Neurophysiology Flashcards
leak
selectively permeable channels that are always open. Responsible for mainatining resting membrane potential
Chemically
open when bound to specific chemicals e.g. ACH. Responsible for maintaining synaptics potentials, the incoming signals to the neuron
Voltage
open in response to electrical changes in TMP e.g. Na, K, Ca ions. Responsible for the production & propagation of action potential, the outgoing signal from the neuron
Mechanically-gated channels
open in response to physical distortion of membrane potential
Trans-membrane potential
the amount of electrical charge(-70mV) difference between the 2 sides of the membrane when the neuron is at rest(not excited)
Notes: A
A resting neuron has - interior & + exterior. The charge of a resting neuron membrane is -70mV
Notes: B
K+ is major internal ion along w/ fewer PO4 -2 & SO4 -2 ions
Notes: C
Na+ is major external ion along w/ fewer Cl- ions
Notes: D
Ion dist. determined by selective ion leak channels & pumps. K+ more permeable than Na+ due to higher number of K+ channels.
Notes: E
As Na+ moves into the cell, depolarization occurs & an electrical signla is produced. Cells that can produce an electrical signal are called excitable cells
Resting potential
The TMP (-70mV) of a neuron at rest (not generating an electrical signal). Regulated by leak channe;s
Graded Potential
a decrease in the TMP w/ distance from the stimulus. Regulated by chemically gated channels
Local currents
Movement of positive ions parallel to the membrane. Internal ions Na move in response tot he negative charges along the inner surface of the membrane
Action Potential (a.k.a Nervous Impulse/ Electrical Signal)
changes in TMO(increases to +30 mV) transmitted (propageted) along axon
Continuous propagation
occurs in unmyelinated axons. A series of local current membrane depolarizations propagate the action potential down the axon membrane
Saltatory propagation
occurs in myelinated axons. Ions cannot flow through myelin so ions cross at nodes
Chemical synapse
rely upon neurotransmitters
Electrical synapse
rely upon direct transmission of electrical impulse from one neuron to neuron another via physical contact of membrannes (no neurotransmitters) via gap junctions
Synapse Transmission
Action potentials(nerve impulses/ information/ messages) must be transmitted across the synapse tp the next neuron
Nervous system functions- sensory
recieve stimuli from environ. via sensory receptors in PNS e.g. temp, soun
Nervous system functions- integration
CNS processes all sensory signals & creates sensations, memory, thoughts or actions
Nervous system functions- motor
CNS sends impulses to stimulate movement in effectors outside of nervous syste e.g., muscles, gland
NS Components- neurons
produce & transmit & interpret nervous impulses
NS Components- neuroglia
supportive cells around neuron, it nourish, insulate & structural support neuron
