Ch02

Question 1

A resting neuron is ______

Answer 1

polarized.

Question 2

What does a cell being polarized mean?

Answer 2

difference in electrical charge between the inside and the outside of the cell.

Question 3

Ions are?

Answer 3

electrically charged molecules

Question 4

What charge do anions have?

Answer 4

negative

Question 5

What charge to cations have?

Answer 5

positive

Question 6

What is the ion channel?

Answer 6

proteins that span the membrane and can allow selective ions to pass through

Question 7

What does it mean if a channel is gated?

Answer 7

it opens and closes in response to signals

Question 8

What does it mean if an ion shows selective permeability?

Answer 8

Allows K+ but not Na+ to enter and leave the cell freely

Question 9

What two opposing forces drive ion movement

Answer 9

Diffusion
Electrostatic pressure

Question 10

Diffusion causes ions to?

Answer 10

spread towards a uniform concentration along a concentration gradient

Question 11

Electrostatic pressure causes ions to flow towards?

Answer 11

oppositely charged areas

Question 12

What is the equilibrium potential

Answer 12

the electrical charge that balances two opposing forces- the concentration gradient and electrostatic pressure and corresponds to the resting potential.

Question 13

Depolarization is a

Answer 13

decrease in membrane potential- the interior of the cell becomes less negative and closer to zero.

Question 14

Hyperpolarization is an

Answer 14

increase in membrane potential- the interior of the cell becomes even more negative and farther from zero

Question 15

Relative stimulus strength is?

Answer 15

the information being encoded in changes in the number of APs produced

Question 16

Afterpotentials

Answer 16

small changes in membrane potential after action potentials

Question 17

What are action potentials produced by?

Answer 17

the sudden rush of Na+ ions

Question 18

What happens during the absolute refractory phase?

Answer 18

no action potentials can be produced?

Question 19

What happens during the relative refractory phase?

Answer 19

only very strong stimulation can produce and action potential.

Question 20

What is myelin?

Answer 20

A sheath of insulation around the axon, formed by glial cells, which speeds conduction.

Question 21

what is the Node of ranvier

Answer 21

a small gap in the insulating myelin sheath

Question 22

What is saltatory conduction

Answer 22

the potential traveling inside the axon ‘jumps’ from node to node

Question 23

What happens when an action potential reaches the axon terminal

Answer 23

it causes the release of a neurotransmitter into the synapse

Question 24

Postsynaptic potentials are

Answer 24

brief changes in the postsynaptic membrane potential of the cell in response to a neurotransmitter.

Question 25

Excitatory postsynaptic potential (EPSP)

Answer 25

a small local depolarizing potential in the postsynaptic membrane that pushes the cell closer to the action potential threshold, increasing the likelihood that the neuron will fire an action potential.

Question 26

Inhibitory postsynaptic potential (IPSP)

Answer 26

a hyperpolarizing potential in the postsynaptic membrane that pushes the cell further away from threshold, decreasing likelihood of neuron firing and action potential.

Question 27

When do inhibitory postsynaptic potential (IPSPs) results?

Answer 27

when chloride ions (Cl-) rush into the cell, making the inside more negative

Question 28

What is the sequence of neurotransmission:

Answer 28

1. Action potential arrives at the presynaptic axon terminal 2. Voltage gated calcium (Ca2+) channels in the terminal membrane open, and Ca2+ ions enter 3. Ca2+ ions cause synaptic vesicles filled with neurotransmitter to fuse with the presynaptic membrane, releasing transmitter into the synaptic cleft 4, Transmitters bind to postsynaptic receptor molecules, causing ion channels to open and leading to an EPSP or IPSP 5. EPSPs or IPSPs spread toward the postsyanptic axon hillock- if threshold is reached, an action potential will occur 6. Synaptic transmission is rapidly stopped 7. Transmitter may activate the presynaptic receptors that decrease transmitter release.

Question 29

What are ligands?

Answer 29

molecules that fit into receptors and activate or block them

Question 30

Neurotransmitter action is brief and is halted by?

Answer 30

Degradation: the rapid breakdown and inactivation of transmitter by an enzyme Acetylcholinesterase (AChe) Reuptake: transmitter is cleared from the synapse by being absorbed back into the presynaptic axon terminal through transporters.

Question 31

What is spatial summation

Answer 31

the summing of all the potentials that reach the axon hillock from locations across the cell body. If the overall depolarization- the sum of EPSPs(+) and IPSPs(-) reaches or exceeds the threshold, an AP is produced

Question 32

Temporal summation is the?

Answer 32

summing of all the potentials that reach the axon hillock based on time of arrival. The closer together in time the potentials arrive, the greater their impact and likelihood of producing an action potential.

Question 33

An electroencephalogram (EEG) is a recording of?

Answer 33

spontaneous brain potentials

Question 34

Event related potentials (ERPs) are EEG responses to a?

Answer 34

single stimulus, such as a flash of light or loud sounds.

Question 35

Tonic clonic seizures

Answer 35

abnormal EEG activity throughout the brian

Question 36

simple partial seizures

Answer 36

brain waves show patterns of seizure activity for 5 to 15 seconds, may occur several times a day

Question 37

complex partial seizures

Answer 37

do not involve entire brain, often preceded by an unusual sensation, or AURA

Question 38

Many seizure disorders can be controlled with what kind of medications?

Answer 38

antiepileptic medications

Question 39

When medication does not work and seizures are severe and frequent, part of an awake patient's brain can be removed

Answer 39

neurosurgery