Lectures 13-15 Flashcards
What are ions responsible for (2)
Responsible for moving ions in an out of cell to make action potential happen
responsible for difference in charge across neural membrane
What are atoms made of and what 3 things does it contain (PEN)
Made of subotomic particles
Protons
Electrons
Neurons
What charges are Protons, neurons and electrons
Protons are positive
electrons are negative
neurons are uncharged in this case
What state allows action potentials to occur? Hint: scale, balance
When there is more positive charge inside a neuron, more negative charge outside of neuron
This state of imbalance is what allows action potential to occur
What do volts measure?
Measure electrical potential
What’s the typical volt charge in humans ?
70 milivolts (mv)
What is membrane permeability and what how is it produced ?
Things that can/t permeate by ion channels
Produced by proteins
what’s 2 forces drive ion to move in or out of cell?
1 concentration gradient force
2 electrical gradient force
What is an ion(definition) Hint: Balance
Atoms that have imbalanced electrical charges
What are the two types of ions and their charges?
Anion- negatively charged
Cation-positively charged
What kind of molecule is water, and what makes it this way?
Polar molecule, one side has more negative charge, other side has more positive charge
What are cations and anions attracted to?
Anions are more attracted to positive end
Cations are more attracted to negative ends (opposites attract)
What is the cell membrane made up of?
Fatty substance, 2 fatty acids back to back create a cell membrane
What are the Cell membranes permeable (1) and non permeable chemicals (2)? (Remember BBB permeables)
Small lipid soluble molecules
can permeate
Large or electrically charged molecules cannot permeate
How do ions move in and out of cell, and what product created it?
By ion channels(holes) created by proteins
What is gating and what are two main factors that influence it?
Channels that change shape(open or closed)
Two factors:
Voltage dependent
Chemical dependent
what does voltage dependent mean?
Opens or closes gate depending on what surround membrane potential is
what does chemical dependent mean?
Chemical is presented and gate decides whether or not it will stay closed or open up,
What are the three ways ions are able to permeate the Cell membrane? (Ch,Ch,S)
1) Through Channels: only allow particular ions to move through
2) Chemical dependent: By being a certain chemical
3) Surroundings: Able to permeate based off of what’s already in the membrane
What are the two forces that drive ion movement?
1) concentration gradient force
2) electrical gradient force
What is the concentration Gradient force? ( think of drop of food dye in glass of water…)
Random motion of matter, chemicals move down the gradient trying to become equally separated . Tries to move to lower area of concentration essentially.
What is electrical gradient force? (the long triangle!!)
Positive and negative charges that are attracted to one another, BUT are repelled by the like charge. (positive charge loves negative charge, but is repped by positive charge )
Why’s there a difference of charge within the membrane potential, and what are they? (4) HINT: banana in the ocean…
Due to 4 ions
Na-sodium
Cl-chloride
K-potassium
Proteins
The 4 ions impacting a difference in charge in the membrane potential,
are found where in higher concentration in a neuron ?
Na and Cl are found in higher concentration outside neuron
K and proteins are found in higher concentration inside neuron
4 factors influencing movement in the membrane (SECS)
Selective permeability
electrical gradient force
Chemical gradient force
sodium potassium pump
What are the 4 changes you can see in membrane potential ?
Hyperpolarization
depolarization
resting potential
action potential
What is the difference between sub threshold de polarization and a supra threshold (opposites)
Sub threshold: not enough threshold to conduct an action potential
Supra threshold: big enough de polarizations to still conduct an action potential
What is an Action potential ?
rapid reversible self propagating change in membrane potential
What are the 3 phases of an action potential?
Rising phase
Peak and falling phase
After hyperpolarization
What happens in the rising phase of an action potential?
Membrane continues to depolarize,
sodium and Potassium
channels open and sodium rushes in
Becomes more positively charged
What happens in the peak and falling phase of an action potential?
Peaks out, while potassium channels still open, leaks out potassium
voltage sensitive sodium channels inactivate(change shape and close).
Becomes more negatively charged overall
What happens in the after hyper polarization phase of an action potential?
Gets even more negatively charged as excessive potassium leaves
Overshoots and returns back to resting membrane potential to rinse and repeat cycle
What are the three steps to how propogation happens?
1) sodium diffuses causing supra threshold
2) depolarization opens voltage gated sodium channels
3) triggers Action potential in adjacent(near) regions
Why do action potentials only move in a forward region?
The inactivating property of sodium channels (during 4 changes in membrane potential) propagate to move things only forward
