6456707
Descripción
Test por Med Student , actualizado hace más de 1 año
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Creado por Med Student
hace alrededor de 8 años
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Pregunta 1
Pregunta
Hormones:
Respuesta
-
are chemical regulators that are conveyed from one organ to another via the blood stream
-
may be secreted by endocrine glands
-
may be secreted by nerve cells
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act only on target cells
-
all of the above
Pregunta 2
Pregunta
For an action potential to occur
Respuesta
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the stimulus must reach or exceed threshold
-
K+ influx must exceed Na+ efflux
-
The cell membrane must be out of the relative refractory period
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The cell membrane must be in absolutely refractory period
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Cl- influx must exceed K+ efflux
Pregunta 3
Pregunta
During the rising phase of the action potential
Respuesta
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voltage-gated Na+ channels open
-
voltage-gated K+ channels open
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voltage-gated Na+ channels close
-
voltage-gated K+ channels close
-
voltage-gated Cl- channels apex
Pregunta 4
Pregunta
The concept of homeostasis
Respuesta
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refers to the unwavering control of a physiological set point
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refers to maintaining physiological functions in a stable condition
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refers only to the regulation of body temperature
-
refers to maintaining a stable external environment
-
refers to the 'all-or-one' law
Pregunta 5
Pregunta
The plasma membrane
Respuesta
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is permeable to lipophilic molecules
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may contain proteins, which confer iron permeability
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may burst in hypotonic extracellular solutions
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can generate action potentials in excitable cells
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all of the above
Pregunta 6
Pregunta
Overcooling the nerve will cause
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decrease of the threshold
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increase of the liability
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increase of the excitability
-
increase of the threshold
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increased release of neurotransmitters
Pregunta 7
Pregunta
The properties of local response:
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'all-or-none’ law
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transmission with energy consumption
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without energy consumption
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summation
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excitability is decreased
Pregunta 8
Pregunta
A “less negative" membrane potential means:
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it is “more positive” than the resting potential
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it is closer to zero mV
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the resting membrane potential is closer to the sodium equilibrium
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slight depolarization
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all of the above
Pregunta 9
Pregunta
The membrane of a typical resting neuron is largely impermeable to
Respuesta
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Na+
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K+
-
Cl-
-
Ca2+
-
none of the above
Pregunta 10
Pregunta
The ion with the lowest intracellular concentration is:
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Na+
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HCO3
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Ca2+
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Mg2+
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K+
Pregunta 11
Pregunta
The most common intracellular cation is:
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calcium
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sodium
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potassium
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phosphorus
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magnesium
Pregunta 12
Pregunta
What is the normal pH value of body fluid?
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7.15-7.25
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7.35-7.45
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7.55-7.65
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7.00-7.35
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6.5-7.5
Pregunta 13
Pregunta
Which of the following requires energy?
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Diffusion
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Osmosis
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Active transport
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Facilitated diffusion
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Filtration
Pregunta 14
Pregunta
Which of the following is not found in the cell membrane?
Respuesta
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Cholestrol
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Phospholipids
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Proteins
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Galactose
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Nucleic acids
Pregunta 15
Pregunta
The local response is:
Respuesta
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A potential that is generated as a result of the action of a subthreshold stimulus and propagated along the nerve cell membrane
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A potential that is generated as a result of the action of a superthreshold stimulus and propagated along the nerve cell membrane
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A potential that is generated as a result of the action of a subthreshold stimulus and could be registered only at the site of irritation
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A potential that is generated on the postsynaptic membrane as a result of the action of a mediator
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A potential that is generated as a result of the action of a superthreshold stimulus and could be registered only at the site of irritation
Pregunta 16
Pregunta
The oculocardiac reflex is an example of:
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soma-somatic reflex
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soma-visceral reflex
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viscera-somatic reflex
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viscera-visceral reflex
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integrated conditioned reflex
Pregunta 17
Pregunta
Norepinephrine is a neurotransmitter with the highest affinity to:
Respuesta
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α-adrenergic receptors
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β-adrenergic receptors
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α- and β-adrenergic receptors
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N-choline receptors
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M-choline receptors
Pregunta 18
Pregunta
The parasympathetic post-ganglionic neurons of the ANS secrete
Respuesta
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Nor-epinephrine (98%) and epinephrine (2%)
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Acetylcholine
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L-DOPA
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Nor-epinephrine (2%) and epinephrine (98%)
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Epinephrine (80%) and nor-epinephrine (20%)
Pregunta 19
Pregunta
The critical (firing) level of depolarization is
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a level of AP at which depolarization goes into repolarisation
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a level of AP at which repolarization goes into depolarization
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a degree of depolarization of the postsynaptic membrane at which further action of the neurotransmitter is abolished
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a degree of depolarization of the nerve cell membrane at which its sources of energy are completely exhausted
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a degree of depolarization of the excitable membrane at which its intensity does not depend on irritant action
Pregunta 20
Pregunta
A structure that permits a neuron to pass an electrical or chemical signal to another cell (neural or otherwise) with excitatory or inhibitory effects is called:
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synapse
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juxtaglomerular apparatus
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intercalated disc
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Golgi apparatus
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modulator
Pregunta 21
Pregunta
H1 receptors are situated an the smooth muscle cell membrane of the:
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gastrointestinal tract
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urinary tract
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bronchi
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uterus
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blood vessels
Pregunta 22
Pregunta
The adrenergic effect an the cardiac conduction system and working myocardium is exercised by affecting:
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M-choline receptors
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α1 receptors
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α2 receptors
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β1 receptors
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β2 receptors
Pregunta 23
Pregunta
The parasympathetic spinal centers, regulating the reservoir functions, are situated in the following
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C8-Th1
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Th1-Th8
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Th10-L2
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S2-S4
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L2-L4
Pregunta 24
Pregunta
Facilitated diffusion is a mechanism:
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Connected with loss of energy
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For transporting substances against their concentration gradient
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Connected with membrane polarity
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That works with the help of a carrier in the membrane
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For transporting lipid soluble substances through the membrane
Pregunta 25
Pregunta
A distinguishing feature of the membrane potential at rest is:
Respuesta
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high permeability for K+ ions
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low permeability for Cl- ions
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low permeability for Na+ and high for K+ ions
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the small difference between the equilibrium potentials for Na+ and K+ ions
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low permeability for Na+
Pregunta 26
Pregunta
Acetylcholine is a neurotransmitter which has:
Respuesta
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always an excitatory effect on the postsynaptic membrane
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always an inhibitory effect on the postsynaptic membrane
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excitatory or inhibitory effect on the postsynaptic membrane depending on the type of receptors
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excitatory or inhibitory effect depending on the amount released
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no effect on the postsynaptic membrane
Pregunta 27
Pregunta
The common expression of excitation is:
Respuesta
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the action potential
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muscle cell contraction
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nerve cell conduction and excitation
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glandular cell secretion
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membrane transport
Pregunta 28
Pregunta
Curare is a substance that blocks
Respuesta
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M-choline receptors
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α-adrenergic receptors
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β-adrenergic receptors
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N-choline receptors in neuromuscular synapses
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all types of cholinoreceptors
Pregunta 29
Pregunta
An example of a ligand dependent membrane is
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the postsynaptic membrane
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the axon membrane
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the nodes of Ranvier
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the skeletal muscle cell membrane
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the axon hillock
Pregunta 30
Pregunta
Throughout the relative refractory period:
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the excitability becomes equal to zero
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the excitability is equal to that at rest
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the excitability is higher than that at rest
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accommodation occurs
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the excitability is lower than that at rest
Pregunta 31
Pregunta
Na/K pump is called electrogenic, because:
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exports equal amount of Na+ and K+
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imports equal amount of Na+ and K+
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exchanges equal amount of Na+ and K+
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the exchanged amount of Na+, and K+ is not equal
-
none of the above
Pregunta 32
Pregunta
The conditioned reflexes are:
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typical of the species
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inborn
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permanent
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formed on the basis of unconditioned reflexes
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all of the above
Pregunta 33
Pregunta
Which of the statements is not true:
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at the chemical synapse transmission of excitation is one way
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at most of the electrical synapses transmission is two-way
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the velocity of transmission of excitation is higher at the chemical synapses than at the electrical ones
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the velocity of transmission of excitation is greater at the electrical synapses than at the chemical ones
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when there is continuous excitation at a synapse, fatigue occurs
Pregunta 34
Pregunta
Which is the basic inhibitory neurotransmitter in CNS:
Respuesta
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Glutamate
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Substance P
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Neuropeptide 4
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GABA
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Nitric Oxide
Pregunta 35
Pregunta
The basic factor for the ion asymmetry on both sides of the excitable membrane is
Respuesta
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Ca++ pump and the low permeability for Na+
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Na+ pump and the low permeability for Na+
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Na+/K+ pump and the low permeability for Na+
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K+ pump and the high permeability for Na+
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Iodine pump
Pregunta 36
Pregunta
The velocity of AP propagation along the axon membrane depends on:
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the strength of irritation
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the duration of irritation
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the cross sectional area of the axon
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the direction of its propagation
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the threshold
Pregunta 37
Pregunta
The sympathetic postganglionic neurons secrete:
Respuesta
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norepinephrine (98%) and epinephrine (2%)
-
acetylcholine
-
L-DOPA
-
norepinephrine (2%) and epinephrine (98%)
-
epinephrine (20%) and norepinephrine (80%)
Pregunta 38
Pregunta
The result of activated α1-adrenergic receptors is:
Respuesta
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relaxation of the gastrointestinal tract smooth muscles and contraction of the sphincters
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constriction of the vessels smooth muscle
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increased heart rate
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dilation of the vessels smooth muscle and relaxation of the uterus
-
none of the above
Pregunta 39
Pregunta
The result of activated α2-adrenergic receptors is:
Respuesta
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relaxation of the gastrointestinal tract smooth muscles and contraction of the sphincters
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constriction of the vessels smooth muscle
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increased heart rate
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dilation of the vessels smooth muscle and relaxation of the uterus
-
none of the above
Pregunta 40
Pregunta
Protein synthesis occurs at the
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mitochondria
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lysosomes
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within the nucleus
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ribosomes
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vacuoles
Pregunta 41
Pregunta
During repolarization of the cell membrane:
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Na+ move inside of the cell
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Na+ move outside of the cell
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K+ move inside of the cell
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K+ move outside of the cell
-
Cl- move outside of the cell
Pregunta 42
Pregunta
In a cell, movement of molecules from an area of low concentration to an area of high concentration:
Respuesta
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uses facilitated diffusion
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requires cellular energy
-
is passive transport
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requires both cellular energy and facilitated diffusion
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uses its concentration gradient to move
Pregunta 43
Pregunta
Movement of solvent and dissolved substances across a cell membrane by hydrostatic pressure is:
Respuesta
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filtration
-
facilitated diffusion
-
osmosis
-
simple diffusion
-
active transport
Pregunta 44
Pregunta
The substance acetylcholine (ACh) is released from synaptic vesicles by the process of:
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phagocytosis
-
simple diffusion
-
passive transport
-
exocytosis
-
endocytosis
Pregunta 45
Pregunta
Cell membranes
Respuesta
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are formed entirely by protein molecules
-
are impermeable to fat soluble substances
-
in some tissues permit transport of glucose at a greater rate in the presence of insulin
-
are not changed throughout life
-
are permeable to water soluble substances
Pregunta 46
Pregunta
Proteins that are secreted by cells are generally:
Respuesta
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not synthesized on ribosomes that are bound to endoplasmic reticulum
-
synthesized in the mitochondria
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packed in the Golgi apparatus
-
across the cell membrane by endocytosis
-
synthesized in the lysosomes
Pregunta 47
Pregunta
The unique feature in mitochondria is:
Respuesta
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myosin
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actin
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DNA
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prothrombin
-
haemoglobin
Pregunta 48
Pregunta
The resting membrane potential of a cell:
Respuesta
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is dependent on the permeability of the cell membrane to K+ being greater to Na+
-
falls to zero if Na+/K+ ATPase in the membrane is inhibited
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is equal to the equilibrium potential for K+
-
is equal to the equilibrium potential of Na+
-
is equal to the equilibrium potential of Cl-
Pregunta 49
Pregunta
Many substances are removed from the cell to the outside by:
Respuesta
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pinocytosis
-
chemotaxis
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phagocytosis
-
exocytosis
-
endocytosis
Pregunta 50
Pregunta
An example of co-transport is:
Respuesta
-
Na+-K+ pump
-
Ca++ pump
-
Na+-H+ pump
-
Na+ glucose transport
-
Na/Ca pump
Pregunta 51
Pregunta
Mitochondria:
Respuesta
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are the Chief site for lipid synthesis
-
are the chief site for protein synthesis
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are the chief sites for generation of ATP
-
are more numerous in white than in brown fat cells
-
are absent near the membranes of actively secreting cells
Pregunta 52
Pregunta
The endoplasmic reticulum:
Respuesta
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is a complex system of intracellular tubules
-
has a membrane structure similar to the cell membrane
-
is associated with ribonucleoprotein
-
is well developed in secretory cells
-
all of the above
Pregunta 53
Pregunta
The mammalian cell membrane:
Respuesta
-
is seen as an optically dense line using light microscopy
-
consists mainly of protein
-
is more permeable to fat- than to water-soluble particles
-
contains enzymes DNA
-
contains the receptors for steroid hormones
Pregunta 54
Pregunta
Membrane ion channels:
Respuesta
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consist mainly of carbohydrates and lipids
-
have a specific structure for each ion species
-
for sodium may be blocked by tetrodotoxin
-
consist mainly of lipids
-
remain open as long as the activating signal is present
Pregunta 55
Pregunta
The speed of conduction of a nerve impulse can be determined by which of the following factors?
1. temperature 2. diameter of axon 3. stimulus frequency 4. myelin sheath; 5. stimulus strength
Respuesta
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1,3, 5 and 4
-
1, 2 and 3
-
3 and 1
-
3 and 2
-
4, 2 and 1
Pregunta 56
Pregunta
The junction between one neuron and the next, or between a neuron and an effector is called:
Respuesta
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a synapse
-
a dendrite
-
a neurotransmitter
-
a ventricle
-
none of the above
Pregunta 57
Pregunta
Which of the following blocks acetylcholine receptor sites causing muscle relaxation?
Respuesta
-
novocain
-
curare
-
nicotine
-
nerve gases
-
carbon monoxide
Pregunta 58
Pregunta
Transmission across a synapse is dependent on the release of?
Respuesta
-
neurotransmitters
-
synaptic vesicle
-
neurons
-
receptor proteins
-
hormones
Pregunta 59
Pregunta
Saltatory conduction:
Respuesta
-
occurs only in myelinated fibres
-
has a slower velocity in cold than in warm conditions
-
is faster than non-saltatory conduction in nerve fibres with diameters around 10 μm
-
transmits impulses with a velocity proportional to fibre diameter
-
all of them
Pregunta 60
Pregunta
An action potential in a nerve fibre:
Respuesta
-
occurs when its membrane potential is hyperpolarized to a critical level
-
is associated with a transient increase in membrane permeability to sodium
-
is associated with a transient decrease in membrane permeability to potassium
-
induces local response
-
has an amplitude which varies directly with the strength of stimulus
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