Practice exam Flashcards
1
Q
- Which of the following correctly describes the effect of morphine on synaptic transmission?
a. Morphine inhibits substance P re-uptake
b. Morphine induces substance P release
c. Morphine reduces membrane permeability to potassium
d. Morphine promotes closing of voltage-gated calcium channels at the presynaptic terminal
A
d. Morphine promotes closing of voltage-gated calcium channels at the presynaptic terminal
2
Q
- A molecule that stimulates neurokinin 1 receptor (NK1-receptor) would produce which of the following effects?
a. Heighten the perception of touch
b. Stimulate a painful sensation
c. Inhibit perception of pain
d. Reduce two-point discrimination threshold
A
stimulates a painful sensation
3
Q
- The area of the somatic sensory cortex devoted to each part of the body is _______.
a. Proportional to the surface area of the part
b. Related to the distance of the part from the brain
c. Proportional to the number of specialized sensory receptors in the part
d. Apparently unrelated to any known aspect of the part
e. Inversely proportional to the surface area of the part
A
c. Proportional to the number of specialized sensory receptors in the part
4
Q
- While recording the responses of a mechanoreceptor to stimulation of the skin, an investigator observes an increase in the number of action potentials generated during one second intervals. This increase usually signifies ________.
a. Increased intensity of a stimulus
b. Cessation of a stimulus
c. Adaptation of the receptor
d. A stimulus of constant strength
e. An increase in the action potential conduction velocity
A
a. Increased intensity of a stimulus
5
Q
- An excitatory postsynaptic potential (EPSP) does which of the following?
a. Depolarizes a neuron, decreasing the likelihood of an action potential
b. Hyperpolarizes a neuron, decreasing the likelihood of an action potential
c. Depolarizes a neuron, increasing the likelihood of an action potential
d. Hyperpolarizes a neuron, increasing the likelihood of action potential
A
c. Depolarizes a neuron, increasing the likelihood of an action potential
6
Q
- Increasing the length of refractory period would have what effect on action potentials?
a. Decrease the amplitude of action potentials
b. Decrease the frequency of action potentials
c. Increase the amplitude of action potentials
d. Increase the frequency of action potentials
A
b. Decrease the frequency of action potentials
7
Q
- Which of the following involved in the peripheral transmission both in sympathetic and parasympathetic nervous system?
a. Nicotinic receptors
b. Muscarinic receptors
c. Norepinephrine
d. Sympathetic ganglia
e. Epinephrine
A
b. Muscarinic receptors
8
Q
- Which of the following is achieved by acetylcholine release from the sympathetic nerve terminals and stimulation of muscarinic receptors?
a. Penile erection
b. Stimulation of sweat glands
c. High epinephrine secretion by the adrenal medulla
d. Constipation
e. Increased heart rate - Acetylcholine released from
A
b. Stimulation of sweat glands
9
Q
- Acetylcholine released from preganglionic autonomic fibers stimulates which type of receptors on postganglionic neurons?
a. Metabotropic cholinergic receptors
b. Nm cholinergic receptors
c. Ionotropic cholinergic receptors
d. Muscarinic and nicotinic cholinergic receptors
e. M3 cholinergic receptors
A
d. Muscarinic and nicotinic cholinergic receptors
10
Q
- Which of the following ligands can activate both ionotropic and metabotropic receptors?
a. GABA
b. Nicotine
c. Muscarine
d. Norepinephrine
e. Epinephrine
A
a. GABA
11
Q
- Administration of the drug which blocks ryanodine receptors (RYR1) channel will result in which of the following?
a. Muscle relaxation
b. Prolonged muscle contraction
c. Failure of muscle to relax
d. Increased concentration of calcium in the sarcoplasm
e. Decreased stimulation of nicotinic cholinergic receptors on the muscle membrane
A
a. Muscle relaxation
12
Q
- The patient is exposed to the toxin which blocks voltage-gated Ca2+ channels at the neuromuscular junction. Which of the following is the most likely explanation for muscle paralysis in this patient?
a. Failure of action potential conduction in the motor nerve terminal
b. Failure of acetylcholine synthesis in the motor nerve terminal
c. Failure of acetylcholine release from the motor nerve terminal
d. Accelerated breakdown of acetylcholine in the synaptic cleft
e. Inhibition of acetylcholinesterase
A
c. Failure of acetylcholine release from the motor nerve terminal
13
Q
- Which of the following occurs during skeletal muscle contraction?
a. A band length remains constant
b. I band length remains constant
c. Z lines move further apart
d. I band increases in size
A
a. A band length remains constant
14
Q
- True of False? Muscle relaxation requires ATP.
a. True
b. False
A
true
15
Q
- A skeletal muscle fiber develops its maximal force if it is at the _______ in the beginning of contraction.
a. Shortest length
b. Intermediate length
c. Maximum length
A
b. Intermediate length
16
Q
- As ATP binds to myosin head at the beginning of a muscle contraction cycle __________.
a. Myosin head binds to actin
b. Myosin head tightens its bond with actin
c. Myosin head detaches from actin
d. ATP does not bind to myosin head
A
c. Myosin head detaches from actin
17
Q
- In the sliding filament mechanism crossbridges are _________.
a. Actin heads bound to myosin filaments
b. Thin filaments bound to each other
c. Two myosin molecules forming a dimer
d. Myosin heads that bind active sites on a thin filament
A
d. Myosin heads that bind active sites on a thin filament
18
Q
- Which of the following drugs can be used to dilate the pupil?
a. Muscarine
b. Nicotine
c. Acetylcholinesterase inhibitor
d. Muscarinic cholinergic antagonist
A
d. Muscarinic cholinergic antagonist
19
Q
- Which of the following is typically caused by activation of the sympathetic nervous system?
a. Anhidrosis (lack of swelling)
b. Bradycardia (decreased heart rate)
c. Ciliary muscle contraction
d. Mydriasis
e. Bronchoconstriction
A
d. Mydriasis
20
Q
- Which has its cell body in a ganglion?
a. Preganglionic neuron
b. Postganglionic neuron
c. Somatic motor neuron
d. Preganglionic neuron and postganglionic neuron
A
b. Postganglionic neuron
21
Q
- The patient experiences mydriasis and constipation upon administration of an experimental drug as a part of clinical trial. Based on the information that you have the drug blocks which of the following receptors?
a. Muscarinic cholinergic receptors
b. Alpha adrenergic receptors
c. Beta adrenergic receptors
d. Muscle type of nicotinic cholinergic receptors
A
a. Muscarinic cholinergic receptors
22
Q
- All of the following are actions of muscarinic receptors except…
a. Increase GI motility
b. Increase GI secretions
c. Increased bronchoconstriction
d. Increase skeletal muscle contraction
A
d. Increase skeletal muscle contraction
23
Q
- Activation of which type of cholinergic receptor will result in faster cell response to acetylcholine?
a. M1 muscarinic cholinergic receptor
b. Nicotinic cholinergic receptor
c. M2 muscarinic cholinergic receptor
d. M3 muscarinic cholinergic receptor
e. M5 muscarinic cholinergic receptor
A
b. Nicotinic cholinergic receptor
24
Q
- Direct activation of which of the following receptors will result in the opening of an ion channel?
a. Alpha-1 adrenergic receptor
b. Nicotinic cholinergic receptor
c. Alpha-2 adrenergic receptor
d. Beta-1 adrenergic receptor
e. Muscarinic cholinergic receptor
A
b. Nicotinic cholinergic receptor
25
Q
- Which of the following is directly responsible for the rising phase of neuronal action potential?
a. Increased membrane permeability to potassium
b. Opening of voltage-gated sodium channels
c. Membrane hyperpolarization
d. Generation of receptor potential
e. Decreased membrane permeability to sodium
A
b. Opening of voltage-gated sodium channels
26
Q
- During a brain surgery, through which the patient remained conscious, a part of the dorsal column-medial lemniscus (DCML) pathway was exposed and stimulated. Which of the following sensations will the patient most likely experience?
a. A feeling that his fingers are warming up
b. A feeling as if something was touching his index finger
c. Mild pain but he is unable to explain exactly where it hurts
d. Strong pain in his arm
A
b. A feeling as if something was touching his index finger
27
Q
- Which property correctly describes receptor (generator) potential?
a. Increases in amplitude as more intense stimulus is applied
b. Always leads to an action potential
c. Is an all-or-none phenomenon
d. Does not require opening or closing of ion channels
A
a. Increases in amplitude as more intense stimulus is applied
28
Q
- Which of the following would be expected to result in increased accumulation of acetylcholine within the synaptic cleft?
a. Inhibition of acetylcholinesterase
b. Decrease release of acetylcholine from presynaptic terminal
c. Decreased acetylcholine synthesis
d. Increased number of nicotinic cholinergic receptors on the postsynaptic membrane
e. Inhibition of voltage-gated calcium channels on the presynaptic membrane
A
a. Inhibition of acetylcholinesterase
29
Q
- Administration of the drug which blocks norepinephrine transporter (NET) on the membrane of presynaptic neuron will result in which of the following?
a. Increased concentration of NE in the synaptic cleft
b. Inhibition of NE-mediated synaptic transmission
c. Decreased activation of adrenergic receptors on the postsynaptic membrane
d. Increased stimulation of cholinergic receptors on the postsynaptic membrane
e. Decreased activation of adrenergic receptors on the presynaptic membrane
A
a. Increased concentration of NE in the synaptic cleft
30
Q
- Activation of which type of receptor will result in faster cell response to GABA?
a. GABAa receptor (ionotropic)
b. GABAb receptor (metabotropic)
A
a. GABAa receptor (ionotropic)
31
Q
- Which of the following axons would be expected to have the fasted conduction velocity?
a. Small diameter myelinated fiber
b. Large diameter unmyelinated fiber
c. Large diameter myelinated fiber
d. Small diameter unmyelinated fiber
A
c. Large diameter myelinated fiber
32
Q
- Action potentials are all or none responses. How then do stronger stimuli from the presynaptic neuron yield a greater response in the postsynaptic neuron?
a. Action potential amplitude varies with stimulus intensity
b. Action potential frequency varies with stimulus intensity
c. Absolute refractory period is shortened with greater stimuli
d. Threshold voltage is lowered with increasing stimuli
A
b. Action potential frequency varies with stimulus intensity
33
Q
- During the falling phase of action potential the membrane repolarizes beyond the resting membrane voltage. This phenomenon is due to __________.
a. An influx of calcium ions into axon
b. A large number of open potassium channels
c. A rapid influx of sodium ions
d. Closing of voltage-gated calcium channels
A
b. A large number of open potassium channels
34
Q
- At the peak of the action potential __________.
a. Voltage-gated sodium channels close, while voltage-gated potassium channels open
b. All voltage-gated channels close
c. The membrane potential reaches its most negative value
d. The membrane becomes hyperpolarized
A
a. Voltage-gated sodium channels close, while voltage-gated potassium channels open
35
Q
- If the membrane potential of a cell increases, the potential has become more ________.
a. Negative
b. Positive
A
a. Negative
36
Q
- Resting cell membranes are most permeable to _____.
a. Na+
b. Cl
c. K+
d. Ca2+
e. Large anions
A
c. K+
37
Q
- The rate of uptake of a toxin into the cell is directly proportional to the magnitude of the concentration gradient across the membrane and does not use energy. Which of the following types of transport is responsible for the cellular uptake of toxin?
a. Secondary active transport
b. Primary active transport
c. Endocytosis
d. Simple diffusion
e. Exocytosis
A
d. Simple diffusion
38
Q
- Which of the following is true of both facilitated diffusion and primary activate transport?
a. They both require energy in the form of ATP
b. They both require carrier proteins
c. They both transport substances down a concentration gradient
d. They both use energy stored in the sodium concentration gradient
A
b. They both require carrier proteins
39
Q
- True or False? The sodium-potassium pump is a transmembrane protein.
a. True
b. False
A
a. True
40
Q
- Diffusion ____________.
a. Creates concentration gradients
b. Moves substance against a concentration gradient
c. Eliminates concentration gradients
d. Increases concentration gradients
A
c. Eliminates concentration gradients
41
Q
- Increasing which of the following will decrease the rate of diffusion?
a. Lipid solubility of the molecule
b. Membrane thickness
c. Concentration gradient
d. All of the above
A
b. Membrane thickness
42
Q
- Disruption of structural integrity of which type of cell junctions can result in blistering diseases, such as pemphigoid and pemphigus?
a. Tight junctions
b. Gap junctions
c. Occluding junctions
d. Anchoring junctions
e. Polarized junctions
A
d. Anchoring junctions
43
Q
- How many odors can be discriminated by a healthy human subject?
a. 10,000 odors
b. 50,000 odors
c. 100,000 odors
d. More than a trillion odors
e. Slightly less than a million odors
A
d. More than a trillion odors
44
Q
- Cholinergic receptors expressed at the neuromuscular junction and responsible for muscle contraction belong to which class of membrane receptors?
a. G protein-coupled receptors
b. Enzyme-lined receptors
c. Tyrosine-kinase receptors
d. Ion channels
e. Cytoskeletal receptors
A
d. Ion channels
45
Q
- What type of receptor is the insulin receptor?
a. G protein-coupled receptor
b. Enzyme-linked receptor
c. Nuclear receptor
d. Ion channel
A
b. Enzyme-linked receptor
46
Q
- Which of the following substances would most easily diffuse across a phospholipid bilayer?
a. Large protein molecules
b. Small ions such as sodium
c. Small lipophilic molecules
d. Large hydrophilic molecules
e. Water
A
c. Small lipophilic molecules
47
Q
- Which of the following factors is important in creating a resting membrane potential of - 70 mV?
a. Number of closed voltage-gated ion channels
b. Equal concentrations of K+ in the intracellular and extracellular fluids c. Size of the cell
d. Different permeabilities of the membrane to Na+ and K+ ions
A
d. Different permeabilities of the membrane to Na+ and K+ ions
48
Q
- When the electrical charge of an ions as well as its concentration gradient favor movement of that ion into the cell, the ion is said to move down its _________ gradient.
a. K+ resting
b. Electrochemical
c. Active
d. Na+ permeability
A
b. Electrochemical
49
Q
- Which cation is most concentrated inside the cell?
a. Na+
b. Cl
c. Protein anions (A-)
d. K+
A
d. K+
50
Q
- A K+ deficiency reduces extracellular K+ concentration from 4 mM to 2 mM. As a result, a neuron’s resting membrane potential will ________.
a. Become more negative
b. Become less negative
c. Remain largely unchanged
A
a. Become more negative
51
Q
- Select the method that correctly represents how the membrane potential of neuron is measured.
a. Use a voltmeter with two electrodes, both placed in the intracellular fluid.
b. Use a voltmeter with two electrodes, both placed in the extracellular fluid.
c. Use a voltmeter with only one electrode placed in the intracellular fluid.
d. Use a voltmeter with two electrodes, one placed in the extracellular fluid and the other placed in the intracellular fluid.
A
d. Use a voltmeter with two electrodes, one placed in the extracellular fluid and the other placed in the intracellular fluid.
52
Q
- At rest, a neuron’s plasma membrane is most permeable to which of the following ions?
a. Potassium (K+)
b. Protein anions (A-)
c. Sodium (Na+)
d. Chloride (Cl-)
A
a. Potassium (K+)
53
Q
- In order to ensure that Na+ concentration remains high outside a neuron, and that K+ concentration remains high inside, the neuron depends on the activity of the __________.
a. Na+/K+ pump
b. Na+ leak channels
c. K+ leak channels
A
a. Na+/K+ pump
54
Q
- Which of the following would increase a neuron’s membrane permeability to K+?
a. Decreasing the number of K+ leak channels
b. Increasing the number of K+ leak channels
c. Making the membrane potential more negative
d. Allowing the membrane potential to stay at rest
A
b. Increasing the number of K+ leak channels
55
Q
- Administration of which of the following drugs would be beneficial in a patient with hypercholesterolemia in order to reduce the risk of adverse cardiovascular events?
a. Drug which increases the number of functional LDL-receptors in the cell membrane
b. Drug which blocks clathrin-mediated endocytosis of LDL
c. Drug which increases plasma concentration of LDL
d. Drug which increases LDL receptor degradation in lysosomes
e. Drug which decreases plasma levels of HDL
A
a. Drug which increases the number of functional LDL-receptors in the cell membrane
56
Q
- A patient poisoned with cyanide cannot utilize ATP. Which of the following transport processes would be most directly affected by this loss?
a. Transport of Na+ out of cells
b. Transport of glucose into red blood cells
c. Osmosis of water into cells
d. Diffusion of CO2 out of cells
e. Diffusion of O2 into the cells
A
a. Transport of Na+ out of cells
57
Q
- Treatment of intestinal epithelial cells with the mitochondrial toxin results in loss of ATP synthesis. Absorption of glucose from intestinal lumen into the epithelial cells in the presence of this toxin will be reduced because:
a. GLUT will not be able to transport glucose
b. Na+ gradient across luminal membrane will be dissipated
c. SLGT on apical membrane will not be able to transport Na+ out of the cell d. Na+/K+-ATPase will not be able to transport glucose out of the cell
A
b. Na+ gradient across luminal membrane will be dissipated
58
Q
- Inside the cell is 300 mOsM solution of non-penetrating solute (NP). The solution that contains the cell (extracellular solution) has a concentration of 200 mOsM NaCl and 200 mOsM urea. NaCl can’t cross the membrane, while urea can. Solution is:
a. Hyosmotic/hypotonic
b. Hyposmotic/hypertonic
c. Hyperosmotic/hypotonic
d. Hyperosmotic/hypertonic
e. None of the above
A
c. Hyperosmotic/hypotonic
59
Q
- A cell placed in a solution of unknown composition soon swelled up and burst, so the solution must have been ________ to the cell when it was originally placed in the solution.
a. Hypotonic and hyposmotic
b. Hypertonic and hyperosmotic
c. Hypotonic and of an undetermined relative osmolarity
d. Hypertonic and of an undetermined relative osmolarity
A
c. Hypotonic and of an undetermined relative osmolarity
60
Q
- Which of the following solutions has the greatest osmolarity? Assume that CaCl2 and NaCl completely dissociate in water for simplicity.
a. 20 mM glucose
b. 1 M CaCl2
c. 6 OsM glucose
d. 5 OsM NaCl
A
c. 6 OsM glucose
61
Q
- If you see varicosities along an axon, you are looking at a(n)
a. Sympathetic neuron
b. Parasympathetic neuron
c. Somatic motor neuron
d. Interneuron
e. Either A or B
A
e. Either A or B
62
Q
- Which has its cell body in a ganglion?
a. Preganglionic neuron
b. Postganglionic neuron
c. Somatic motor neuron
d. Preganglionic neuron and postganglionic neuron
e. Preganglionic neuron, postganglionic neuron, and somatic motor neuron 63.
A
b. Postganglionic neuron
63
Q
The enzyme monoamine oxidase (MAO) catalyzes the breakdown of _______.
a. Acetylcholine
b. Glutamate
c. GABA
d. Carbachol
e. Catecholamines
A
e. Catecholamines
64
Q
- Which of the following is typically caused by activation of the sympathetic nervous system?
a. Anhidrosis (lack of sweating)
b. Bradycardia
c. Ciliary muscle contraction
d. Mydriasis
e. Bronchoconstriction
A
d. Mydriasis
65
Q
- A decrease in which of the following occurs during fight or flight response?
a. Pupil diameter
b. Glucose consumption
c. Blood pressure
d. Gastrointestinal secretion
e. Bronchiolar diameter
A
d. Gastrointestinal secretion
66
Q
- Which of the following is involved in the peripheral transmission both in autonomic and somatic nervous system?
a. Nicotinic receptors
b. Muscarinic receptors
c. Norepinephrine
d. Sympathetic ganglia
A
a. Nicotinic receptors
67
Q
- Which of the following is achieved by acetylcholine release from the sympathetic nerve terminals and stimulation of muscarinic receptors?
a. Penile erection
b. Stimulation of sweat glands
c. High epinephrine secretion by the adrenal medulla
d. Constipation
e. Increased heart rate
A
b. Stimulation of sweat glands
68
Q
- A 6-year-old boy is brought to the emergency department by his mother. The boy was playing in the yard while she was gardening and ingested some berries. He present with dilated pupils, blurred vision, dry mouth, elevated heart rate and apparent disorientation. His symptoms are a result of a chemical in the berries interfering with the normal functioning of the autonomic nervous system. Inhibition of which receptor or enzyme is consistent with the boy’s presentation?
a. Acetylcholinesterase
b. Alpha-adrenergic receptor
c. Beta-adrenergic receptor
d. Muscarinic cholinergic receptor
e. Nicotinic cholinergic receptor
A
d. Muscarinic cholinergic receptor
