Exam 2 - nervous system - action potential and synapses

Question 1

Name for the net charge (aka potential) across a membrane when neuron is not firing

Answer 1

resting membrane potential

Question 2

at rest, the intracellular fluid is ______ charged

Answer 2

negatively

Question 3

the sending neuron is also called the

Answer 3

presynaptic neuron

Question 4

the receiving neuron is also called the

Answer 4

postsynaptic neuron

Question 5

at rest, the extracellular fluid around a neuron has higher concentrations of ___ and ___ than the inside

Answer 5

Cl- and Na+

Question 6

At rest, the intracellular fluid has higher concentrations of _____ and ___ than the outside fluid

Answer 6

potassium and negatively charged protein anions

Question 7

Once the threshold stimulus is reached, ___ channels open

Answer 7

sodium

Question 8

Action potential originates from the _____

Answer 8

trigger zone (aka top of axon)

Question 9

what are the five phases of action potential?

Answer 9

1. Local signals sent
2. Local signals cause threshold
3. Depolarization
4. Repolarization
5. Hyperpolarization

Question 10

What part(s) of a neuron send local signals to the trigger zone?

Answer 10

dendrites and body

Question 11

local signals are also called

Answer 11

graded potential

Question 12

Sodium channels opening causes the net charge inside the cell to _____. This continues throughout the ____ phase

Answer 12

increase; depolarization

Question 13

At the end of depolarization, ____ channels start to chose and ____ channels stat to open, which causes the net cell charge to ___

Answer 13

sodium; potassium; drop

Question 14

_____ is the phase of action potential where the charge goes from positive to negative

Answer 14

repolarization

Question 15

During this action potential phase, the cell charge goes below its resting state

Answer 15

hyperpolarization

Question 16

______ ends when ____ channels close and the cell returns to its resting state charge

Answer 16

hyperpolarization; potassium

Question 17

why do neurons have a net negative charge at rest?

Answer 17

some potassium channels are open which causes positive charge to leave, and negatively charged protein ions are in the cell