問題一覧
1
why do alkalosis and acidosis affect neural impulse conduction
because the concentration of H+ affects the potential difference across the cell membrane
2
which of the following is NOT a basic function of the nervous system
interpretative
3
why does continuous propagation of the action potential not occur in the myelinated axons
because the myelin sheath blocks the flow of ions across the membrane
4
an action potential is a change in membrane potential during ? of a neuron
excitation
5
pick the correct statement. slow postsynaptic receptors
may trigger more than one response in the postsynaptic cell
6
electrical synapses are rare and occur when presymaptic and postsynaptic membranes are locked together tightly by
gap junctions
7
in a chemical synapse, communication across the synaptic cleft requires the release of a ? from the presynaptic membrane
neurotransmitter
8
activation of the ? branch of the autonomic nervous system causes rest and repose responses, associated with relative inactivity and digestion
parasympathetic
9
the axons of some neurons are wrapped in an insulating sheath made of
myelin
10
neurons use ? to carry information from the cell body to the synaptic terminal
electrical impulses
11
the electroencephalogram provides a clinical assessment of overall brain function, and records each of the following except
sigma waves
12
what function of neurons is performed by summation
integration of several different synaptic inputs
13
according to the lock and key model, the same neurotransmitter may act on
several different types of receptors
14
in a neural action potential repolarisation involves the loss of ? ions
potassium
15
what is the relationship between action potentials abs graded potentials
action potentials are initiated when the membrane is depolarised to threshold by a graded potential
16
what determines the duration of an action potential
cell type
17
atropine binds to muscarinic acteylcholine receptors and prevents their activation by acteylcholine. Thai means it acts as an
antagonist
18
the tendon stretch reflex can be classified as a
monosynaptic reflex
19
a number of organs have ? by both sympathetic and parasympathetic nerves, with opposite effects
dual innervation
20
substance start can bind to a receptor are called ligands. ligands that block or reduce neurotransmitter action are called
antagonist
21
the principle neurotransmitter of the sympathetic nervous system, which may act on alpha and beta reception is
no adrenaline
22
a reflex arc contains each of the following except
am efferent junction
23
the region of the brain which performs higher functions and planning and execution of voluntary motor action is called the
cortex
24
the autonomic nervous system provides regulation of each of the following except
skeletal muscle
25
why do voltage regulated K+ channels not need to inactivate
because the equilibrium potential for K+ is lower that the threshold of the K+ channels (ca -60 mV)
26
the ? is an area of the brain responsible for maintenance of homeostasis by controlling behaviours essential to survival of the individual or species via hormones and the sympathetic nervous system
hypothalamus
27
neurons are classified on the basis of structure as each of the following except
dipolar
28
the multipolar neuron consists of all of the following excepr
myelin
29
an action potential is delayed along the axon of a neuron in a series of steps, with action potentials in one section of the axon bringing the adjacent region to ? and handing on the impulse
threshold
30
continuous propagation is the basic mechanism by which an action potential is propagated along a ? appearing to move along the membrane in a series of tiny steps
unmyelinated axon
31
from the time an action potential begins until the normal resting potential has stabilised, the membrane will not respond normally to additional depolarising stimuli, this period is known as the
refractory period
32
when signals from another nerve terminal at the presynaptic membrane causes a decreased release of neurotransmitter, it is called
presynaptic inhibition
33
an excitory postsynaptic potential is a ? caused by the arrival of a neurotransmitter
graded depolarisation
34
which of the following is not an accurate event at the cholinergic synapse
calcium ions enter the synaptic terminal from the intracellular calcium stores, triggering the exocytosis of ACh
35
the ? exchange pump slowly restores intracellular and extracellular ion distribution to pre stimulation levels when the neuron is not active
sodium potassium
36
damage to which areas of the brain would be expected to impair control of food intake
hypothalamus
37
neurotransmitters that may be either excitatory or inhibitory depending on the postsynaptic receptor are called ? neurotransmitter
dual function
38
what terminates transmission at the cholinergic synapse?
breakdown of ACh by AChE
39
supporting the cells of the nervous system, called neuralgia, perform all of the following except
act as lymphocytes
40
Parkinson’s diseases is caused by deficient dopamine pathways in the brain. it is therefore best treated with
dopamine agonists
41
which of the following is part of the rest and repose response
decrease in heart rate
42
which feature of voltage regulated ion channels is responsible for neurons refractory period
Na+ channel inactivation
43
selective serotonin regulator inhibitors prolong the action of serotonin (5HT) at a synapse by preventing its removal from the synaptic cleft. this means they act as
agonists
44
events that make initiation of an action potential less likely are
inhibitory
45
which of the following cannot initiate a graded potential
action potentials
46
why can an action potential not be initiated during the refractory period?
because the voltage gated Na+ channels are inactivated
47
the basic functional units of the nervous system are individual cells called
neurons
48
the addition of stimuli occurring in rapid succession is called
temporal summation
49
where in a neuron is the highest density of voltage gated sodium channels found
axon hillock
50
the insulating sheath is interrupted at regular intervals, exposing the neural membrane. these interruptions are called ? of ranvier
nodes
51
the principle neurotransmitter of the parasympathetic system is ? acting on muscarinic receptors
acetylcholine (ACh)
52
individual postsynaptic potentials can combine by the process of summation, which integrates the effect of
graded potentials
53
ACh is the neurotransmitter of the neuromuscular junction, the specialised synapse between a motor neuron and a muscle, where it acts on the ? ACh receptor
nicotinic
54
pick the correct statement. at a chemical synapse
generally communication only occurs in one direction
55
electrical impulses are passed from neurons or other cells at a specialised junction called
synapse
56
why do action potentials travel along distances while graded potentials do not
because action potentials are actively propagated
57
what is the term for the nervous system comprising all neurons outside the brain and spinal cord
peripheral nervous system
58
where action potentials jump along the axon in a series of steps, this is known as
saltatory propagation
59
which of the following is a correct step in the generation of an action potential
inactivation of sodium channels and the activation of potassium channels