Lecture 3: The Nervous System and Nervous Tissue (Part 2) Flashcards
Neurons are highly _______
Irritable
Action potential (nerve impulse) is always the ______ regardless of stimulus
Same
___________ is required to separate opposite charges across a membrane
Energy
Measure of potential energy generated by separated charge
Voltage
Voltage measured between 2 points
Potential difference
The flow of electrical charge (ions) between two points
Current
Hindrance to charge flow (provided by the plasma membrane)
Resistance
Substance with high electrical resistance
Insulator
Substance with low electrical resistance
Conductor
Ohm’s Law
V=IR
Voltage =Current*Resistance
2 main types of ion channels
Leakage (nongated) channels and gated channels
3 types of gated channels
Chemically (ligand), Voltage, and Mechanically
Open with binding of a specific neurotransmitter
Chemically gated (ligand-gated) channels
Open and close in response to changes in membrane potential
Voltage-gated channels
Open and close in response to physical deformation of receptors
Mechanically gated channels
When gated channels are open, Ions diffuse quickly across the membrane along their electrochemical gradients: Along __________ from higher concentration to lower concentration, and along _________ toward opposite electrical charge
Chemical concentration gradients; Electrical gradients
Potential difference across the membrane of a resting cell
Resting membrane potential
Resting membrane potential is approximately –70 mV in neurons (cytoplasmic side of membrane is __________ charged relative to outside)
Negatively
Resting membrane potential is generated by:
- Differences in ________ of ICF and ECF, and
- Differential __________ of the plasma membrane
Ionic makeup; Permeability
