Overview and Evaluation of the Nervous System

Question 1

The ____ (____ ____) is a specialized cell that is directly involved in mental processes and behavior. In humans, most of the brain’s neurons are ____ at ____. Although neurons die at a rate of about __ ____ ____, because of their ____ ____ ____, ____ ____ _% of the ____ ____ is lost by the age of _.

Answer 1

Neuron (Nerve Cell); Present at Birth; 10,000 Per Day; Enormous Initial Quantity; Less than 2%; Original Supply; 70

Question 2

There is evidence that neurons may ____ through ____ in some ____ of the ____. The creation of new neurons is referred to as ____ and, in the human brain, has been observed in the ____ and ____ ____.

Answer 2

Regenerate; Adulthood; Areas of the Brain; Neurogenesis; Hippocampus; Caudate Nucleus

Question 3

____ of the ____: Neurons vary in ____, ____, and ____; but most consist of three distinct components: ____, ____ ____ (____), and ____. The branch-like ____ receive information from other ____ and conduct it toward the ____ ____, which integrates information received from the dendrites and passes it on to the ____.

Answer 3

Structure of the Neuron; Shape, Size, and Function; Dendrites, Cell Body (Soma), and Axon; Dendrites; Cells; Cell Body; Axon

Question 4

The cell body contains several structures including the ____, ____, ____, and ____ ____. The ____ are sites where the cell performs its metabolic activities, while the ____ are sites at which the cell synthesizes new protein molecules. Some ribosomes ____ ____ within the ____ but others are embedded in the smooth ____ ____, which consists of ____ that ____ ____ to other ____ in the ____.

Answer 4

Nucleus; Mitochondria, Ribosomes, and Golgi Complex; Mitochondria; Ribosomes; Float Freely; Cell; Endoplasmic Reticulum; Channels that Transport Proteins; Locations in the Cell

Question 5

The ____ ____ is a system of membranes that prepare neurotransmitters and other substances for secretion.

Answer 5

Golgi Complex

Question 6

The ____ transmits information from the ____ ____ to other ____. Most neurons have a ____ ____ that divides into ____ ____ (collaterals), and many axons are covered by a ____ ____, which is a fatty substance that acts as an insulator and speeds up the conduction of nerve impulses. The myelin sheath is made up of ____ ____ that also serve several other important functions including ____ ____ ____, providing neurons with ____, and removing ____ ____.

Answer 6

Axon; Cell Body; Cells; Single Axon; Numerous Branches; Myelin Sheath; Glial Cells; Holding Neurons Together; Nutrients; Cellular Debris

Question 7

____ ____ and ____ ____: Communication in the nervous system involves a combination of ____ and ____ ____. Messages within a neuron are transmitted from a ____ ____ to the end of its ____ through an electrical process called ____. In its resting state, the inside of the cell is ____ ____ relative to the ____ of the ____.

Answer 7

Communication Within and Between Neurons; Electrical and Chemical Processes; Neuron’s Dendrites; Axon; Conduction; Negatively Charged; Outside of the Cell

Question 8

However, when the dendrites of the cell receive ____ ____ from other ____ , this electrical balance is ____: With sufficient stimulation, ____ ____ in the cell’s membrane ____, which allows ____ ____ ____ ____ to ____ the ____ and create a state of ____ (i.e., the interior of the cell becomes less negative). This depolarization triggers an ____ ____, which is an electrical impulse that travels quickly through the cell.

Answer 8

Sufficient Stimulation; Cells; Altered; Sodium Channels; Open; Positively Charged Sodium Ions to Enter the Cell; Depolarization; Action Potential

Question 9

Depolarization is followed by ____, in which sodium channels close and potassium channels open, which allows positively charged potassium ions to leave the cell. Note that the action potential operates on the ____ -or-____ ____, which means that, whenever the stimulation received by a neuron exceeds a given threshold, the resulting action potential will always be of the same intensity.

Answer 9

Repolarization; All-or-None Principle

Question 10

In contrast to the electrical conduction of information within a nerve cell, the transmission of ____ from one ____ ____ to another is usually ____ ____ and occurs when the action potential reaches the ____ ____. This process is referred to as ____ ____ and involves the release of a neurotransmitter into the ____ ____, which is the small gap between the axon terminal of the presynaptic cell and the receptor on the dendrite of a postsynaptic cell.

Answer 10

Information; Nerve Cell; Chemically Mediated; Axon Terminal; Synaptic Transmission; Synaptic Cleft

Question 11

____ are chemical substances that transmit signals from one neuron to another.

Answer 11

Neurotransmitters

Question 12

____ (ACh) is found throughout the peripheral and central nervous systems and acts on two different types of receptors – ____ and ____. In the ____ ____ ____, ACh is released into the ____ ____ where it causes muscles to contract.

Answer 12

Acetylcholine; Muscarinic and Nicotinic; Peripheral Nervous System; Neuromuscular Junction; Muscles to Contract

Question 13

____ ____ is an autoimmune disorder that attacks ACh receptors at neuromuscular junctions, resulting in profound weakness of the skeletal muscles. In the ____ ____ ____, ACh is involved in ___ ____, the regulation of the ____ -____ ____, and ____ and ____. Regarding memory, there is evidence that ____ enhances memory and alertness by ____ ___ at ____ ____ ____.

Answer 13

Myasthenia Gravis; Central Nervous Stem; REM Sleep; Sleep-Wake Cycle, and Learning and Memory; Nicotine; Mimicking ACh at Nicotinic Receptor Sites

Question 14

____ of ____ (ACh) ____ in the ____ ____ end other areas that communicate directly with the ____ is believed to underlie the memory deficits associated with ____ ____. Recognition of the impact of ACh on memory led to the use of ____ ____ to slow ____ ____ in patients with this disorder. These drugs reduce the ____ of ___ and include tacrine (Cognex), donepezil (Aricept). galantamine (Reminyl), and rivastigmine (Exelon).

Answer 14

Degeneration of Cholinergic Cells; Entorhinal Cortex; Hippocampus; Alzheimer’s Disease; Cholinesterase Inhibitors; Memory Declines; Breakdown of ACh

Question 15

____ and other neurotransmitters classified as ____ (norepinephrine and epinephrine) are involved in several functions including ____, ____, ____, and ____. Dopamine was identified as a contributor to ____ in the 1960s, and the ____ ____ predicts that this disorder is due to ____ ____ ____ or ____ of ____ ____.

Answer 15

Dopamine; Catecholamines; Personality, Mood, Memory, and Sleep, Schizophrenia; Dopamine Hypothesis; Elevated Dopamine Levels or Oversensitivity of Dopamine Receptors

Question 16

Dopamine is also involved in the ____ of ____ and has been linked to several disorders with prominent motor symptoms including ____ ____ and ____ ____. The research suggests that ____ ____ or ____ ____ in the ____ ____ contributes to ____ ____, while a ____ of ____ ____ in the ____ ____ and nearby areas underlies the tremors, muscle rigidity, and other motor symptoms of ____ ____.

Answer 16

Regulation of Movement; Tourette’s Disorder and Parkinson’s Disease; Oversensitivity To or Excessive Dopamine; Caudate Nucleus; Tourette’s Disorder; Degeneration of Dopamine Receptors; Substantia Nigra; Parkinson’s Disease

Question 17

____ ____ of ____ in the ____ ____ (areas in the midbrain and limbic system) have been implicated in the reinforcing actions of stimulant drugs, opiates, alcohol, and nicotine. For example, ____ blocks the reuptake of dopamine at synapses in this area of the brain, while ____ stimulates its release.

Answer 17

Elevated Levels of Dopamine; Mesolimbic System; Cocaine; Nicotine

Question 18

____ plays an important role in mood, attention, dreaming, learning, and certain autonomic functions. Regarding mood, the ____ ____ predicts that some forms of depression are due to lower-than-normal levels of this neurotransmitter.

Answer 18

Norepinephrine; Catecholamine Hypothesis

Question 19

____ (____) usually exerts an inhibitory effect and has been implicated in mood, hunger, temperature regulation, sexual activity, arousal, sleep, aggression, and migraine headache. Elevated levels of serotonin contribute to ____, ____ ____, and food restriction associated with ____ ____, while low levels play a role ________________________________. There is also evidence that abnormalities in serotonin and dopamine levels or transmission play a role in ____ ____.

Answer 19

Serotonin (5-HT); Schizophrenia, Autistic Disorder; Anorexia Nervosa; Aggression, Depression, Suicide, Bulimia Nervosa, PTSD, and Obsessive-Compulsive Disorder; Social Phobia

Question 20

____ -____ ____ (____) is an inhibitory neurotransmitter and plays a role in eating, seizure, and anxiety disorders, motor control, vision, and sleep. ____ ____ of ____ have been linked to anxiety disorders, and ____ and other ___ ____ reduce anxiety by enhancing the effects of ____.

Answer 20

Gamma-Aminobutyric Acid (GABA); Low Levels of GABA; Benzodiazepines; CNS Depressants; GABA

Question 21

Evidence for the role of GABA in motor control is provided by studies showing that ____ of ____ that ____ ____ in the ____ ____ contributes to the ____ ____ of ____ ____.

Answer 21

Degeneration of Cells that Secrete GABA; Basal Ganglia; Motor Symptoms of Huntington’s Disease

Question 22

____ acts as an excitatory neurotransmitter in many areas of the brain. It Plays a role in ____ and ____ and, more specifically, in ____ -____ ____ (___), a brain mechanism that is believed to be responsible for the formation of long-term memories. ____ ____ ____ ____ (“excitotoxicity”) can lead to seizures and may contribute to stroke-related brain damage, Huntington’s disease, Alzheimer’s disease, and other neurodegenerative disorders.

Answer 22

Glutamate; Learning and Memory; Long-Term Potentiation (LTP); Excessive Glutamate Receptor Activity

Question 23

____ (“endogenous morphines”) are inhibitory neuromodulators that lower the sensitivity of postsynaptic neurons to neurotransmitters. The endorphins have ____ ____ and may be responsible for the ____ ____ produced by ____. One theory is that their analgesic properties are due to their ability to ____ the ____ of ____ __, which is involved in the transmission of ____ ____. The endorphins have also been implicated in certain ____ ____ (e.g., the “runner’s high”), ____, ____ and ____ and ____ ____.

Answer 23

Endorphins; Analgesic Properties; Pain Relief; Acupuncture; Prevent the Release of Substance P; Pain Impulses; Pleasurable Experiences, Emotions, Memory and Learning, and Sexual Behavior

Question 24

The divisions and major structures of the nervous system are depicted in Figure 1.

Answer 24

Question 25

The ____ ____ ____ (___) consists of the ____ and spinal cord. The brain includes numerous structures that are highly interrelated in terms of function. These structures are distinguished by the kinds of ____ they contain, the way the neurons are ____, and the way the ____ are ____.

Answer 25

The Central Nervous System (CNS); Brain; Neurons; Arranged; Axons; Distributed

Question 26

The primary structures of the brain are illustrated in Figure 2.

Answer 26

Question 27

The ____ ____ is made up of bundles of myelinated axons (nerve tracts) as well as dendrites, cells bodies, and interneurons. It carries information between the ____ and the ____ ____ ____, coordinates activities of the ____ and ____ ____ of the ____, and controls ____ ____ that do not involve the ____.

Answer 27

Spinal Cord; Brain; Peripheral Nervous System; Left and Right Sides of the Body; Simple Reflexes; Brain

Question 28

____ ____ in the superior portion of the spinal cord, the dorsal horns, carry ____ (____) ____, while fibers in the ____ ____, the ventral horns, ____ ____ (____) ____. The spinal cord consists of _ ____ that are divided into ____ ____ which, from the top to the bottom of the spinal cord, are ____ , ____, ____, ____, and ____.

Answer 28

Nerve Fibers; Sensory (Afferent) Messages; Inferior Portion; Transmit Motor (Efferent) Messages; 31 Segments; Five Groups; Cervical, Thoracic, Lumbar, Sacral, and Coccygeal

Question 29

The consequences of injury to the spinal cord depend on its ____. Damage at the cervical level is likely to result in ____, which is also known as ____ and involves a loss of ____ and ____ ____ ____ in the ____ and ____.

Answer 29

Location; Quadriplegia; Tetraplegia; Sensory and Voluntary Motor Functioning; Arms and Legs

Question 30

Damage at the thoracic level causes ____ which entails a loss of ____ and ____ ____ in the ____. The consequences also depend on whether the injury is ____ or ____. A complete transection of the spinal cord produces a lack of ____ and ____ ____ ____ the ____ of ____, but when the transection is incomplete, some sensory and motor ____ ____ the ____ of ____ are ____. For example, a person with an incomplete injury may have sensation in one limb or parts of the body that cannot be moved or may be able to move one limb more than another.

Answer 30

Paraplegia, Sensory and Voluntary Functioning in the Legs; Complete or Incomplete; Sensation and Voluntary Movement Below the Level of Injury; Functions Below the Level of Injury are Maintained

Question 31

The brain and spinal cord are ____ -____. Both are encased in ____ and are covered by three membranes (meninges) — ____ ____, ____, and ____ ____. Additional protection is provided by the ____ ____ (___), which fills the ____ ____ (the space between the arachnoid and pia mater), the ____ ____ of the ____ ____, and the four ____ ____.

Answer 31

Well-Protected; Bone; Dura Mater, Arachnoid, and Pia Mater; Cerebrospinal Fluid (CSF); Subarachnoid Space; Central Canal; Spinal Cord; Cerebral Ventricles

Question 32

Several disorders are related to ____ ____. For example, ____ is caused by an obstruction of the flow of CSF that leads to a build-up of fluid and enlargement of the ventricles; and larger-than-normal ventricles have also been found in some individuals with ____.

Answer 32

Ventricular Abnormalities; Hydrocephalus; Schizophrenia

Question 33

The ____ ____ ____ (___) is made up of nerves (bundles of axons) that relay messages between the central nervous system and the body’s sensory organs, muscles, and glands. The PNS consists of _ ____ of ____ ____ that connect directly to the ____ and ¬¬_ ____ of ____ and ____ ____ (spinal nerves) that connect with the ____ ____.

Answer 33

Peripheral Nervous System (PNS); 12 Pairs of Cranial Nerves; Brain and 31 Sets of Sensory and Motor Nerves; Spinal Cord

Question 34

The PNS is divided into the ____ and the ____ ____ ____, The ____ ____ ____ (___) consists of sensory nerves that carry information from the body’s sense receptors to the CNS and motor nerves that carry information from the CNS to the skeletal muscles.

Answer 34

Somatic; Autonomic Nervous Systems; Somatic Nervous Systems (SNS)

Question 35

The SNS governs activities that are ordinarily considered ____.

Answer 35

Voluntary

Question 36

The ____ ____ ____ (___) is comprised of sensory nerves that convey signals from receptors in the viscera to the CNS and motor nerves that carry signals from the CNS to the smooth muscles, cardiac muscle, and glands.

Answer 36

Autonomic Nervous System (ANS)

Question 37

Although the ANS is associated primarily with ____ ____, biofeedback, hypnosis, and other techniques have shown that some autonomic activities can be brought under ____ ____.

Answer 37

Involuntary Activities; Voluntary Controls

Question 38

The ANS is further divided into the ____ and ____ ____. The sympathetic branch. is associated with arousal and the expenditure of energy. For example, in reaction to an external threat, the ____ ____ causes dilation of the pupils, inhibition of peristalsis, dry mouth, sweating, and increased blood pressure and heart rate to ready the body for “____ or ____.”

Answer 38

Sympathetic and Parasympathetic; Sympathetic Branch; Fight or Flight

Question 39

The ____ ____ is involved in the conservation of energy and is active during digestion and periods of rest and relaxation. Meditation, hypnosis, biofeedback, and other techniques that are used to foster the “____ ____” do so by activating the ____ ____.

Answer 39

Parasympathetic Branch; Relaxation Response; Parasympathetic Branch

Question 40

Although it may seem that the sympathetic and parasympathetic branches work in opposition, they often function ____. For example, during sexual activity, the parasympathetic branch mediates erection in males while the sympathetic branch stimulates ejaculation.

Answer 40

Cooperatively

Question 41

The development of the human brain involves five main stages: _____________________

Answer 41

Proliferation; Migration; Differentiation; Myelination; Synaptogenesis

Question 42

____: New cells are produced inside the neural tube beginning when the embryo is about 2-1/2 weeks old.

Answer 42

Proliferation

Question 43

____: Immature neurons ____ to their final destination in the brain beginning at about 8 weeks. Once these cells reach their destination, they begin to aggregate with other cells to form the structures of the brain.

Answer 43

Migration; Migrate

Question 44

____: Neurons initially look very much like other cells of the body but, following migration, develop axons and dendrites.

Answer 44

Differentiation

Question 45

____: The axons of some neurons ____, which occurs when glial cells form an insulating sheath around the cell’s axon. Much ____ occurs postnatally.

Answer 45

Myelination; Myelinate; Myelination

Question 46

____: The timing of ____ (formation of synapses) depends on the specific area of the brain, but most occurs postnatally. ____ appears to be influenced by both endogenous (e.g., genetic) and exogenous (e.g., experience) factors.

Answer 46

Synaptogenesis; Synaptogenesis; Synaptogenesis

Question 47

Neurons are initially ____ -____. and many undergo an active ____ ____ during ____ ____ and for several years following ____. This form of ____ ____ is referred to as ____ and apparently serves to “____ -____” ____ ____.

Answer 47

Over-Produced; Pruning Process; Prenatal Development; Birth; Cell Death; Apoptosis; Fine-Tune Brain Development

Question 48

____ of ____ ____ ____ and ____: Several tests are conducted to identify the location and extent of ____ ____ ____ and ____. A ____ __-____ is often the initial diagnostic test and is used to identify fractures, dislocations, or other injury to the bones of the spine. This is often followed by ____ ____ ____ (___), which permits evaluation of the soft tissues of the spinal column.

Answer 48

Evaluation of Spinal Cord Injuries and Disease; Simal Cord Injury and Disease; Spinal X-Ray; Magnetic Resonance Imaging (MRI)

Question 49

In some cases, ____ ____ with ____ (which involves injecting a dye into the spinal canal) may be used to obtain more detailed information about the extent of the injury.

Answer 49

Computed Tomography with Myelogram

Question 50

The evaluation of an injury may also include an ____ (___), ____ ____ ____ (___), or other type of ____ ____ to determine if the injury or disease has impacted the ____ of ____ ____ in the ____ ____.

Answer 50

Electromyography (EMG), Somatosensory Evoked Potentials (SSEP); Electrodiagnostic Monitoring; Conduction of Nerve Signals; Spinal Cord

Question 51

The evaluation of brain injury and disease is a comprehensive process that incorporates a ____ ____ and ____ ____, ____ and ____ ____, and ____ ____ that provide information on the structure and function of the brain.

Answer 51

Thorough History and Physical Exam, Behavioral and Neuropsychological Assessments, and Neuroimaging Techniques

Question 52

Computed tomography (CT) and magnetic resonance imaging (MRI) are structural neuroimaging techniques that provide information on the ____ ____ of the ____. CT is also known as ____ ____ ____ (CAT) and utilizes X-rays to obtain images of horizontal slices of brain tissue.

Answer 52

Physical Structure of the Brain; Computerized Axial Tomography

Question 53

A CT scan is useful for diagnosing various ____ ____ such as tumors, blood clots, and multiple sclerosis. MRI also provides ____ -____ ____ of the ____ but does so by using ____ ____ and ____ ____.

Answer 53

Pathological Conditions; Cross-Sectional Images of the Brain; Magnetic Fields and Radio Waves

Question 54

An MRI has several advantages over a CT scan: It does not use X-rays; it has better resolution and provides more detailed images, it provides images at any angle (not just in the horizontal plane), and it generates-three-dimensional pictures of the brain. However, MRI is more expensive than a CT scan and may require that the patient be sedated.

Answer 54

X-Rays; Resolution; Detailed Images; Any Angle; Three-Dimensional Pictures of the Brain; More Expensive; Sedated

Question 55

____ -____ ____ (___), ____ ____ ____ ____ (___), and ____ ____ ____ ____ (___) are ____ ____ ____ that provide information on ____ ____.

Answer 55

Positron-Emission Tomography (PET), Single Proton Emission Computed (SPECT), and Functional Magnetic Resonance Imaging (fMRI) are Functional Neuroimaging Techniques; Brain Activity

Question 56

When using PET, the individual is injected with a ____ ____ ____ that is taken up by ____ ____ ____. The images produced by a PET scan provide information on ____ ____ ____ ____, ____, ____, and ____ ____, which are presumed to correlate with level of ____ ____.

Answer 56

Radioactive Tracer Substance; Active Brain Cells; Regional Cerebral Blood Flow, Glucose, Metabolism, and Oxygen Consumption; Neural Activity

Question 57

___ ____ are used to assess cerebrovascular disease, Alzheimer’s disease and other forms of dementia, Schizophrenia, and other disorders and to identify brain areas that are active during the performance of ____ ____ and the experience of ordinary ____. (Note that, in the initial stages of Alzheimer’s disease and other neurodegenerative disorders, PET scans are usually ____.)

Answer 57

PET Scans; Ordinary Tasks; Emotions; Negative

Question 58

___ is similar to PET but has ____ ____. ___ is similar to MRI but also provides information on ____ ____ (blood oxygenation) and, in comparison to PET and SPECT, provides images that have better ____ and ____ ____.

Answer 58

SPECT; Lower Resolution; fMRI; Brain Activity; Temporal and Spatial Resolution

Question 59

Most neurons consist of three distinct components: The branch-like (1) ____ receive information from other cells and conduct it toward the (2) ____, which integrates information received from the dendrites and passes it on to the (3) ____. Most neurons have a single axon that divides into numerous branches (collaterals), and many axons are covered by a myelin sheath that is made up of (4) ____ cells.

Answer 59

(l) dendrites; (2) cell body (soma); (3) axon; (4) glial

Question 60

Conduction of information within neurons is an (5) ____ process. With sufficient stimulation, the interior of the neuron becomes less negative and tracers an (6) ____, which operates on the (7) ____ principle. Communication between neurons usually involves the release of a (8) ____ by the presynaptic cell into the synaptic cleft.

Answer 60

(5) electrical; (6) action potential; (7) all-or-none; (8) neurotransmitter

Question 61

In the peripheral nervous system, the neurotransmitter (9) ____ is released into the neuromuscular junction where it causes muscles to contract; and, in the central nervous system, it’s involved in the regulation of the sleep-wake cycle and learning and memory. (10) ____ plays a role in Schizophrenia and is involved in the regulation of movement and has been linked to several disorders with prominent motor symptoms including Tourette’s Disorder and Parkinson’s disease.

Answer 61

(9) ACh (acetylcholine); (10) Dopamine

Question 62

Elevated levels of (11) ____ contribute to Schizophrenia, Autistic Disorder, and food restriction associated with Anorexia Nervosa, while low levels play a role in aggression, depression, suicide, Bulimia Nervosa, PTSD, and Obsessive-Compulsive Disorder. Benzodiazepines reduce anxiety by enhancing the effects of (12) ____.

Answer 62

(11) serotonin; (12) GABA

Question 63

The central nervous system (CNS) includes the brain and the spinal cord. The consequences of damage to the spinal cord depend on its location and extent. For example, complete transection at the cervical level results in (13) ____, while damage at the thoracic level causes (14) ____. The brain and spinal cord are protected by three meninges and the cerebrospinal fluid (CSF). Accumulation of CSF in the (15) ____ as the result of an obstruction can cause hydrocephalus.

Answer 63

(13) quadriplegia; (14) paraplegia; (15) cerebral ventricles

Question 64

The peripheral nervous system (PNS) is divided into the (16) ____ nervous system, which carries information between the CNS and the body’s sensory systems and skeletal muscles, and the (17) ____ nervous system, which regulates the activities of the visceral muscles and glands.

Answer 64

(16) somatic; (17) autonomic

Question 65

The autonomic nervous system has two subdivisions: The (18) ____ branch prepares the body for “fight or flight,” while the (19) ____ branch is associated with the conservation of energy and states of rest and relaxation. The development of the CNS involves five stages. During the (20) ____ stage, each cell moves to its ultimate destination in the nervous system.

Answer 65

(18) sympathetic; (19) parasympathetic; (20) migration

Question 66

Computed tomography (CT) and magnetic resonance imaging (MRI) provide information on the (21) ____ of the brain, while (22) ____, SPECT, and MRI provide information on the brain’s (23) ____ activities.

Answer 66

(21) structure; (22) PET; (23) functional