Nerves Flashcards
What do Astrocytes, microglia, and ependymal cells do?
Astrocytes -form the BBB
Microglia-phagocytic cells
Ependymal- secrete CSF
What does SAME stand for?
Sensory Afferent
Motor Efferent
What do oligodendrocytes produce?
Myelin sheath
What does an axon and a dendrite do in a neuron?
Dendrite- receiving end
Axon-transmit AP release neurotransmitter
What are ganglia, nuclei, tracts and nerves?
Ganglia-cell bodies
Nuclei- cell bodies
Tracts- bundles of nerves in cns & pns
Nerves-
What makes solvutory conduction possible?
Myelin sheath
What are the 2 types of cells that produce myelin sheaths ?
Oligodendrocytes and Schwann cells
What gates open and close during depolarization, repolarization, and hyperpolarization and what ions are moving?
Depolarization - na+ gates open
Repolarization - K+ open
Hyperpolarization - K+ stays open too long
Graded Potentials
Short lived Decrease in intensity with distance Strength varies with stimulus Use chemical gates for depolarization Occur at dendrites and soma
Action potentials
Long lived
Do not decrease intensity strength never varies. All or none
Voltage gates
Axons
Resting membrane potential
-70mV
Involves passive/leakage gates
More K+ moves out of the cell than Na+ moves into the cell
negative charge
Schwann cells and oligodendrocytes
Schwann- PNS, neurolemma, evenly
Oligodendrocytes - CNS. No neurolemma, random
How do ions move through a channel/gate?
Electrical & chemical gradient
What determines the stimulus strength?
Frequency
What are the characteristics of the absolute and relative refractory periods?
Can’t get another AP during absolute- occurs during depolarization/repolarization
Relative refractory period next one occurs at hypolarization.
How are neurotransmitters removed?
Fused out get lost
What kind of potential can produce an action potential?
Post synaptic, excitatory not by itself
Threshold
-55
What causes and maintains the RMP?
More K+ going out than Na+ going in. More is leaking out. Maintains = Na+ K+ pump
Summation
Needed to make an AP.
2 types- temporal-rapid
Spacial- more than 1
A,B,C fibers
A- fast thickest lots of (myelin)
B- moderate (organs)
C- slowest thinnest (brain)
Serial and parallel processing
Serial - smart thinker
Parallel - slow simple thinking
Epinephrine is an example of
Biogenic amines
Peptides
Endorphins
Acetylcholine
Released by all neurons stimulating skeletal muscle
Released by parasympathetic neurons of the ANS
GABA
Amino acids found only in CNS
