89. neurotransmitters and transporters 90. neuroglia Flashcards
what are neurotransmitters made from and where are they stored and how are they released
amino acids
stored in vesicles in presynaptic neuron
released into synaptic cleft by exocytosis
received by receptors on postsynaptic membrane
opens either ion channels or initiate second messenger cascades
What do neurotransmitters from excitary synapses cause
what do neurotransmitters from inhibitory synapses cause
postsynaptic Na+ channels open causing influx then depolarization in postsynaptic neuron or effector cell
open Cl- or other anion channels causing hyperpolarization of postsynaptic neuron making membrane more negative and resistant to depolarization
What is the chemical transmiter used at neuromuscular junctions or some synapses in CNS
acetylcholine
what are neuroglia cells
cells that arent neurones but maintain homeostasis, form myelin, provide support and protction for neurones
where do glial cells develop from and their functions
progenitor cells of embryonic neural plate
- hold neurons in place
- supply nutrients and oxygen to neurons
- isolate neurons from one another
- destroy pathogens and remiove dead neurons
- help neurons form synaptic connections
What are the 6 major types of glial cells
oligodendrocyte (CNS): creates myelin sheath around multiple axons for electrical insulation
astrocyte (CNS): most abundant macroglial.Structural and metabolic support of neurons, especially at synapses; repair
processes
ependymal cells (CNS): creation and secretion of cerebrospinal fluid and make up blood-CSF barrier
Schawann cells (PNS): provide myelination to axons in PNS
satellite cells ( PNS): structural and metabolic support for neural bodies
What is microglia?
orginates from circulating blood monocytes
involved with immune defece in CNS and removes damaged synapses (macrophage qualities)
they proliferate when brain is damaged and they act like antigen presenting cells
