Psychology - Problem Drill 04: The Nervous System, Neuroanatomy, & Neurotransmitters

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1 Psychology - Problem Drill 04: The Nervous System, Neuroanatomy, & Neurotransmitters No. 1 of Which of the following statements is FALSE regarding psychology s understanding of the brain-mind connection? (A) Everything psychological is simultaneously biological. (B) The brain s ultimate challenge is to understand itself. (C) The ancient philosopher Plato correctly located the mind in the spherical head. (D) Phrenology, claimed bumps on the skull could reveal our mental abilities and our character traits. (E) A scientific understanding of the brain-mind connection began to emerge thousands of years ago. Everything psychological is simultaneously biological is the central principle of psychology. It is true that psychology believes the brain s ultimate challenge is to understand itself. It is true that the ancient philosopher Plato correctly located the mind in the spherical head. It is true that at one point in the 1800 s, Britain had 29 phrenological societies, and phrenologists traveled North America giving skull readings. E. Correct! A scientific understanding of how the brain-mind connection began to emerge over only the last 150 years. Everything psychological is simultaneously biological. No principle is more central to today s psychology. Every idea, every mood, every urge is a biological happening. You think, feel, and act with your body. You relate to the world through your body. Without your body; your genes, brain, body chemistry, appearance; you are indeed, nobody. Although we find it convenient to talk separately of biological and psychological influences on behavior, we need to remember that to think, feel, or act without a body would be like running without legs. Today s science is riveted on the most amazing parts of our body: our brain, its component neural systems, and their genetic blueprints. The brain s ultimate challenge is to understand itself. How does our brain organize and communicate with itself? How does our heredity pre-wire the brain and our experience modify it? How does the brain process the information we need? A scientific understanding of how the brain-mind connection began to emerge over only the last 150 years. The ancient philosopher Plato correctly located the mind in the spherical head. However, his student, Aristotle, believed the mind was in the heart, which pumps warmth and vitality to the body. In the 1800 s, Franz Gall invented phrenology which is an ill-fated theory that claimed bumps on the skull could reveal our mental abilities and our character traits. At one point, Britain had 29 phrenological societies, and phrenologists traveled North America giving skull readings.

2 No. 2 of Which of the following statements is FALSE regarding neurons? (A) The body s information system is built from billions of interconnected cells called neurons. (B) All neurons are exactly the same with only one type in the nervous system. (C) Human beings are bio-psycho-social systems. (D) Each neuron consists of a cell body and its branching fibers. (E) The speed of neural impulses can vary from 2 to 200 miles per hour. It is true that the body s information system is built from billions of interconnected cells called neurons. B. Correct! There are many different types of neurons but all are variations on the same theme. It is true that human beings are bio-psycho-social systems. It is true that each neuron consists of a cell body and its branching fibers. Depending on the type of fiber, the neural impulse travels at speeds ranging from a sluggish 2 miles per hour to, in some myelinated fibers, a breakneck 200 or more miles per hour. The body s information system is built from billions of interconnected cells called neurons. We are each a system composed of subsystems that are in turn composed of even smaller subsystems. Tiny cells organize to form body organs, such as the brain and the stomach, which in turn form larger systems, such as information processing and digestion, and these systems together are part of an even larger system; a human being. A human being is in turn a part of a larger system such as the family, community, and culture. We are bio-psycho-social systems. To more deeply understand our behavior, we need to understand how these biological, psychological, and social systems work and interact. Our body s neural information system is complexity built from simplicity. Its building blocks are neurons, or nerve cells. There are many different types of neurons but all are variations on the same theme. Each consists of a cell body and its branching fibers. The bushy dendrite fibers receive information, and the axon fibers pass it along to other neurons or to muscles or glands. Unlike the short dendrites, axons are sometimes very long, projecting several feet through the body. The axons from a number of neurons are bundled together into a nerve that will also contain its own blood vessels to feed and nourish the axons. Many axons are wrapped in a layer of fatty tissue, called a myelin sheath. This sheath insulates the axon and helps speed their impulses. Depending on the type of fiber, the neural impulse travels at speeds ranging from a sluggish 2 miles per hour to, in some myelinated fibers, a breakneck 200 or more miles per hour. But even this top speed is 3 million times slower than that of electricity through a wire. We measure brain activity in milliseconds. A neuron fires an impulse when it receives signals from sense receptors stimulated by pressure, heat, or light, or when it is stimulated by chemical messages from neighboring neurons. The impulse, called an action potential, is a brief electrical charge that travels down the axon.

3 No. 3 of 10 on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 3. Which of the following statements is TRUE regarding neuronal signaling? (A) The chemistry-to-electricity process involves neutral molecules. (B) The membrane is said to be impermeable. (C) Neurons generate electricity from chemical events. (D) The movement of sodium ions into the cell causes a hyperpolarization in that portion. (E) Each neuron receives input on its dendrites and cell body from a few other neurons. The chemistry-to-electricity process involves the exchange of electrically charged atoms, called ions. The membrane is said to be selectively permeable; which means it is very selective about what it allows in. C. Correct! It is true that neurons, like batteries, generate electricity from chemical events. The first bit of the axon opens its gates and the positively charged sodium ions flood through the membrane channel. This depolarizes that part of the axon. Each neuron receives input on its dendrites and cell body from hundreds to thousands of other neurons not just a few neurons. Neurons, like batteries, generate electricity from chemical events. The chemistry-toelectricity process involves the exchange of electrically charged atoms, called ions. The fluid interior of a resting axon has an excess of negatively charged ions while the fluid outside the axon membrane has more positively charged ions. This environment is called the resting membrane potential and is very carefully maintained by the membrane. The membrane is said to be selectively permeable; which means it is very selective about what it allows in. By being so selective, it can set up the positive-outside/negative-inside state. However, when a neuron fires, the environment changes. The first bit of the axon opens its gates and the positively charged sodium ions flood through the membrane channel. This depolarizes that part of the axon, causing the axon s next channel to open, and then the next, like dominoes falling, each one tripping the next. During a resting pause, called the refractory period, the neuron pumps the positively charged sodium ions back outside. Then it can fire again. In myelinated neurons, the action potential speeds up by hopping from one myelin section to the next. This process is repeated up to 100 or even 1000 times a second. The neuron is a miniature decision-making device that performs some complex calculations. Each neuron receives input on its dendrites and cell body from hundreds to thousands of other neurons. Some stimuli are excitatory while others are inhibitory. If the excitatory stimuli minus inhibitory stimuli exceed a minimum intensity, called the threshold, the combined stimulus triggers an action potential. The action potential transmits down the axon, which branches into junctions with hundreds or thousands of other neurons and with the body s muscles and glands. The strength of the stimulus does not affect the action potential s speed. However, increasing the stimulus above the threshold will not increase the action potential s intensity. The neuron s reaction is an all-or-nothing response; it either fires or it doesn t. So how do we detect the intensity of a stimulus? How do we distinguish a gentle touch from a big hug? A strong stimulus cannot trigger a stronger or faster impulse in a neuron; just as squeezing a trigger harder won t make a bullet go faster. But a strong stimulus can trigger more neurons to fire, and to fire more often.

4 No. 4 of Which of the following statements is false regarding neurotransmitters? (A) Acetylcholine enables muscle action, learning, and memory. (B) Serotonin affects mood, hunger, sleep, and arousal. (C) Agonists excite. (D) Dopamine influences movement, learning, attention, and emotion. (E) GABA is a major excitatory neurotransmitter. It is true that Acetylcholine enables muscle action, learning, and memory. It is true that Serotonin affects mood, hunger, sleep, and arousal. It is true that agonists excite. It is correct that Dopamine influences movement, learning, attention, and emotion. E. Correct! GABA is a major inhibitory neurotransmitter, not a major excitatory neurotransmitter. Acetylcholine enables muscle action, learning, and memory. Dopamine influences movement, learning, attention, and emotion. Serotonin affects mood, hunger, sleep, and arousal. Norepinephrine helps control alertness and arousal. GABA is a major inhibitory neurotransmitter. Glutamate is a major excitatory neurotransmitter and is involved in memory. This is a small list of the major neurotransmitter with a general overview of their functions. If the transmission of acetylcholine is blocked, our muscles cannot contract. Curare is a poison that certain South American Indians have put on the tips of their hunting darts. This substance occupies and blocks acetylcholine receptor sites, leaving the neurotransmitter unable to affect the muscles. Struck by one of these darts, an animal becomes paralyzed. Botulin is a poison that can form in improperly canned food. This substance causes paralysis by blocking acetylcholine release from the sending neuron. Botox is a pharmaceutical made from botulin which smoothes wrinkles by paralyzing the underlying facial muscles. By contrast, the venom of the black widow spider causes a synaptic flood of acetylcholine with the result being violent muscle contractions, convulsions, and possible death. Various drugs affect communication at the synapse. This can occur by either exciting or inhibiting the neuron's firing. Agonists excite. Agonists can do this by either being similar enough to the neurotransmitter to mimic its effects or by blocking a neurotransmitter s reuptake. For example, some opiates are agonists that cause a temporary high by amplifying normal sensations of arousal or pleasure. Antagonists inhibit. Antagonists may affect the neuron in one of two possible ways. It might inhibit a neurotransmitter s release. Alternatively, it could be enough like a neurotransmitter to attach to the receptor site and block the neurotransmitter from attaching but still not be similar enough to stimulate the receptor. As mentioned earlier, this is how Curare works. It blocks the acetylcholine receptor but is not similar enough to cause muscle contraction.

5 No. 5 of Which of the following statements is TRUE regarding the central nervous system? (A) The spinal cord is part of the central nervous system. (B) The central nervous system sends instructions out to the body s tissues via the sensory neurons. (C) Interneurons are not found in the central nervous system. (D) It includes the somatic subdivision. (E) There are very few interneurons. A. Correct! It is true that the spinal cord is part of the central nervous system. The sensory neurons send information from the body s tissues and sensory organs inward to the brain and spinal cord, which process the information. Interneurons are only found in the central nervous system. It is the peripheral nervous system that includes the somatic subdivision. Our nervous system has a few million sensory neurons, a few million motor neurons, but billions and billions of interneurons. There are two main divisions of the nervous system. The nervous system is composed of a central division that includes the brain (with all its structures) and the spinal cord. All the structures of the Central Nervous System are encased within the skull and vertebrae. The Peripheral Nervous System includes almost all other neuronal-related structures that lie outside the skull and vertebrae. This includes both the somatic and the visceral peripheral nervous system subdivisions. Information travels in the nervous system through three types of neurons. The sensory neurons send information from the body s tissues and sensory organs inward to the brain and spinal cord, which process the information. This processing involves a second class of neurons, the central nervous system s own interneurons, which enable its internal communication. The central nervous system then sends instructions out to the body s tissues via the motor neurons. Our complexity resides mostly in our interneuron systems. Our nervous system has a few million sensory neurons, a few million motor neurons, but billions and billions of interneurons.

6 No. 6 of 10 on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 6. Which of the following statements is TRUE regarding the peripheral nervous system? (A) The somatic PNS includes all the nerves that innervate the internal organs, blood vessels and glands. (B) The somatic motor fibers command contraction and relaxation of smooth, involuntary muscles of the organs, blood vessels and glands. (C) The visceral motor fibers derive from the ventral spinal cord and have their cell bodies within the CNS. (D) The visceral subdivision of the PNS is also referred to as the autonomic nervous system. (E) The visceral sensory axons enter the spinal cord but their cell bodies lie outside the spinal cord in clusters called dorsal root ganglia. It is the autonomic PNS that includes all the nerves that innervate the internal organs, blood vessels and glands, not somatic PNS. It is the Visceral motor fibers that command contraction and relaxation of smooth, involuntary muscles of the organs, blood vessels and glands, instead of somatic motor fibers. It is the somatic motor fibers that derive from the ventral spinal cord and have their cell bodies within the CNS, instead of visceral motor fibers. D. Correct! It is true that the visceral subdivision of the PNS is also referred to as the autonomic nervous system. It is the somatic sensory axons enter the spinal cord but their cell bodies lie outside the spinal cord in clusters called dorsal root ganglia. Visceral sensory axons bring information about visceral function to the CNS such as pressure and oxygen content of the blood in the arteries. As mentioned earlier, the peripheral nervous system consists of the visceral and the somatic subdivisions. We will start with the Visceral PNS. This portion of the PNS is also referred to as the autonomic nervous system as it usually deals with bodily functions that are controlled without the need to conscious attention. The autonomic PNS includes all the nerves that innervate the internal organs, blood vessels and glands. The Visceral motor fibers command contraction and relaxation of smooth, involuntary muscles of the organs, blood vessels and glands The Visceral sensory axons bring information about visceral function to the CNS such as pressure and oxygen content of the blood in the arteries. The autonomic nervous system also contains a dual system of both the sympathetic and the parasympathetic nervous system. The sympathetic division arouses us for defensive action such as the fight or flight response. This can include such things as accelerating your heartbeat, slowing your digestion, raising your blood sugar level, dilating your arteries, and cooling you with perspiration. All this is one to make you alert and ready for action. The parasympathetic division has the opposite effect. It conserves energy as it calms you. In everyday life, both the sympathetic and parasympathetic nervous systems work together to keep us in a steady internal state. In contrast to the visceral PNS, the somatic PNS includes all the nerves that innervate the skin, joints, and muscles that are under voluntary control. The Somatic motor fibers derive from the ventral spinal cord and command voluntary muscle contraction. Their cell bodies are within the CNS but their axons are mostly in the PNS. The Somatic sensory axons collect information from skin, joints and muscles and enter the spinal cord but their cell bodies lie outside the spinal cord in clusters called dorsal root ganglia.

7 No. 7 of 10 on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 7. Which of the following statements is FALSE regarding the Central Nervous System? (A) The brain is composed of the cerebrum and the cerebellum. (B) The cerebrum has two main subdivisions, the neocortex and the basal ganglia. (C) When looking at the brain from the front, the terms anterior or dorsal are used. (D) With a few exceptions, most structures within the nervous system come in pairs. (E) A slice resulting in splitting the brain into equal left and right halves (down the midline) is called a midsagittal section. It is true that the brain is composed of the cerebrum and the cerebellum. It is true that the cerebrum has two main subdivisions, the neocortex and the basal ganglia. C. Correct! When looking at the brain from the front, the terms anterior or rostral are used. It is true that with only a few exceptions, most structures within the nervous system come in pairs (one on the right side and one on the left). It is true that a slice resulting in splitting the brain into equal left and right halves (down the midline) is called a midsagittal section with sections parallel to the midsagittal plane being sagittal sections. The Central Nervous System is composed of the brain and the spinal cord. The brain consists of the cerebrum and the cerebellum. The cerebrum has two main subdivisions, the neocortex and the basal ganglia,. The central nervous system is also composed of the brainstem and the spinal cord. The central nervous system s spinal cord is an information highway connecting the peripheral nervous system to the brain. Ascending neural tracts send up sensory information and descending tracts send back motor-controlling information. However, the neural pathways governing our reflexes do not rely on the brain s intervention. A simple spinal reflex pathway is composed of a single sensory neuron and a single motor neuron that often communicate through an interneuron. By the time your brain becomes aware of your hand over a hot flame, you have already pulled your hand to safety. The brain is composed of the cerebrum and the cerebellum. A basic orientation of the brain includes terms that help you find your way around. When looking at the brain from the front, the terms anterior or rostral are used. Viewing from the back of the brain is referred to as posterior or caudal. The top of the brain is the dorsal or superior view while the underside of the brain is referred to as the ventral or inferior view. With a few exceptions, most structures within the nervous system come in pairs (one on the right side and one on the left). The invisible line that runs down the middle is known as the MIDLINE. Structures that are closer to the midline are referred to as MEDIAL while structures that are further away from the midline are LATERAL. To view the interior structures, it is usually necessary to slice through the brain or other structure (with a slice called a section). The standard approach is to make cuts parallel to one of the anatomical planes of section. A slice resulting in splitting the brain into equal left and right halves (down the midline) is called a midsagittal section with sections parallel to the midsagittal plane being sagittal sections. When the slice is made parallel to the ground, it is a horizontal section. A slice perpendicular to the ground and to the sagittal plane is a coronal section.

8 No. 8 of Which of the following would NOT be considered a basal ganglion? (A) The cerebellum. (B) Putamen. (C) Substantia nigra. (D) Globus pallidus. (E) Caudate nucleus. A. Correct! The cerebellum is the most prominent feature of the brainstem. The putamen is considered to be a basal ganglion. The substantia nigra is considered to be a basal ganglion. The globus pallidus is considered to be a basal ganglion. The caudate nucleus is considered to be a basal ganglion. The last topic within our exploration of the neocortex involves the circuit of nuclei lying mainly beneath the anterior regions of the neocortex. They include the Putamen, globus pallidus, caudate nucleus, amygdala and the substantia nigra. These structures form circuits within the cortex. For example, the cuadate nucleus receives projections from all areas of the neocortex and then projects the information through the putamen and globus pallidus to the thalamus. With the thalamus being the relay center in the cortex, the information is then relayed on to the motor cortex. The basal ganglia also have reciprocal connections with the midbrain; especially with the substantia nigra. This projection provides the chemical dopamine to the basal ganglia. Parkinson s disease is a motor disorder that results when dopamine is lost. The basal ganglia have also been shown to be involved in maintenance of posture, motor function, sequencing of movements into a smoothly executed response, and stimulus response or habit learning. Taken together, this thin sheet of gray matter that is the outer layer of our brain includes a great many structures with a great many functions. The cerebellum is the most prominent feature of the brainstem and extends over much of the dorsal surface of the brainstem. It contains as many neurons as both the cerebral hemispheres combined all packed together within the folia.

9 No. 9 of Which of the following is NOT an example of a research method used to study the brain? (A) Clinical observation (B) Surveys (C) Electrical stimulation (D) Lesion studies (E) EEG Clinical observation is the oldest research method used to study the brain. B. Correct! Surveys are not a common method used to study the brain. Electrical stimulation is a common research method used to study the brain. The use of lesions in animals is a common research method used to study the brain. The electroencephalogram (EEG) is a common research method used to study the brain. The oldest method of studying brain-mind connections is to observe the effects of brain diseases and injuries. Although such observations have been recorded since ancient times, it was only in the past two centuries that physicians began systematically recording the results of damage to specific brain areas. Some noted that damage to one side of the brain often caused numbness or paralysis to the opposite side of the body; suggesting that the right side of the brain is wired to the left side of the body and visa versa. Others noted that damage to the back of the brain disrupted vision, and that damage to the left-front part of the brain produced speech difficulties. Gradually, the brain was being mapped. Today, records of more than 1500 brain injured patients have been assembled into the largest-ever braindamage registry. Their stories provide clues to our own brain s inner workings. However, today s scientists do not need to await brain injuries. Modern techniques allow scientists to electrically, chemically, or magnetically stimulate various parts of the brain and note the effects. They can surgically lesion (meaning destroy) tissue in specific brain areas in animals. For example, a lesion in one area of the hypothalamus in a rat s brain reduces eating, causing the rat to starve unless forcefed. A lesion in another area produces overeating. Right now, your mental activity is giving off telltale electrical, metabolic, and magnetic signals that would enable scientists to eavesdrop on your brain. The tips of modern electrodes are so small they can detect the electrical pulse in a single neuron, making some astonishingly precise findings. Electrically activity in the brain s billions of neurons sweeps in regular waves across its surface. The electroencephalogram (EEG) is an amplified tracing of such waves. Studying the EEG of the gross activity of the whole brain is like studying the activity of a car engine by listening to the hum of its motor. However, by presenting a stimulus repeatedly and having a computer filter out brain activity unrelated to the stimulus, one can identify the electrical wave evoked by the stimulus.

10 No. 10 of 10 on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. 10. Which of the following comparisons is FALSE regarding neuroimaging techniques? (A) The CT scan (computed tomography) examines the brain by taking x-ray photographs that can reveal brain damage. (B) The PET scan (positive emission tomography) which depicts brain activity by showing each brain area s consumption of its chemical fuel, the sugar glucose. (C) MRI is effective because it relies on the fact that the centers of atoms don t normally spin. (D) MRI scans reveal enlarged fluid-filled brain area in some patients who have schizophrenia. (E) Functional MRI scans can take pictures less than a second apart. It is true that the CT scan (computed tomography) examines the brain by taking x-ray photographs that can reveal brain damage. It is true that the PET scan (positive emission tomography) which depicts brain activity by showing each brain area s consumption of its chemical fuel, the sugar glucose. C. Correct! MRI exploits the fact that the centers of atoms, including those in our brains, spin like tops. It is true that MRI scans reveal enlarged fluid-filled brain area in some patients who have schizophrenia. By taking pictures less than a second apart, functional MRI scans can therefore show the brain lighting up as a research participant performs different mental functions. Other new windows into the brain give us an incredible ability to see inside the brain without lesioning it. These new brain imaging instruments are doing for psychological science what the microscope did for biology and the telescope for astronomy. Data from different brainimaging techniques are appearing faster than anyone can read and remember them, and researchers are assembling this information into computer databases for all researchers to have instant access to. Clearly, this the golden age of brain science. For example, the CT scan (computed tomography) examines the brain by taking x-ray photographs that can reveal brain damage. Even more dramatic is the PET scan (positive emission tomography) which depicts brain activity by showing each brain area s consumption of its chemical fuel, the sugar glucose. Active neurons are glucose hogs. A person is given a temporarily radioactive form of glucose and the PET scan locates and measures the radioactivity. By noting where this radioactive glucose goes in the brain, researchers can see which brain areas are most active as the person performs mathematical calculations, listens to music, daydreams, or any other stimulus provided in the study. Another new way of looking into the living brain exploits the fact that the centers of atoms, including those in our brains, spin like tops. In MRI (magnetic resonance imaging), the head is put in a strong magnetic field, which aligns the spinning atoms. Then a brief pulse of radio waves disorients the atoms momentarily. When the atoms return to their normal spin, they release detectable signals, which become computer-generated images of their concentrations. The result is a detailed picture of the brain s soft tissues. For example, MRI scans reveal enlarged fluid-filled brain area in some patients who have schizophrenia. When the brain is especially active, blood flow to these areas increase. This increase in oxygenated blood increases the signal of the MRI. By taking pictures less than a second apart, functional MRI scans can therefore show the brain lighting up as a research participant performs different mental functions. Such snapshots of the brain s activity provide new insights into how the brain divides its labor. They also reveal when things happen, how brain areas change with experience, and what brain area work together. For example, imaging research reveals that similar brain areas are involved in reading and remembering words.