Module 12 CNS Flashcards
What body cavities is the CNS in
Dorsal cavities
What does the CNS develop from
Neural tube
Describe the neural tube
Fluid filled cavity enlarged at rostral end( anterior)
What are the 3 primary vesicles
Forebrain
Midbrain
Hindbrain
What are the long names of the primary vesicles
Prosencephalon
Mesencephalon
Rhombencephalon
How many secondary vesicles are there
4 Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon
When do secondary vesicles arise
Week 5 of embryonic development
What vesicles come from forebrain
Telencephalon
Diencephalon
What vesicles come from hindbrain
Metencephalon
Myelencephalon
What primary vesicles remains undivided
Mesencephalon
What does telencephalon become
Cerebrum
What does diencephalon become
Thalamus
Hypothalamus
Epithalamus
What does mesencephalon become
Brain stem: midbrain
What does metencephalon become
Brain stem: pons
Cerebellum
What does myelencephalon become
Brain stem: medulla oblongata
Where do ventricles come from
Expansion of the lumen of the neural tube
What canal region does the telencephalon form
Lateral ventricles
What canal region does the diencephalon form
Third ventricle
What canal region does the mesencephalon form
Cerebral aqueduct
What canal region do the metencephalon and myelencephalon form
Fourth ventricle
What determines the shape of adult brain
Space restrictions in the skull during development
What ventricles are paired
Lateral ventricles
Where do you find the fourth ventricle
Between the pons and cerebellum
What is the basic pattern of the spinal cord
Central canal surrounded by grey matter
External white matter- myelinated fiber tracts
What is the basic pattern of the brain
Similar to spinal cord with more grey matter In nuclei
What is the pattern of grey matter in the cerebellum and cerebrum
Grey matter in scattered nuclei
Outer cortex
And inner grey matter
What is the largest area of the brain
Cerebrum
What are some functions of the cerebrum
Conscious thought
All intellectual functions
Processing of somatic sensory and motor info
What is the cortex around the cerebrum called
Cerebral cortex
What are gyri
Ridges
What are sulci
Shallow grooves
What increases the surface area of the cerebral cortex
Gyri and sulci
What separates the cerebral hemispheres
Longitudinal fissure
What are the 2 cerebral hemispheres divided into
Lobes for areas of skull bones
What divides the frontal and parietal lobes
Central sulcus
What divides the frontal and temporal lobes
Lateral sulcus
Where does the insula lie
Medial to the lateral sulcus
What seperates the parietal and occipital lobes
Parieto occipital sulcus
How many lobes is each hemisphere divided into and what are their names
5 Frontal Parietal Temporal Occipital Insula
What are 3 main points to remember about the cerebral hemispheres
- Receives sensory info from and sends motor info to the opposite side
- Hemispheres have different functions
- Corresponds between specific function and specific region is imprecise
Conscious behavior involves what portion of the cerebral cortex
The whole cortex
What are the 3 functional areas of the cerebral cortex
Motor areas
Sensory areas
Association areas
What do motor areas control
Voluntary movement
What do sensory areas control
Conscious awareness of sensations
What separates the motor and sensory areas of the cerebral cortex
Central sulcus
What do association areas control
They integrate information, interpret data, coordinate response
What is the percentral gyrus
Primary motor cortex
How do neurons direct voluntary movements
By controlling somatic motor neurons in the brain stem and spinal cord
What does stimulating specific neurons in the primary motor cortex do
Generates contraction in specific skeletal muscles
What separates the motor and sensory areas of the cortex
The central sulcus
What is the post central gyrus
Primary somatosensory cortex
What do neurons in the primary somatosensory cortex recieve
Somatic sensory info
Touch, pressure, pain, taste, temperature
Where is the visual cortex found
Occipital lobe
Where is the auditory cortex
Temporal lobe
Where is the olfactory cortex
Temporal lobe
Where is the gustatory cortex
Insula lobe
What is the function of association areas
Interpret incoming data
Coordinate response
What areas of the cerebral cortex have association areas
Sensory and motor areas
What is the function of the somatosensory association center
Monitor activity of primary somatosensory cortex
Example of somatosensory association center function
Allow you to perceive that a light touch is a mosquito
What is the speech center called
Broca’s area
Where is Broca’s area found
Usually only in left hemisphere
What does Broca’s area do
Directs muscles involved in speech production
What is the function of the visual association center
To monitor patterns in the visual cortex
What is an example function of the visual association center
You see specific letters when stimulation of receptors in your stimulate visual cortex
Association center recognizes these letters and what they spell
What is the function of the auditory association center
To monitor sensory activity in the auditory cortex
Example function of auditory association area
Word recognition
What is premotor cortex
Somatic motor association center
What is premotor cortex responsible for
Coordination of learned movement
Controls learned, repetitious, patterned motor skills
Coordinates simultaneous or sequential actions
Planning of movements
What is the frontal eye field responsible for
Controls learned eye movements like scanning a page
What are 2 examples of multimodal association areas
Prefrontal cortex
Wernickes area
what is the function of the prefrontal cortex
Coordinate info relayed from association areas of entire cortex
Perform abstract intellectual functions like predicting consequences
Feeling of frustration or anxiety are interpreted
What does damage to prefrontal cortex cause
Difficulty estimating relationships between events
What is prefrontal cortex closely linked to
Limbic system
What does a lobotomy do
Remove prefrontal cortex
Removes anxiety
Where does wernickes area receive info from
All association areas
Where is wernickes area located
Left side of brain
Connected to Broca’s
Where is spatial analysis area
On the right side
What is role of wernickes area
Understanding and comprehending spoken language
If you are right handed what part of brain is larger
Premotor cortex on the left side
What is the idea that the 2 hemispheres have different cortical functions called
Lateralization
What is the left hemisphere known for
Interpretive and speech centers
Reading, writing, speaking
Analytical tasks
What is right hemisphere known for
Relating body to sensory environment
Permits object identification by senses
Dominant role in face recognition
What are basal nuclei
Grey matter deep within cortical white matter
Where do internal capsule fibers run
Between and through caudate and lentiform nuclei
Collectively called corpus striatum
What is the lentiform nucleus made of
Putamen and globus pallidus
What are the functions of basal nuclei
Subconscious control of skeletal muscle tone and learned movement patterns
Provides general pattern and rhythm to movements
Processes info received
What do basal nuclei not do
Initiate particular movements
Where does information to the basal nuclei come from
Sensory, motor, integrative areas of cerebral cortex
Where is info from basal nuclei output
Output to the thalamus
What happens once info has reached thalamus
Thalamus outputs info to appropriate area of the cerebral cortex to control muscle movement
Example functions of basal nuclei
Subconscious level of positioning and stabilizing arm/ shoulder for movement
Control cycle of movement for Walking
What is the interior of cerebrum mainly made of
White matter
What are the 3 axon classifications of white matter
Association fibers
Commissural fibers
Projection fibers
What do association fibers do
Interconnect areas of cortex within a single hemisphere
What do commissural fibers do
Interconnect between the hemispheres
Example of commissural fibers
Corpus callosum
What do projection fibers do
Go to lower areas outside of cortex
Or
Enter from lower brain and spinal cord
Run through basal nuclei
Example of projection fibers
Corona radiata and internal capsule
The pathway to spinal cord for motor commands
What is the central core of the forebrain
Diencephalon
What are the 3 structures of the diencephalon
Thalamus
Hypothalamus
Epithalamus
What encloses the third ventricle
Diencephalon
What part of the third ventricle does the thalamus form
Superolateral walls
What connects the 2 paired masses of the thalamus
The intermediate mass
How many groups of nuclei are in the thalamus
What are they called
4 nuclei groups Anterior Ventral Dorsal Posterior
What do the thalamus nuclei do
Project and receive fibers from the cerebral cortex
What type of impulses converge at the thalamus
Sensory afferent impulses
What occurs at the thalamus
Impulses of similar function are sorted out, edited, and relayed as group
All inputs that ascend to cerebral cortex must go through thalamus
What is the “cap” of the brain stem
Hypothalamus
What part of third ventricle does hypothalamus form
The inferolateral walls
What are 2 portions of the hypothalamus
Mammillary bodies
Infundibulum
What do the mammillary bodies do
Act as relay station for olfactory pathways
What is the infundibulum
Stalk of hypothalamus connected to pituitary gland
What are the functions of the hypothalamus
Visceral control Regulate BP Rate of heart beat Digestive tract motility Rate of breathing Maintain body temp Regulate feeling of hunger Regulate sleep cycle Perception of pleasure, fear, rage
How is the hypothalamus involved in the endocrine system
Produces releasing hormones that control hormone secretion of anterior pituitary
What hormones are produced by hypothalamus
ADH
Oxytocin
What part of third ventricle is the epithalamus
The roof
What is the dorsal portion of the diencephalon
Epithalamus
What are 2 portions of the epithalamus
Pineal gland
Choroid plexus
What does the pineal gland secrete
Melatonin
Where is the pineal gland located
Extends from the posterior border of the epithalamus
What does the hormone melatonin do
Regulates sleep and mood
What does choroid plexus do
Secrete CSF
Help clean and remove waste from CSF
Alter ion concentration of CSF
Have cilia to move CSF
What are the 3 areas of the brain stem
Midbrain
Pons
Medulla oblongata
What does the brain stem control
Autonomic behaviors
Needed for survival
How many cranial nerves is the brain stem associated with
10 of the 12 pairs
Where is the midbrain
Between the diencephalon and pons
What are some midbrain structures
Cerebral peduncles
Cerebral aqueduct
Nuclei: substantia nigra & red nucleus
Corpora quadrigemina: superior/ inferior colliculi
What are the cerebral peduncles
2 structures that contain descending pyramidal motor tracts
What is the cerebral aqueduct
Hollow tube that connects the 3rd and 4th ventricle
Where is the corpora quadrigemina
Dorsal portion of midbrain
What do the superior colliculi do
Act as visual reflex center
Track moving objects
What do the inferior colliculi do
Act as auditory relay center
Startle reflex
What kind if neurons does the substantia nigra contain
Dopamine releasing neurons
What is the substantia nigra functionally related to
The basal nuclei of the cerebrum
What disease is caused be degeneration of substantia nigra
Parkinson’s
What are red nuclei involved in
Reticular formation
Relay nuclei for some descending motor pathways
Where is the pons
Between midbrain and medulla oblongata
What part of 4th ventricle does pons form
Anterior wall
What do the fibers of the pons connect and do
Connect higher brain centers to spinal cord
Relay impulses from motor cortex to cerebellum
Contain nuclei for reticular formation
What are 2 parts of the medulla oblongata
Pyramids
Inferior olivary nuclei
What forms the pyramids
Corticospinal tracts
What is the cross over point of the Corticospinal tracts called
Decussation of the pyramids
What portion of the fourth ventricle does the medulla oblongata form
Anterior wall
With the pons
What type of info do inferior olivary nuclei relay
Where is info sent to
Relay sensory info about muscle stretch to cerebellum
What kind of reflex centers does medulla oblongata have
Specific examples
Autonomic reflex centers
Cardiovascular control
Respiratory center
What other area of the brain does the medulla oblongata specifically work with
Hypothalamus
Where is the cerebellum
Dorsal to pons and medulla
Protruding under occipital lobe of cerebrum
What kind of processing center is cerebellum
Automatic processing center
What are the functions of the cerebellum
Adjusting postural muscles
Fine tuning movement at conscious and unconscious levels
Calculating the best way to perform a movement
What is the neural cortex made of
Perkinje cells
What is the white matter of the cerebellum called
Arbor vitae
What is the general structure of the cerebellum
2 bilaterally symmetrical hemispheres connected by vermis
How many lobes does each hemisphere of the cerebellum have
What are they called
3
Anterior
Posterior
Flocculonodular
What is the role of the anterior and posterior lobes of the cerebellum
To coordinate body movements
What is the flocculonodular lobe involved in
Involved in posture and balance
What are the cerebellar peduncles
3 paired fiber tracts that connect the cerebellum to the brain stem
What do the superior peduncles do
Connect the cerebellum to the midbrain
What do the middle peduncles do
Connect the pons to the cerebellum
What do the inferior peduncles do
Connect the medulla to the cerebellum
How is the cerebellum notified of intent to initiate voluntary muscle contraction
Motor areas of cerebral cortex via the nuclei in the pons
What informs the cerebellum of the body’s condition
Impulses from proprioceptors and visual signals
What happens if cerebellum is injured
Clumsiness
Ataxia
Where does cerebellum send blueprint for coordinated movements
Back to the cerebral motor cortex
What part of brain detects mismatches between plan for motor action and feedback about how it is going
The cerebellar cortex
What are functional brain systems
Networks of neurons that work together and span wide areas
What are 2 examples of functional brain systems
Limbic system
Reticular formation
Where is the Limbic system
In nuclei and tracts along the border of cerebellum and brain stem
What are the functions of the Limbic
Establish emotional state
Links conscious of cerebral cortex with autonomic function of brain stem
Facilitates memory storage and retrieval
What are the structures of the Limbic system
Amygdala Limbic lobe of cerebral hemisphere (3 gyri) Cingulate gyrus Hippocampus Fornix
What is the role of the amygdala and cingulate gyrus
Regulate heart rate in fight or flight
Link emotions with memories
Act as interface between Limbic system, cerebrum, and sensory systems
What is role of hippocampus
Important for learning
Storage and retrieval of new long term memories
What is the Fornix
White matter that connects the hippocampus with the hypothalamus
What is the reticular formation composed of
3 broad columns along the brain stem
Red nucleus
Midbrain
Nuclei in pons
What are far flung reticular formation axons connected to
Hypothalamus
Thalamus
Cerebellum
Spinal cord
What are functions of the reticular formation
Reticular activating system
Motor function
What does RAS do
Send impulses to cerebral cortex to keep it alert and conscious
Filters out repetitive / weak stimuli
Sensory dampener
What drug interferes with RAS
LSD
What is the role of the motor function of reticular formation
Help control course motor movements
Help Autonomic centers regulate visceral motor functions
What are done visceral motor functions that reticular formation helps
Vasomotor
Cardiac
Respiratory centers
What does EEG stand for
Electroencephalogram
What are the 4 types of brain waves
Alpha
Beta
Theta
Delta
Describe alpha waves
Regular
Low amp
Slow
Indicate idling brain
Describe beta waves
More irregular
During awake and alert state
Describe theta waves
More irregular
Common in children
And frustrated adults
Describe delta waves
High amp
Deep sleep
Infants
And when RAS is damaged
What is a seizure
Temporary Uncontrolled electrical activity of neurons in brain
With abnormal movements/ behhaviors
Describe focal seizure
One affecting little cortical area
Sensory or motor symptoms
Remain conscious
Symptoms provide indication if which cortical area involved
Describe temporal lobe seizure
One that is spread to sensory cortex and association centers
May have unusual experiences
Sudden emotion change- Limbic
Describe convulsive seizures
Uncontrolled muscle contraction
Tonic clinic
Absence seizures
Describe tonic clonic
Grand mal
Start at focus and spread to entire cortical surface
Lose consciousness
Describe absence seizure
Petite mal
Brief loss of consciousness
Often not diagnosed
What does consciousness involve
Simultaneous activity of large areas of cerebral cortex
Associated with higher mental processing
Describe clinical consciousness
Continuum that grades behavior Alertness Drowsiness Stupor Coma
What is sleep
State of partial unconsciousness
Can be aroused
What are the 2 types of sleep
Deep aka slow wave
REM
What happens during deep sleep
Heart rate BP Respiratory rate Energy utilization All decline up to 30%
What happens during REM
BP and respiratory rate increase
Dreaming occurs
EEG resembles awake state
Motor neurons inhibited
What regulates sleep cycle
Hypothalamus
What type of brain activity declines during sleep
RAS declines
Cerebral cortex is not being kept alert
What is the restorative sleep stage
NREM slow wave
When is the reverse learning process
REM
Info is purged
What side of cerebral hemisphere is for language
Mainly left
What happens if Broca’s is damaged
Not able to speak
What happens if wernickes is damaged
Nonsense speech
What part of language is the right cerebral cortex responsible for
Body language
Emotion
What part f memory has limited space
STM
Only about 7-8 pieces of info
What is the working memory
SHort term
What factors influence memory transfer
Emotional state
Rehearsal
Association
Automatic memory
What is automatic memory
Subconscious info stored in LTM
What aspect of memory takes time
Consolidation
Fitting in new info with stored info in cerebral cortex
What are the 2 categories of memory
Declarative
Nondeclarative
What category of memory is related to conscious thought and language ability
Declarative
What is unconscious learning
Non declarative
What are the subcategories if non declarative memory
Procedural
Motor
Emotional
How are non declarative memories aquired
Experience and repetition
Where are visual memories stored
Occipital cortex
Where are music memories stored
Temporal cortex
Where is sensory input processed
Association cortices
What do cortical neurons communicate with for memory creation
With hippocampus and amygdala
What does temporal lobe communicate with for memories
Specific areas of thalamus and prefrontal cortex
What does basal forebrain communicate with for memories
With prefrontal cortex and temporal lobe
Via Ach
What structures are involved in declarative memory creation
Hippocampus Amygdala Temporal lobe Prefrontal cortex Basal forebrain Thalamus
What leads to anterograde amnesia
Damage to both sides of hippocampus and temporal lobe structures
What structures are involved for skill memory
Thalamus
Premotor cortex
Basal nuclei
What is CNS protected by
Bone
Meninges
CSF
How is brain shielded from harmful substances
Blood brain barrier
What are meninges made of
Connective tissue
What are the functions of the meninges
Cover and protect CNS
Protect blood vessels
Enclose venous sinuses
Contain CSF
What meninge has two layers
Dura mater around brain
What are the 2 dura mater layers and what does each do
Periosteal
Attach to skull- periosteeum
Meningeal
Cover brain
What is in between the dura mater layers
Dural sinuses
What is in dural sinuses
Venous blood
What meninge extends inward to stabilize brain
Meningeal layer of dura
What is falx cerebri
Dura mater fold into longitudinal fissure
What is falx cerebelli
Dura mater that runs along vermis
What is the tentorium cerebelli
Dural fold that goes into transverse fissure
What is attached to the crista galli
Falx cerebri
What meninge does not follow sulci
Arachnoid mater
Where is subdural space
Between dura and arachnoid
Where is subarachnoid space
Between arachnoid and pia
What fills subarachnoid space
CSF
Large blood vessels
What do arachnoid villi do
Protrude into dural sinuses
Allow CSF to be absorbed by venous blood
What meninge follows sulci
Pia mater
What does pia mater contain
Many tiny blood vessels
What is encephalitis
Inflammation of brain
What causes meningococcal meningitis
Neisseria meningitis
What causes viral meningitis
Enteroviruses
What causes viral encephalitis
Arboviruses
West nile
What is CSF similar to
Blood plasma
What is CSF formed from
Blood plasma
Via choroid plexuses
How is CSF different from blood plasma
Less protein
Different ion concentration
More NA
Less K
What helps nourish brain
CSF
What are choroid plexuses
Clusters of capillaries surrounded by ependymal cells
How do choroid plexuses alter ion concentration of CSF
Have ion pumps
What functions do choroid plexuses have
Make CSF
Clean CSF
Move CSF by cilia
What are the layers of the blood brain barrier
Endothelium of capillary walls
Thick basal lamina
Bulbous feet of Astrocytes
Where is there no blood brain barrier
3rd and 4th ventricle areas
For vomiting center
And hypothalamus
What is contusion
Permanent brain damage
Coma if RAS damaged
What are cerebrovascular accidents
Strokes
What are causes of strokes
Cerebral artery blocked
Compression of brain by hemorrhage or edema
Atherosclerosis
What are TIAs
Transient ischemic attacks
Reversible cerebral ischemia
What occurs in Alzheimer’s patients brains
Brain accumulates beta amyloid peptide outside neurons
Tau tangles inside neurons
Neurons die
What particular areas of the brain shrink during Alzheimer’s
Basal forebrain
Hippocampus
What drugs help Alzheimer’s
Ones that. Inhibit ach breakdown
What is degraded in Parkinson’s
Dopamine releasing neurons in substantia niagra( midbrain)
What drugs help Parkinson’s
Ldopa
Supply dopamine
Inhibit dopamine breakdown
What does the degeneration of substantia niagra cause
Over stimulated target basal nuclei
Parkinson’s
Movements are difficult
What causes huntingtons
Accumulation of Huntingtin protein
Leads to degeneration of basal nuclei
Then cerebral cortex
What can treat huntingtons
Drugs that block dopamine
What does huntingtons cause
Jerky movement - chorea
Mental deterioration
Where is spinal cord
From foremen Magnum to L1
What is function of spinal cord
Communication to and from brain
What is conus medullaris
Terminal portion of cord at L1
What is filum terminale
Extention of pia
Anchors cord to coccyx
What are denticulate ligaments
What do they do
Shelves of pia
Attach cord to vertebre
How many spinal beers are there
31 pairs
How are spinal nerves attached to cord
By paired roots
- dorsal and ventral
Where does the spinal cord enlarge
At cervical and lumbar areas
What is cauda equina
Collection of nerve roots at end of vertebral canal
Where can a lumbar tap be done
Beyond L3
No more cord or spinal roots
Where is epidural space
Between vertebrae and dura
What is epidural space filled with
Fat and network of veins
What does anterior median fissure divide
Anterior funiculi
What does posterior median sulcus divide
Posterior funiculi
What are funiculi made of
White matter
Myelinated nerve fibers
What is spinal grey matter made of
Soma
Unmyelinated processes
Neuroglia
What does grey commissural do
Connect grey matter
Enclose central canal
What are the names of te grey matter structures in spinal cord called
Dorsal horns
Ventral horns
Lateral horns
What is dorsal half of spinal cord for
Sensory roots and ganglia
What is ventral half of spinal cord for
Motor roots
What forms spinal nerves
Fused dorsal a ventral roots
What type of neurons are in dorsal horns
Interneurons
What type of neurons are in ventral horns
Somatic motor and interneurons
What kind of neurons are in lateral horns
Neurons of sympathetic nervous system ANS
Where are sensory pathways
Ascending
Where are motor pathways
Descending
What are example of ascending pathways
Dorsal column medial lemniscal pathway
Spinocerebellar tracts
What does dorsal column medial lemniscal pathway do
Send sensory info to sensory cortex
For conscious perception
What does spinocerebellar tract do
Send impulse to cerebellum
What tract is not for sensory perception
Spinocerebellar tract
What does spinocerebellar tracts involve
Proprioceptors send impulse to dorsal horns
Synapse with second order neurons
Go to cerebellum
What does medial lemniscal system involve
Touch receptors or proprioceptors to dorsal horn
Synapse with medulla nuclei - second order
Ascend to thalamus to find third order
Third order synapse with post central gyrus of cerebral cortex
Where does decussation occur
Medulla oblongata
Second order neurons
What pathway does not involve decussation
Spinocerebellar
What do descending tracts do
Deliver efferent Impulses from brain to cord
What is the direct pathway
Pyramidal tracts
What occurs in pyramidal tracts
Start at pyramidal neurons of precentral gyrus
Impulses sent via Corticospinal tracts to anterior horn
Anterior horn neurons activate skeletal muscles
What type of movements does direct pathway regulate
Fast and fine skilled movements
What is flaccid paralysis
Damage to central root or anterior horn
What does flaccid paralysis cause
Lower motor neuron damage
Inpulses can’t reach muscle
No movement
What is spastic paralysis
Only upper neurons are damaged
In the primary motor cortex
What does spastic paralysis cause
Muscles are stimulate irregularly
Spinal neurons intact
No voluntary control
