Neuro Physiology Flashcards
Glial cells: Which is more numerous: glial cells or neurons?
Glial cells (10:1 ratio)
Glial cells: produces CSF
Ependymal cells
Glial cells: macrophage of the brain
Microglia
Glial cells: regulates ECF ion levels, gives mechanical support; forms BBB
Astrocyte (nurse cells)
Glial cells: creates myelin in the CNS
Oligodendrocytes
Glial cells: creates myelin in the PNS
Schwann cells
Glial cells: brain tumors from non-mature neurons
Retinoblastoma, Neuroblastoma
Parts of a neuron: receiving portion for neurotransmitters of the neuron
Dendrites
Parts of a neuron: where action potential in a neuron actually starts
Axon hillock
Parts of a neuron: function of myelin sheath
Insulator
Parts of a neuron: Unmyelinated portion of the acon
Nodes of Ranvier
Parts of a neuron: branches of the axons
Neural fibril
Parts of a neuron: terminal portion of a neural fibril that contains NT-containing vesicles
Axon terminal/boutons/end-feet
Parts of a neuron: space between 2 neurons
Synapse
Differentiate anterograde and retrograde axonal transport
Anterograde: soma to axon terminal; Retrograde: axon terminal to soma
What do you call the death of the axon distal to the site of injury after an axon is transected?
Anterograde/Orthograde/Wallerian degeneration
What do you call the changes to the soma after an axon is transected?
Axonal reaction/Chromatolysis
Axonal regeneration occurs better in the CNS or PNS?
PNS
Where in the basal ganglia is acetylcholine secreted?
Nucleus Basalis of Meynert
What enzyme is used in the synthesis of acetylcholine?
Choline acetyltransferase
What enzyme is used in the degradation of acetylcholine?
Acetylcholinesterase
What enzyme triggers sleep and is deficient is Alzheimer’s disease?
Acetylcholine
Where is Dopamine mainly found?
Substantia nigra pars compacta & ventral tegmental area
What enzyme degrades Dopamine?
MAO in presynaptic nerve terminals, COMT in tissues including liver
What condition is caused by Dopamine deficiency?
Parkinson’s disease
What condition is caused by Dopamine excess?
Schizophrenia
Norepinephrine is secreted by:
locus ceruleus in the pons, and postganglionic neurons of sympathetic nervous system
Phenylalanine Derivatives
Phenylalanine, Tyrosine, L-Dopa, Dopamine, Norepinephrine, Epinephrine, Thyroxine, Melanin
Tryptophan Derivatives
Tryptophan, MelaTOnin, Serotonin, Niacin
Serotonin is secreted mainly by:
Median raphe of the brain stem
Low levels of this substance causes clinical depression
Serotonin (also inhibits pain pathways in the spinal cord)
Substance responsible for long term behavior and memory
Nitric oxide (from Arginine)
What is the property of NO that differs from other neurotransmitters?
NO is not preformed and stored in vesicles. It is synthesized almost instantly as needed
Histamine is mainly located within the:
tuberomammilary nuecleus of the hypothalamus
What is the function of histamine?
Involved in control of arousal, sleep and circadian rhythm
Inhibitory neurotransmitter usually found in spinal interneurons; increases chloride influx
Glycine
Number one inhibitory neurotransmitter in the brain; comes from Glutamate; increases chloride influx or potassium efflux
GABA
Number one excitatory neurotransmitter in the brain; involved in fast pain
Glutamate
Inhibit neurons in the brain involved in the perception of pain
Opioid peptides (enkephalins, endorphins, dynorphins)
Involved in slow pain transmission; in specific areas of the brain, primary sensory neurons, GI plexus neurons
Substance P
Basis for the resting membrance potential and action potential
Ion channels
potential difference that exist across the membrane; exhibited by almost all cells; refers to INTRAcellular charge
Resting Membrane Potential
3 things that contribute to the resting membrane potential
- Nernst potential for Na and K diffusion
- Na-K leak channels/ K leak channels
- Na-K-ATPase pump
What types of cells exhibit action potential?
Only excitable cells (neurons, muscles, cells)
Action Potential: each normal AP for a given cell type looks identical, depolarizes to the same potential and repolarizes to the same RMP
Stereotypical size and shape
Action Potential: AP at one cell causes depolarization of adjacent cells in a nondecremental manner
Propagating
Action Potential: If threshold is reached, a full-sized AP will be produced, otherwise, none at all
All-or-none
RMP & AP: make the membrane potential less negative
Depolarization
RMP & AP: make the membrane potential more negative
Hyperpolarization
RMP & AP: positive charges flowing into the cell
Inward current
RMP & AP: positive charges flowing out of the cell
Outward current
RMP & AP: MP in which AP is inevitable
Threshold
RMP & AP: portion of the AP where MP is positive
Overshoot
RMP & AP: portion of the AP where MP is less than RMP
Undershoot (hyperpolarizing afterpotential)