Textbook Chapter 2.4-2.9 Flashcards
(28 cards)
A barrier between the blood and the fluid that surrounds the cells of the brain:
The Blood-Brain Barrier
Is the blood-brain barrier selectively permeable?
Yes
What is the function of the blood-brain barrier?
It helps regulate the composition of the fluid surrounding brain cells.
Any difference in charge across a membrane:
Membrane Potential
The membrane potential when a neuron is at rest, approximately -70 mV:
Resting Potential
When the inside of an axon becomes more negative relative to the outside:
Hyperpolarization
What does it mean for an axon to be depolarized?
The inside of the axon becomes more positive relative to the outside.
A set point for depolarization to trigger an action potential:
Threshold of Excitation
A burst of rapid depolarization followed by hyperpolarization:
Action Potential
The process by which molecules distribute themselves evenly in a medium:
Diffusion
Substances that split into charged particles (ions) when dissolved in water:
Electrolytes
Charged particles formed when electrolytes dissolve in water:
Ions
What are the two types of ions?
Cations (positive charge) and anions (negative charge).
The force exerted by particle attraction or repulsion:
Electrostatic Pressure
The fluid inside cells:
Extracellular Cells
The fluid surrounding cells:
Extracellular Fluid
What do sodium-potassium transporters do?
They exchange Na+ for K+, pumping three sodium ions out for every two potassium ions in.
Molecules that contain passages that can open or close:
Ion Channels
Sodium channels that are only opened by changes in the membrane potential:
Voltage-Dependent Ion Channels
The movement of a message (axon potential) down the axon:
Conduction of the Action Potential
An action potential either occurs or does not occur, and, once triggered, it is transmitted down the axon to its end. An action potential always remains the same size, without growing or diminishing:
All-or-None Law
Action potentials in axons control the strength of muscular contractions and represent the intensity of a physical stimulus:
Function of Action Potentials in Axons
Variable information is represented in the axon by this:
Rate of Firing Action Potentials
The principle that variations in the intensity of a stimulus or other information being transmitted in an axon are represented by variations in the rate at which the axon fires:
Rate Law
