Neuroscience Exam 3 Terms

Lectures 22-30. Exam 11/6.

Glia Cells

provide structural support for neurons, hold the nervous system together

Macroglia

astrocytes and oligodendrocytes

Microglia

immune cells of CNS

Astrocytes

most abundant and complex glial cells

Astrocyte Leaflets

spine-like protrusion, makes connections with other cells: synapses and Node of Ranvier

Astrocyte End-Foot

extends to make contact with blood vessels, access to the bloodstream, maintains the blood brain barrier (BBB)

Astrocyte Functions

provide nutritional support, maintain/reinforce blood brain barrier, maintain extracellular and synaptic environments

Astrocytes Express:

K+ channels, Glutamate Transporters, Metabotropic Glutamate Receptors

Astrocyte Membrane Depolarization

no axon, so no action potential → converted to other signals

Protoplasmic Astrocyte

grey matter, lots of cell bodies and synapses, handles ion channels

Fibrous Astrocyte

white matter, corpus callosum, axons, and oligodendrocytes, makes contact with Nodes of Ranvier and oligodendrocytes

Oligodendrocytes

has myelinated connections between neighboring axons, myelinating cells in the CNS, primarily lipids

Myelin Basic Protein (MBP)

anchor that allows for concentric circles of lipids to stay anchored to each other, helps glue/lock layers to one another

Oligodendrocyte Pre-Cursor Cells (OPC’s)

receives signal from a nearby active axon, signal then stimulated oligodendrocyte to grow a projection towards the source

Myelin Deposit

changes ability to conduct action potentials

Kir4.1 Channels

specialized K+ channels expressed by oligodendrocytes at the myelin-axon connection

Functions Stimulated by Kir4.1 Channels

remodeling and growth of myelin, stimulation of pre-cursor cells to become new oligodendrocytes, expresses transporters which shuttle glucose and glucose metabolites to the axon to maintain energy balance in active neurons

Microglia

bone-marrow derived immune cells that gain access to the CNS, undergo’s functional changes to become these cells

Ramified Microglia

stage I, surveys for damage/danger, small cell body with long projections

Bushy Microglia

stage II, resolves disfunction happening, by secretion of pro and anti-inflammatory factors (cytokines & chemokines), heals wounds, infections, and diseases

Amoeboid Microglia

stage III, huge cell body was less projections, causes enzymatic breakdown, breaks down disease and damaged tissue to clean up the nervous system

Microglia Motility

structurally flexible, can move, pushes and pulls out their projections

Microglia Receptors

monitors extracellular environment: neurotransmitters, cytokines & chemokines, danger associated signals, infection and disease

Microglia Signal

purpose is to depolarize the microglia and produce changes in the morphology to determine function

Microglial Functions

self-renews, recognizes and responds to antigens, cell damage, and danger-associated signals, produces and secretes signaling molecules that alter the function of neurons, astrocytes, and oligodendrocytes, maintenance of synapses (synaptic pruning), phagocytosis of cellular debris, and regulates the permeability of the blood brain barrier

Immunosenescence

microglia can adapt to the environment over time

Microglial Disease

overactive microglia, too much pro-inflammatory tone (depression & anxiety), too much phagocytosis (schizophrenia & multiple sclerosis)