipolar neurons.
- Associated with the special senses (vision, hearing, balance, smell)
- Dendrite in the periphery
- Axon terminates in brainstem