Physiology

222. Which of the following reflexes is correctly paired with the sensory structure that mediates the reflex? A) Autogenic inhibition—muscle spindle B) Reciprocal inhibition—Golgi tendon organ C) Reciprocal inhibition—Pacinian corpuscle D) Stretch reflex—muscle spindle E) Golgi tendon reflex—Meissner corpuscle

215.The withdrawal reflex is initiated by stimulation delivered to which of the following receptors? A) Muscle spindle B) Joint capsule receptor C) Cutaneous free nerve ending D) Golgi tendon organ E) Pacinian corpuscle

214. Evaluation of a patient reveals the following deficits:(1) decreased aggressiveness and ambition, and inappropriate social responses; (2) inability to process sequential thoughts in order to solve a problem; and (3) inability to process multiple bits of information that could then be recalled instantaneously to complete a thought or solve a problem. Damage to which of the following brain regions might be responsible for such deficits? A) Premotor cortex B) Parieto-occipital cortex in nondominant hemisphere C) Broca’s area D) Limbic association cortex E) Prefrontal association cortex

208. Output signals from Golgi tendon organs are transmitted to which of the following higher centers? A) Inferior colliculus B) Globus pallidus C) Cerebellum D) Red nucleus E) Substantia nigra

206.Which statement best describes a characteristic functional difference between a Golgi tendon organ and a muscle spindle? A) The output signals of a Golgi tendon organ lead to inactivation of the muscle associated with the active tendon organ B) Golgi tendon organs do not function in the course of voluntary movements that require a normal level of tension development in the associated muscle C) Signals arising from Golgi tendon organs do not contribute to conscious proprioception D) Signals arising from Golgi tendon organs are synaptically linked directly to an alpha motor neuron E) The signals from a Golgi tendon organ are conducted along sensory fibers that conduct more rapidly than those of the muscle spindle

202.Which of the following neurotransmitters is used by the axons of substantia nigra neurons that project to the caudate and putamen? A) Norepinephrine B) Dopamine C) Serotonin D) Acetylcholine E) GABA

185.When a muscle is suddenly stretched, a signal is transmitted over Ia sensory fibers from muscle spindles.Which of the following statements best describes the response elicited by these spindle afferent signals? A) Contraction of the muscle in which the active spindles are located B) Relaxation of the muscle in which the active spindles are located C) Contraction of muscles antagonistic to those in which the active spindles are located D) Relaxation of intrafusal fibers in the active spindles E) Direct synaptic activation of gamma motor neurons

187.There is an area in the dominant hemisphere, which when damaged, might leave the sense of hearing intact but not allow words to be arranged into a comprehensive thought.Which of the following terms is used to identify this portion of the cortex? A) Primary auditory cortex B) Wernicke’s area C) Broca’s area D) Angular gyrus E) Limbic association cortex

183.The phenomenon of decerebrate rigidity can be explained, at least in part, by which of the following? A) Stimulation of type 1b sensory neurons B) Loss of cerebellar inputs to the red nucleus C) Overactivity of the medullary reticular nuclei involved in motor control D) Unopposed activity of the pontine reticular nuclei E) Degeneration of the nigrostriatal pathway

177. In a muscle spindle receptor, which type of muscle fiber is responsible for the dynamic response? A) Extrafusal muscle fiber B) Static nuclear bag fiber C) Nuclear chain fiber D) Dynamic nuclear bag fiber E) Smooth muscle fibers

172.Which of the following statements about muscle and passive stretch of muscle spindles is true? A) Primary (Ia) sensory fibers increase their firing rate B) Secondary sensory fibers decrease their firing rate C) Alpha motor neurons are inhibited D) Gamma motor neurons are stimulated E) Muscle spindles go completely slack

170. Signals from motor areas of the cortex reach the contralateral cerebellum after first passing through which one of the following structures? A) Thalamus B) Caudate nucleus C) Red nucleus D) Basilar pontine nuclei E) Dorsal column nuclei

164. Broca’s area is a specialized portion of motor cortex.Which of the following conditions best describes the deficit resulting from damage to Broca’s area? A) Spastic paralysis of the contralateral hand B) Paralysis of the muscles of the larynx and pharynx C) Inability to use the two hands to grasp an object D) Inability to direct the two eyes to the contralateral side E) Inability to speak whole words correctly

154.Which statement concerning the premotor cortex is correct? A) The premotor cortex is located just posterior to the primary motor cortex. B) The lateral to medial sequence in the somatotopic organization of the premotor cortex is just the reverse of that seen in the primary motor cortex. C) Stimulation of a small discrete group of neurons in premotor cortex will produce contraction of an individual muscle. D) Stimulation of premotor cortex does not lead to any muscle activation. E) The premotor cortex sets the specific posture required for the limb to produce the desired movement.

65.Which of the following is the middle ear ossicle that is attached to the tympanic membrane? A) Columella B) Incus C) Malleus D) Modiolus E) Stapes

46.The ability to detect two points simultaneously applied to the skin is based on which of the following physiologic mechanisms? A) Presynaptic inhibition B) Lateral inhibition C) Medial inhibition D) Feed-forward inhibition

39. Pain from the stomach is referred to which area of the body? A) upper right shoulder area B) abdominal area above the umbilicus C) proximal area of the anterior and inner thigh D) abdominal area below the umbilicus

40.Which one of the following statements concerning visceral pain signals is correct? A) They are transmitted along sensory fibers that course mainly with sympathetic nerves in the abdomen and thorax B) They are not stimulated by ischemia in visceral organs C) They are transmitted only by the lightly myelinated type A delta sensory fibers D) They are typically well localized

35.The gray matter of the primary somatosensory cortex contains six layers of cells.Which of the following layers receives the bulk of incoming signals from the somatosensory nuclei of the thalamus? A) Layer I B) Layers II and III C) Layer III only D) Layer IV

34.Within the primary somatosensory cortex, the various parts of the contralateral body surface are represented in areas of varying size that reflect which of the following? A) The relative size of the body parts B) The density of the specialized peripheral receptors C) The size of the muscles in that body part D) The conduction velocity of the primary afferent fibers