All Questions: 121-150
121. The sodium-potassium pump is a protein pump whose main function is to transport sodium ions out of the cell and potassium ions into the cell. Each cycle of the pump moves ____ sodium ions out of the cell and ____ potassium ions into the cell.
- A. 1, 3
- B. 2, 3
- C. 3, 2
- D. 3, 1
Show Answer
Correct answer: C
Each cycle of the pump moves 3 sodium ions out of the cell and 2 potassium ions into the cell. The actions of the pump help to ensure that sodium ions are more concentrated outside the cell and potassium ions are more concentrated inside the cell.
122. What essential amino acid is necessary for the production of serotonin?
- A. tryptophan
- B. histidine
- C. lysine
- D. phenylalanine
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Correct answer: A
Tryptophan is necessary for serotonin production. It needs to be taken in through the diet, and once in the body it is converted into 5-hydroxytryptophan (5-HTP) by the enzyme tryptophan hydroxylase. 5-HTP is then converted into serotonin (5-HT).
123. Where is the subarachnoid space located?
- A. between the dura mater and the arachnoid mater
- B. between the pia mater and the brain
- C. between the arachnoid mater and the pia mater
- D. between the dura mater and the skull
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Correct answer: C
The subarachnoid space is found between the arachnoid mater and the pia mater. The subarachnoid space is filled with cerebrospinal fluid (CSF).
124. People with prosopagnosia have a deficit in their ability to perceive or recognize:
- A. language
- B. inanimate objects
- C. faces
- D. movement
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Correct answer: C
Prosopagnosia, also sometimes referred to as "face blindness," involves a deficit in the ability to perceive or recognize faces. The severity of the disorder varies, with the most extreme cases being unable to perceive facial features at all and milder cases having a difficult time recognizing people based solely on facial features. It can come about after some sort of damage to the brain, but congenital cases also occur.
125. These receptors are responsible for detecting painful stimuli:
- A. mechanoreceptors
- B. proprioceptors
- C. nociceptors
- D. thermoreceptors
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Correct answer: C
Nociceptors are cutaneous receptors that are specialized to detect noxious stimuli like extreme pressure, very hot or cold temperatures, or tissue damage. When activated, nociceptors convey information regarding a painful stimulus to the spinal cord, and from there it gets sent up to the brain.
126. Although the neuroscience of PTSD is not fully understood, one supported hypothesis suggests that the disorder involves increased activity in the _________ and decreased activity in areas of the _________.
- A. amygdala, prefrontal cortex
- B. nucleus accumbens, amygdala
- C. cerebellum, hippocampus
- D. insula, ventral tegmental area
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Correct answer: A
One supported hypothesis suggests that PTSD involves decreased activity in the medial prefrontal cortex and increased activity in subnuclei of the amygdala that are involved in the identification of threats.
127. NMDA glutamate receptors are involved in long-term potentiation (LTP), but their ion channels are blocked by this type of ion until depolarization causes the blockade to be removed:
- A. potassium
- B. magnesium
- C. sodium
- D. chloride
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Correct answer: B
NMDA receptors are not activated by low levels of glutamate release because the ion channel of an NMDA receptor is typically blocked by a magnesium ion. If frequent action potentials cause greater depolarization of the neuron, however, the magnesium blockade is removed, allowing calcium ions to flow in through the NMDA receptor.
128. The mesolimbic dopamine pathway plays an important role in reward. It connects the ventral tegmental area (VTA) to several limbic structures, with the primary part of the pathway extending from the VTA to the:
- A. cerebellum
- B. thalamus
- C. raphe nuclei
- D. nucleus accumbens
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Correct answer: D
The main portion of the mesolimbic pathway connects the VTA with the nucleus accumbens. This pathway is activating during rewarding experiences, such as the use of addictive drugs.
129. This part of the brain is known for its role in regulating homeostasis throughout the body. Through its connections to the the autonomic nervous system and endocrine system, as well as its ability to influence behavior, it is involved in the regulation of thirst, hunger and feeding, body temperature, and circadian rhythms, among many other things:
- A. amygdala
- B. hypothalamus
- C. hippocampus
- D. cerebellum
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Correct answer: B
The hypothalamus is involved in many processes that are critically important to maintaining homeostasis across various bodily systems. Some of the major functions generally attributed to the hypothalamus include the regulation of: thirst and drinking behavior, fluid and electrolyte balance, hunger and feeding, body temperature, stress responses, aggressive behaviors, reproductive behaviors, circadian rhythms, the sleep-wake cycle, and more.
130. This cranial nerve innervates the lateral rectus muscle to move the eye laterally, toward the side of the head:
- A. optic nerve (CN II)
- B. oculomotor nerve (CN III)
- C. trochlear nerve (CN IV)
- D. abducens nerve (CN VI)
Show Answer
Correct answer: D
The abducens nerve innervates the lateral rectus muscle to move the eye laterally.
131. This neuroscientist coined the term "synapse":
- A. Santiago Ramon y Cajal
- B. John Hughlings Jackson
- C. Eric Kandel
- D. Charles Scott Sherrington
Show Answer
Correct answer: D
Sherrington coined the term "synapse." Sherrington had originally planned to use the term syndesm to describe the functional junction between neurons, but a friend suggested synapse, from the Greek meaning "to clasp," since it "yields a better adjectival form."
132. This reflex can be used to test the integrity of the glossopharyngeal and vagus nerves:
- A. corneal reflex
- B. withdrawal reflex
- C. pupillary light reflex
- D. gag reflex
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Correct answer: D
The gag reflex, also known as the pharyngeal reflex, can be used to test the integrity of the glossopharyngeal (IX) and vagus (X) nerves. The glossopharyngeal nerve is the main sensory limb of the reflex (it detects the sensation), and the vagus nerve is the primary motor limb of the reflex (it helps to contract throat muscles and expel what is in the throat).
133. This early neurodevelopmental structure will form the cerebral hemispheres:
- A. diencephalon
- B. telencephalon
- C. mesencephalon
- D. metencephalon
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Correct answer: B
The nervous system forms from the neural tube during neural development. As the neural tube matures, it develops several vesicles; these give rise to specific parts of the nervous system. The telencephalon forms the cerebral hemispheres, including the cerebral cortex and a number of subcortical structures.
134. This part of a neuron is the region where neurotransmitters are typically released from:
- A. axon
- B. dendrite
- C. cell body/soma
- D. axon terminal/synaptic bouton
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Correct answer: D
When an action potential reaches the axon terminals/synaptic boutons, it causes an influx of calcium ions. These ions prompt vesicles to fuse with the presynaptic membrane, and cause the release of neurotransmitters into the synaptic cleft.
135. Where is most of the cerebrospinal fluid (CSF) in the central nervous system located?
- A. in the ventricles
- B. in the central canal
- C. in the subarachnoid space
- D. in the cerebral aqueduct
Show Answer
Correct answer: C
CSF is produced in the ventricles, but the ventricles only contain about 1/8 of the total CSF in the central nervous system. The rest of the CSF is primarily found in the subarachnoid space.
136. Most of the neurons in the optic tracts terminate in this nucleus in the thalamus:
- A. medial geniculate nucleus
- B. lateral geniculate nucleus
- C. ventral posterolateral nucleus
- D. pulvinar nucleus
Show Answer
Correct answer: B
Most of the neurons in the optic tracts terminate in the lateral geniculate nucleus of the thalamus. Here, the optic tracts synapse on neurons that leave the lateral geniculate nucleus and extend toward the back of the brain as bundles of fibers called the optic radiations. The optic radiations travel back to the primary visual cortex.
137. This is the most common type of primary brain tumor:
- A. meningioma
- B. medulloblastoma
- C. low-grade astrocytoma
- D. glioblastoma multiforme
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Correct answer: A
Meningiomas are the most common primary brain tumor. (If a brain tumor begins in the brain, it’s called a primary brain tumor. If it spreads to the brain from some other location, it’s known as a secondary brain tumor.) Meningiomas form in the meninges, and are usually benign.
138. Alan Hodgkin and Andrew Huxley won the Nobel Prize in 1963 for helping understand how the flow of ions across the cell membrane of a neuron leads to an action potential. What organism were their most famous experiments conducted with?
- A. squid
- B. mouse
- C. frog
- D. fruit fly
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Correct answer: A
Hodgkin and Huxley studied action potentials in the relatively enormous axons of the squid. They chose the squid because their largest axons (up to 1 mm in diameter) made studying action potentials much easier. Their work specifically explained how action potentials are generated and propagated in neurons, and they shared the Nobel Prize in 1963 with John Eccles (for his work on synaptic transmission).
139. These glial cells are responsible for myelinating neurons in the peripheral nervous system:
- A. Schwann cells
- B. microglia
- C. astrocytes
- D. oligodendrocytes
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Correct answer: A
Myelin is an insulating material that covers the axons of most neurons in the nervous system. Oligodendrocytes are the cells responsible for myelinating central nervous system neurons, while Schwann cells myelinate neurons in the peripheral nervous system.
140. Which cells carry visual signals out of the eye, forming the optic nerve?
- A. photoreceptor cells
- B. bipolar cells
- C. ganglion cells
- D. horizontal cells
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Correct answer: C
The visual signal travels from photoreceptors to bipolar cells to ganglion cells. The ganglion cells carry the signal out of the eye, forming the optic nerve.
141. Current estimates suggest that humans use somewhere around 10-20% of our brains, suggesting that we have yet to tap into the full capabilities of the brain.
- A. True
- B. False
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Correct answer: B
The idea that we use only a fraction of our brain is a myth that was long ago debunked by neuroscience research. Modern neuroimaging methods in particular have demonstrated that nearly every part of the brain is active at some point.
142. Which of the following structures is NOT considered part of the basal ganglia?
- A. caudate
- B. putamen
- C. globus pallidus
- D. red nucleus
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Correct answer: D
The red nucleus is found in the brainstem, and is thought to be involved in motor coordination (among other things). It is not, however, considered part of the basal ganglia. Major structures of the basal ganglia include the caudate, putamen, globus pallidus, substantia nigra, and subthalamic nucleus.
143. These midbrain structures are recognizable as two small bumps on the dorsal surface of the brainstem. They are a critical component of the auditory pathway:
- A. superior colliculi
- B. cerebral peduncles
- C. inferior colliculi
- D. cerebellar peduncles
Show Answer
Correct answer: C
The inferior colliculi form two bumps on the posterior surface of the brainstem just below the superior colliculi. The inferior colliculus is best known for its role in hearing. It is the largest nucleus of the auditory system in humans, and it is the point in the brainstem where all auditory pathways traveling through the brainstem converge.
144. Someone with damage to their accessory nerve (CN XI) would have the most trouble with which of the following activities?
- A. moving their eyes laterally (i.e., to the side)
- B. swallowing
- C. standing on one foot
- D. raising their arms above their head
Show Answer
Correct answer: D
The accessory nerve is primarily considered a motor nerve that supplies two muscles: the sternomastoid muscle and the trapezius muscle. The sternomastoid helps to turn your head to the side, as well as bend your neck down or to the side. The trapezius is involved with the movement of the neck and scapula, or shoulder blade. The trapezius is important to a variety of shoulder and arm movements, such as shrugging your shoulders or raising your arms above your head.
145. How does a cochlear implant improve hearing in someone who is deaf or has severe hearing loss?
- A. it causes vibration of the eardrum to create the sensation of sound
- B. it enhances auditory processing through stimulation of brainstem nuclei
- C. it amplifies existing sound waves so they are loud enough to detect
- D. it stimulates the auditory nerve to send auditory information to the brain
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Correct answer: D
Cochlear implants involve a microphone that detects sound, as well as a sound processor that converts the sound into a radio frequency signal. The signal is transmitted to a receiver implanted under the skin behind the ear. The receiver decodes the signal, then converts it into electrical currents. The currents are sent along wires to stimulate the auditory nerve, which sends auditory information to the brain.
146. This neural tube structure will eventually form the pons and cerebellum:
- A. prosencephalon
- B. diencephalon
- C. mesencephalon
- D. metencephalon
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Correct answer: D
The pons and cerebellum form from the metencephalon, a secondary vesicle of the neural tube.
147. This part of the brain is best known for its role in pain inhibition. Neurons leave here and form part of a pathway that extends down to the spinal cord to inhibit the transmission of pain signals.
- A. amygdala
- B. hippocampus
- C. precentral gyrus
- D. periaqueductal gray
Show Answer
Correct answer: D
The periaqueductal gray, or PAG, is an area of gray matter found in the brainstem. Although the functions of the PAG are complex and not fully understood, it is best known for its role in the inhibition of pain.
148. This neurotransmitter and hormone binds to opioid receptors and is thought to play a role in natural pain inhibition:
- A. dopamine
- B. substance P
- C. beta-endorphin
- D. serotonin
Show Answer
Correct answer: C
Beta-endorphin is one of a class of substances called endogenous opioids, which received their name because they are produced by the body and bind to the same receptors that opioid drugs like morphine bind to. By binding to opioid receptors, beta-endorphin can elicit natural pain-relieving effects that have been found to be more potent than morphine.
149. When referring to the brain, the term dorsal describes areas that are:
- A. closer to the top of the brain (i.e., superior)
- B. closer to the middle of the brain
- C. closer to the bottom of the brain (i.e., inferior)
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Correct answer: A
When used for animals that move through the world horizontally (e.g., on all fours), dorsal refers to the back and ventral refers to the abdominal region. With humans, the same usage applies when we are looking at the spinal cord. At the junction between the top of the brainstem and the diencephalon, however, the axis shifts due to the fact that humans walk upright. Above this level dorsal refers to the superior portion of the brain and ventral refers to the inferior portion.
150. After a severe stroke that impacted a large region of the left cerebral hemisphere, a patient displays substantial deficits in both language production and comprehension. He can speak only a few words and has trouble understanding what others say to him. What type of aphasia does this sound most like?
- A. Broca's aphasia
- B. Wernicke's aphasia
- C. anomic aphasia
- D. global aphasia
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Correct answer: D
Broca's aphasia mostly involves deficits in producing language, and Wernicke's aphasia mostly involves deficits in language comprehension and the production of meaningful language. Global aphasia, however, involves a combination of symptoms from Broca's and Wernicke's aphasia. Patients with global aphasia experience deficits in both the production and comprehension of speech.
