Intro: Structures of the CNS Flashcards
neurons are formed by what major components?
how do these major components create the architecture of the nervous system?
- perikaryon (cell body / nuclei): the processing center - forms the gray matter
- axon: output portion of neuron - forms the white matter
what forms the gray matter in the brain?
what is the role of gray matter?
neuronal cell bodies (perikaryons)
are the “processing centers”
what forms the white matter in the brain?
what are the roles of white matter?
axons
are the “outflow tracts” (no processing occurs here)
what occurs during the embryological development of the brain?
why is this important?
during embryonic development, the brain undergoes two 90 degree bends, forming the cervical and cephalic flexures
this results in anatomical planes that change around the midpoint of the brain
- above midpoint: dorsal-ventral = superior-inferior
- below midpoint: dorsal-ventral = posterior-anterior
label
what is cerebelli tentorium and its
- attachments
- anatomical relations
- roles
- Tentorium cerebelli: a sheet of dura that
- covers the cerebellum
- attaches to the:
- inferior clinoid processes
- petrous ridge
- separates the brain into two compartments:
-
Supra-tentorial: brain that sits above it:
-
prosencephalon, made of the
- telencephalon (superfiical portion)
- diencephalon (deep portion)
-
prosencephalon, made of the
-
Infra-tentorial (posterior fossa): brain that below it
- cerebellum
- brainstem
-
Supra-tentorial: brain that sits above it:
what is the prosencephalon composed of?
where does it exist with the cerebri tentorium?
= supratentorial
- made of the
- telecephalon (superfiical component)
-
diencephalon (deep component), which contains the
- hypothalamus (ventral / inferior part)
what portions of the brain are infratentorial?
aka posterior fossa
- cerebellum
- brainstem
what is the brainstem composed of?
- midbrain
- pons
- medula oblongota
mamillary body
- define
- anatomical relations
- roles
- definition: paired projections coming off the ventral (in anat, inferior) surface of the hypothalamus (ventral component of the diencephalon)
- anatomic relations:
- is contained within the interpendular fossa
- is immediately caudad (in anatomy, post) to the pituitary infundubilum, another projection off the ventral hypothalamus
- roles: is in line with the cerebelli tentorum, & can thus also be used to designated supra vs intra tentorial
label
- infratentorial / posterior fossa:
- 2,3,4 = brainstem
- 1= cerebellum
- mamillary body & infundulum: on ventral (anat = inf) portion of hypothalamus (diencehpalon) th mamillary body more caudad (anat = post) & superior
what is the cerebral cortex?
describe its structure and why this is important?
- cerebral cortex = superficial component of the prosencephalon, i.e., the telencephalon.
- organized into a highly convoluted series of ridges that allow for more surface area:
- gyri = ridges: are grey matter, thus packed nuclei
-
sulci = in between ridges
- deep sulci are fissures
- organized into a highly convoluted series of ridges that allow for more surface area:
what are gyri?
ridges forming the cerebral cortex (outer, superfiical prosencephalon) that are made of grey matter (nuclei)
the central sulcus
- has what path?
- forms what anatomical compartments?
- fissure (deep sulcus) that runs superior-inferior in a frontal lobe & parietal lobe gyri, intersecting the longtiduninal fissure
- creates the following anatomical compartments:
- Frontal lobe: anything rostral (ant in anat) to central sulcus
- Parietal lobe: anything from the central sulcus to the -> parietal occipital fissure
- creates the following anatomical compartments:
the longitudinal fissure
- has what path?
- divides the brain into what anatomical compartments?
- pathway: runs along the sagittal midline, i.e. rostral -> caudal (ant to post in anat), ultimately intersecting the longitudinal fissure, dividing the cerebral cortex into
- right hemisphere
- left hemisphere
the lateral fissure
- has what path?
- divides the brain into what anatomical compartments?
- pathway: runs along the rotral 3/4th (ant in anat) of the lateral surface of the cerebral cortex
- comparments - n/a
the parieto-occipital fissure
- has what path?
- divides the brain into what anatomical compartments?
- pathway: course superior-inferiorly between parietal and occipital gyri, perpendicular to and just caudad from (post in anat) the lateral fissure (only visible on medial side)
- creates the following anatomical apartments:
- parietal lobe: anyhing in between central sulcus and parieto-occipital fissure
- occipital lobe: anything caudad (post in anat) to it
what is the coroada radiata?
what are the components of the coronada radiata?
= mass of axons (i.e., white matter) coming of the gyri (grey matter) covering off the cerebra cortex. The corona radiata runs mainly to 3 places
- corpus callosum: u-shape running from between hemispheres
- internal capsule (IC): group of axons running up & down (bi-directional) from the brainstem to the cerebral cortex
- accessory fibers: interconnect ispilateral cortical regions
- insula: on lateral surface, near gyri
corpus collosum
- definition
- has what anatomical associations?
- definition: portion fo the corona radiata (white matter) bridging the cerebral hemispheres
- association:
- cingulate gyrus: superiorly, parallel its dorsal surface
- lateral ventricles: inferiorly
- septum pellicudim: an extension of of its ventral (inferior surface) that separate the lateral ventricles
internal capsule
- definition
- has what anatomical associations?
- definition: portion the corona radiata (white matter) with sup-inf fibers to the brainstem & an arrow shape rosral-caudally
- asssociations:
- thalamus: medially, between IC & 3rd ventricle
- caudate nucleus: medially, in betwen IC & lateral ventricles
- basal ganglia: laterally, between IC & insula
insula
- definition
- anatomical relations?
- definition: portion of the corona radiata that is a deep infolding on the lateral cerebral cortex
- anatomical relations:
- basal ganglia (other than the caudate nucleus): medially, between insul & IC
the internal capsula can be further divdided into what segments?
- anterior crus
- genu
- posterior crus
label
ventricles of the brain
- definition
- list each one
- definition: fluid-filled chambers containing CSF
- lateral ventricles (1 & 2), 3rd ventricle, 4th ventricle
lateral ventricles
- location within the brain
- components
- key associations
- = ventricles 1, 2: (are paired)
- location: sit deep within the cerebral cortex
- components: are subdivided into the
- anterior horn: in the frontal & parietal lobes
- occipital horn: in the occipital lobe
- inferior horn: in the temporal lobe
- associations:
- interventricular foramen / foramen of monroe: an inferior projection each ventricle gives of - is connected to the 3rd ventricle
- corpus collosum: above ventricles
- septum pellucidum: separates the ventricles
- other: LARGEST VENTRICLES (contain most of CSF)
what is the foramen of monroe? describe it.
= interventricular foramen
- a projection coming off the ventral side of each lateral ventricle to connect them to the 3rd ventricle
3rd ventricle
- location within the brain
- components
- key associations
- location: in the diencephalon + midbrain (brainstem)
- components:
- most of ventricle: within the dienceaphlon
- cerebral adeqeduct: narrow extension that moves cadually (post) & extends through the brainstem to open ventral (ant) cerebellum
- key associations
- interventricular foramen / foramen of monroe
- 4th ventricle: via cerebral adequate
what is the cerebral aqeduct? describe it.
the portion of the 3rd ventricle that extends cadually from the diencephalon to
- cross the brainstem
- open in front of cerebellum
4th ventricle
- location within the brain
- components
- key associations
- location: ventral to the cerebellum
- components: n/a
- associations: is continuous with the central canal of the spinal cord
the central canal is continuous with..?
the 4th ventricle
what is the cingulate gyrus?
a portion of the cerebral cortex that parallels the dorsal surface of the coropus collosum
what is the septum primidum?
a projection off the ventral surface of the corpus collosum which separates the lateral ventricles
what comprises the diencephalon?
supraventricular
- made largely of the
- thalamus
- hypothalamus (ventrl / inferior)
- plus the epithalamus: gives off pineal gland
what are the anatomical relations of the thalamus?
- is dorsal (superior) to the hypothalamus
- is ventral (inferior) to the lateral ventricles*
- is lateral to the 3rd ventricle
- is medial to the internal capsule
what are the basal ganglia?
where are they located in the brain?
- basal ganglai are sections are gray matter (nuclei) that are split up by the internal capsule. are divided into three main components
- caudate nucleus: between IC & lateral ventricles
- remainder: between IC & insula
- globus pallidus - more medial
- putamen - more lateral
describe the anatomic associations of the caudate nucleus
piece of basal ganglia between the internal capsule (anterior crus) and lateral ventricles
- lateral to lateral ventricles
- medial to internal capsule
describe the anatomic associations of the globus pallidus
piece of basal ganglia in between the internal capsule and insula
- lateral to internal capsule
- medial to putamen
describe the anatomic associations of the putamen
piece of basal ganglia in between the internal capsule and the insula
- medial to the insula
- lateral to the globus pallidus
list the three prominent features coming off the ventral surface of the hypothalamus & their relationship to one another
-
from rostral -> caudal (ant to post in anatomy)
- optic chiasm
- infundibulum (connection of hypothalamus to pituitary)
- mamillary bodies
note the mamillary bodies also exist within the intepeduncular fossa*
what are the cerebral peduncles?
what their pertinent anatomical associations?
- are the terminal portions of the internal capsule (white matter)
- the region between the cerebral peduncles forms the interpenducular fossa, within which the mamillary bodies (caudal-most feature of ventral hypothalamus( lie
what is the uncus?
what are its pertinent anatomic associations?
- definition: the uncus is a rounded prominence of the cerebral cortex
- associations: projects towards the optic chiasm
label
what forms the hippocampus?
a tight coil of cerebral cortex continuing from the uncus
the cerebral aqueduct creates what anatomical compartments?
(caudal most part of the 3rd ventricle)
- since the cerebral aqueduct extends through the midbrain (the rostral most part of the brainstem), it divides the midbrain into a dorsal and ventral portion
- tegmentum - ventral (anterior in this case)
- tectum - dorsal (posterior in this case)
label
tectum
- anatomical location
- components
- associations
- the dorsal portion of the mibrain, designated by the cerebral aqeduct
-
components, from rostral / superior -> caudal / inferior:
- pineal gland (part of diencephalon)
-
corpora quadrigemina, made of:
- superior colliculi: rostral / superior
- inferior colliculi: caudal / inferior
- associations:
- inferior / posterior to thalamus
- dorsal to tegmentum
corpora quadrigemina
- location
- components
- makes up a large portion of the tectum, the dorsal midbrain
- componnets:
- superior colliculi: rostral / superior
- inferior colliculi: caudal / inferior
label
diencephalon, \superior -> inferior:
- epithalamus: gives off pineal gland (enters tentum portion of midbrain, forming the most superior component)
- thalamus: in between IC and 3rd ventricles
- hypothalamus: contains lower portion 3rd ventricles
where is the 4th ventricle with respect to the tectum?
inferior
where is the thalamus with respect to the tectum?
superior / anterior
what is the crus cerebri?
what are its pertinent anatomic associations?
- crus cerebri: most external portion of the cerebral peduncles, which are the most external portion of the internal capsule
- associations:
- are lateral to the mamillary bodies
- are ventral to the tegmentum (in midbrain, deep cerebral peduncles formed by substantia nigra, external cerebra penduncles formed by crus cerebri)
tegmentum
- location
- components
- anatomic associations
- location: ventral portion of midbrain, designated by cerebral aqueduct
- features: from deep / superior -> superficial / inferior
- red nuclei - contains red iron pigment
- substantia nigra - specialized nucleus that produces black pigment
- crus cerebri - external most portions of cerebral peduncles
- associations:
- ventral to: tectum
- deep to: crus cerebri
what structure lies ventral to the tegmentum?
the crus cerebri (external most portion of the cerebral peduncles, thus the internal capsule)
label
pons
- definition
- components
- associations
- definitions: are the middle segment of the midbrain
- components:
-
basis pontis: ventral expansion comprising bulk of the pons, contains
- pontine nuclei
- pontocerebral tracts / fibers
-
superior / inferior pontine sulci: dermarcate basis pons
- contain cranial nerves
-
basis pontis: ventral expansion comprising bulk of the pons, contains
- associations:
- superior-inferior line:
- inferior to the midbrain
- superior to the medulla oblongota
- anterior-posterior line: the center of the pons ventral to the 4th ventricle, which is directly ventral to the cerebellum
- superior-inferior line:
label
superior & inferior pontine sulcus - cranial nerves
basis pontis - pontinue nuclei & pontocerebellar fibers
where are the pontocerebellar fibers found?
- found in the basis pontis (ventral expansion of pons)
- can also deuccusate across the midline to form the middle cerebellar peduncle, which rests dorsal to the pons
cerebellum
- architecture
- copmonents
- anatomic associations
- components:
-
is organized into gray & white matter like the brain
-
cerebellar cortex - gray matter
- outer layer
- organized into “plates” called folia
-
arbor vitae - white matter
- inner cortex
- made of deep cerebellar nuclei
-
at ventral margin, arbor vitae radiate to form three cerebellar
- superior
- middle
- inferior
-
cerebellar cortex - gray matter
- vermis: divides cerebellar hemispheres
-
is organized into gray & white matter like the brain
- associations - is dorsal to the expanded 4th ventricle
label, note important features
label
what forms the cerebellar peduncles?
what do the cerebellar peduncles connect to?
formed by outward radiations of arbor viate (white matter) the ventral margin of cerebellum. each one interacts with a different section of the brainstem
- superior cerebellar peduncle - connects with red nucleus (tegmentum, midbrain)
- middle cerebellar peduncle - connects with pontine nucleus (pons)
- inferior cerebellar peduncle - connects with medulla oblongota
medulla oblongota
- anatomic location
- components
- associations
- is the lowest segment of the brainstem
- components:
- ventral:
- medullary pyramids (paired)
- olive bodies - lateral
- dorsal:
- gracile tubercles - medial
- cuneate tubercles - lateral
- ventral:
- associations:
- inferior to pons
- ventral to the floor of the 4th ventricle: the caudal (inferior) borders of the 4th ventricle are formed by demarcations on the dorsal medulla oblongota:
- gracile tubercles - medial
- cuneate tubercles - lateral
label
label
- can tell this is the dorsal face based off tectum corpora quadrigemina: superior & inferior colliculi
- gracile & cuneate tubercles form caudal (inferior) borders of 4th ventricle
what cranial nerves exit in proximty to the pons & medulla? explain their specific locations
- pons - CN 5-8: exit thorugh the inferior pontine sulcus
- medulla - CN 9-12: exit between the ventral pyramids and olives
