Nerve Tissue: Neurons + Glial Cells Flashcards
Nerve Tissue
is composed of cells (neurons) that are specialized at conveying information and their support cells (glial)
What is the Neuron doctrine (1891)?
individual neurons serve as the signaling elements of the nervous system
How many neurons are in the human body?
> 100 billion neurons that vary in size and shape
How do neurons receive, process, and transport signals?
Neurons utilize electrical and chemical mechanisms
What are electrical signals used for?
To convey information rapidly from one neuron to another
What are chemical signals used for?
To carry information between part of one neuron and part of a second neuron or effector cell (via synapse)
Why are neurons structured into regions?
So that organelles are distributed in a pattern that supports neuronal function
Neurons-Regions: Cell body (a.k.a Perikaryon)
Contains the nucleus and surrounding cytoplasm, but does NOT include cell processes
Neuron-Regions: Cell Body Structure
Nucleus
-Euchromatic (pale-staining; active in RNA synthesis) with a prominent nucleolus–> 92% of the human genome is euchromatic.
Neuron-Regions: Cell Body Structure
Cytoplasm
- Abundant rough endoplasmic recticulum (a.k.a RER & Nissl substance) and polysomes
- Well developed cytoskeleton
Neuron-Cell Body Functions
(1) Trophic (related to nutrition/metabolism) center of the cell
(2) Receptive to stimuli
Neuron-Regions: Dendrites
Elongated processes emanating from the cell body; most neurons have multiple dendrites
Neuron-Regions: Dendrites Structure
Short, tapered, and highly branched
Neuron-Regions: Cell Body Structure
Large and spherical in shape
Neuron-Regions: Dendrites Structure
Cytoplasm
Organelles are similar to cell body except their are NO Golgi complexes
Neuron-Regions: Dendrites Structure
Dendritic Spines
Specializations at some synapses