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Chapter 12
Central Nervous System
198
Anatomy
Undergraduate 2
12/02/2011

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Term
CNS
Definition
composed of the brain and spinal cord
Term
Cephalization
Definition
Elaboration of the anterior portion of the CNS
INcrease in number of neurons in the head
Highest level is reached in the human brain
Term
Brain surface anatomy
Definition
Cerebral hemispheres, cerebellum, and brain stem
Term
Adult brain structures: secondary brain vesicles
Definition
Telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon
Term
Telencephalon
Definition
cerebrum: cortex, white matter, and basal nuclei
Term
Diencephalon
Definition
thalamus, hypothalamus, and epithalamus
Term
Mesencephalon
Definition
brainstem: midbrain
Term
Metencephalon
Definition
brainstem: pons
Term
Myelencephalon
Definition
brainstem: medulla oblongata
Term
Lateral Ventricles
Definition
Telencephalon
Term
Third ventricle
Definition
Diencephalon
Term
Cerebral aqueduct
Definition
mesencephalon
Term
Fourth ventricle
Definition
metencephalon and myelencephalon
Term
Basic pattern: Spinal Cord
Definition
Central cavity surround by a gray matter core. External to which is white matter composed of myelinated fiber tracts
Term
Basic Pattern: Brain
Definition
Similar to spinal cord but with additional areas of gray matter
Cerebellum has gray matter in nuclei
Cerebrum has nuclei and additional gray matter in cortex
Term
Ventricles of the Brain
Definition
Arise from expansion of the lumen of the neural tube
Term
Cerebral Hemisphere
Definition
Form the superior part of the brain and make up 83% of its mass
Contains ridges (gyri) and shallow grooves (sulci)
Contains deep grooves called fissures
Term
What divides the cerebral hemispheres?
Definition
the longitudinal fissure
Term
Three regions of the Cerebral hemispheres
Definition
cortex, white matter, and basal nuclei
Term
Major lobes of the Cerebral Hemisphere
Definition
Frontal, parietal, temporal, occipital, and insula (internal)
Term
Major Sulci of the Cerebral Hemisphere
Definition
Central, Parieto-occipital, Lateral
Term
Major gyri of the Cerebral Hemisphere
Definition
Precentral and postcentral gyri
Term
Precentral and postcentral gyri: location
Definition
border the central sulcus
Term
Central sulcus
Definition
separates the frontal and parietal lobe
Term
Parieto-occipital sulcus
Definition
separates the parietal and occipital lobes
Term
Lateral sulcus
Definition
separates the parietal and temporal lobes
Term
Cerebral cortex
Definition
superficial gray matter; accounts for 40% of the mass of the brain
Enables sensation, communication, memory, understanding, and voluntary movements
Term
Cerebral cortex: Hemispheres
Definition
Each acts contralaterally (controls the opposite side of the body)
Are not equal in function
Term
Cerebral cortex: Functional areas
Definition
No singular one acts alone; conscious behavior involves the entire cortex
Term
Functional areas of the Cerebral Cortex: 3 types
Definition
Motor, Sensory, Association
Term
Functional motor areas
Definition
control voluntary movement
Term
Functional sensory areas
Definition
conscious awareness of sensation
Term
Functional Association areas
Definition
integrate diverse information
Term
Cerebral Cortex: Motor Areas
Definition
Primary (somatic) motor cortex, premotor cortex, Broca's area, Frontal eye field
Term
Primary (somatic) motor cortex
Definition
Located in the precental gyrus
Pyramidal cells whose axons make up the corticospinal tracts
Allows conscious control of precise, skilled, voluntary movements
Term
Premotor Cortex
Definition
Located anterior the the precentral gyrus. Controls learned, repetitious, or patterned motor skills. Coordinates simultaneous or sequential actions. Involved in the planning of movements.
Term
Broca's Area
Definition
Located anterior to the inferior region of the premotor area. Present in one hemisphere (usually left). A motor speech area that directs muscles of the tongue. Is active as on prepares to speak
Term
Frontal Eye Field
Definition
located anterior the premotor cortex and superior to Broca's area. Controls voluntary eye movemnt
Term
Sensory Areas
Definition
Primary somatosensory cortex, somatosensory association cortex, visual and auditory areas, olfactory, gustatory, and vestibular cortices
Term
Primary Somatosensory cortex
Definition
Located in the post central gyrus
Receives information from the skin and skeletal muscles
Exhibits spatial discrimination
Term
Somatosensory Association Cortex
Definition
Located posterior to the primary somatosensory cortex
Integrates sensory information
Forms comprehensive understanding of the stimulus
Determines size, texture, and relationship of parts
Term
Visual Areas
Definition
Primary visual (striate) cortex, Visual association area
Term
Primary visual (striate) cortex
Definition
Seen on the extreme posterior tip of the occipital lobe. Most of it is buried in the calcarine sulcus. Receives visual information form the retinas
Term
Visual association area
Definition
Surrounds the primary visual cortex
Interprets visual stimuli (color, form, and movement)
Term
Auditory areas
Definition
Primary auditory cortex, Auditory association area
Term
Primary auditory cortex
Definition
Located at the superior margin of the temporal lobe. Receives information related to pitch, rhythm, and loudness
Term
Auditory association area
Definition
Located posterior to the primary auditory cortex, stores memories of sounds and permits perception of sounds. Wernicke's area
Term
Association Areas
Definition
Prefrontal cortex, language areas, general (common) interpretation area, visceral association area
Term
Prefrontal cortex
Definition
Located in the anterior portion of the frontal lobe. Involved with intellect cognition, recall, and personality. Necessary for judgement, reasoning, persistence, and conscience. Closely linked to the limbic system (emotional part of the brain)
Term
Language Areas
Definition
Located in a large area surrounding the left (or language-domniant) lateral sulcus
Term
Major parts of Language Areas
Definition
Wernicke's Area, Broca's area, Lateral prefrontal cortex, Lateral and ventral temporal lobe
Term
Wernicke's area
Definition
sounding out unfamiliar words
Term
Broca's area
Definition
speech preparation and production
Term
Lateral prefrontal cortex
Definition
language comprehension and word analysis
Term
Lateral and ventral temporal lobe
Definition
coordinate auditory and visual aspects of language
Term
Visceral association area
Definition
Located in the cortex of the insula. Involved in conscious perception of visceral sensations
Term
Lateralization of Cortical Function
Definition
Lateralization, Cerebral dominance, Left hemisphere, right hemisphere
Term
Lateralization
Definition
each hemisphere has abilities not shared with its partner
Term
Cerebral dominance
Definition
designates the hemisphere dominant for language
Term
Left hemisphere
Definition
controls language, math, and logic
Term
Right hemisphere
Definition
controls visual-spatial skills, emotion, and artistic skills
Term
Cerebral White Matter
Definition
Consists of deep myelinated fibers and their tracts. Responsible for communication between the cerebral cortex and lower CNS center, and areas of the Cerebrum
Term
Cerebral White Matter types
Definition
Commissures, Association fibers, Projection fibers
Term
Commissures
Definition
connect corresponding gray areas of the two hemisphers
Term
Association fibers
Definition
connect different parts of the same hemisphere
Term
Projection fibers
Definition
enter the hemispheres from lower brain or cord centers
Term
Diencephalon
Definition
Central core of the forebrain. Encloses the third ventricle
Term
Diencephalon: consists of...
Definition
Three paired structures -thalamus, hypothalamus, and epithalamus
Term
Thalamus
Definition
paired, egg-shaped masses that form the superolateral walls of the third ventricle. Connected at the midline by the intermediate mass.
Term
Thalamus nuclei
Definition
Four groups: Anterior, ventral, dorsal, and posterior
Project and receive fibers from the cerebral cortex
Term
Thalamic Function
Definition
Sensual afferent impulses converge and synapse in the thalamus
Impulses of similar function are sorted out, edited, and relayed as a group
All inputs ascending to the cerebral cortex pass through the thalamus. Mediates sensation, motor activities, cortical arousal, learning, and memory
Term
Hypothalamus
Definition
Located below the thalamus, it caps the brainstem and forms the inferolateral walls of the third ventricle
Term
Mamillary bodies
Definition
Small, paired nuclei bulging anteriorly from the hypothalamus. Relay station for olfactory pathways
Term
Infundibulum
Definition
stalk of the hypothalamus, connects to the pituitary gland. Main visceral control center of the body
Term
Hypothalmic function
Definition
Regulates blood pressure, rate, and force of heartbeat, digestive tract motility, rate and depth of breathing, and many other visceral activities
Perception of pleasure fear, and rage
Maintains normal body temperature
Regulates feelings of hunger and satiety
Regulates sleep and the sleep cycle
Term
Endocrine Functions of the Hypothalamus
Definition
Releasing hormones control secretion of hormones by the anterior pituitary. The supraoptic and paraventricular nuclei produce ADH and oxytocin
Term
Epithalamus
Definition
Most dorsal portion of the diencephalon, forms roof of the third ventricle
Term
Epithalamus - pineal gland
Definition
extends from the posterior border and secretes melatonin.
Term
melatonin
Definition
a hormone involved with sleep regulation, sleep-wake cycles, and mood
Term
Epithalamus - choroid plexus
Definition
a structure that secretes cerebral spinal fluid
Term
Brain Stem - three regions
Definition
Midbrain, pons, and medulla oblongata
Term
Brain stem - controls
Definition
automatic behaviors necessary for survival
Term
Brain stem - pathways and associations
Definition
Provides the pathway for tracts between higher and lower brain centers. Associated with 10 of the 12 pairs of cranial nerves
Term
Midbrain
Definition
Located between the diencephalon and the pons
Term
Midbrain structures
Definition
Cerebral peduncles and Cerebral aqueduct
Term
Cerebral peduncles
Definition
two bulging structures that contain descending pyramidal motor tracts
Term
Cerebral aqueduct
Definition
Hollow tube that connects the third and fourth ventricles
Term
Midbrain Nuclei
Definition
Nuclei that control cranial nerves III (oculomtor) and IV (trochlear)
Term
Midbrain Nuclei - superior colliculi
Definition
visual reflex centers
Term
Midbrain Nuclei - Inferior colliculi
Definition
Auditory relay centers
Term
Midbrain Nuclei - Substantia nigra
Definition
functionally linked to basal nuclei
Term
Midbrain Nuclei - Red nucleus
Definition
largest nucleus of the reticular formation; red nuclei are relay nuclei for some descending motor pathways
Term
Pons
Definition
bulging brainstem regions between the midbrain and the medulla oblongata.
Forms part of the anterior wall of the fourth ventricle
Term
Fibers of the pons
Definition
connect higher brain centers and the spinal cord. relay impulses between the motor cortex and the cerebellum
Term
Pons - Nerve origins
Definition
Origin of cranial nerves V (trigeminal), VI (abducens), and VII (facial)
Term
Medulla Oblongata
Definition
Most inferior part of the brain stem
Along with the pons, forms the ventral wall of the fourth ventricle. Contains a choroid plexus of the fourth ventricle
Term
Medulla Oblongata - Pyramids
Definition
two longitudinal ridges formed by corticospinal tracts
Term
Medulla Oblongata - decussation of the pyramids
Definition
crossover points of the corticospinal tracts
Term
Medulla Nuclei - Inferior olivary nuclei
Definition
gray matter that relays sensory information
Term
Medulla Nuclei - vestibular nuclear complex
Definition
synapses that mediate and maintain equilibrium
Term
Medulla Nuclei
Definition
Cranial nerves X, XI, and XII are associated with the medulla
Ascending sensory tract nuclei, including nucleus cuneatus and nucleus gracilis
Term
Medulla Nuclei
Definition
Cardiovascular control center, respiratory centers, additional centers
Term
Medulla Nuclei - Cardiovascular Control Center
Definition
adjusts force and rate of heart contraction
Term
Medulla Nuclei - Respiratory centers
Definition
control rate and depth of breathing
Term
Medulla Nuclei - Additional Centers
Definition
regulate vomiting, hiccuping, swallowing, coughing, and sneezing
Term
The Cerebellum - Trivia
Definition
Located dorsal to the pons and medulla. Protrudes under the occipital lobes of the cerebrum. Makes up 11% of the brain mass.
Term
The Cerebellum - function
Definition
Provides precise timing and appropriate patterns of skeletal muscle contraction. Cerebellar activity occurs subconsciously
Term
Anatomy of the Cerebellum
Definition
Two bilateraly symmetrical hemispheres connected medially by the vermis
Term
Anatomy of the Cerebellum - Folia
Definition
transversely oriented gyri
Term
Anatomy of the Cerebellum - Hemisphere anatomy
Definition
Three lobes: Anterior, posterior, and flocculondular
Term
Anatomy of the Cerebellum - Neural Arrangement
Definition
gray matter cortex, internal white matter, scattered nuclei
Term
Anatomy of the Cerebellum - Arbor vitae
Definition
distinctive tree like pattern of the cerebellar white matter
Term
Cerebellar Penduncles
Definition
Three paired fiber tracts that connect the cerebellum to the brain stem. All fibers in the cerebellum are ipsilateral. Superior, Middle, and Inferior peduncles.
Term
Cerebellar Penduncles - Superior Peduncles
Definition
Connect the cerebellum to the midbrain
Term
Cerebellar Penduncles - Middle peduncles
Definition
connect the pons to the cerebellum
Term
Cerebellar Penduncles - Inferior peduncles
Definition
connect the medulla to the cerebellum
Term
Cerebellar Processing
Definition
Cerebellum receives impulses of the intent to initiate voluntary muscle contraction. Proprioceptors and visual signals "inform" the cerebellum of the body's condition. Cerebellar cortex calculates the best way to perform movement. A "blueprint" of coordinated movement is sent to the cerebral motor cortex
Term
Cerebellar Cognitive Function
Definition
Plays a role in language and problem solving. Recognizes and predicts sequences of events
Term
Functional Brain System
Definition
Networks of neurons working together and spanning wide areas of the brain.
Term
Functional Brain system: Two systems
Definition
Limbic system and reticular formation
Term
Limbic System
Definition
Structures located on the medial aspects of cerebral hemispheres and diencephalon.
Term
Limbic System - Structures
Definition
Rhiencephalon, amygdala, hypothalamus, and anterior nucleus of the thalamus
Term
Limbic System: Parts especially important to emotions
Definition
Amygdala, Cingulate gyrus. Put emotional responses to odors
Term
Amygdala
Definition
deals with anger, danger, and fear responses
Term
Cingulate gyrus
Definition
plays a role in expressing emotions via gestures, and resolves mental conflicts
Term
Limbic System: Emotion and Cognition
Definition
Interacts with the prefrontal lobes, therefore: one can act emotionally to conscious understandings, consciously aware of emotion in one's life
Term
Hippocampal structures
Definition
convert new information into long-term memories
Term
Memory
Definition
Storage and retrieval of information
Term
Memory - THree principles
Definition
Storage, Processing, and Memory traces
Term
Memory - Storage
Definition
occurs in stages and is continually changing
Term
Memory - Processing
Definition
accomplished by the hippocampus and surrounding structures
Term
Memory - Memory traces
Definition
chemical or structural changes that encode memory
Term
Two stages of memory
Definition
Short-term and long-term.
Term
Short-term memory
Definition
Working memory
A fleeting memory of events that continually happen. Lasts seconds to hours and is limited to 7 or 8 pieces of information
Term
Long-term memory
Definition
Limitless capacity
Term
Factors that effect transfer of memory from STM to LTM include
Definition
Emotional State, Rehearsal, Association, Automatic Memory
Term
Transfer from STM to LTM - Emotional State
Definition
we learn best when we are alert, motivated, and aroused
Term
Transfer from STM to LTM - Rehearsal
Definition
repeating or rehearsing material enhances memory
Term
Transfer from STM to LTM - Association
Definition
associating new information with old memories in LTM enhances memory
Term
Transfer from STM to LTM - automatic memory
Definition
subconscious information stored in LTM
Term
Two categories of memory
Definition
Fact memory and skill memory
Term
Fact (declarative) memory
Definition
Entails learning explicit information. Is related to our conscious thoughts and our language ability. Is stored with the context in which it was learned
Term
Skill memory
Definition
Less conscious than fact memory and involves motor activity. Acquired through practice. Do not retain the context in which they were learned
Term
Structures involved in Fact memory
Definition
Hippocampus and the amygdala, both limb system structures
Specific areas of the thalamus and hypothalamus of the diencephalon
Ventromedial prefrontal cortex and the basal forebrain
Term
Structures Involved in Skill Memory
Definition
Corpus Striatum, Portion of the brain receiving the stimulus, promtor and motor cortex
Term
Corpus Striatum
Definition
mediates the automatic connections between a stimulus and a motor response
Term
Mechanisms of Memory
Definition
Neuronal RNA content is altered. Dendritic spines change shape. Extracellular proteins are deposited at synapses involved in LTM. Number and size of presynaptic terminals may increase. More neurotransmitter is release by presynaptic neurons. New hippocampal neurons appear
Term
Protection of the Brain
Definition
The brain is protected by bone, meninges, and csf. Harmful substances are shielded from the brain by the blood-brain barrier
Term
Meninges
Definition
Three connective tissue membranes lie external to the CNS - Duramater, arachnoid mater, and pia matter
Term
Functions of the meninges
Definition
Cover and protect the CNS. Protect blood vessels and enclose venous sinuses. Contains CSF. Form partitions within the skull
Term
Dura mater
Definition
leathery, strong, menix composed of two fibrous connective tissue layers. Two layers separate in certain areas and form dural sinuses
Term
Three dural septa...
Definition
extend inward and limit excessive movement of the brain. Falx cerebri, falx cerebelli, tentorium cerebelli
Term
Falx cereberi
Definition
fold that dips into the longitudinal fissure
Term
Falx cerebelli
Definition
runs along the vermis of the cerebellum
Term
Tentorium cerebelli
Definition
horizontal dural fold extends into the transverse fissure
Term
Arachonid Mater
Definition
Middle menix, which forms a loose brain covering. Separated from the dura mater by the subdural space. Beneath the arachnoid is a wide subarachnoid space filled with CSM and large blood vessels. Arachnoid villi protrude superiorly and permit CSF to be absorbed into venous blood
Term
Choroid plexuses
Definition
Clusters of capillaries that form tissue fluid filters, which hang from the room of each ventricle. Have ion pumps that allows them to alter ion concentrations of the CSF. Helps cleanse CSF by removing waste
Term
Blood Brain Barrier
Definition
Protective mechanism that helps maintain a stable environment for the brain. Selective barrier that allows nutrients to pass freely. Is ineffective against substances that can diffuse through plasma membranes. Absent in some areas (vomiting center and the hyopthalamus) allowing these areas to monitor the chemical composition of the blood. Stress increases the ability of chemical to pass through the blood-brain barrier
Term
Spinal Cord
Definition
CNS tissue is enclosed within the vertebral cloumn from the foramen magnum to L1. Provides two-way communication to and from the brain
Term
Spinal Cord - protection
Definition
Protected by bone, meninges, and CSF
Term
Epidural Space
Definition
space between the vertebrae and the dural sheath (dura mater) filled with fat and a network of veins
Term
Corus medullaris
Definition
terminal portion of the spinal cord
Term
Filum terminale
Definition
fibrous extension of the pia mater; anchors the spinal cord to the coccyx
Term
Denticulate ligaments
Definition
delicate shelves of pia mater; attach the spinal cord to the vertebrae
Term
Spinal Cord: number of nerves
Definition
31 pairs attach to the cord by paired roots
Term
Cervical and lumbar enlargements
Definition
sites where nerves serving the upper and lower limbs emerge
Term
cauda equina
Definition
collection of nerve roots at the inferior end of the vertebral column
Term
Cross-Sectional anatomy of the spinal cord
Definition
Anterior median fissure, Posterior median sulcus
Term
Anterior median fissure
Definition
separates anterior funiculi
Term
Posterior median sulcus
Definition
divids posterior funiculi
Term
gray matter
Definition
consists of soma, unmyelinated processes, and neuroglia
Term
gray commissure
Definition
connects masses of gray matter; encloses central canal
Term
Posterior (dorsal) horns
Definition
interneurons
Term
Anterior (ventral) horns
Definition
interneurons and somatic motor neurons
Term
Lateral horns
Definition
contain sympathetic nerve fibers
Term
Gray matter organization
Definition
Dorsal half, ventral half, Dorsal and ventral roots
Term
Gray matter organization: dorsal half
Definition
sensory roots and ganglia
Term
Gray matter organization: ventral half
Definition
motor roots
Term
Gray matter organization: dorsal and ventral roots
Definition
fuse laterally to form spinal nerves
Term
Gray matter organization: four zones
Definition
Somatic sensory (SS) visceral sensory (VS), visceral motor (VM), somatic motor (SM)
Term
White matter in the Spinal Cord
Definition
Fibers run in three directions: ascending, descending, and transversely. Divided into three funiculi (columns) posterior, lateral, and anterior
Term
White matter in the spinal cord: funiculus
Definition
Each contains several fiber tracks. Fiber tract names reveal their origin and destination. Fiber tracts are composed of axons with similar function
Term
White Matter: Pathway Generalizations
Definition
Pathways decussate. Most consist of two or three neurons. Most exhibit somatotopy (precise spatial relationships). Pathways ares paired (one on each side of the spinal cord or brain)
Term
Main Ascending Pathways
Definition
The central processes of first-order neurons branch diffusely as they enter the spinal cord and medulla. Some branches take part in spinal cord reflexes. Others synapse with second-order neurons in the cord and medullary nuclei. Fibers from touch and pressure receptors form collateral synapses with interneurons in the dorsal horns
Term
Three Ascending Pathways
Definition
Nonspecific, Specific, Spinocerebellar
Term
Three Ascending Pathways: Nonspecific and specific ascending pathways
Definition
Send impulses to the sensory cortex. Responsible for discriminative touch and conscious proprioception
Term
Three Ascending Pathways: Spinocerebellar tracts
Definition
Send impulses to the cerebellum and do not contribute to sensory perception
Term
Nonspecific ascending pathway
Definition
Pain, temperature, and crude touch within the lateral spinothalamic tract
Term
Specific and Posterior Spinocerebellar Tracts
Definition
Specific ascending pathways within the fasciculus gracilis and fasciuculus cuneatus tracts, and their contiunation in the medial lemniscal tracts. The posterior spinocerebellar tract
Term
Descending (Motor) Pathways
Definition
Deliver efferent impulses from the brain to the spinal cord, and are divided into two groups. Motor pathways involve two neurons (upper and lower)
Term
Descending Motor Pathways: Two groups
Definition
Direct pathways: Equivalent to the pyramidal tracts
Indirect pathways: Essentially all others
Term
The Direct (Pyramidal) System
Definition
Originate with the pyramidal neurons in the precentral gyri. Impulses are sent through the corticospinal tracts and synapse in the anterior horn. Stimulation of anterior horn neurons activates skeletal muscles. Corticobulbar tracts, innervate cranial nerve nuclei. Regulates fast and fine (skilled) movements
Term
Indirect (Extrapyramidal) System
Definition
Includes brain stem, motor nuclei, and all motor pathways not part of the pyramidal system. Includes the rubrospinal, vestibulospinal, recticulospinal, and tectospinal tracts
Term
Indirect (Extrapyramidal) System: Regulate
Definition
Axial muscles that maintain balance and psoture, Muscles controlling coarse movments of the proximal portions of limbs, head, neck and eye movement
Term
Extrapyramidal (Multineuronal) Pathways
Definition
Reticulospinal tracts, Rubrospinal tracts, Superior colliculi and tectospinal tracts
Term
Reticulopsinal tracts
Definition
maintain balance
Term
Rubrospinal tracts
Definition
control flexor muscles
Term
Superior colliculi and tectospinal tracts
Definition
mediate head movements
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