CNS Ch 12 Flashcards
Primary brain vesicles : 4 weeks
Prosencephalon
Mesencephalon
Rhombenephalon
Cephalization
Brain embryonic development
Prosenrphalon ( optic vesicles
Telencephalon : cerebral hemispheres
Diencephlon : epithalamus, thalamus, hypothalamus and retina
Mesencephalon / midbrain
Merenicephon- pond and cerebellum
Myelencephalon- medulla oblongata
Central cavity of neural tube - ventricles
Brain directional terms and landmarks
Rostral : towards the forehead
Causal : towards the cord
Major part of brain: cerebrum, cerebellum and brain stem
Longitudinal fissure
Separates the cerebral hemispheres
Guri are the folds and sulcus the grooves
Surface layer of gray matter called cortex
Deeper masses of gray mater are call nuclei
Bundles of axons ( white matter) are tracts
Cranial meninges
Dura mater - outter most tough membrane
Separated from inner meninges like layer in some places, forms rural venous sinuses draining blood from brain
Supportive structure : fall cerebral, cerebellum and tentotoriun cerebellum no epidural space
Cranial men cont.
arachnoid vs pia mater
Spider web like filamentous layer
A thin vascular layer adherent to contours of brain
Meningitis
Inflammation of the meninges
Serious disease of infancy and childhood ( 3 m -2yrs )
Bacterial and virus invasion of the cns by way of nose and throat
( pia most likely to be affected )
Sings: fever, stiff neck, drowsiness and intense headache
Diagnose by examining the csf ( spinal tap)
Ventricles vs cerebrospinal fluid
Internal chambers within the cns ( lateral, third and fourth ventricles )
Ventricles lined with pendymal cells and containing choroid plexus of capillaries that produce CSF
Clear plasma like liquid filled ventricles and canals and bathes external surfaces of brain and spinal cord
Rscsiea the 4th ventricle to surround the brain
Reabsored by arachnoid villi into dural venous sinuses
Blood-brain and blood CSF barries
Blood brain barrier- tightly joined endothelium of brown capillaries ( brain tissue)
- all material pass thru cell not between them
Blood CSf Barrie- at choroid plexus is ependymal cells joined by tight junction
Circumventricular organs - in 3rd and 4th ventricles at breaks in the barrier where blood has direct access to brain
Allow monito of ph, glucose and osmolarity , possible route of infection ( HIV)
Cerebrum : cross anatomy
Layer of Gray matter with extensive folds to increase surface area, divided into lobes and divide into 3 kinds of functional area : motor, sensory and association areas
Cortex : motor control
Motor association area
Where planning of the voluntary movement occurs
Control of learned motor skills of a repetitious or patterned nature ( typing , playing instrument )
Coordination of movement
Sends activating impulses to primary motor cortex
Correct motor control con
Primary motor cortext: ( precentral gurus)
Processs order from premotorr cortex then sends motor aid las to spinal cord pyramidal cells called upper motor nuerons
Corticospinal tract
Decussate at medulla
Mother homunculus :
Distorted map of the body alone the orexenrral gurus
Larger area require more motor unite for fine control ( hands , face lips and tongue )
Cortex sensory area
Primary somewthric cortex : some static signals travel up gracile and cuneate fascicui and spunothalamic tracts of spinal cord
Somatosensory area is post central gurus
Sensory homunculus
Larger areas of the gurus related to more sensitive areas of body (fingertip , lips, tongue and genitalia ) areas with high # of receptors
Cortex ; sensory areas
Somatosensory association cortex
Integration of sensory inputs from primary somatise sort cortex to produce an understanding of object being felt ( size and texture and it’s meaning )
Sensory areas cont
Visual areas vs visual association
Primary visual cortex
Posterior tip of occipital lobe
Receives visual info from retinas
Visual association
Most of occipital lobe
Uses part visual experience to interpret visual stimuli
Auditory areas
Primary auditory cortex : cochea
Puperior margin of temporal lobe
Interpreted sonic impulses from inner ear in term of pitch , loudness and location
Association areas ;
Perception of the sound stimulus we” hear”these sounds as speech , music , thunder scream etc
Cortex : sensory areas
Primary olfactory: medial temp lobe , receives olfactory signals from nasal cavity via olfactory nerves
Olfactory association area : perception and recognition of odors
Gustatory( tastes )
Deep temp lobe insulat
Visceral sensory area : Insula, upset stomach , full bladder etc
Vestibular ( equilibrium )
Posterior insula
Awareness of balance , head position in space
Language : includes reading, writing, speaking and understanding words
Wernicke’s area : permits recognition of spoken and written lanaguge and creates plan of speech
Broca’d area : generate motor program for larynx, tongue , cheeks and lips transmit that to primary motor cortex for action
Multimodal association areas
Sensory receptors- primary sensory cortex- sensory association cortex - multimodal association cortex ( gives meaning to info we device , tie it to previous experience , stores memory if needed , decide what actions to take
-premotor Cortex- primary Cortex
Cognition
Mental processes such as awareness, perception, thinking, knowledge and memory ( 75% of brain is multimodal where integration of sensory and motor information occurs
Eg. Functions of these areas are learned by observing what happens when they are damage
Prefrontal cortex- prob with personality ( inability to plan &execute appropriate behavior )
Partial lobe: contra lateral neglect syndrome
Temp lobe: agnosia ( inability to recognize objects ) prosopagnosia inability to recognize faces
Accidentally lobotomy of phi was gage
Accidental destruction of ventromdedial region of both frontal lobe ( pre frontal cortex )
Personality change to irreverent, profane and fitful person
Neuroscientist believe planning, moral judgement and emotional control are functions of the prefrontal cortex
Cerebral white matter
Most of volume of cerebrum ( myelinated. Glial cells )
Types of tracts :
Projection tracts : extend vertically between brains and spinal cord forming the internal capsule
Commusural tract : cross from one hemisphere to another
- corpus callousness is wide band of white for we tract
- anterior and posterior commisures are penciled lead size
Association tracts : connects lives and gyri within each hemisphere
Basal nuclei
Masses of subcritical gray matter
Recieive I put from substantia nigra and motor cortex a d output to premotor and prefrontal corticosteroids
Inhibit antagonist or unnecessary movement
Function of basal nuclei
Influence muscle movements
Tilde in cognition and emotion
Regulate intensity of slow or stereotyped movement
Filter out incorrect/I appropriate responses
Inhibit antagonistic /unnecessary movement
Limbus system
Loop of cortical structures surrounding deep brain
Hippocampus : impotent In memory recall
Amygdala : important in emotional learning ( fear and reward condiontining)
Emotion n cognition
Interacts with prefrontal lobes
Reacts emotionally to things we consciously understand to be happening
Diencephalon: thalamus
Consists of bilateral egg shaped nuclei deep in cerebral hemispheres that form suoerolatedal walls of 3rd ventricular
Revives nearly all sensory info on its ways to the cerebral cortex ( relay station)
Thalamus function :
Fastest to cerebral cortex
Sorts edits and replays ascending input
Impulses from hypothalamus fro regulation of emotion and visceral function
Impulses from cerebellum and basal nuclei to help direct motor cortices,
Mediate sensation , motor activities and cortical arousal , learning and memory
Hypothalamus:
Walls and floor of 3rd ventricle Functions : Harmony secretion and pituitary And control center Thermoregumation Food and water intake Sleep and circadian rhythms Memory ( mammillary bodies ) Emotional behavior
( limbic system ( pleasure, fear range )
Brain steam: midbrain
Cerebral aqueduct
Can 111 and 1v ( every movement)
Substantia nigra : sends inhibitory signals to basal nuclei and thalamus
( degeneration leads to tremors and Parkinson’s diseases )
Brain stem : pone
Bulge in the brain stem , Rostral to the medulla
Ascending sensory tracts
Defending motor tract
Relay center
Cerebrum to center you vellum
Up to thalamusMedulla oblongata
3 cm extension of spinal cord
Ascending and descend nerve tract
Nuclear cranial nerves ( 9-12)
Cardiac center - adjust rate/force or heat
Vasomotir center : adjust blood vessels diameter
Respiratory centers: control rate and depth of breathing
Reflex center for coughing, sneezing gagging swallowing, vomiting , salivation, sweating and movements of tongue n head
Cerebellum
Right and left hemisphere connects vermis
Parallel surface folds called folia are gray matter
White matter ( arbor vitae ) visible in Sagittal section
Muscular coordination: motor control and balance, posture
Spinal cord
Info highway between brain/bod
Extends thru vertebral canal from firemen mag to L1
Each pair of spinal nerves receives sensory info and issues motor signal to muscle gland ( mixed)
Component of cns and pns
Anatomy of the spinal cord
Cylllindrr of nerves tissues within the center rental canal
31 pairs of spinal nerves
Cetvical, lumbar enlargements
Medullary cone: is tapered tip of spinal cord ( filum terminale)
Cauda equines : l2 to s5 nerve root resemble horse tail
Meninges or the spinal cord
3 fibros layer enclosing spinal cord
Dura mater : tough collageneour membrane surrounded by epidural space filled with fat and blood vessels
Arachnoid: layer of simple squamous epithelium lining dura mater and lose mesh of fibers filled with CSf
Pia mater: delicate membrane adherent to spinal cord
Filium terminale and denticulate ligaments anchor the cord
Cross sectional anatomy of spinal cord
Centra area of gray matter shaped like butterfly , surrounded by white matter in 3 columns
Gray matter - neuron cell bodies with myelin
White matter - myelinated axons
Gray matter in spinal cord
Pair of dorsal or posterior horns
Foral root of spinal nerve is totally sensory fibers
Pair of central and Anterior horns
Connected by gray commissire punctured by ventral canal and continuous above with 4th ventricle
White matter in spinal cord
White column- bundle of myelinated axons that carry singable up and down
Dorsal ( posterior ) volume , lateral volume and central ( anterior columns)
Each column filled with names tracts
Spinal tracts
Ascending and deserving tray head up and down while decussation means that the fibers cross sides
Contra lateral means origin and destination are on opposite sides while ipsilatetl means on same side
Ascending ( sensory ) pathways
Consist of 2 or 3 new irons
First order neuron:
Conducts impulses from cantankerous receptors and proprioceptors
Enters special cord through dorsal root
Synapses with second order neuron
Immediately at level of entry or
Ascends and synapses in medulla
Decussates and then ascendsAscending pathways
Second order neuron
Interneurons
Cell body location in dorsal horn of spinal cord at level of entry of 1st order neuron or medullary nuclei
Axons extend to 3rd order neurons in thalamus or terminates in cerebellum
Third: interneurons
Cell body in thalamus
Axon extend to soma stows sort cortex
(No third order neuron In cerebellum)
Descending pathways and tracts
Deliver efferent impulses from brain and spinal cord
Two groups
Direct pathways - pyramid tracts
Indirect pathways - all others
Descending pathways tracts
Motor pathways invoices two neurons :
Upper motor neuron : pyramidal cells in primary motor cortext
Lower motor neurons
Central horn motor neurons
Inner are skeletal muscles
Direct pyramidal pathways
Impulses from pyramidal neurons in precentral gyri pass through pyramidal corticospinal tract
Descend without say passing
Axons synapse with interneurons or central horn motor neurons
Direct pathways regulates fast snd fine ( skilled) movements
