Chapter 12; The Central Nervous System
Terms in this set (223)
degenerative brain disease resulting in progressive loss of memory and motor control, and increasing dementia
web-like; specifically, the web-like arachnoid mater, the middle layer of the three meninges
functional areas of the cerebral cortex that act mainly to integrate diverse information for purposeful action
specific gray matter areas located deep within the white matter of the cerebral hemispheres; see Basal nuclei
Basal Nuclei (Basal Ganglia)
specific gray matter areas located deep within the white matter of the cerebral hemispheres
mechanism that inhibits passage of materials from the blood into brain tissues; reflects relative impermeability of brain capillaries
state of irreversible coma, even though life-support measures may have restored other body organs
collectively the midbrain, pons, and medulla of the brain
fluid-filled cavity of the brain
Central Nervous System (CNS)
brain and spinal cord
brain region most involved in producing smooth, coordinated skeletal muscle activity
the slender cavity of the midbrain that connects the third and fourth ventricles
the outer gray matter region of the cerebral hemispheres
designates the hemisphere that is dominant for language
neuromuscular disability in which voluntary muscles are poorly controlled or paralyzed as a result of brain damage
Cerebral White Matter
consists largely of myelinated fibers bundled into large tracts; provides for communication between cerebral areas and lower CNS centers
plasma-like fluid that fills the cavities of the CNS and surrounds the CNS externally; protects the brain and spinal cord
Cerebrovascular Accident (CVA)
condition in which brain tissue is deprived of a blood supply, as in blockage of a cerebral blood vessel; a stroke
the cerebral hemispheres (including the cerebral cortex, white matter, and basal nuclei)
a capillary knot that protrudes into a brain ventricle; involved in forming cerebrospinal fluid
the ability to perceive, communicate, remember, understand, appreciate, and initiate voluntary movements
(1) arrangement of elongated follicle cells around a mature ovum; (2) crown-like arrangement of nerve fibers radiating from the internal capsule of the brain to every part of the cerebral cortex
that part of the forebrain between the cerebral hemispheres and the midbrain including the thalamus, the epithalamus, and the hypothalamus
Dorsal Root Ganglion
peripheral collection of cell bodies of first-order afferent neurons whose central axons enter the spinal cord
outermost and toughest of the three membranes (meninges) covering the brain and spinal cord
graphic record of the electrical activity of nerve cells in the brain
inflammation of the brain
area between the bony vertebrae and the dura mater of the spinal cord
abnormal electrical discharges of groups of brain neurons, during which no other messages can get through
most dorsal portion of the diencephalon; forms the roof of the third ventricle with the pineal gland extending from its posterior border
(1) a groove or cleft; (2) the deepest depressions or inward folds on the brain
anterior portion of the brain consisting of the telencephalon and the diencephalon
gray area of the central nervous system; contains neuronal cell bodies and their dendrites
an outward fold of the surface of the cerebral cortex
limbic system structure that plays a role in converting new information into long-term memories
hereditary disorder leading to degeneration of the basal nuclei and the cerebral cortex
region of the diencephalon forming the floor of the third ventricle of the brain
(1) a stalk of tissue that connects the pituitary gland to the hypothalamus; (2) the distal end of the uterine (fallopian) tube
lobe of the cerebral cortex that is buried in the lateral sulcus beneath portions of the parietal, frontal, and temporal lobes
band of projection fibers that runs between the basal nuclei and the thalamus
situated on the same side
local decrease in blood supply
functional brain system involved in emotional response and memory formation
central portion of certain organs
inferiormost part of the brain stem
protective coverings of the central nervous system; from the most external to the most internal, the dura mater, arachnoid mater, and pia mater
inflammation of the meninges
one of the three primary vesicles of the developing brain; becomes the midbrain
a secondary brain vesicle; anterior portion of the rhombencephalon of the developing brain; becomes the pons and the cerebellum
region of the brain stem between the diencephalon and the pons
functional areas in the cerebral cortex that control voluntary motor functions
Myelencephalon (Spinal Brain)
a secondary brain vesicle; lower part of the developing hindbrain, especially the medulla oblongata
fetal structure which gives rise to the brain, spinal cord, and associated neural structures; formed from ectoderm by day 23 of embryonic development
neurodegenerative disorder of the basal nuclei due to insufficient secretion of the neurotransmitter dopamine; symptoms include tremor and rigid movement
Pineal Gland (Body)
a hormone-secreting part of the diencephalon of the brain thought to be involved in setting the biological clock and influencing reproductive function
(1) any bridge-like structure or part; (2) the part of the brain stem connecting the medulla with the midbrain, providing linkage between upper and lower levels of the central nervous system
major motor pathways concerned with voluntary movement; descend from pyramidal cells in the frontal lobes of each cerebral hemisphere
Rapid Eye Movement (REM) Sleep
stage of sleep in which rapid eye movements, an alert EEG pattern, and dreaming occur
Reticular Activating System (RAS)
diffuse brain stem neural network that receives a wide variety of sensory input and maintains wakefulness of the cerebral cortex
functional system that spans the brain stem; involved in regulating sensory input to the cerebral cortex, cortical arousal, and control of motor behavior
caudal portion of the developing brain; constricts to form the metencephalon and myelencephalon; includes the pons, cerebellum, and medulla oblongata
functional areas of the cerebral cortex that provide for conscious awareness of sensation
that part of the sensory system dealing with reception in the body wall and limbs; receives inputs from exteroceptors, proprioceptors, and interoceptors
the ability of neurons to identify the site or pattern of stimulation
the bundle of nervous tissue that runs from the brain to the first to third lumbar vertebrae and provides a conduction pathway to and from the brain
condition in which brain tissue is deprived of a blood supply, as in blockage of a cerebral blood vessel; see Cerebrovascular accident
a furrow on the brain, less deep than a fissure
anterior subdivision of the primary forebrain that develops into olfactory lobes, cerebral cortex, and basal nuclei
a mass of gray matter in the diencephalon of the brain
a collection of axons in the central nervous system having the same origin, termination, and function
(1) paired, inferiorly located heart chambers that function as the major blood pumps; (2) cavities in the brain
white substance of the central nervous system; myelinated nerve fibers
Describe how space constraints affect brain development.
The brain provides for voluntary movements, interpretation and integration of sensation, consciousness, and cognitive function.
Early brain development yields the primary brain vesicles: the prosencephalon (cerebral hemispheres and diencephalon), mesencephalon (midbrain), and rhombencephelon (pons, medulla oblongata, and cerebellum).
As a result of cephalization, the diencephelon and superior brain stem are developed by the cerebral hemispheres.
Because the brain grows more rapidly than the membranous skull that contains it, it folds up to occupy the available space.
Name the major regions of the adult brain.
In a widely used system, the adult brain is divided into the cerebral hemispheres, diencephelon, brain stem, and cerebellum.
The cerebral hemispheres and cerebellum have gray matter nuclei surrounded by white matter and an outer cortex of gray matter. The diencephalon and brain stem lack a cortex.
Name and locate the ventricles of the brain.
The brain contains four ventricles filled with cerebrospinal fluid. The lateral ventricles are in the cerebral hemispheres; the third ventricle is in the diencephalon; the fouth ventricle is between the brain stem and the cerebellum and connects with the central canal of the spinal cord.
Which ventricle is surrounded by the diencephalon?
The third ventricle is surrounded by the diencephalon.
Which two areas of the adult brain have an outside layer of gray matter in addition to central gray matter and surrounding white matter?
The cerebral hemispheres and the cerebellum have an outside layer of gray matter in addition to central gray matter and its surrounding white matter.
What is the function of convolutions of the brain?
Convolutions increase surface area of the cortex, which allows more neurons to occupy the limited space within the skull.
List the major lobes, fissures, and functional areas of the cerebral cortex.
The two cerebral hemispheres exhibit gyri, sulci, and fissures. The longitudinal fissure partially separates the hemispheres; other fissures or sulci subdivide each hemisphere into lobes.
Each cerebral hemisphere consists of the cerebral cortex, the cerebral white matter, and basal nuclei (ganglia).
Each cerebral hemisphere receives sensory impulses from, and dispatches motor impulses to, the opposite side of the body. The body is represented in an upside-down fashion in the sensory and motor cortices.
Functional areas of the cerebral cortex include: (1) motor areas: primary motor and premotor cortices of the frontal lobe, the frontal eye field, and Broca's area in the frontal lobe of one hemisphere (usually the left); (2) sensory areas: primary somatosensory cortex and somatosensory association cortex in the parietal lobe; visual areas of the occipital lobe; olfactory and auditory areas in the temporal lobe; gustatory, visceral, and vestibular areas in the insula; and (3) association areas: anterior association area in the frontal lobe, and posterior and limbic association areas spanning several lobes.
Explain lateralization of hemisphere function.
The cerebral hemispheres show lateralization of cortical function. In most people, the left hemisphere is dominant (i.e., specialized language and mathematical skills); the right hemisphere is is more concerned with visual-spatial skills and creative endeavors.
Differentiate between commissures, association fibers, and projection fibers.
Fiber tracts of the cerebral white matter include commissures, association fibers, and projection fibers.
Commissural fibers connect corresponding gray areas of the two hemispheres.
Association fibers connect different parts of the same hemisphere.
Projection fibers either enter the cerebral cortex from lower brain or cord centers or descending from the cortex to lower areas.
Describe the general function of the basal nuclei (basal ganglia).
The paired basal nuclei (also called basal ganglia) include the globus pallidus, putamen, and caudate nucleus. Functionally, they are closely associated with the substantia nigra of the midbrain. The basal nuclei recieve input from the entire cerebral cortex as well as other subcortical nuclei and each other. The basal neclei are subcortical nuclei that help control movements.
What anatomical landmark of the cerebral cortex separates primary motor areas from somatosensory areas?
The central sulcus separates primary motor areas from somatosensory areas.
Mike, who is left-handed, decided to wear his favorite t-shirt to his anatomy class. On his t-shirt were the words "Only left-handed people are in their right minds." What does this statement mean?
Motor functions on the left side of the body are controlled by the right hemisphere of the brain because motor tracts from the right hemisphere cross over (in the medulla oblongata) to the left side of the spinal cord to go to the left side of the body.
Which type of fiber allows the two cerebral hemispheres to "talk to each other"?
Commissural fibers (which form commissures) allow the cerebral hemispheres to "talk to each other".
Name the components of the basal nuclei.
The caudate nucleus, putamen, and globus pallidus together form the basal neclei.
Describe the location of the diencephalon, and name its subdivisions and functions.
The diencephelon includes the thalamus, hypothalamus, and epithalamus ans encloses the third ventricle.
The thalamus is the major relay station for (1) sensory impulses ascending to the sensory cortex, (2) inputs from subcortical motor nuclei and the cerebellum traveling to the cerebral motor cortex, and (3) impulses traveling to association cortices from lower centers.
The hypothalamus is an important control center of the autonomic nervous system and a pivotal part of the limbic system. It maintains water balance and regulates thirst, eating behavior, gastrointestinal activity, body temperature, and the activity of the anterior pituitary gland.
The epithalamus includes the pineal gland, which secretes the hormone melatonin.
Why is the thalamus called the "gateway to the cerebral cortex"?
Virtually all inputs ascending to the cerebral cortex synapse in the thalamus en route.
The hypothalamus oversees a branch of the peripheral nervous system. Which branch?
The hypothalamus oversees the autonomic nervous system.
Identify the three major regions of the brain stem, and not the functions of each area.
The brain stem includes the midbrain, pons, and medulla oblongata.
The midbrain contains the corpora quadrigemina (visual and auditory reflex centers), the red nucleus (subcortical motor centers), and the substantia nigra. The periaqueductal gray matter is involved in pain suppression and contains the motor nuclei of cranial nerves III and IV. The cerebral peduncles on its ventral face house the pyramidal fiber tracts. The midbrain surrounds the cerebral aqueduct.
The pons is mainly a conduction area. Its nuclei contribute to regulating respiration and cranial nerves V - VII.
The pyramids (descending corticospinal tracts) form the ventral face of the medulla oblongata. These fibers cross over (decussation of the pyramids) before entering the spinal cord. Important nuclei in the medulla regulate respiratory rhythm, heart rate, and blood pressure and serve cranial nerves VIII - XII. The olivary nuclei and cough, sneezing, swallowing, and vomiting centers are also in the medulla.
What are the pyramids of the medulla? What is the result of decussation of the pyramids??
The pyramids of the medulla are the corticospinal (pyramidal) tracts, the large voluntary motor tracts descending from the motor cortex. The result of decussation (crossing over) is that each side of the motor cortex controls the opposite side of the body.
Which region of the brain stem is associated with the cerebral peduncles and the superior and inferior colliculi?
The cerebral peduncles and the colliculi are associated with the midbrain.
Describe the structure and function of the cerebellum.
The cerebellum consists of two hemispheres, marked by convolutions and separated by the vermis. It is connected to the brain stem by superior, middle, and inferior peduncles.
The cerebellum processes and interprets impulses from the motor cortex and sensory pathways and coordinates motor activity so that smooth, well-timed movements occur. It also plays a poorly understood role in cognition.
In what ways are the cerebellum and the cerebrum similar? In what ways are they different??
Structurally, the cerebellum and cerebrum are similar in that they both have a thin outer cortex of gray matter, internal white matter, and deep gray matter nuclei. Also, both have body maps (homunculi) and large fiber tracts connecting them to the brain stem. Both receive sensory input and influence motor output. A major difference is that the cerebellum is almost entirely concerned with motor output, whereas the cerebrum has much broader responsibilities. Also, while a cerebral hemisphere controls the opposite side of the body, the cerebellar hemisphere controls the same side of the body.
Locate the limbic system and the reticular formation, and explain the role of each functional system.
The limbic system consists of numerous structures that encircle the brain stem. It is the "emotional-visceral brain." It also plays a role in memory.
The reticular formation is a diffuse network of neurons and nuclei spanning the length of the brain stem. It maintains the alert state of the cerebral cortex (RAS), and its motor nuclei serve both somatic and visceral motor activities.
The limbic system is sometimes called the emotional-visceral brain. Which part of the limbic system is responsible for the visceral connection?
The hypothalamus is part of the limbic system and also an autonomic (visceral) control center.
When Taylor begins to feel drowsy while driving, she opens her window, turns up the volume of the car stereo, and sips ice-cold water. How do these actions keep her awake?
Taylor is increasing the amount of sensory stimuli she receives, which will relay to the reticular activating system, which, in turn, will increase activation in the cerebral cortex.
Define EEG and distinguish between alpha, beta, theta, and delta brain waves.
Patterns of electrical activity of the brain are called brain waves; a record of this activity is and electroencephalogram (EEG). Brain wave patterns, identified by their frequencies, include alpha, beta, theta, and delta waves.
Alpha waves (8 - 13 Hz) are relatively regular and rhythmic, low-amplitude, synchronous waves. In most cases, they indicate a brain that is "idling" -- a calm, relaxed state of wakefulness.
Beta waves (14 - 30 Hz) are also rhythmic, but less regular than alpha waves and with a high frequency. Beta waves occur when we are mentally alert , as when concentrating on some problem or visual stimulus.
Theta waves (4 - 7 Hz) are still more irregular. Though common in children, theta waves are uncommon in awake adults but may appear when concentrating.
Delta waves (4 Hz or less) are high-amplitude waves seen during deep sleep and when the reticular activating system is damped, such as during anesthesia. In awake adults, they indicate brain damage.
Epilepsy results from abnormal electrical activity of brain neurons. Involuntary muscle contractions and sensory auras are typical during some epileptic seizures.
Describe consciousness clinically.
Consciousness is described clinically on a continuum from alertness to drowsiness to stupor and finally to coma.
Human consciousness is thought to involve holistic information processing, which is (1) not localizable, (2) superimposed on other types of neural activity, and (3) totally interconnected.
Fainting (syncope) is a temporary loss of consciousness that usually reflects inadequate blood delivery to the brain. Coma is loss of consciousness in which the victim is unresponsive to stimuli.
Compare and contrast the events and importance of slow-wave and REM sleep, and indicate how their patterns change through life.
Sleep is a state of partial consciousness from which a person can be aroused by stimulation. The two major types of sleep are non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep.
During stages 1 - 4 of NREM sleep, brain wave frequency decreases and amplitude increases until delta wave sleep (stage 4) is achieved. REM sleep is indicated by a return to alpha waves on the EEG. During REM, they eye moves rapidly under the lids. NREM and REM sleep alternate throughout the night.
Slow-wave sleep (stages 3 and 4 of NREM) appears to be restorative. REM sleep is important for emotional stability.
REM occurs half of an infant's sleep time and then declines to about 25% of sleep time by age 10. Time spent in slow-wave sleep declines steadily throughout life.
What is the importance of sleep, why do we sleep?
Slow-wave and REM sleep seem to be important in different ways. Slow-wave sleep is presumed to be restorative, the time when most neural activity can wind down to basal levels. When deprived of sleep, we spend more time than usual in slow-wave sleep during the next sleep episode.
People who are persistently deprived of REM sleep become moody and depressed, and exhibits various personality disorders. REM sleep may give the brain an opportunity to analyze the day's events and work through emotional problems in dream imagery.
Another idea is that REM sleep is reverse learning. According to this hypothesis, accidental, repetitious, and meaningless communications continually occur. Dreaming eliminates them from our neural networks so the cortex remains a well-behaved and efficient thinking system. In other words, we dream to forget.
Name some of the most common sleep disorders.
Narcolepsy is involuntary lapses into REM sleep that occur without warning during waking periods. Insomnia is a chronic inability to obtain the amount or quality of sleep needed to function adequately. A person with sleep apnea stops breathing temporarily during sleep, causing hypoxia.
Explain language function in the brain.
In most people, the left hemisphere controls language. The language implementation system, which include Broca's and Wernicke's areas and basal nuclei, analyzes incoming and produces outgoing language. The opposite hemisphere deals with the emotional content of language.
When would you see delta waves in an EEG?
Delta waves are typically seen in deep sleep in normal adults.
Which two states of consciousness are between alertness and coma?
Drowsiness (or lethargy) and stupor are stages of consciousness between alertness and coma.
During which sleep stage are most skeletal muscles actively inhibited?
Most skeletal muscles are actively inhibited during REM sleep.
Compare and contrast the stages and categories of memory.
Memory is the storage and retrieval of information. It is essential for learning and is part of consciousness.
Memory storage has two stages: short-term memory (STM) and long-term memory (LTM). transfer of information from STM to LTM takes minutes to hours, but more time is required for LTM consolidation.
Describe the roles of the major brain structures believed to be involved in declarative and procedural memories.
Declarative memory is the ability to learn and consciously remember information. Procedural memory id the learning of motor skills, which are then performed without conscious thought.
Declarative memory appears to involve the medial temporal lobe (hippocampus and surrounding temporal cortical areas), thalamus, basal forebrain, and prefrontal cortex. Procedural memory ( a type of non-declarative memory) relies on the basal nuclei.
The nature of memory formation at the molecular level is not fully known, but NMDA receptors (essentially calcium channels), activated by depolarization and glutamate binding, play a major role in long-term potentiation (LTP). The calcium influx that follows NMDA receptor activation mobilizes enzymes that mediate events necessary for memory formation.
Name the three factors that can enhance transfer of information from STM to LTM.
Transfer of memory from STM to LTM is enhanced by (1) rehearsal, (2) association (trying "new" information to "old" information), and (3) a heightened emotional state (for example, alert, motivated, surprised, or aroused).
Which functional areas of the cerebrum are involved in the formation of procedural (skill) memory, but not involved in declarative memory?
The basal nuclei and premotor cortex are involved in procedural (skill) memory, but not in declarative memory.
Describe how meninges, cerebrospinal fluid, and the blood brain barrier protect the CNS.
The delicate brain is protected by bone, meninges, cerebrospinal fluid, and the blood brain barrier.
The meninges from superficial to deep are the dura mater, arachnoid mater, and pia mater. They enclose the brain and spinal cord and their blood vessels. Inward folds of the inner layer of the dura mater secure the brain to the skull.
The cerebrospinal fluid supports and cushions the brain and cord and helps to nourish them.
The blood brain barrier reflects the relative impermeability of the epithelium of capillaries of the brain. It allows watery, respiratory gasses, essential nutrients, and fat-soluble molecules to enter the neural tissue, but blocks other, water-soluble, potentially harmful substances.
Explain how cerebrospinal fluid is formed and describe its circulatory pathway.
Cerebrospinal fluid (CSF), formed by the choroid plexuses from blood plasma, circulates through the ventricles and into the subarachnoid space. It returns to the dural venous sinuses via the arachnoid villi.
Explain what head trauma is.
Head trauma may cause brain injuries called concussions or, in severe cases, contusions (bruising). When the brain stem is affected, unconsciousness (temporary or permanent) occurs. Trauma-induced brain injuries may be aggravated by intracranial hemorrhage or cerebral edema, both of which compress brain tissue.
Describe the cause (if known) and major signs and symptoms of cerebrovascular accidents, Alzheimer's disease, Parkinson's disease, and Huntington's disease.
Cerebrovascular accidents (also known as a stroke) result when blood circulation to brain neurons is impaired and brain tissue dies. The result may be hemiplegia, sensory deficits, or speech impairment. The most common cause of CVA is a blood clot that blocks a cerebral artery.
General symptoms of CVA include:
- sudden numbness, tingling, weakness, or loss of movement in the face, arm, or leg, especially on only one side of the body
- sudden vision changes
- difficulty speaking
- sudden confusion or difficulty understanding simple statements
- sudden difficulties with balance or walking
- a sudden, severe headache that is different from past headaches
CVA Symptoms can vary depending on whether the stroke is caused by a blood clot (ischemic stroke) or bleeding (hemorrhagic stroke), where the stroke occurs in the brain, and how bad it is.
Alzheimer's disease is a degenerative brain disorder in which beta-amyloid peptide deposits and neurofibrillary tangles appear. Its victims exhibit memory loss (particularly for recent events) shortened attention span, disorientation, and eventual language loss. Over a period of several years, formerly good-natured people may become irritable, moody, and confused. Hallucinations may ultimately occur. Alzheimer's disease also causes changes in thinking, behavior, and personality. Close family members and friends may first notice these symptoms, although the person may also realize that something is wrong.
Mild symptoms of Alzheimer's include:
- person may avoid new and unfamiliar situations
- person may have delayed reactions and slowed learning ability
- person may begin speaking more slowly than in the past
- person may start using poor judgment and making inappropriate decisions
- person may have mood swings and become depressed, irritable, or restless
Moderate symptoms of Alzheimer's include:
- has problems recognizing close friends and family
- becomes more restless, especially in late afternoon and at night, this is called sundowning
- has problems reading, writing, and dealing with numbers
- has trouble dressing
- cannot work simple appliances such as a microwave
Severe symptoms pf Alzheimer's includes:
- can no longer remember how to bathe, eat, dress, or go to the bathroom independently
- no longer knows when to chew and swallow
- has trouble with balance or walking and may fall frequently
- becomes more confused in the evening (sundowning) and has trouble sleeping
- cannot communicate using words
- loses bowel or bladder control (incontinence)
Parkinson's disease and Huntington's disease are neurodegenerative disorders of the basal nuclei. Both involve abnormalities of the neurotransmitter dopamine (too little or too much secreted) and are characterized by abnormal movements.
Symptoms of Parkinson's disease differ from person to person. They also change as the disease progresses. Symptoms that one person gets in the early stages of the disease, another person may not get until later - or not at all.
Symptoms typically begin appearing between the ages of 50 and 60. They develop slowly and often go unnoticed by family, friends, and even the person who has them.
The disease causes motor symptoms and non-motor symptoms. Motor symptoms are those that have to do with how you move. The most common one is tremor.
Other common symptoms of Parkinson's disease include:
- stiff muscles (rigidity) and aching muscles
- slow, limited movement
- weakness of face and throat muscles
- difficulty with walking and balance
- freezing, a sudden, brief inability to move, it most often affects walking
Huntington's disease is a genetic, progressive, neurodegenerative disorder characterized by the gradual development of involuntary muscle movements affecting the hands, feet, face, and trunk and progressive deterioration of cognitive processes and memory (dementia). Neurologic movement abnormalities may include uncontrolled, irregular, rapid, jerky movements (chorea) and athetosis, a condition characterized by relatively slow, writhing involuntary movements. Dementia is typically associated with progressive disorientation and confusion, personality disintegration, impairment of memory control, restlessness, agitation, and other symptoms and findings. In individuals with the disorder, disease duration may range from approximately 10 years up to 25 years or more. Life-threatening complications may result from pneumonia or other infections, injuries related to falls, or other associated developments.
Some common early symptoms of Huntington's disease include:
- slight changes in coordination, affecting balance or making you more clumsy
- fidgety movements that you can't control
- slowing or stiffness
- trouble thinking through problems
- depression or irritability
Some common middle stage symptoms of Huntington's disease include: With time, symptoms begin to interfere more with your day-to-day life. For example, you might start to drop things or to fall. Or you may have trouble speaking or swallowing. Staying organized may be difficult and emotional changes may put pressure on relationships.
Some common late stage symptoms of Huntington's disease include: In this stage, people with Huntington's must depend on others for their care. Walking and speaking are not possible, Most likely you will still be aware of loved ones around you. Fidgety movements may become severe, or may subside.
In children or teens, Huntington's may progress more quickly and cause symptoms like:
- stiff or awkward walking
- increased clumsiness
- changes in speech
- trouble learning new information, or loss of previously learned skills
What is CSF? Where is it produced?? What are its functions???
CSF, formed by the choroid plexuses as a filtrate of blood plasma, is a watery "broth" similar in composition to plasma. It protects the brain and spinal cord from blows and other trauma, helps nourish the brain, and carries chemical signals from one part of the brain to another.
What is a transient ischemic attack (TIA) and how is it different from a stroke?
A TIA is a temporary loss of blood supply to brain tissue, and it differs from a stroke in that the resultant impairment is fully reversible.
Mrs. Lee, a neurology patient, seldom smiles, has a shuffling, stooped gait, and often spills her coffee. What degenerative brain disorder might she have?
Mrs. Lee might have Parkinson's disease.
Describe the gross and microscopic structure of the spinal cord.
The spinal cord, a two-way impulse conduction pathway and a reflex center, resides within the vertebral column and is protected by meninges and cerebrospinal fluid. It extends from the foramen magnum to the end of the first lumbar vertebra.
Thirty-one pairs of spinal nerves issue from the cord. The cord is enlarged in the cervical and lumbar regions, where spinal nerves serving the limbs arise.
The central gray matter of the cord is H-shaped. Ventral horns mainly contain somatic motor neurons. Lateral horns contain visceral (autonomic) motor neurons. Dorsal horns contain internuerons.
Axons of neurons of the lateral and ventral horns emerge in common from the cord via the ventral roots. Axons of sensory neurons (with cell bodies located in the dorsal root ganglion) from the dorsal roots and enter the dorsal aspect of the cord. The ventral and dorsal roots combine to form the spinal nerves.
Each side of the white matter of the cord has dorsal, lateral, and ventral columns (funiculi), and each funiculus contains a number of ascending and descending tracts. All tracts are paired and most decussate.
List the major spinal cord tracts, and classify each as a motor or sensory tract.
Ascending (sensory) tracts include the fasciculi gracilis and cuneatus, spinothalamic tracts, and spinocerebellar tracts.
The dorsal column -- medial lemniscal pathway consists of the dorsal white column (fasciculus cuneatus, fasciculus gracilis) and the medial lemniscus, which are concerned with straight-through, precise transmission of one or a few related types pf sensory input. The spinothalamic pathways transmit pain, temperature, and course touch, and permits brain stem processing of ascending impulses. The spinocerebellar tracts, which terminate in the cerebellum, serve muscle sense, not conscious sensory perception.
Descending tracts include the pyramidal tracts (ventral and lateral corticospinal tracts) and a number of motor tracts originating from subcortical motor nuclei. These descending fibers issue from the brain stem motor areas (indirect system) and cortical motor areas (direct pyramidal system).
What is the explanation for the cervical and lumbar enlargements of the spinal cord?
The nerves serving the limbs arise in the cervical and lumbar enlargements of the spinal cord.
Where are the cell bodies of the first-, second-, and third-order sensory neurons in the spinothalamic pathway located?
In the spinothalamic pathway, the cell bodies of the first-order sensory neurons are outside the spinal cord in a ganglion, cell bodies of the second-order sensory neurons are in the dorsal horn of the spinal cord, and cell bodies of third-order sensory neurons are in the thalamus.
Distinguish between flaccid and spastic paralysis, and between paralysis and paresthesia.
Injury to the ventral horn neurons or the ventral roots result in flaccid paralysis. (Injury to the upper motor neurons in the brain result in spastic paralysis.) If the dorsal roots or sensory tracts are damaged, paresthesia occurs.
Poliomyelitis results from inflammation and destruction of the ventral horn neurons by the Polio virus. Paralysis and muscle atrophy ensue.
Amyotrophic lateral sclerosis (ALS) results from the destruction of ventral horn neurons and the pyramidal tracts. The victim eventually loses the ability to swallow, speak, and bathe. Death generally occurs within five years.
List and explain several techniques used to diagnose brain disorders.
Diagnostic procedures used to assess neurological condition and function range from routine reflex testing to sophisticated techniques such as cerebral angiography, CT scans, MRI scans, and PET scans.
Roy was tackled while playing football. After hitting the ground, he was unable to move his lower limbs. What is a loss of motor function called? What level of his spinal cord do you think was injured (cervical, thoracic, lumbar, or sacral)?? Is this a permanent injury??? What diagnostic procedure might be helpful????
A loss of motor function is called paralysis. Lower limb paralysis could be caused by a spinal cord injury in the thoracic region (T1 and L1). If the spinal cord is transected, the result is paraplegia. If the cord is only bruised, he may regain function in the limbs. An MRI scan (or CT scan) of the spinal cord would be helpful.
Describe the development of the brain and spinal cord.
The CNS develops from the embryonic neural tube -- the brain from the rostral part and the spinal cord from the caudal part.
The gray matter of the spinal cord forms from the alar and basal plates. Fiber tracts from the outer white matter. The neural crest forms the sensory (dorsal root) ganglia.
Indicate several maternal factors that can impair development of the nervous system in an embryo.
Maternal and environmental factors may impair embryonic brain development, and oxygen deprivation destroys brain cells. Severe congenital brain disorders include cerebral palsy, anencephaly, hydrocephalus, and spina bifida.
Premature babies have trouble regulating body temperature because the hypothalamus is one of the last brain areas to mature prenatally.
Development of motor control indicate progressive myelination and maturation of a child's nervous system.
Explain the effects of aging on the brain.
Brain growth ends in young adulthood. neurons die throughout life and most are not replaced; brain weight and volume decline with age.
Healthy elders maintain nearly optimal intellectual functions. Disease -- particularly cardiovascular disease -- is the major cause of declining mental function with age.
What functional type of neuron is derived from the alar plate? From the basal plate??
Alar plate neuroblasts become interneurons, whereas basal plate neuroblasts become motor (efferent) neurons.
Premature babies have problems controlling their body temperature. Why?
Premature babies have trouble regulating body temperature because the hypothalamus is immature.
List several causes of reversible dementia in the elderly.
Reversible cause of dementia includes prescription drug effects, low blood pressure, poor nutrition, hormone imbalances, depression, and dehydration.
The primary motor cortex, Broca's area, and the premotor cortex are located in which lobe?
The innermost layer of the meninges, delicate and closely apposed to the brain tissue, is the
a. dura mater
b. corpus callosum
c. arachnoid mater
d. pia mater
Cerebrospinal fluid is formed by
a. arachnoid villi
b. dura mater
c. choroid plexuses
d. all of these
A patient has suffered a cerebral hemorrhage that has caused dysfunction of the precentral gyrus of his right cerebral cortex. As a result,
a. he cannot voluntarily move his left arm or leg
b. he feels no sensation on the left side of his body
c. he feels no sensation on the right side of his body
he cannot voluntarily move his left arm or leg
Which term is best stated by "basal nuclei involved in fine control of motor activities"?
b. corpora quadrigemina
c. corpus callosum
Which term is best stated by "region where there is a gross crossover of fibers of descending pyramidal tracts"?
b. corpora quadrigemina
c. corpus callosum
Which term is best stated by "control of temperature, autonomic nervous system reflexes, hunger, and water balance"?
b. corpora quadrigemina
c. corpus callosum
Which term is best stated by "houses the substantia nigra and cerebral aqueduct"?
b. corpora quadrigemina
c. corpus callosum
Which term is best stated by "relay stations for visual and auditory stimuli input; found in midbrain"?
b. corpora quadrigemina
c. corpus callosum
Which term is best stated by "houses vital centers for control of the heart, respiration, and blood pressure"?
b. corpora quadrigemina
c. corpus callosum
Which term is best stated by "brain area through which all the sensory input is relayed to get to the cerebral cortex"?
b. corpora quadrigemina
c. corpus callosum
Which term is best stated by "brain area most concerned with equilibrium, body posture, and coordination of motor activity"?
b. corpora quadrigemina
c. corpus callosum
Which of the following tracts convey vibration and other specific sensations that can be precisely localized?
a. pyramidal tract
b. medial lemniscus
c. lateral spinothalamic tract
d. reticulospinal tract
Destruction of the ventral horn cells of the spinal cord results in loss of
a. integrating impulses
b. sensory impulses
c. voluntary motor impulses
d. all of these
voluntary motor impulses
Fiber tracts that allow neurons within the same cerebral hemisphere to communicate are
a. association fibers
c. projection fibers
A number of brain structures are listed below. If an area is primarily gray matter, write (a); if mostly white matter, respond with (b)
1. cerebral cortex
2. corpus callosum and corona radiata
3. red nucleus
4. medial and lateral nuclear groups
5. medial lemniscus
6. cranial nerve nuclei
7. spinothalamic tract
9. cingulate and precentral gyri
A professor unexpectedly blew a loud horn in his anatomy and physiology class. The students looked up, startled. The reflexive movement of their eyes were mediated by the
a. cerebral cortex
b. inferior olives
c. raphe nuclei
d. superior colliculi
e. nucleus gracilis
Identify the stage of sleep best described by "the stage when blood pressure and heart rate reach their lowest levels".
a. stage 1
b. stage 2
c. stage 3
d. stage 4
Identify the stage of sleep best described by "indicated by movement of the eyes under the lids; dreaming occurs".
a. stage 1
b. stage 2
c. stage 3
d. stage 4
Identify the stage of sleep best described by "when nightmares are likely to occur".
a. stage 1
b. stage 2
c. stage 3
d. stage 4
stage 3 and stage 4
Identify the stage of sleep best described by "when the sleeper is very easily awakened; EEG shows alpha waves".
a. stage 1
b. stage 2
c. stage 3
d. stage 4
All of the following descriptions refer to dorsal column-medial lemniscal ascending pathways except one:
a. they include the fasciculus gracilis and fasciculus cuntaeus
b. they include a chain of three neurons
c. their connections are diffuse and poorly localized
d. they are concerned with precise transmission of one or a few related types of sensory input.
their connections are diffuse and poorly localized
In which of the following areas does sorting and editing of sensory impulses take place?
b. basal nuclei
c. postcentral cortex
d. prefrontal cortex
e. thalamic nuclei
Which of the following is a function of the pons?
a. acts to regulate body temperature
b. nucleus for the abducens nerve
c. provides motor signals to the red nucleus
d. controls vomiting and coughing
e. contains nuclei that relay information from the cerebrum to cerebellum
contains nuclei that relay information from the cerebrum to cerebellum
Which of the following areas is NOT involved in speech processing?
a. Wernicke's area
b. superior colliculi
c. lateral prefrontal cortex
d. Broca's area
Which of the following areas of the brain is most involved in maintaining the body's homeostasis?
a. cerebral cortex
c. medulla oblongata
Which of the following centers is NOT located in the hypothalamus?
a. autonomic control center
b. food intake regulation center
c. body temperature regulation center
d. center for central balance
e. a center for regulation of sleep-wake cycles
center for central balance
Which of the following coordinate head and eye movements when we visually follow a moving object?
a. substantia nigra
b. pneumotaxic center
c. superior colliculi
d. red nucleus
e. inferior colliculi
Which of the following is a function of the basal ganglia?
a. starting, stopping, and monitoring arm swinging and gait
b. regulation of body temperature
c. processing of sensory information
d. determining whether a person is left- or right-handed
e. connecting corresponding areas of the cerebral cortex to enable them to function as a coordinated whole
starting, stopping, and monitoring arm swinging and gait
Which of the following is NOT one of the basal nuclei?
a. corpus callosum
b. globus pallidum
c. caudate nucleus
Which of the following is the autonomic control center?
c. medulla oblongata
Which type of brain waves are seen when a person is concentrating on solving a problem?
a. beta waves
b. delta waves
c. theta waves
d. alpha waves
e. gamma waves
Which part of the brain is involved in thirst sensations?
a. temporal lobe
c. cerebral cortex
Which part of the brain produces dopamine?
a. pontine nuclei
b. reticular formation
c. substantia nigra
d. pineal gland
e. red nucleus
Which of the following statements concerning epilepsy is INCORRECT?
a. It can have a genetic factor.
b. It involves abnormal discharges from a group of brain neurons.
c. Most cases are caused by brain injuries, such as blows to the head, stroke, or infections.
d. It is associated with intellectual impairment.
e. It affects < 5% of the population.
It is associated with intellectual impairment.
Which of the following is the central layer of the meninges?
a. pia mater
b. dural sinuses
c. dura mater
d. arachnoid mater
The average weight of the adult brain is _____.
a. 1 - 1.5 lbs
b. 2 - 2.5 lbs
c. 3 - 3.5 lbs
d. over 5 lbs
3 - 3.5 lbs
The CNS starts differentiating from the neural tube in the developing embryo after week _____.
Which of the following landmarks separates the cerebral hemispheres?
a. the central sulcus
b. the longitudinal fissure
c. the transverse cerebral fissure
d. septum pelllucidum
the longitudinal fissure
Which of the following is NOT a feature of the cerebral cortex?
a. it is composed of white matter
b. it accounts for 40% of the brain mass
c. it is arranged in six layers
d. its convoluted surface triples its surface
it is composed of white matter
The visceral sensory area of the cerebral cortex is involved in the conscious perception of all the following EXCEPT _____.
a. the feeling that your lungs will burst when you hold your breath
b. upset stomach
c. full bladder
In which part of the cerebral cortex do sensations, emotions, and thoughts come together and make us who we are?
a. the motor cortex
b. the multimodal association areas
c. the premotor cortex
d. the primary sensory cortex
the multimodal association areas
Which part of the cerebellum is involved in planning, rather that executing, movement?
a. the intermediate parts of each hemisphere
b. the posterior lobe
c. the anterior lobe
d. the lateral part of each hemisphere
the lateral part of each hemisphere
All the following are attributed to the function of the amygdaloid body EXCEPT _____.
a. recognition of fear
b. assessment of danger
c. resolving mental conflict
d. eliciting the fear response
resolving mental conflict
The sensory hallucinations experienced by epileptic patients are known as _____.
a. a tonic-clonic seizure
b. the aura
c. a petit mal seizure
d. an absence seizure
Which of the following statements about language is INCORRECT?
a. Patients who have difficulty understanding language have a lesion in Wernicke's area.
b. Patients who can speak but produce nonsense have a lesion in Wernicke's area.
c. Patients who understand language but have difficulty speaking have lesions affecting Broca's area.
d. All the associated areas on the right side of the cerebral cortex are involved in language.
All the associated areas on the right side of the cerebral cortex are involved in language.
Working memory _____.
a. stores memories immediately and permanently in the long-term memory
b. has limitless capacity
c. stores only 5% of sensory input
d. is limited to seven or eight chunks of information
is limited to seven or eight chunks of information
Which of the following neurotransmitters is thought to prime the prefrontal cortex and the medial temporal lobes to form memories?
If you are having a conversation with a person, excuse yourself for five minutes, and come back and the person no longer knows you, the person would be suffering from _____.
a. retrograde amnesia
c. sleep apnea
d. anterograde amnesia
Acting as an excitotoxin, the main culprit in the damage caused by a cerebral vascular accident (CVA) is _____.
b. low levels of calcium
All of the following features can be seen in the brain tissue of patients suffering from Alzheimer's disease EXCEPT _____.
a. increased levels of acetylcholine in the basal forebrain
b. shrinkage of all the brain tissue
c. toxic beta amyloid peptide
increased levels of acetylcholine in the basal forebrain
Deep brain stimulation via implanted electrodes has been used to treat some of the symptoms of _____.
b. Alzheimer's disease
c. anterograde amnesia
d. Parkinson's disease
The somatosensory and visual primary sensory areas in the brain have association areas where integration takes place.
There are no significant gender differences in brain development.
The growth and shape of the brain is influenced by the limited space and slower growth of the membranous skull that contains it.
The amygdaloid body is functionally part of the limbic system.
The basic pattern of the CNS in the spinal cord is a central cavity surrounded by a gray matter core and a white matter layer lying outside of that.
The creases and folds on the surface of the cerebral hemispheres allow more neurons to occupy a limited amount of space.
The CSF is produced in the choroid plexus.
The entire body is represented by somatotopy in the primary motor cortex of each hemisphere.
Lateralization usually causes the left cerebral hemisphere to be dominant in most people, as it is mainly involved with visual-spatial skills.
The relay stations for the olfactory pathways are located in the hypothalamus.
The adult rhinencephalon is involved only in the processing of olfactory information.
Non-rapid eye movement (NREM) and rapid eye movement (REM) sleep alternate through most of the sleep cycle. During REM, most of the body's skeletal muscles are inactive.
REM sleep declines from infancy until death.
The limbic system functions as our emotional brain.
The "heart" of the limbic system is the medulla oblongata.
Regulation of food intake is a function of the hypothalamus.
Regulation of temperature is a function of the thalamus.
The dura mater is the innermost layer of the meninges.
All of the structures of the CNS originate from the _____.
b. neural tube
Which of the following is NOT one of the three basic regions of the cerebral hemisphere?
a. the internal white matter
b. the superficial cortex of gray matter
c. the basal nuclei
d. the diencephalon
Choose the true statement regarding pyramidal cells.
a. They integrate sensory input to produce an understanding of an object being felt.
b. They provide for control of our involuntary muscles.
c. They are found within the cerebral sulci.
d. They allow us to control our skeletal muscles.
They allow us to control our skeletal muscles.
What is the main role of the olfactory cortex?
a. detection of odors
b. sound interpretation
c. spatial discrimination
detection of odors
Spatial discrimination is the ability to identify the specific region of the body being stimulated.
Which of the following is true of the multimodal association cortex?
a. It allows us to tie information that we receive to previous experience and knowledge, and then helps us decide what action to take.
b. It regulates our heart and other involuntary muscles in response to environmental stimuli.
c. It permits the perception of sound stimuli and stores them for future reference.
d. It integrates sensory input to produce understanding of an object being felt.
It allows us to tie information that we receive to previous experience and knowledge, and then helps us decide what action to take.
_____ is a division of labor in which each cerebral hemisphere has unique abilities not shared by its partner.
a. hemispherical association
c. cortical association
_____ is responsible for communication between cerebral areas and between the cerebral cortex and lower CNS centers.
a. the thalamus
b. the hypothalamus
c. Broca's area
d. the cerebral white matter
the cerebral white matter
Which of the following is NOT a part of the diencephalon?
Which of the following areas regulates body temperature, food intake, and endocrine functions?
a. pineal body
Which of the following is NOT one of the major regions of the brain stem?
b. medulla oblongata
Which of the following regions acts as an autonomic reflex center of the brain?
c. medulla oblongata
_____ is a homeostatic brain imbalance that causes a temporary cessation of breathing during sleep.
b. sleep apnea
Which of the following meninges forms the loose, mid-layer brain covering?
a. pia mater
b. arachnoid mater
c. dura mater
d. casa mater
Which of the following is a protective mechanism that helps maintain a stable environment for the brain?
a. dura mater
b. blood-brain barrier
c. pia mater
d. cerebrospinal fluid
Which of the following is a progressive degenerative disease of the brain that ultimately results in dementia?
a. mad cow disease
b. Parkinson's disease
c. Alzheimer's disease
d. Huntington's disease
Choose the true statement regarding second-order neurons.
a. Second-order neuron cell bodies reside in the dorsal horn of the spinal cord.
b. Second-order neurons conduct impulses to the spinal cord or brain stem, where they synapse.
c. Second-order neuron cell bodies reside in the thalamus.
d. Second-order neuron cell bodies reside in a ganglion.
Second-order neuron cell bodies reside in the dorsal horn of the spinal cord.
Which of the following conditions results from viral destruction of ventral horn motor neurons?
d. Amyotrophic Lateral Sclerosis
Cerebral palsy may be caused by a temporary lack of oxygen during birth.
Anencephaly is a result of incomplete formation of the vertebral arches, and can be caused by inadequate folic acid in the maternal diet.
What is located in the lateral horn of the spinal cord grey matter?
a. interneurons that receive input from somatic sensory neurons
b. visceral motor soma
c. somatic motor soma
d. interneurons that receive input from visceral sensory neurons
visceral motor soma
Transection of the spinal cord at T3 results in _____.
d. spinal shock
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