Midterm 1 Flashcards
(73 cards)
Structure of Neurons
-soma/cell body w/ nucleus
-dendrites (receiving end)
-axon terminal (covered by myelin sheath insulation)
-presynaptic terminal buttons
What are glia?
type of cells in the nervous system
that, in contrast to neurons, does not
conduct impulses over long distances
What are the 5 types of glia?
- astrocytes
- microglia
- oligodendrocytes
- Schwann cells
- radial glia
Astrocytes are?
-star shaped
-shields synapses from chemicals
-synchronizes neural signals (taking up/releasing ions/transmitters)
Microglia are ?
-part of the immune system
-white blood cells of the brain
What do oligodendrocyes and Schwann cells do?
-build myelin sheaths
-supply axon with nutrients
What do radial glia do?
-guide migration of neurons and their axons during embryonic development, then differentiate into neurons
What is the resting potential?
When a neuron fires, the resting potential changes, and and the cell becomes DEPOLARIZED moving signals down axons to terminal buttons and releasing into adjacent extracellular space/synapse.; ~-70mV
What forces act on sodium & potassium ions ?
-selective permeability of cell membranes
-sodium-potassium pump
-electrical gradient (-70mV inside)
-concentration gradient (high to low)
Describe the sodium potassium pump?
-closed at rest
-3 Na+ 2 K+ in
-Na+ is 10x more concentrated outside
-active transport (requires energy)
What is Activation Potential?
AP is an explosion of electric activity created by a depolarizing current (message sent by axons).
The chemical events at a Synapse:
1) neuron synthesizes NT (small- axon terminals, neuropeptides-cell body)
2) AP travels down axon, calcium enters releasing NT
3) NT diffuse across synaptic cleft & attach to receptors
4) NT separate from receptors
5) NT diffuse or re-uptake
6) Post synaptic cells send reverse messages to end further NT release
Types of Neurotransmitters
glutamate, GABA, glycine, aspartate, acetylcholine, serotonin, dopamin, norepinephrine, epinephrine, endorphins, substance P, neuropeptide Y, ATP, adenosine, NO (nitric oxide)
Synthesize of Transmitters
-made from AA from proteins in diet
-made in presynaptic terminal
Storage of Transmitters
-stored in vesicles (tiny spherical packets)
-MAO (monamine oxidase)- breaks down into inactive chemicals to prevent accumulation
Release of Transmitters
Depolarization opens voltage-dependent calcium gates in the presynaptic terminal –> exocytosis (release of NT)
Drugs that bind to receptors include:
1) Hallocinogenic (distort perception)
2) Nicotine (increase dopamine)
3) Opiate (eg. morphine & heroin) relieve pain
Neuropeptide
influence ongoing synaptic activity; enhancing or impeding neurotransmission
What does the spinal chord do?
communicates with all sense organs except those of the head
What is the thalamus?
main source of input to the cerebral cortex; separate left and right structures located in the center of the midbrain
What is the hypothalamus?
-structure under thalamus,
-regulates most motivated behavior (sleep, eating, etc.)
What is the pituitary gland?
-endocrine (hormone producing gland) attached to the base of the thalamus
What is the hippocampus?
forms, organizes, stores memory; lies between thalamus & cerebral cortex, mostly towards posterior of the forebrain
What are the ventricles?
4 fluid filled cavities within the brain