Central nervous system Flashcards

Question

corpus callosum

Answer 1

- starts at anterior commissure at the upper end of the lamina terminalis - 4 parts: rostrum, genu, body, splenium - splenium is a free border - forceps minor- arc of fibres that radiate to frontal lobe off the rostrum - forceps major - fibres that spread from the splenium to the occipital lobe - forms room of anterior horn and body of ventricle - tapetum - the fibres of teh corpus callosum that forms the lateral wall of the inferior and posterior horns of the ventrcile

Answer 2

``` MsI - precentral gyrus- motor for body. Face lies lowest, followed by hand, arm, trunk and leg and perineum on medial part. Inputs: cerebellum and thalamus, outputs corticonuclear and cortico spinal MsII- receives from basal nuclei- postural mechanisms Motor speech (brocas, areas 44, 45)- inferior frontal gyrus on left. located on pars triangularis (motor aphasia - difficulty finding right words) posterior speech area (Wernicke's)- in the posterior parts of the superior and middle temporal gyrus and into the lower part of parietal lobe (involved in understanding speech) ```

Answer 3

fontal eye field (6,8, 9) - voluntary eye movement and accommodation reflex- centre of middle frontal gyrus SmI- touch, kinaesthesia aand vibration (ordered the same as MsI) SmII- pain localisation (registration of pain occurs at thalamic level) gustatory area- inferior part of post central gyrus in the frontoparietal operculum- near tongue taste area of SmI

Answer 4

auditory (41 and 42)- hidden in the lateral sulcus in the anterior transverse temporal gyrus. It also extends into the superior temporal gyrus below the sulcus- this part is surrounded by the auditory assocaition cortex --- cochlear is represented bilateral ---receive fibres from Medial geniculate body via auditory radiation olfactory- uncus of the parahippocampal gyrus

Answer 5

area 17 - medial surface of occipital lobe, in calcarine sulcus- more specifically it lies in the lower lip of the anterior part of the sulcus and along both upper and lower lips of the posterior part and extends approx 1cm onto the lateral surface of the occipital lobe as far as the lunate sulcus ---- the true visual area is characterised by a white line, (stria of Gennari) - which bisects the cortex areas 18 and 19- surrounding cortex of the stria of Gennari - each cortex registers the opposite visual field --- upper half of cortex recieves fibres from upper half of retina and lower half from the lwoer (ie the lower visual field is carried by the upper fibres- so the visual fields are crossed) -- macula is at the posterior part of the cortex and peripheral parts as moving anteriorly

Answer 6

retinal rods and cones--> bipolar cell--> ganglion cells (inner retina netx to vitrous body, 1 cell for 1 cone and 1 cell for 80 rods, 2nd order neurons) --> ganglion cell axons runs through optic disc and form optic nerve --> nasal fibres decussate at optic chiasma--> optic tract (left responsible for right vision and vice versa)-->optic tract passes around the cerebral peducle high up against the temporal lobe reaching the side of the thalamus --> divides into two (superior brachium, the smaller branch, passes between the Lateral and medial geniculate bodies to superior colliculus; the larger branch continues on to the LGN) optic nerves is covered in meninges- which attaches to the sclera - anterior to optic foramen - has dura, arachnoid and pia mater -- > posterior to foramen has just pia mater to the optic chiasma the optic chiasma is attached to the floor of the 3rd ventricle

Answer 7

the lateral geniculate nucleus lies below the pulvinar on posterior thalamic surface -- has 6 layers - fibres from the retina on same side (temporal retina) synapse ar layers 2, 3, 5; nasal fibres (ones that have crossed) at 1, 4 and 6 From LGN --> optic to occipital cortex --- optic radiation lies in calcarine sulcus superior brachium--> superior colliculus--> tectobulbar and tectospinal tracts --> general light reflexes (blinking, turning away from bright light) ---- superior colliculi are linked by the posterior commissure - general light reflexes are bilateral

Answer 8

pupillary light reflexes fibres do not synapse at the superior colliculus - but rather the pretectal nucleus located at the upper lateral margin of the superior colliculus in teh tegmentum - - the pretectal nucleus - passes to the Edinger Westpthal nucleus on both sides --> sphincter pupillae - - crossing from the pretectal nucleus and also the nasal fibres ensures bilateral pretectal nculeus are excited to light--> direct (same side contract) and consensual (opposite contracts) - --- lesion of the pretectal nucleus - Argyll Rovbertson - small, does not constrict to light, but restricts to accommodation-convergence (as this is a different pathway not involving the pretectal nucleus)

Answer 9

1) complete optic nerve --> blindness in that eye 2) optic chaism- bitemporal hemianopia 3) left optic tract - homonymous hemianopia- left sided causes right sided vision loss (medial on same side and lateral on opposite) 4) lower fibres of optic radiation - temporal lobe - on left causes right upper quadrantic homonymous hemianopia 5) lower optic radiation - left causes right lower quadantric homonymous hemianopia 6) anterior left visual cortex- caused by PCA stroke - causes a right homonymous hemianopia with macula sparing because macula is spared as it is posterior and supplied by the MCA 7) posterior visual cortex- on left gives right homonymous macular defect - often traumatic

Answer 10

1) teh septal and piriform areas of the cerebral cortex near lamina terminalis (anterior boundary of 3rd ventricle) 2) uncus, insula and cingulate and parahippocampal gyri 3) amygdaloid body 4) hippocampus, fibria, fonix and mamillary body

Answer 11

- efferent pathway of the

Answer 12

formed by blood vessels lined by pia mater and ependymal cells - secretes CSF

Answer 13

motor somatic: superior, medial, inferior rectus, inferior oblique and levator palpebrae superioris visceral motor: Edinger Wespthal - to ciliargy ganglion for sphincter pupillae and cillairy body location is near mdilin in floor of aqueduct of midbrain level with superior colliculus

Answer 14

lateral ventricle --> interventricular foramen (foramen of Monro)--> 3rd ventricle--> cerebral aqueduct--> 4th ventricle --> central canal of spinal cord--> filum terminale -- only apertures in roof of 4th ventricle --> opens into subarachnoid space

Answer 15

white matter forms walls elsewhere, except in places where the the bottom of sulcus grey matter form wall- these include the parahippocampal, calcarine, and colateral sulcus (form convexities in the ventricle) and the thalamus and caudate nucleus

Answer 16

C shaped .............. (to do)

Answer 17

medial wall - septum pellucidum roof- fibres that run laterally from the genu and rostrum of the corpus callosum (forceps minor) lateral wall - is the caudate nucleus - meeting the roof at a lateral angle -- the caudate is separated from the fornix at the floor by the septum pellucidum - which atatches the fornix to the corpus callosum behind the anterior column of the fornix and anterior to anterior pole of thalamus at floor of anterior horn is the interventricular foramen --- the choroid travels through here without going into the anterior horn

Answer 18

lies behind the level of the interventricular foramen floor- thalamus and body of caudate ----- the thalamostriate groove lies between the the thalamus and caudate --------- within this groove lies: stria medullaris - a band of white matter running the length of the caudate; thalamostriate vein roof: copus callosum medial wall: crus and body of fornix and septum pellucidum between the thalamus of the floor and the fornix of the medial wall - the choroid plexus evaginates with pia and ependyma-- forming the start of the choroid plexus. The choroid plexus is limited anteriorly by the interventicular foramen

Answer 19

floor: collateral eminence (convex in shape) - which is formed by the collateral sulcus medial wall: consists of two convexities - the upper is the bulb of the posterior horn- formed by fibres of forceps major; the lower is the calcar avis formed by the calcarine sulcus roof and lateral wall: tapetum of the corpus callosum, with the optic radiation lying against the tapetum in the lateral wall

Answer 20

floor: medially the hippocampus, covered by the alveus forms the floor. laterally the collateral eminence which expands posteriorly into the collateral trigone, there the posterior and inferior horns diverge roof: tail of the caudate, which is continuous anteriorly with the amygdaloid body, which lies to the lateral side of the anterior perforated substance. lateral: closed laterally by white matter of tapetum The fimbriae forms the lower lip of the choroid fissure in the inferior horn, they lie in a continuity with the fornix in a C shape The Caudate forms a C shape - head is in anterior horn, body is floor of body, tail form the roof of interiro horn the amygdaloid body produces a shallow convexity at the tip of the roof of the inferior horn, just above the pes hippocampi.

Answer 21

lamina terminalis forms the anterior wall of the third ventricle and anterior boundary of the hypothalamus. - -- anterior border of diencephalon - -- extends from the rostrum of the corpus callosum to the top of the optic chiasm

Answer 22

double layered - connects rostrum, genu and front of the body of the corpus collosum to the anterior column of the fornix ---cavum septum pellucidum when these two layers do not adhere

Answer 23

- slit like space in sagittal plane - lateral wall: thalamus - bulges into the space- causing slit like appearance and hypothalamus - seperated by hypothalamic groove ------interthalamic adhesion - in 60% joins the two thalamus inside the 3rd ventricle Floor: TOM-PIT - in order: Tegmentum of midbrain, optic chaism, mamillary bodies, posterior perforated substance, infundibulm and tuber cinereum --- behind the infundibulum the floor of the third ventricle slopes upwards and backwards to the aqueduct, exterenaly this is marked by the mamillary bodies and behind them the posterior perforated substance --- the part of the floor between the mamilalry bodies and the infundibulum is the tuber cinereum see other card for roof, Anterior wall and Posterior wall

Answer 24

- The hypothalamic sulcus (sulcus of Monro) is a groove in the lateral wall of the third ventricle, marking the boundary between the thalamus and hypothalamus. - it curves down from the interventricular foramen towards the cerebral aqueduct - the more caudal part of the area below the groove that merges with the midbrain is the subthalamus - ---- principle feature is the subthalamic nucleus - ----- this nucleus lies adjacent to the substantia nigra

Answer 25

supraoptic and paraventricular nuclei - these cells axons run in the pituitary stalk to form the posterior lobe of the pituitary Sympathetic nervous system--> cells axons pass via the spinal sympathetic tract to preganglionic cells in lateral grey in thoracic and upper lumbar

Answer 26

The infundibulum passes behind the optic chiasm to form the pituitary stalk

Answer 27

The median eminence is the part of the tubercinerium located at the base of the infundibulum - location of cells that control anterior pituitary secration

Answer 28

A space in the anterior wall of the third ventricle formed between the optic chiasma and lamina terminalis

Answer 29

It’s a deep tunnel-shaped recess extending downward via the tuber cinereum into the infundibulum, i.e., the stalk of the pituitary gland

Answer 30

Anterior wall: -- the anterior commissure is attached at the upper end of the lamina terminalis ---- just behind the anterior commissure - the anterior columns of the fornix are joined before they diverge to sink into the lateral wall of the ventricle --- the interventricular foramen is located behind the anterior column Roof: the of the third ventricle is formed by ependyma which stretches from the anterior columns to the anterior pole of the thalamus ---- it is the anterior limit of the tela chordninae (name given to a double fold of pia mater)-- Involved in CSF production with choroid plexus --- it is invaginated by the choroid plexus - which therefore hangs of the roof of the third ventricle Posterior wall: created from above downward by: Pineal gland, Posterior commissure, Commencement of cerebral aqueduct.

Answer 31

the medullary stria is a thin band of white matter located on the upper curvature of the thalamus -- these join posteriorly to form the habenular commissure the fibres start below the interventricular foramen, anteriorly- and passes posterioly in an upside down U shape alongside the anterior collumn of the fonix and so to the piriform area - the ependyma that makes up the roof of the thalamus passes over this on the thalamus

Answer 32

It’s a reasonably capacious blind diverticulum of the third ventricle, which goes posteriorly above the stalk of the pineal gland and below the tela choroidea. Pineal recess: It’s a small diverticulum which widens posteriorly between the superior and inferior laminae of the stalk of the pineal gland

Answer 33

- Is attached at the habenular commissure - lies above the superior colliculus and between the posterior thalamus, just below the splenium - no blood brain barrier - contains many corpora amylacea which calcify past age 40 - secretes melatonin - pineal stalk is also attached to the posterior commissure (which connects the two superior colliculi) above the entrance to the aqueduct

Answer 34

space formed by the hollowing of the the pineal stalk between the habenular and posterior commissures in the posterior wall of the 3rd ventricle

Answer 35

Medial part is covered with the ependyma of the third ventricle - The pulvinar is located on the posterior surface - is the large posterior convexity - the lateral geniculate body lies below the pulvinar on the posterior surface - medial geniculate body (relays auditory sensation) - superior thalamus is convex and triangular in outline (base is pulvinar - thins to apex at anterior pole) - superior and posterior surface are on the external surface of the diencephalon -- covered in pia mater - an oblique strip along the lateral margin of the superior surface lies in the lateral ventricle - body and tail of the caudate are in contact with lateral margin of the thalamus - the lateral surface of the thalamus is bevelled by the internal capsule --> descending fibres are in contact with thalamus (ascending fibres lateral)

Answer 36

cochlear nerves --> lateral lemniscus --> sublentiform part of internal capsule --> auditory cortex (below lateral fissure)

Answer 37

- there are lateral, medial, anterior and other nuclei with numerous subdivisions - ventroposterior part of the lateral nucleus - receives inputs from the medial and spinal lemniscus and reticular formation and projects to the sensory areas of the cortex - other parts from the lateral - receive fibres from the dentate nuclues (cerebellum) and globus pallidus and project to the motor nucleus - medial cell groups - receive fibres from the hypothalamus and corpus striatum and connect to the frontal lobe (emotion and memory) - anterior thalamic nucleus - recieves input from hypothalamus vis mammillothalamic tract and projects via the cingulate gyrus as part of limbic system - medial and lateral geniculate - hearing and vision

Answer 38

C shaped slit in the medial wall of the cerebral hemisphere - it extends from the interventricular foramen, around the thalamus and cerebral peduncle as far as the uncus - its convexity is contained by the body and crus (pillar) of the fornix, the fimbria and the hippocampus - concavity is contained by the thalamus (upper and posterior surfaces) and the tail of the the caudate nucleus - within the slit pia mater and ependyma come in contact with each other and both are invaginated into the lateral ventricle as the choroid plexus - in development the choroid fissure is on the roof of the cerebral vesicle

Answer 39

Venous pattern only follows arterial in places where there are no sinuses, other wise blood flows to sinus Cortical veins travel superficial, adherent to arachnoid mater, unlike arteries which travel in the depths of the sulcus - superolateral surfaces drain into the superior sagittal sinus via the superior cerebral veins - superior veins if they encounter a blood lake - will pass below the arachnoid on the surface of the brain - the superficial middle cerebral vein is adherent deep to the arachnoid mater and empties into the cavernous sinus - the superior and inferior anastomotic veins join the superficial middle cerebral vein to the superior sagittal and the transverse sinus

Answer 40

- deep middle cerebral vein drains veins from the insula and the depths of the lateral sulcus - ------- This vein drains into the basal vein - medial and inferior surfaces drained by the inferior cerebral veins into the nearest sinus (two sagittal and straight sinus) - ---- the exception to this is the anteriorly as there is no sinus at the margin of the falx --> drains into teh anterior cerebral vein - the anterior cerebral vein - returns around the genu of the corpus callosum alongside the anterior cerebral artery to join the basal vein (also drains orbital surface of frontal lobe)

Answer 41

- striate veins emerge from the anterior perforated substance - they drain the lower part of the corpus striatum - the striate veins join the deep middle cerebral vein and the anterior cerebral vein --> these three sources form the basal vein - basal vein passes around the cerebral peduncle below the optic tract and anterior choroidal artery, with the 4th nerve and posterior cerebral artery - ----- it receives veins from the posterior perforated substance and drains the lower part of the thalamus - basal veins (see card) - drains the lower part of the of the basal ganglia (upper are drained by internal cerebral vein) - internal cerebral vein

Answer 42

basal veins, also known as the veins of Rosenthal, are paired, paramedian veins which originate on the medial surface of the temporal lobe and run posteriorly and medially. Each vein passes lateral to the midbrain through the ambient cistern to drain into the vein of Galen with the internal cerebral veins. They are closely related to the posterior cerebral arteries (PCA).

Answer 43

receives blood from 3 sources 1+2) formed at the interventricular foramen by the meeting of the choroidal vein (draining the the choroid plexus of lateral ventricle) and thalamostriate vein (drains thalamus and caudate nucleus) 3) the veins of the septum pellucidum drain into the thalamstriate vein (drain the corpus callosum, adjacent cortex and head of the caudate) - the internal cerebral vein runs back in the tela choroidea and recieves veisn from the choroid plexus of the third ventricle - the two internal cerebral veins join to form the Vein of Galen (great cerebral vein) just beneath the splenium ---- the two basal veins drain into here

Answer 44

layers vary depending on region - motor cortex has many large pyramidal cells- layer V- giant pyramidal cells of Betz - sensory cortexes (post central, superior temporal (hearing) and calcarine sulcus (sight)) have many granular cells - all cells intermixed with neuroglial cells and their processes with blood capillaries In most parts - 6 layers of nerve cells layer I: plexiform layer: few cells, abundant fibres II: external granular III: pyramidal IV: internal granular V: ganglionic VI: multiform In layers IV and V often prominent strands of horizontal fibres - external and internal bands of Baillarger --- in visual cortex the external band is the Stria of Gennari White mater: bound together by neuroglia, myelin produced by oligodendrocytes

Answer 45

1) nuclei of the 3rd to 12th nuclei 2) named nucleus: colliculi, red nucleus, substantia nigra, pontine nucleus, olivary nucleus 3) reticular formation - intermingled with the other nuclei and tracts - forms vital centres that are not anatomically demonstrate able

Answer 46

midbrain - 3rd and 4th pons- motor nucleus of the 5th, 6th and 7th three sensory nuclei of the 5th are in the midbrain, pons and medulla 8th lies at the junction of the pons and medulla and lies in both medulla:9-12 11th also has a spinal part from cervical cord

Answer 47

- extends just above the level of the dorsum sellae of the sphenoid to a line that joins both apices of the petrous parts of the temporal bone - --- the upper part passes through the tentorial notch - cerebellum lies behind, - pineal body and splenium of the corpus callosum lie over the superior colliculus - midbrain consists of two halves - a left and a right. - the anterior (ventral) part of each is the base and yje dorsal part is the tegmentum - the aqueduct of sylvius runs through the tegmentum - the tectum is the part of the tegmentum dorsal to the aqueduct on the ventral surface - the bases (often called the crura) lie in a V shape, enclosing the posterior perforated substance of the diencephalon - converge at the pons dorsally the pons - two pairs of rounded eminences - the superior and inferior colliculus -- superior lie below the pineal gland - behind the posterior ends of the thalamus and roof of the 3rd ventricle and overlapped by the splenium of the corpus collosum lateral to superior colliculus is the medial geniculate body below the inferior colliculus is the superior cerebellar peduncle The oculomotor nerve leaves through the medial surface of the crus and passes forward between the posterior cerebral and superior cerebellar arteries in the interpeduncular cistern to reach the roof of the cavernous sinus trochlear nerve: leaves the dorsal midbrain, behind the inferior colliculus. This nerve curls around the lateral midbrain and passes through the posterior cerebral and superior cerebellar but more laterally, to run just below the free edge of the tentorium to enter the cavernous sinus at the site where the tentorium margins cross This nerve is unique in 3 aspects 1) smallest cranial nerve 2) only to emerge from posterior brain stem 3) only to decussate within brain stem The optic tract curls round the peduncle; ventral to this is the basal vein, on its way from the anterior perforated substance, along with the posterior communicating artery joining the carotid and posterior cerebral

Answer 48

- ventral surface (crus) is separated from dorsal (tegmentum) via a the pigmented Substantia nigra - - nigrostriatal fibres project to the caudate and putamen from here - at level of superior colliculus - red nucleus, fibres of the 3rd nerve - colliculi lie superficial on dorsal surface - the Superior Colliculus - general light reflexes - --- receive input from the retina, project to motor nuclei and spinal nerves by tectobulbar and tectospinal tracts - inferior contains sound reflexes from sound, projects via the same - grey matter around the aqueduct contain the nucleus of the 3rd, 4th and the mesencephalic nucleus of the 5th - the red nucleus is in the tegmentum- ventral to the third nucleus (in which its axons pass through) - ----- receives fibres from the dentate nucleus of the opposite cerebellum hemisphere via superior cerebellar peduncle - ------ efferent decussate at level of inferior colliculus and descend to the pontine nuclei and spinal cord via via rubrospinal tract - pretectal nuclei - lies cranial to superior colliculus at the junction of midbrain and diencephalon (pupillary light reflex) - oculomotor nucleus - lies in the midline, ventral to the aqueduct, in line with the other somatic motor nuclei (4th, 6th, 12th) - --- The edinger-Westphal lies near the midline in the cranial part of the nucleus --> fibres travel in 3rd nerve innervate the ciliary ganglion --> post ganglionic to sphincter pupilae and ciliary nucleus - --- third nerve fibres travel through red nucleus --> exit at medial base of peduncle - the medical geniculate body - dorsal surface of midbrain - the mesencephalic nucleus lies lateral to the aqueduct throughout whole midbrain - ---- proprioceptive reception of the muscles of mastication from mandibular branch of the trigeminal nerve and muscles of face - reticular formation - fragments of grey mater broken up by criss cross white matter bundles throughout the other defined nuclei

Answer 49

- trochlear nucleus lies caudal to the occulomotor, ventral to the aqueduct - --- the nerve passes dorsally and decussates just dorsally to the aqueduct - --- nerve emerges through the superior medullary velum, behind the inferior colliculus - mesencepahlic nucleus of 5th in periaqueductal grey

Answer 50

PCA and Superior cerebellar as they curl around the cerebral peduncle - medial and laterla central branches enter the crura to supply the substantia nigra and red nucleus, and the colliculi, periaqueductal grey and pineal body mor dorsally Venous drainage is via the basal vein as it passes around the peduncle -- some from the colliculi enter the great cerebral brain

Answer 51

- recognised by bulge - bulge curves to the side to sink into the cerebellum as the middle cerebellar peduncle - Only cranial nerve nerves from the pons are the large sensory root and small motor root-- their point of emergence marks the change from pons to peduncle - --- these two roots pass together in the posterior fossa below the tentorium and run over the groove on the petrous apex into the trigeminal cave in the middle cranial fossa - ventral surface has a midline groove with a bulge on either side - in the bulge is the pontine nuclei + fibres of corticospinal and cotriconuclear fibres - ventral surface lies on the clivus, seperated by prepontine cistern in which the basilar artery runs - superior cerebellar artery curls around the upper pons - --- the labyrinthine artery passes laterally to reach the internal acoustic meatus - 7th and 8th nerve exits at the junction of pons and medulla - 6th nerve runs upward to enter the dura on the clivus - Most laterally the flocculus of the cerebellum emerge from the lateral recess of the 4th ventricle, along with the choroid plexus in the cerebello-pontine angle - dorsal surface is concealed by cerebellum - aqueduct opens at the upper border of the pons into the 4th ventricle - the pontine part of the roof of the ventricle consists of white mater sheet of the superior medullary velum, attached at the sides to the superiro cerebellar peduncles. - ---- The lingula of the cerebellum lies on this

Answer 52

- ventral part - contains pontine nuclei - fibres from these emerge to cross to the opposite side and form the middle cerebellar peduncle - dorsal part contain nuclei of 5th to 8th nerves and salivary nucleus - motor nucleus of the trigeminal nerve is in the upper pons below the lateral part of the fourth ventricle-- fibres pass ventral and laterally to emerge as small motor root at junction of pons and middle cerebellar peduncle - lateral to motor nucleus is the main sensory nucleus - receives sensory roots subserving touch - ---- its caudal continuation into the lower pons- is the spinal nucleus- receives pain and temperature fibres - --- its cranial continuation is the mesencephalic tract of the trigenminal leading to the mesencephalic nucleus - for proprioception - lower pons is the abducens nucleus - lies near the midline just below the 4th ventricle, with the fibres of the facial nerve lying over this superficially to form the facial colliculus in the ventricular floor - ---- the facial nucleus lies deeper and away form the midline - the superior salivary nucleus- lies alongside the facial nucleus -- its nerves pass out in the nervus intermedius part of the facial nerve and reach the pterygo-palantine and submandibular ganglia - inferior salivary nucleus, lies below the superior just above the pontomedullary junction --> fibres join teh glossopharyngeal nerve tor each the otic ganglion

Answer 53

corticopontine fibres travel via the crus synapse with pontine nuclei --> pontine nucleus fibres decussates--> middle cerebellar peduncle --> cerebellum

Answer 54

- nuclei of vestibular lie in beneath the floor of the - lateral angle of the 4th ventricle in both pons and medulla the vestibular and cochlear nuclei are separate - The vestibular fibres emerge from the internal acoustic meatus and pass anterior to the inferior cerebellar peduncle (of the medulla) to synapse at vestibular nuclei, whose fibres then pass in the inferior peduncle --- the other fibres of the vestibular nuclei join the medial longitudinal bundle and connect with other extraoccular nuclei + cervical anterior horn cells for the vestibulo-occular reflexes - cochlear nuclei are mainly medullary but extend into the lower pons ---- they receive fibres from the spiral ganglia of the cochlear and send their axons to the dorsal and ventral cochlear nuclei ---- axons from the dorsal and ventral cochlear nuclei form the trapezoid body as they decussate - the upper parts of the dorsal nucleus of the vagis and nucleus of tractus solitarius extends into the pons - reticular formation lies dorsal to the pontine nucleus

Answer 55

pontine branches of the basilar some contribution from the SCA and AICA Venous return is into the inferior petrosal sinuses and basilar plexus

Answer 56

- lies vertically from a line joining the jugular tubercles of the occipital bone to the atlas - dorsally lies in the vallecula of the cerebellum - the closed part is the part continuous with central canal of the spinal cord - the open part contains the floor of the 4th ventricle - ventrally- the midline is grooved, with lateral convexities - the pyramids (contains corticospinal tracts) - lateral to the pyramid is the olive (underlies the olivary nucleus) - lateral to the olive is the inferior cerebellar peduncle - the last 7 cranial nerves- have relations to medulla - --- 6th exits between pons and pyramids - --- 7th exits between pons and olives - --- 8th exits at the junction between pons and inferior cerebellar peduncles - --- rootlets of 9th, 10th, 11th emerge lateral to the olives - ---- 12th - emerges as 2 groups of rootlets between the pyramid and the olive dorsal - open part - lower part of the roof of the 4th ventricle forms the upper par of the medulla - ----- roof of the ventricle is the ependyma and pia mater - at the lower corner of the diamond shaped floor the hypoglossal trigone is adjacent to the midline - --- the vagal trigone lies lateral to this - higher up on the lateral corner of the diamond is the vestibular area and the medullary striae in the closed part - 4th ventricle becomes narrowed as the central canal; - external dorsal surface shows two elevations - the gracile and cuneate tubercles and the less defined trigeminal tubercle

Answer 57

upper medulla (open) - olivary nucleus on ventral surface under the olives - ---- Is a C shaped group of nucleus -- fibres decussate across the midline and enter the inferior cerebellar peduncle as the olivocerebellar parthway - most of the nuclei in the medulla are below the floor of the 4th ventricle - -- hypoglossal nuclei lies below the hypoglossal trigone in the midline - ----- its axons exit as the nerve between the olive and pyramid - - the dorsal nucleus of the nucleus of vagus lies under the vagal trigone - lateral to hypoglossal - ------ fibres in DNotV contain motor cell bodies of the cardiac and visceral muscle and secetory motor fibres of the glands - --- more lateral are the nucleus tractus solitarius and spinal nucleus and tract of the trigeminal nerve - -------- NTS -- a tract of axons surrounded by nuclei in a circle- these nuclei meet on the lowest part of the open medulla to form a V shaped collection - --------- At the upper part receive taste from the corda typani (nervus intermedium of facial nerve), lingual branch of the glossopharynglea and internal laryngeal branch of the vagus - ----------- the rest of the NTS nuclei receieve afferent input from the glosopharyngeal, and vagus from thoracic and abdominal viscer, including the baro and chemoreceptors from the carotid body, sinus and aortic arch - ------------ these nuclei connect with the dorsal nucleus of vagus and reticualr formation for cough, sneeze, gag, vomiting reflexes - -at the dorsal edge lies the vestibular and cochlear nuclei most laterally as part of the 4th ventricle floor - --- at a deeper level lies the nucleus ambiguus and inferior olivary nucleus most ventral (see above) - --------- The nucleus ambiguus- contains motor cell bodies for skeletal muscle of the larynx, soft palate and oesophagus --> output via the vagus except the stylopharyngeus which is controlled by glossopharyngeal - ---------- upper part of the nucleus control palate, middle controls pharynx and oeseophagus, lower supplies larynx - ---------- fibres from nucleus join with NTS and DNotV to form rootlets emerging lateral to the olive --> contributing to vagus, accessory and glossopharyngeal nerves - - The spinal tract and nucleus of the trigeminal lies lateral to the NTS

Answer 58

- cuneate and gracile tubercles consisting off the gracile and cuneate nuclei lie dorsally in the lower medulla - ---- cell bodies receive sensory input from the cuneate and gracile tracts, their axons give rise to the medial lemniscus - some of the cuneate nuclei constitute the accessory cuneate nucleus whose fibres via the inferior peduncle form the cuneocerebellar pathway - provides some proprioceptive impulses from the upper limb - medial to the cuneate nucleus is the area postrema of the reticular formation--- contains vomiting centre and chemoreceptor trigger zone - ---- here there is no blood brain barrier - lowest part of medulla has pyramidal decussation - above pyramidal decussation --> decussation of sensory fibres forms medial lemniscus the medullary reticular formation is continuous with the pons and travels downwards into the spinal cord at the lateral margins of the central grey - - occupies area between olivary nuclues and floor of 4th ventricle and the other cell bodies - -- cell near near the NTS, constitute cardiac,r respiratory and vasomotor centres but are not anatomically demonstrateable

Answer 59

only nuclei are the gracile and cuneate nucleus | - rest is white matter tracts

Answer 60

ventral supply is off the vertebral and basialr arteries lateral and dorsal supply is via the Posterior inferior cerebellar ---- the anterior spinal artery of teh vertebral supplies the midline containing the pyramid, medial lemniscus and hypoglossal nucleus (the medial medullary syndrome) - paralysis of the tongue, hemiplegia on the same side and loses of touch on the opposite ----- lateral medullary syndrome (PICA)- loss of nucleus ambiguus- paralysis of pharynx on same side - dysphonia and dysphagia, uncrossed spinal tract and crossed spinal lemniscus results of loss of pain and temperature on the same side of teh body and face on the opposite, Horners syndrome- ipsilateral becasue disruption of descending SNS, vestibular nuclei-- nystagmus, vertigo, Nand V venous drainage to the occipital sinus dorsally and ventrally into the basilar plexus and inferior petrosal sinus --- medullary veins communicate with spinal veins

Answer 61

1) corticonuclear (facial muscle) 2) corticospinal 3) reticulospinal 4) vestibulospinal 5) corticopontine

Answer 62

- start in primary motor cortex in layer 5 of the cortex - pass through the corona radiata - corticonuclear fibres run through the genu of the internal capsule - some go straight to occulomotor and trochlear nuclei - others collect in the medial 3/5th of the crus of the midbrain and reach the other nuclei - most of the cranial nerve nuclei innervated are innervated bilaterally - -- the exception to this is the lower part of the facial nucleus which is innervate by the opposite cortex only

Answer 63

- corticospinal fibres lie in the anterior 2/3rds of the posterior limb of the internal capsule - they then occupy the central and lateral 3/5th of the crus of the midbrain peduncle, arm fibres medial and leg lateral - in the pons the fibres become broken up into small bundles among the pontine nuclei, visible as white strands on longitudinal sections - passing into the medulla, forms the pyramid anteriorly - in the medulla 85% of the fibres decussate in the pyramids to form the lateral corticospinal tract of the cord - the 15% that do not decussate continue down as the anterior corticospinal tract --> which eventually cross in the spinal cord - all finish in the ventral horn

Answer 64

- fontopontine fibres occupy the medial 1/5th of the crus - the temporo, occipito and parieto-pontine fibres occupy the lateral 1/5th of the crus - all synapse with the pontine nuclei - axons of teh pontine nuclei decussate in the pons to form the pontocerebellar fibres, which then travel in the middle cerebellar peduncle to the cerebellum

Answer 65

- The superior cerebellar peduncle joins at the midbrain tegmentum and decussates at the level of the inferior colliculi - synapse at the red nucleus at level of superior colliculus - efferent form the rubrospinal tracts which immediately decussate (in the ventral tegmental decussation) before passing downwards note: the dorsal tegmental decussation is formed by the smaller tectospinal tracts, directly dorsally in the tegmentum

Answer 66

- lies immediately ventral to the grey around the aqueduct - remains adjacent to the midline from the upper border of the midbrain to the upper cervical cord (all levels) - connects the vestibular nuclei with motor nuclei of 3rd, 4th and 6th for audiovisual reflexes and movements of the eyes, head and neck (which the tectospinal and rubrospinal tracts assist but descend no further than the Cervical spine

Answer 67

- lateral arises in the medulla reticular formation - anterior arises in the pontine reticualr formation - fibres are ill defined and mixed with the corticospinal fibres of the cord

Answer 68

- originates from the lateral vestibular nucleus and enters the cord - ends at anterior horn

Answer 69

- Begins at hypothalamus - fibres run in spinal lemniscus - ends at thoracolumbar horn located in medial brain stem

Answer 70

- Dorsal column decussates as the internal arcuate fibres --> synapses with cuneate and gracile nucleus - medial lemniscus begins in lower medulla from the gracile and cuneate nucleus - at first it is longitudinally located next to the midline, but as it passes upwards through the pons and midbrain it deviates to be lateral before reaching the thalamus - on its way up it is joined by the trigeminal lemniscus

Answer 71

- continuation of the lateral spinothalamic tract - lies near the middle of the lateral medulla and runs up the lateral and then dorsal edge of the medial lemniscus - becomes much smaller as gives fibres to reticular formation

Answer 72

- formed by the upgoing fibres of the trapezoid body (the decussating fibres of the cochlear nuclei at the ponto medullary junction - terminates on the inferior colliculus and medial geniculate body for auditory reflexes - both trapezoid body and lateral lemniscus contain cell stations which connect with extraocular nuclei via medial longitudinal bundle

Answer 73

- formed by incoming pain and temperature fibres from trigeminal nerve - passes downwards and synapses with the spinal nucleus - fibres from the spinal nucleus join the medial lemniscus

Answer 74

- lie in the lateral margin of the lower medulla - the posterior tract enters at the inferior cerebellar peduncle in the medulla - the anterior continues up to the superior cerebellar peduncle in the lateral brain stem

Answer 75

- lies midbrain to lower medulla - roof: tent shaped, covered by the cerebellum - -- the upper part of this roof is the superior medullary velum, covered by the superior cerebellar peduncles in the midbrain - -- the lower part of the roof is formed by the inferior medullary velum in the medulla (a thin sheet of white matter from the base of the flocculus) but the lower part is the pia mater only - --- the lower margins are attached at the cuneate and gracile tubercles - --- lower part of the roof is perforated in the midline (foramen of magendie - median aperture) --> CSF exits into the cerebellomedullary cistern The cavity of the 4th Ventricle is prolonged laterally around and behind the inferior cerebellar peduncle; here the roof is attached to the lower margins of the medullary striae - the lateral recess opens via the lateral aperture (foramen of Luschka), the lateral aperture opens anteriorly just behind the 8th nerve into the pontine cistern

Answer 76

- L shaped structure which indents the medullary part of the roof - commences at lateral aperture from a branch of the PICA, lying just below the flocculus - as the artery enters it indents the roof of the lateral recess, meets its fellow and turns down towards the median aperture, forming a T - Veins drain into the occipital sinus

Answer 77

- floor is diamond shaped - known as the rhomboid fossa - upper boundaries are the superior cerebellar peduncles, lower by the gracile and cuneate tubercles and above then the inferior cerebellar peduncles - midline groove- the median sulcus runs from the aperture of the aqueduct in the midbrain to just above the central canal - symmetrical both sides of this - at its widest part, the rhomboid fossa is trans versed by the medullary striae horizontally - these lie between the pontine and medullary part of the floor and are aberrant fibres from the pontine nuclei destined by the cerebellum via the inferior peduncle

Answer 78

- characterised by the median eminence (also a median eminence on the 3rd ventricle), a raised point next to median sulcus - the facial colliculus lies in its lower end - formed by the abducent nucleus + overlying facial nerve fibres - vestibular area lies at the floor of the lateral angle of the diamond - superior fovea - is a groove that lies between the facial colliculus and vestibular area, which leads up to the opening of the aqueduct - ---- the locus caerulus lies in the upper part of the fovea - pigmented blue due to noradrenalin

Answer 79

- smaller than pontine aprt - lateral angle is occupied by the lower part of the vestibular area - the inferior angle, contains the inferior fovea which passes up to the medullary striae to meet the edge of the vestibular area - the inferior fovea divides the floor into two smaller triangular area - --- the medial one, apex facing down is the hypoglossal trigione -- beneath lies the 12th nerve nucleus - --- the lateral triangle, apex upwards - between the hypoglossal and vestibular nuclei is the vagal trigone - overlies the dorsal nucleus of the vagus

Answer 80

70% produced by choroid plexus of lateral, 3rd and 4th ventricles total volume = 130mls, pressure is 130mm of water 30mls in the ventricle 100ml in the subarachnoid space (75ml spinal, 25ml cranial) CSF pressure is regulated by venous pressure, in that CSF pressure increases if venous pressure increases

Answer 81

2 motor: somatic and visceral lies near midline in floor of aqueduct - somatic motor: innervates superior, inferior and medial rectus and inferior oblique - visceral: edinger westpthal nucleus - cranial to somatic part--> ciliary ganglion --> sphincter pupillae and ciliary body

Answer 82

1x motor: somatic - near midline in the floor of aqueduct of midbrain, at level of inferior colliculi - innervates superior oblique

Answer 83

One motor and three sensory - motor brachial: off centre in the upper pons deep to the floor of the 4th ventricle. Controls muscles of mastication, mylohyoid and tensor palati - Sensory - 3 parts continuous throughout the whole brain stem - exiting at the upper cervical cord - ---- mesenchephalic - grey lateral to aqueduct of midbrain - proprioception of facial, mastication, tongue and orbit muscles - ----- main sensory: in lateral, upper part of pons, lateral to the motor nucleus. Touch sensation for trigeminal nerve distribution - ------ spinal nucleus - lower pons, through medulla and continuous in gelatinous substance of spinal cord. temperature and pain from the trigeminal nerve

Answer 84

1x motor | - somatic motor - near the midline of the pons, deep to facial colliculus. Innervates lateral rectus

Answer 85

2x motor, 2 x sensory - motor brachial: off centre in pons, deep and lateral to facial colliculus - facial muscles - visceral motor: superior salivary nucleus lies adjacent to facial nerve nucleus- pterygopalatine and submandibular ganglion innervation for lacrimation and saliva secretion - sensory brachial:

Central nervous system Flashcards

(109 cards)