Module 3 Lecture 2 Flashcards
True of False
The greater the permeability of a plasma membrane is to an ion, that ion will dictate the membrane resting potential
True
Are there more potassium leak channels than sodium leak channels?
yes there are more potassium leak channels
What does it mean when there are more K+ channels than Na+ channels?
that potassium will leave the cell at a higher rate than sodium entering the cell
The resting membrane potential is more dictated by which ion?
Potassium
What is the normal resting cell mV in regards to K+ being -90 and Na+ being +65
-70mV
What are passive channels?
channels that allow molecules to go in and out of the membrane without the use of energy, using an ion/molecules concentration gradient or electrochemical gradient
What is an example of a passive channel?
leak channels
What is active transport?
ability to pass ions/molecules across the membrane with the use of energy (ATP)
What is an example of active transport?
sodium-potassium pump
Passive ion movement are responsible for what percentage of the resting membrane potential?
80%
The sodium-potassium pump is responsible for what percentage of the resting membrane potential?
20%
Which two types of our cells are our “excitable” cells?
- Neural
- Muscle
What are the 3 bases of neuron communication?
- Receive a signal
- Initiate a message
- Transmit a message
What is polarization?
charges are separated across the membrane
What is a depolarization?
cell is negative but a little less negative, aka closer to 0, where there are less separated charges
What is repolaritzation?
the membrane was depolarized and now it is returning to the resting membrane potential where charges are separated
What is hyperpolarlization?
going from resting membrane to further negative, separated even more charged
True or False
Repolarization will always follow Depolarization?
True
What is upward deflection?
decrease in potential
What is downward deflection?
increase in potential
What are the 2 forms of electrical signals?
- Graded potentials (short distance)
- Action potentials (long distance)
True or False
If graded potentials become large enough, they can trigger action potentials?
True
What is a graded potenital?
- local changes in the membrane potential
- short distance signals
- they can have different magnitudes and durations
What are gated channels?
passive channels that are closed until a trigger opens the channel
- ions use their electrochemical gradient to flow through the gate
- causes depolarization
What are a couple of types of gated channels?
- mechanically gated channels (by touch for example)
- chemically gated channels
(by ion binding for example)
What is an active area?
area inside the cell where we have a gated channel on the membrane allowing lot’s of Na to come into the cell making that area of the cell depolarized
What causes the spread of depolarization?
when we have a gated potential occur and have all these Positive Na+ ions in the active area causing an imbalance in the resting cells charge, allowing these sodium ions to spread laterally to the negative charges along the membrane
- aka spreading the depolarization
Why are graded potentials decremental?
as the potential (being the depolarization spread) moves across the membrane the potential progressively decreases
What are action potentials?
the are just changing the potential of the membrane through the flow of ions
Are Action potentials decremental?
naurrr
True of False
The membrane potential reverses after action potentials, meaning the inside of the cell is more positive than the outside
true
