OS 202 B Samplex 2014 A Flashcards
Which of the following statements is/are true of generator potentials? All generator potentials are:
A. Produced by changes in membrane potential through opening of ligand gated channels B. Depolarizing currents C. Local and graded potentials D. All of the above statements are true
C
Which of the following somatic sensations may be
reflexively mediate
A. Pressure
B. Proprioception
C. Two-point discrimination
D. Vibration
B
What encodes the intensity of a sensation?
A. Spatial and temporal patterns of activation of
receptors
B. Size of the receptive field
C. Amplitude of the action potential
D. Lateral inhibition in the higher order neuron
A
The following sensory receptors respond to low
threshold mechanical stimulation EXCEPT
A. Meissner’s corpuscle
B. Merkel’s disk
C. Ruffini’s endings
D. Free nerve endings
D
Two-point discrimination is best perceived at the
finger tips because
A. There is a high density of receptors in the area.
B. The receptors are innervated by the fastest
conducting A fibers
C. There is less overlapping of sensory units
D. Receptors are rapidly adapting.
A
Which of the following statements is true of lateral
inhibition in sensory systems? Lateral inhibition:
A. modulates perception of intensity
B. defines the type of sensory modality
C. sharpens discrimination of stimuli
D. determines the duration of the stimuli
C
What would be an evidence that parallel processing of various sensory information of a given modality exists in the nervous system?
A. Specific sensory pathways are discrete from the sense organ to the cortex.
B. Excitation of any region along a sensory pathway always gives the same sensation.
C. The phenomenon of phantom limb is an evidence of parallel processing.
D. A discrete lesion in the temporal lobe produces deafness for low tones but not for high tones.
D
Sensory afferent input to the amygdala which processes the affect of a given sensation is through which sensory pathway?
A. Paleospinothalamic tract
B. Spinoreticular tract
C. Spinomesencephalic tract
D. Neospinothalamic tract
C
Which of the following receptors signal changes in muscle activity?
A. Golgi tendon organs
B. Nuclear chain fibers
C. Nuclear bag fibers
D. AOTA
D
Which of the following statements is/are true of muscle spindles?
A. They detect changes in both muscle length and tension
B. They are innervated by both gamma and alpha motor neurons.
C. Activation of muscle spindles increases muscle tension to oppose the stretch.
D. All of the above statements are true.
C
During withdrawal reflex, the following sensory receptors are activated
A. Proprioceptors B. Bare nerve endings C. Muscle spindles D. Only a and b E. AOTA
E
The terminals of nociceptive afferents when stimulated release which of the following neurotransmitters?
A. Substance P B. Glutamate C. Enkephalins D. Only and b D. AOTA
D
Which type of nerve fibers innervate the polymodal nociceptors?
A. A-alpha fibers
B. A-beta fibers
C. A-delta fibers
D. C fibers
D
A medical student observed that stimulating the neurons located in the midline of the medulla attenuates pain sensation in animals. Which of the following mechanisms could explain this observation?
A. Serotonin was released which inhibited the dorsal horn cells.
B. Noradrenaline was released which inhibited the dorsal horn cells.
C. Enkephalin was released which inhibited the dorsal horn cells.
D. Release of substance P from the axons of the dorsal root ganglion was inhibited.
A
Armed with knowledge of neurophysiology, what type of drug or substance would you develop that can relieve pain?
A. a drug that inhibits synaptic calcium channels
B. a drug that inhibits sodium channels
C. a drug that blocks glutamate receptors
D. any of the above
D
Which of the following mechanisms explain why visceral pain tends to be vague and poorly localized than somatic pain?
A. There are more C fibers in visceral afferents than A delta.
B. There is less overlapping of receptive fields in the viscera.
C. There are more visceral afferents that cover a wide area.
D. Visceral afferents demonstrate more converging synaptic pattern than somatic afferents.
A
Which of the following statements is true of hyperopic individuals?
A. The image formed falls in front of the retina.
B. They have sharp vision for near but blurred vision far.
C. They require some degree of accommodation at all times to bring the image onto the retina.
D. To correct the refractive error, the use of concave lens is prescribed.
C
The following events that occur in the rods in response to light are listed below in random sequence:
- decrease in intracellular cGMP
- activation of transducin
- closure of sodium channels
- conformational changes in rhodopsin
- decreased release of glutamate from the terminal ends of the rods
What is the right sequence in which the above events normally occur?
A. 1,2,3,4,5
B. 1,4,2,5,3
C. 2,4,1,3,5
D. 2,1,4,5,3
C
Dark adaptation is best illustrated when one enters a dimly lighted theater. It takes sometime before one gets used in the dark. Which of the following statements is true of dark adaptation?
A. As the eyes become more adapted in the dim, rhodopsin stores diminishes in amount.
B. During dark adaptation, there is a decline in the visual threshold.
C. Dark adaptation takes a shorter period of time than light adaptation.
D. Rods adapt more rapidly than cones
B
Stimulation of which of the following fibers give rise to a longer-lasting, burning and pricking pain?
A. A-alpha fibers
B. A-beta fibers
C. A-delta fibers
D. C fibers
D
The parvocellar cells process which submodality of the visual sensation?
A. location
B. depth
C. movement
D. color
D
What cranial nerves innervate the olfactory epithelium?
A. CN I and V
B. CN I and VII
C. CN I and IX
D. CN I and XII
A
What is the function of the odorant binding proteins?
A. They facilitate transport of the odorant through the epithelium.
B. They make the odorant more water soluble.
C. They also act as receptors for the odorants.
D. They are enzyme inducers of the second messenger signal.
A
Which taste sensations below utilize direct ion
channel signalling in generating action potentials?
A. sweet
B. salty
C. bitter
D. umami
B
Which of the following events is elicited by the mechanical displacement of the cochlear hair cells toward the kinocilium?
A. The hair cells on which the cilia are located are hyperpolarized.
B. There is an influx of K+ ions through the apical membrane of the cilia.
C. There is an influx of Na+ ions through the apical membrane of the cilia.
D. There is an efflux of Ca++ ions through the voltage-gated channels in the apical membrane of the cilia.
B
Which of the following items are incorrectly paired?
A. localization of sound- harmonic vibrations
B. loudness of sound- amplitude of sound waves
C. pitch of sound- frequency of sound waves
D. None of the above
A
Which physiologic mechanism/s prevent/s the sound energy from being lost as it travels from air through the liquid compartment of the inner ear?
A. high aerial ratio between the tympanic membrane and oval window
B. the lever system increases efficiency of sound transmission
C. The flexibility of the Reissner’s membrane conserves the energy of the travelling waves.
D. All of the above
E. Only a and b are correct.
E
The following statements are true of the vestibulococular reflex EXCEPT
A. It is initiated by impulses from the photoreceptors
B. The movement of the eyes is opposite to the head movement
C. It can be elicited even under dark illumination.
D. It does not require feedback from its receptors to function normally
A
Which of the following conditions may give a negative caloric test?
A. hypofunction of the vestibular apparatus
B. inadequate temperature of the test stimuli
C. inappropriate head positioning
D. AOTA
E. Only a and b will give a negative caloric test.
D
Majority of neurons in the somatosensory and special sensory systems are of which polarity?
A. unipolar
B. pseudounipolar
C. bipolar
D. multipolar
B
Majority of neurons in the central nervous system, as a whole, are which polarity?
A. unipolar
B. pseudounipolar
C. bipolar
D. multipolar
D
Receptor neurons in the retina and olfactory epithelium are of which polarity?
A. unipolar
B. pseudounipolar
C. bipolar
D. multipolar
C
The spinal nucleus of the trigeminal nerve is equivalent to the:
A. Lissauer’s tract
B. dorsal horn of the spinal cord
C. anterior horn of the spinal cord
D. intermediate horn of the spinal cord
B
In the general scheme of the somatic sensory system, the neurons which give rise to ascending fibers that cross the midline are the:
A. first-order neuron
B. second-order neuron
C. third-order neuron
D. receptor neuron
B
At the level of the cervical spinal cord, the pain fibers from the leg and genitalia within the spinothalamic tract are located
a. Most medially
b. Most laterally
c. Most dorsally
d. Most ventrally
B
The sensory pathway that ascends uncrossed until the level of the medulla is the:
a. Spinothalamic tract
b. Posterior column – medial lemniscal tract
c. Trigeminothalamic tract
d. Gustatory fibers
B
Proprioceptive fibers from the leg terminate in the
a. Nucleus gracilis
b. Nucleus cuneatus
c. Principal nucleus
d. Spinal nucleus of V
A
Which is not a pain-sensitive structure in the head?
a. Middle meningeal artery
b. Superior saggital venous sinus
c. Occipital lobe
d. Periosteum of the skull
C
Which of the following does not transmit pain impulses within the head and neck?
a. Trigeminal nerve
b. Vestibulocochlear nerve
c. Glossopharyngeal nerve
d. None of the above
B
Tooth pulp is innervated by which nerves?
a. Facial neves
b. Alveolar nerves
c. Buccal nerves
d. Dentic nerves
B
Pain fibers receiving the head will eventually terminated in the thalamus, specifically in:
a. Lateral inferior nucleus
b. Ventroposterolateral nucleus
c. Ventroposteromedial nucleus
d. Mediodorsal nucleus
C
The cranial nerve nucleus that is analogous to the cuneate and gracile nuclei is the
a. Spinal nucleus
b. Principal nucleus
c. Ambiguous nucleus
d. Solitary nucleus
B