L2

Question 1

-Minute synaptic knobs calledpresynaptic terminals lie on ?

Answer 1

the surfaces of the dendrites and soma of
the motor neuron

Question 2

-terminal has two internal structures?

Answer 2

the transmitter vesicle
mitochondria

Question 3

-released transmitter causes an immediate change in……………………………………characteristics of the postsynaptic neuronal membrane, — this leads to excitation or inhibition
of the postsynaptic neuron,depending on the neuronal ……………………….

Answer 3

permeability

receptor characteristics

Question 4

-quantity of neurotransmitter released ?from the terminal into the synaptic cleft is directly related to the

Answer 4

number of Ca ++

Question 5

four changes by 2ed messenger system ?

Answer 5

— 1. Opening specific ion channels through the postsynaptic cell membrane( K+ mostly)
2. Activation of cAMP , cGMP (alters long-term excitability of the neuron.)
3. Activation of one or more intracellular enzymes
4. Activation of gene transcription

Question 6

-most important effects of activation of the second messenger systems

Answer 6

Activation of gene transcription

Question 7

-most widely used means for causing excitation?

Answer 7

Opening of sodium channels to allow large numbers of positive electrical charges to flow to the interior of the postsynaptic cell.

Question 8

How Excitation occur ?

Answer 8

1. Opening of sodium channels
2. changes in the internal metabolism of the post-synaptic neuron to excite cell activity
3. Depressed conduction through chloride or potassium channels, or both

Question 9

How inhibition occur ?

Answer 9

1. Opening of chloride ion channels
2. Increase in conductance of potassium ions out of the neuron.
3. Activation of receptor enzymes

Question 10

-most acute responses of the nervous system occur by which type of neurotransmitter?

Answer 10

small-molecule, rapidly acting transmitters

Question 11

small molecule (Inhibitory) transmitters?

Answer 11

Dopamine
GABA
Glycine
Serotonin

Question 12

-Resting membrane potential of about …… millivolts

Answer 12

−65

Question 13

Electrical events during neuronal excitation

Answer 13

— Resting Membrane
Potential of the Neuronal Soma.

Question 14

-decreasing the voltage to a less negative value makes the membrane of the neuron………excitable

Answer 14

more

Question 15

-voltage to a more negative value makes the neuron…………….. excitable.

Answer 15

less

Question 16

-Excitatory Postsynaptic Potential (EPSP)?

Answer 16

increase the membrane’s permeability to Na+

Question 17

-positive increase in voltage above the normal resting neuronal potential—that is, to a less negative value—is called?

Answer 17

the excitatory postsynaptic potential (or EPSP),

Question 18

-AP does not begin adjacent to the excitatory synapses Instead, it begins in the ?

Answer 18

initial segment of the axon where the axon leaves the neuronal soma.

Question 19

-Inhibitory Postsynaptic Potential.
The inhibitory synapses open
mainly?

Answer 19

chloride channels,

Question 20

both chloride influx and potassium efflux increase the degree of intracellular negativity, which is called ……………..?

Answer 20

hyperpolarization.

Question 21

-an increase in negativity beyond the normal resting membrane potential level
is called……………….?

Answer 21

an inhibitory postsynaptic
potential (IPSP)

Question 22

-most common neurotransmitter used in Presynaptic Inhibition?

Answer 22

GABA (gamma-aminobutyric acid).

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