Medical Physiology Paper I — Exam I, Q51–100 OmpathStudy

Continued from $1. Question 51 are collections of 50-150 cells and are located on the surface of your tongue, back of your mouth, and roof of your mouth. a) Taste receptor cellsb) Taste budsc) Taste poresd) Tastants Answer: b) Taste buds Explanation: Taste buds are the sensory organs containing 50-150 taste receptor cells, located on the tongue, soft palate, and other oral structures. --- Question 52 In which of the following ascending pathways or tracts do the secondary neurons decussate within the spinal cord? a) fasciculus cuneatusb) posterior spinocerebellar tractsc) fasciculus gracilisd) spinothalamic tracts Answer: d) spinothalamic tracts Explanation: In the spinothalamic tract, second-order neurons cross (decussate) in the spinal cord at the level of entry, unlike the dorsal column pathways which decussate in the medulla. --- Question 53 An injury to the lateral portion of the postcentral gyrus in the right hemisphere would result in some loss of sensation in the? a) left lower limbb) right lower limbc) left facial aread) right facial area Answer: c) left facial area Explanation: The lateral portion of the postcentral gyrus (primary somatosensory cortex) processes sensations from the face and upper body. Due to decussation, the right hemisphere processes left-sided sensations. --- Question 54 What best describes medial lemniscus? a) is a tract of nerve fibers that conveys sensory signals to the thalamusb) receives information from the brain and spinal cord and relays it to the cerebellumc) provides an avenue of communication between the two cerebral hemispheresd) links the primary motor area to the primary sensory area Answer: a) is a tract of nerve fibers that conveys sensory signals to the thalamus Explanation: The medial lemniscus is the ascending sensory pathway that carries fine touch, vibration, and proprioceptive information from the dorsal column nuclei to the ventral posterior lateral nucleus of the thalamus. --- Question 55 Severing which part of the spinothalamic tract would result in pain impulses from the right side being blocked? a) right anteriorb) left anteriorc) right laterald) left lateral Answer: d) left lateral Explanation: Pain and temperature fibers cross in the spinal cord and ascend in the lateral spinothalamic tract. To block right-sided pain, you would need to sever the left lateral spinothalamic tract (due to decussation). --- Question 56 A pen is placed in your left hand behind your back. Which of the following tracts would NOT be involved in your ability to state what is in your hand? a) associationb) commissuralc) corticobulbard) corticospinal Answer: )d Question 57 Which of these events occur when a person steps on a tack with their right foot? a) The right foot is pulled away from the tack because of the Golgi tendon reflex b) The left leg is extended to support the body because of the stretch reflex c) The flexor muscles of the thigh contract, and the extensor muscles relax because of reciprocal innervation d) The extensor muscles of both thighs contract because of the crossed extensor reflex Answer: c) --- Question 58 Inhibitory interneurons are involved in the following reflexes? a) knee jerk reflex b) flexor reflex c) stretch reflex d) Golgi tendon reflex Answer: d) Golgi tendon reflex Explanation: The Golgi tendon reflex uses inhibitory interneurons to relax the contracting muscle when excessive tension is detected, preventing muscle damage. This is the only reflex listed that requires inhibitory interneurons. --- Question 59 A ventrolateral cordotomy is performed that produces relief of pain in the right leg. It is effective because it interrupts the: a) left dorsal column b) left ventrolateral spinothalamic tract c) right ventrolateral spinothalamic tract d) right medial lemniscal pathway Answer: b) left ventrolateral spinothalamic tract Explanation: Pain fibers cross over at the spinal level, so pain from the right leg travels in the left spinothalamic tract. Cutting the left ventrolateral spinothalamic tract interrupts pain signals from the right side of the body. --- Question 60 Which of the following CNS regions is not correctly paired with a neurotransmitter or chemical involved in pain modulation? a) Periaqueductal gray matter and morphine b) Nucleus raphe magnus and norepinephrine c) Spinal dorsal horn and encephalin d) Spinal dorsal horn and serotonin Answer: b) Nucleus raphe magnus and norepinephrine Explanation: The nucleus raphe magnus primarily releases serotonin, not norepinephrine, for pain modulation. Norepinephrine is more associated with the locus coeruleus in pain pathways. --- Question 61 How is the HCO3- content of saliva altered in the presence of food? a) Food stimulates the parasympathetic nervous system to reduce HCO3- secretion into the saliva b) Food stimulates the sympathetic nervous system to increase HCO3- secretion into saliva c) Food stimulates the parasympathetic nervous system to increase HCO3- secretion into the saliva d) Food i