Nervous System Intro Flashcards
Name the parts of a neuron and their function
Soma - cell body, support metabolic and synthetic needs of the cell; nucleus is contained within the soma
Dendrites - Extensions of the cell membrane; receive information
Axon - information conduction
Axon Terminals - Distal end of axon filled with vesicles (neurotransmitters contained within vesicles)
Name the Types of Neurons
Multipolar - many dendrites, single axon; 2 types:
- Pyramidal: 1 primary apicle dendrite, axon from base, send information long distances
- Stellate: Many dendrites no definitive axon, send information locally
Bipolar - one dendrite, one axon
Unipolar/Pseudounipolar - Single process that acts as axon and dendrite (sends and receives information); tend to be in the periphery; pseudounipolar start as bipolar and as they develop the axon and dendrite slide off to one side
Describe Interneurons
Small neurons with all connections within a small area; CNS only; Tend to be multipolar; process information
Projection neurons
Larger afferent neurons with long axons connecting different parts of the nervous system; CNS & PNS
- Sensory: Directly sensitive to various stimuli; carry ascending information in the spinal cord
- Motor: Efferent neurons that end directly on a muscle, gland, or autonomic neuron; carry descending information in the spinal cord
Nuclei
Specific areas of functionally related cell bodies
Cortex
Area where grey matter forms a layered surface that covers some parts of the CNS
White Matter
Myelinated axons; subdivisions in axon bundles are called tracts, which are named for the parts that they connect
Organelles of Neurons
Nucleus - DNA, Nucleolus (RRNA synthesized here)
Mitochondria - Produces ATP
Rough ER - protein synthesis
Golgi Apparatus - packages proteins before they are sent out
Cytoskeleton Components
Microtubules - organelle and vesicle transport
Neurofilaments - mainly structural, regulate axon diameter
Microfilaments - helps with anchoring cells as well as acts as a shuttle to/from the membrane; also helps with cell movement from outside the cell
Axon hillock
Attachment of axon to cell body; site of action potential initiation
Kinesin
Anterograde transport away from cell; goes down to axon terminal
Dynein
Retrograde transport towards the cell body; allows for organelles or vesicles to walk towards the cell body
Astrocytes
Structural role; serve as electrical insulators; help provide blood brain barrier; help regulate ionic concentration gradient; absorb excess neurotransmitter; help form glial scar
Microglia
Become macrophages when activated; part of immune/pathology response to remove pathogens and neuronal debris
Specialized immune system of the CNS
Ependymal cells
Epithelial lining of ventricles; cover/form the choroid plexus for CSF production and circulation; help makes blood/CSF barrier
Oligodendrocytes (Myelin CNS)
Single cell has many branches that encircle sections of axons
White matter for CNS
Schwann Cells (Myelin PNS)
Single cell creates myelinated internode in PNS; allow axon regeneration
White matter in PNS
Nodes of Ranvier
Areas between myelination along axons where ion channels reside
