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young ap 2401 chap12
Professor Young LSCS chap 12 - cns
Question | Answer |
---|---|
CNS is composed of the _____ and ______ | Brain and Spinal Cord |
Cephalization | Elaboration of the anterior portion of the CNS, increase in number of neurons, highest level in human brain |
3 main surface areas of the brain | Cerebral Hemispheres Cerebellum Brain Stem |
Spinal Cord Features | Central cavity surrounded by gray matter core around which is white matter composed of myelinated fiber tracts |
Ventricles | "paired C shaped lateral ventricles" Prosencephalon (forebrain), mesencephalon (midbrain), & rhombencephalon (hindbrain) |
Cerebral Hemisphere contains ridges called ___ and grooves called ___ and deep grooves called ___ | Ridges - Gyri and Grooves - Sulci Deep Grooves - Fissures |
The cerebral hemispheres are seperated by _______ | Longitudinal Fissure |
Three basic regions of the cerebral hemispheres | cortex, white matter, and basal nuclei |
The cerebral hemispheres form the _____ part of the brain and make up _____% of its mass | Superior and 83% of mass |
The cerebral cortex is made up of superficial ____ matter and accounts for ___% of brain mass | Gray Matter and 40% of brain mass |
The cerebral cortex enables ______, ______, _____, ______ and _____movements. | It enables sensation, communication, memory, understanding, and voluntary movements |
Hemispheres of the brain control ______ sides of the body and are equal/unequal in function | Opposite sides of the body and are not equal in function. |
Conscious behavior involves the ______ cortex. | ENTIRE |
Three functional areas of the cerebral cortex | Motor, sensory, association |
Motor areas of the cerebral cortex control ____ | Voluntary Movement |
Sensory areas of the cerebral cortex control ______ | Conscious awareness of sensation |
Association areas of the cerebral cortex control _______ | Integration of diverse information |
List 5 functional areas of the anterior cerebral cortex | Primary motor area, premotor cortex, frontal eye field, brocca's area, prefrontal cortex, |
List 8 functional areas of the posterior cerebral cortex | prim. somatosensory cortex, somatosensory assoc. cortex, gustatory cortex, Wernicke's area, prim. visual cortex, visual assoc. area, auditory assoc. area, prim. auditory area, visceral sensory area |
Primary motor cortex | Allows conscious control of precise, skilled, voluntary movements |
Premotor cortex | Controls learned, repetitious, or patterned motor skills Coordinates simultaneous or sequential actions Involved in the planning of movements |
Broca's area | Present in one hemisphere (usually the left) A motor speech area that directs muscles of the tongue Is active as one prepares to speak - speech preparation and production |
Frontal Eye Field | Controls voluntary eye movement |
Primary somatosensory cortex | Upside down and back wards input from various body regions |
Somatosensory association cortex | Temp, pressure, etc |
Visual association area | Uses past visual experience to interpret visual stimuli (color form and movement) |
Auditory association area | "perceives" sound stimulus using sound memories. |
Gustatory (taste) cortex | perception of taste. |
Visceral sensory area | conscious perception of visceral senses |
Primary visual (striate) cortex | Receives visual information from the retinas |
Primary auditory cortex | Receives information related to pitch, rhythm, and loudness |
Prefrontal Cortex | Involved with intellect, cognition, recall, and personality Necessary for judgment, reasoning, persistence, and conscience Closely linked to the limbic system (emotional part of the brain) |
Wernicke’s area | involved in sounding out unfamiliar words, maybe |
Lateral prefrontal cortex | language comprehension and word analysis |
Lateral and ventral temporal lobe | coordinate auditory and visual aspects of language |
List the language areas 4 | Wernicke's area Broca's area Lateral prefrontal cortex Lateral and ventral temporal lobe |
General (Common) Interpretation Area Facts | Ill-defined region including parts of the temporal, parietal, and occipital lobes Found in one hemisphere, usually the left Integrates incoming signals into a single thought Involved in processing spatial relationships |
Lateralization | each hemisphere has abilities not shared with its partner |
Cerebral dominance | designates the hemisphere dominant for language |
Left hemisphere controls | controls language, math, and logic |
Right hemisphere controls | controls visual-spatial skills, emotion, and artistic skills |
Cerebral white matter consists of _____ and is responsible for communication between _____ | deep myelinated fibers and their tracts The cerebral cortex and lower CNS center, and areas of the cerebrum |
Diencephalon | Central core of the forebrain |
Three paired structures of the diencephalon | Thalamus Hypothalamus epithalamus |
The diencephalon encloses the ____ ventricle | 3rd |
thalamic function | Afferent impulses from all senses converge Impulses are sorted out, edited, and relayed as a group All inputs pass through the thalamus Plays a key role in mediating sensation, motor activities, cortical arousal, learning, and memory |
Hypothalamus areas | Located below the thalamus Mammillary bodies Relay station for olfactory pathways Infundibulum – stalk of the hypothalamus; connects to the pituitary gland Main visceral control center of the body |
Mammillary bodies | Relay station for olfactory pathways |
Infundibulum | stalk of the hypothalamus; connects to the pituitary gland Main visceral control center of the body |
Hypothalamic Function | regulates blood pressure, breathing, visceral activities, body temp, feelings of hunger and involved with perception of fear pleasure, and rage |
Endocrine Functions of the Hypothalamus | Releasing hormones control secretion of hormones by the anterior pituitary Produce ADH and oxytocin |
Epithalamus areas | Most dorsal portion of the diencephalon pineal gland and choroid plexus |
Pineal gland | secretes melatonin Melatonin – a hormone involved with sleep regulation, sleep-wake cycles, and mood |
Choroid plexus | a structure that secretes cerebral spinal fluid (CSF) |
Three regions of brain stem | midbrain, pons, and medulla oblongata |
brain stem facts | Similar to spinal cord but contains embedded nuclei Controls automatic behaviors necessary for survival Provides the pathway for tracts between higher and lower brain centers Associated with 10 of the 12 pairs of cranial nerves |
Midbrain structures | Cerebral peduncles Cerebral aqueduct |
midbrain funtions | Visual reflex centers and auditory relay |
Parkinson's disease is a degeneration of _____ releasing neurons | Dopamine |
Pons description | Bulging brainstem region between the midbrain and the medulla oblongata |
fibers of the pons do two things _______ and ______ | Connect higher brain centers and the spinal cord Relay impulses between the motor cortex and the cerebellum |
Medulla Oblongata facts | Most inferior part of the brain stem Decussation of the pyramids – crossover points of the corticospinal tracts Cardiovascular center Respiratory center Vomiting, hiccupping, swallowing, coughing, and sneezing |
Cerebellum facts | Makes up 11% of the brain’s mass Provides precise timing and appropriate patterns of skeletal muscle contraction Cerebellar activity occurs subconsciously |
Cerebellar Processing | receives impulses of the intent to initiate voluntary muscle contraction Proprioceptors and visual signals “inform” the cerebellum of the body’s condition calculates the best way to perform a movement "blueprint" is sent to cerebral motor cortex |
Cerebellar Cognitive Function | Plays a role in language and problem solving Recognizes and predicts sequences of events |
List the two functional brain systems | Limbic system Reticular formation |
Amygdala | deals with anger, danger, and fear responses |
Cingulate gyrus | plays a role in expressing emotions via gestures, and resolves mental conflict |
The limbic system interacts with the prefrontal lobes, therefore: | One can react emotionally to conscious understandings One is consciously aware of emotion in one’s life |
Hippocampal structures | convert new information into long-term memories |
Reticular Formation: RAS – reticular activating system | Sends impulses to the cerebral cortex to keep it conscious and alert Filters out repetitive and weak stimuli |
Reticular Formation: Motor Function | Helps control coarse motor movements Autonomic centers regulate visceral motor functions – e.g., vasomotor, cardiac, and respiratory centers |
Brain Waves facts | Continous electrical activity EEG records activity Unique Peaks and troughs expressed in Hertz(Hz) |
Alpha waves | regular and rhythmic, low-amplitude, slow, synchronous waves indicating an “idling” brain |
Beta waves | rhythmic, more irregular waves occurring during the awake and mentally alert state |
Theta Waves | more irregular than alpha waves; common in children but abnormal in adults |
Delta Waves | high-amplitude waves seen in deep sleep and when reticular activating system is damped |
Epilepsy facts | A victim of epilepsy may lose consciousness, fall stiffly, and have uncontrollable jerking, characteristic of epileptic seizure Epilepsy is not associated with, nor does it cause, intellectual impairments Epilepsy occurs in 1% of the population |
Absence Seizure or petit mal seizure description | mild seizures seen in young children where the expression goes blank |
Grand mal seizures | victim loses consciousness, bones are often broken due to intense convulsions, loss of bowel and bladder control, and severe biting of the tongue |
Control of Epilepsy | Epilepsy can usually be controlled with anticonvulsive drugs Vagus nerve stimulators can be implanted under the skin of the chest and can keep electrical activity of the brain from becoming chaotic |
Consciousness facts | Higher mental processes perception of sensation voluntary initiation and control of movement holistic and interconnected |
Clinical consciousness | is defined on a continuum that grades levels of behavior – alertness, drowsiness, stupor, coma |
2 types of sleep | REM and Non REM |
One passes through four stages of NREM during the first _______ of sleep | 30-45 minutes |
REM sleep occurs after the ______ NREM stage has been achieved | fourth |
Stage 1 NREM description | eyes are closed and relaxation begins; the EEG shows alpha waves; one can be easily aroused |
Stage 2 NREM description | EEG pattern is irregular with sleep spindles (high-voltage wave bursts); arousal is more difficult |
Stage 3 NREM description | sleep deepens; theta and delta waves appear; vital signs decline; dreaming is common |
Stage 4 NREM description | EEG pattern is dominated by delta waves; skeletal muscles are relaxed; arousal is difficult |
REM 4 characteristics | EEG pattern reverts through the NREM stages to the stage 1 pattern Vital signs increase Skeletal muscles (except ocular muscles) are inhibited Most dreaming takes place |
Sleep pattern Descriptions | alternating cycles of sleep and wakefulness reflect a natural cicadian rhythm RAS activity declines typical pattern alternates between REM and NREM |
Narcolepsy | – lapsing abruptly into sleep from the awake state |
Insomnia | chronic inability to obtain the amount or quality of sleep needed |
Sleep apnea | temporary cessation of breathing during sleep |
Memory is ____ and ____ of information | storage and retrieval |
The three principles of memory are: | Storage – occurs in stages and is continually changing Processing – accomplished by the hippocampus and surrounding structures Memory traces – chemical or structural changes that encode memory |
The two stages of memory are ____ memory and ____ memory | short-term long-term |
Short term memory | – a fleeting memory of the events that continually happen lasts seconds to hours and usually limited to 7-8 pieces of info |
Factors that effect transfer of memory from STM to LTM include: | Emotional state –alert, motivated, and aroused Rehearsal – repeating or rehearsing material enhances memory Association – associating new information with old memories in LTM enhances memory Automatic memory – subconscious information stored in LTM |
Two categories of memory | Fact memory and skill memory |
Fact (declarative) memory: | Entails learning explicit information Is related to our conscious thoughts and our language ability Is stored with the context in which it was learned |
Skill Memory: | less conscious than fact memory and involves motor activity acquired through practice do not retain the context in which they were learned |
The brain is protected by ____, ____ and _____ | bone, meninges, and cerebrospinal fluid |
Harmful substances are shielded from the brain by the __________ | blood brain barrier |
Three connective tissue membranes lie external to the CNS: | dura mater, arachnoid mater, and pia mater |
Functions of the meninges | Cover and protect the CNS Protect blood vessels and enclose venous sinuses Contain cerebrospinal fluid (CSF) Form partitions within the skull |
meninges layers | Skin of scalp Periosteum Bone of skull dura matter arachnoid mater pia mater |
Dura Mater | Leathery, strong meninx composed of two fibrous connective tissue layers The two layers separate in certain areas and form dural sinuses Three dural septa extend inward and limit excessive movement of the brain |
Arachnoid Mater | The middle meninx, forms a loose brain covering separated from the dura mater by subdural space Beneath the arachnoid is a wide subarachnoid space filled with CSF and lg bld vess. Arachnoid villi protrude superiorly and permitCSFto absb to venous blood |
Pia Mater | Deep meninx composed of delicate connective tissue that clings tightly to the brain |
Cerebrospinal Fluid (CSF) | watery solution similar to blood plasma liquid cushion prevent brain from crushing under its wieght protects from trauma nourishes and carries chem signals |
Blood-Brain Barrier | Protective mechanism that helps maintain a stable environment for the brain |
Bloodborne substances are separated from neurons by: | Continuous endothelium of capillary walls Relatively thick basal lamina Bulbous feet of astrocytes |
Blood-Brain Barrier: Functions | allows nutrients to pass absent in some areas allowing these areas to monitor chem composition of blood stress increases the ability of chems to pass through |
Cerebrovascular Accidents (Strokes) | caused when blood circulation to brain is blocked and brain tissue dies |
strokes are commonly caused by ___ and ____ | Most commonly caused by blockage of a cerebral artery Other causes include compression of the brain by hemorrhage or edema, and atherosclerosis |
Transient ischemic attacks (TIAs) | temporary episodes of reversible cerebral ischemia |
Tissue plasminogen activator (TPA) | is the only approved treatment for stroke |
Alzheimer’s disease | a progressive degenerative disease of the brain that results in dementia |
Parkinson’s disease | degeneration of the dopamine-releasing neurons |
Huntington’s disease | a fatal hereditary disorder |
Spinal Cord | CNS tissue is enclosed within the vertebral column from the foramen magnum to L1 Provides two-way communication to and from the brain |
spinal cord is protected by _______ | Protected by bone, meninges, and CSF |
Epidural space | space between the vertebrae and the dural sheath (dura mater) filled with fat and a network of veins |
Conus medullaris | terminal portion of the spinal cord |
Denticulate ligaments | – delicate shelves of pia mater; attach the spinal cord to the vertebrae |
Spinal nerves have ___ pairs attach to the cord by ______ | 31 paired roots |
Cervical and lumbar enlargements | sites where nerves serving the upper and lower limbs emerge |
Cauda equina | – collection of nerve roots at the inferior end of the vertebral canal |
paralysis is ____ | loss of motor function |
Flaccid paralysis | severe damage to the ventral root or anterior horn cells |
flaccid paralysis facts | Lower motor neurons are damaged and impulses do not reach muscles There is no voluntary or involuntary control of muscles |
Spastic paralysis | – only upper motor neurons of the primary motor cortex are damaged |
spastic paralysis facts | Spinal neurons remain intact and muscles are stimulated irregularly There is no voluntary control of muscles |
Transection paralysis | Cross sectioning of the spinal cord at any level results in total motor and sensory loss in regions inferior to the cut |
Paraplegia | – transection between T1 and L1 |
Quadriplegia | – transection in the cervical region |
Poliomyelitis facts | Destruction of the anterior horn motor neurons by the poliovirus Early symptoms – fever, headache, muscle pain and weakness, and loss of somatic reflexes Vaccines are available and can prevent infection |
Amyotrophic Lateral Sclerosis (ALS) facts | Lou Gehrig’s disease – neuromuscular condition involving destruction of anterior horn motor neurons and fibers of the pyramidal tract Symptoms – loss of the ability to speak, swallow, and breathe Death occurs within five years |
Fibers & tracts have 3 classification directions. | Commissural (horizontal), association (verticle), or projection (verticle). |
Commissures | Composed of commissural fibers (horizontal) - connect gray areas of both hemispheres - largest is corpus callosum. |
Corpus Callosum | Deep w/in longitudinal fissure - largest commissure - connects both hemispheres so they can coordinate. |
Association Fibers | Connect different parts of same hemisphere. |
Projection Fibers | Tie cortex to rest of nervous system - run vertically. |
Basal Nuclei | Regulate attention & cognition - Caudate nucleus, putamon, & globus pallidus - collection of nerve bodies in CNS |
What is known as the "gateway to the cerebral cortex?" | the thalamus |
Cerebral peduncles | Verticle pillars holding up cerebrum. |
__ nerve carries signals to the heart. | vagus |
__ controls unconscious control of motor activity. | cerebellum |
retircular formation | Balance, posture, & muscle tone - Low-level motor pathway - major network of interneurons. |
__ activity is depressed during sleep, but not __ functions. | Cortical activity - brainstem |
Oxygen use by brain during REM sleep is __ than awake state. | Greater |
Cerebrospinal fluid reduces brain weight by __. | 97% - by floating it. |
ischemia | Deprivation of blood supply to a tissue. |
The spinal cord typically ends between __. | L1 & L2 |
Filum terminale | Anchors spinal cord to coccyx. |
From external to internal, the meninges are: | Dura mater, arachnoid mater, & pia mater. |
Dura Mater | "Tough Mother" - strongest meninx - surrounds brain. |
3 basic kinds of neurons. | Sensory neurons, interneurons, & motor neurons. |
Sensory neurons | Collect & relay info about stimuli to spinal cord & brain. |
Interneurons | In the spinal cord & brain - receive & process sensory input & send signals to other neurons. |
Motor neurons | Relay signals from interneurons to effectors - muscles & glands - that carry out responses. |
Each nerve exits from column via the __. | Intervertebral formina |
All neurons whose cell bodies are in the spinal cord gray matter are __. | Multipolar |
The dorsal horns of spinal cord are __. | Interneurons |
Ventral horns of spinal cord are mostly __. | Somatic motor neurons. |
Hemiplegia | Paralyzed on one side of body. |
Two areas of limbic system | amygdala and cingulate gyrus |