quiz 2 (nerve impluse)

Question 1

what is nerve impluse

Answer 1

Consists of a series of action
potentials

Question 2

where does action potenital occur in Unmyelinated Neurons

Answer 2

Action potential occurs all along the axon

Question 3

where does action potential occur in Myelinated Neurons

Answer 3

Action potential jumps from between the nodes

Question 4

which type of neuron would the action potential occur faster in

Answer 4

myelinated

Question 5

How Does Nerve Impulse
Move?

Answer 5

-Areas of axon where
action potential just
occurred are in
refractory period so
cannot be stimulated
yet
-Prevents impulses
from traveling
backwards

Question 6

Ligand-gated Channels-
AP

Answer 6

also referred as ionotropic receptors, are a group of transmembrane ion-channel proteins which open to allow ions such as Na+, K+, Ca2+, and/or Cl− to pass through the membrane in response to the binding of a
chemical messenger (i.e. a ligand), such as a neurotransmitter.

Question 7

The Synapse

Answer 7

Small space
between neurons or
between a neuron
and an effector

Question 8

The space between
a neuron and a
muscle is called

Answer 8

neuromuscular
junction

Question 9

Neurotransmitter

Answer 9

Chemical messenger
released across the
synapse
 Can be excitatory or
inhibitory

Question 10

Excitatory Neurotransmitter

Answer 10

Excitatory: receptor
proteins trigger
sodium channels to
open causing
depolarization lowering
threshold level

Question 11

inhibitory Neurotransmitter

Answer 11

inhibitory: receptor
proteins trigger
potassium channels
to open causing
hyperpolarization

Question 12

Acetylcholine

Answer 12

Neurotransmitter across
neuromuscular junction
 Excites muscle cells
causing depolarization
and contraction
 If remained in synaptic
cleft, muscle would
remain excited
(dangerous for heart and
diaphragm)
Excitatory to skeletal
muscles; excitatory or
inhibitory at other
locations

Question 13

Cholinesterase

Answer 13

An enzyme that
destroys
acetylcholine
 This closes Na+
channels allowing a
recovery phase
 Nerve gas and some
insecticides work to
block release of
cholinesterase

Question 14

Summation

Answer 14

When one postsynaptic
neuron is excited by
more than one
presynaptic neuron.
* More realistic
representation of
neurons in body

Question 15

Effects of stimulants on neurotransmission

Answer 15

Drug mimics neurotransmitter, stimulating receptor
* Drug decreases rate of breakdown or diffusion of
neurotransmitter from receptor site
* Drug increases rate of release from presynaptic neuron

Question 16

Effects of depressants on neurotransmission

Answer 16

Drug blocks receptor site so neurotransmitter can’t reach
it
* Drug decreases synthesis and storage of neurotransmitter at presynaptic neuron
Drug increases rate of breakdown of neurotransmitter on
postsynaptic neuron or in cleft
Examples: tranquillizers, opiates, barbiturates,
alcohol

Question 17

order of Synapse

Answer 17

1. Nerve impulse reaches the synapse
2. Impulse stimulates synaptic vesicles to move to presynaptic
   membrane
3. Synaptic vesicles release neurotransmitter into the synaptic
   cleft through a process called exocytosis
4. Neurotransmitter diffuses across the synaptic cleft
   5.neurotransmitter fits onto receptor protein
5. An action potential is stimulated at the postsynaptic
   membrane and the impulse travels down the dendrite.
6. An enzyme destroys the neurotransmitter and clears out the
   synaptic cleft

Question 17

what is pain controlled by

Answer 17

-neurotransmitter
-The greater the release of the
neurotransmitter, the more
pain is sensed, the more it
hurts