Lecture: Neurophysiology Flashcards
What is the analogy to remember for the semipermeable membrane
A screen door
Diffusion causes ions to flow from areas of ____ to ____ concentration, along their concentration gradient.
High to low
the difference in the concentration of a substance between two areas.
Concentration gradient
Like charges (repel/attract)
Repel
Opposite charges (repel/attract)
Attract
What is the process if particles moving down their concentration gradient called?
Diffusion
the force that results from the repulsion or attraction of charged particles
Electrostatic pressure
What is the term for electrostatic pressure causing ions to flow towards oppositely charged areas
Electrical gradient
What makes neurons similar to batteries?
They store charge to use when needed
The inside of a neuron is more (negative/positive) than the outside
Negative
The outside of a neuron is more (negative/positive) than the inside
Positive
What structure is the key to how diffusion works in a neuron?
The cell membrane
What is the neuron cell membrane composed of?
a lipid bilayer and membrane proteins
Proteins spanning the membrane so ions can pass in and out
Ion channels
In which order did the methods of opening/closing gated channels evolve?
Mechanical action
Chemicals
Voltage changes
Why do membranes need ion channels?
The neuronal cell membrane repels water, and ions are surrounded in water, so they can only enter the cell through a channel
What are the three states ion channels can be in?
open
closed and unlocked
closed and locked
Are neuronal membranes permeable to large negatively charged proteins?
No
Where are the large negatively charged proteins inside the neuron created?
Inside the cell
What makes the inside of a neuron negative?
Large negatively charged proteins that cannot leave
Which ion is the only one able to enter and leave the cell freely?
K+
(Potassium)
What do K+ ions do when the neuron is at rest?
Move into the negative interior
Why do K+ ions move into the negative interior of the neuron when it is at rest?
Electrostatic pressure
When does K+ reach equilibrium for a neuron?
When ion movement out is balanced by ion movement in