anatomy of cerebrum & cerebellum Flashcards
the R and L hemispheres contain:
a deep longitudinal fissure that contains the corpus callosum
the hemispheres = enveloped by:
the meninges (protection), where cerebrospinal fluid circulates
the grey matter forms the:
(a collection of nerve cell bodies) outer layer surface of cerebral hemispheres
the white matter:
(myelinated axons and forms a bulk of deeper structures), connects various areas of the cerebrum together (structurally + functionally)
what is the only area that can be called the cerebral cortex ?
outer grey matter layer
the cerebrum is derived embryologically from:
telencephalon
what is the telencephalon/ cerebrum:
region of the brain that includes the cerebral cortex and the hippocampus and the basal ganglia
diencephalon =
thalamus + hypothalamus + epithalamus + metathalamus
allocortex ?
includes: - archicortex: has the hippocampus + dentate gyrus
- paleocortex: includes olfactory cortex
each cerebral hemisphere has 6 lobes:
frontal + parietal + occipital + temporal + insula (central) + limbic
- among 2 cerebral, one is dominant by its functions, language speech + comprehension
the cerebrum is full of:
grooves:
the central sulcus separates:
frontal motor cortex from parietal sensory cortex
the lateral (sylvian) sulcus separates:
the frontal lobe and the temporal lobe anteriorly and the parietal and temporal lobes posteriorly
cingulate sulcus separates:
cingulate gyrus and the sup frontal and parietal gyrus
parieto-occipital sulcus separates:
the parietal lobe and the occipital lobe
the calcarine sulcus divides:
the occipital lobe horizontally into cuneus superior and lingual inferior gyus
sulci and gyri of frontal lobe:
sulci: precentral + sup frontal + inf frontal + lateral
gyri: precentral + middle frontal + sup frontal + inf frontal + pars opercularis + pars orbitalis
OR
the anterior centoral (precentral) gyrus, the 1st frontal or superior, the 2nd frontal or middle, the 3rd frontal or lower (slide 26)
para central lobule = (higher center for micturition and defecation)
continuation of precentral and postcentral gyri (It is formed by the union of the precentral and postcentral gyri, extending from the frontal lobe into the parietal lobe)
PS: pre-central = anterior to central sulcus + in frontal lobe and post-central = posterior to central sulcus = in parietal lobe
Isthmus =
narrow region between splenium and calcarine sulcus
sulci and gyri of temporal lobe:
sulci: inf temporal sulcus, post ramus of lat sulcus, sup temporal sulcus
gyri: sup temporal gyrus, inf temporal gyrus (in the extremity of the first temporal furrow by AREA OF WERNICKE responsible for the understanding of language), middle temporal gyrus
OR
the 1st temporal, superior. the 2nd temporal, middle the 3rd temporal, inferior. the 4th temporal, is located on the lower face. the 5th temporal, the most internal, is called the convolution of the hippocampus. Its anterior end curves into a hook, it is the uncus of the hippocampus.
sulci and gyri of parietal lobe:
sulci: central (roland), lateral (sylvius), parieto-occipital
gyri:
✓the postcentoral gyrus
✓the superior parietal or
the 1st parietal
✓the inferior parietal or
the 2nd parietal.
sulci and gyri of occipital lobe:
sulci: internal and external
perpendicular sulci.
gyri: cuneus, paraterminal gyrus, medial frontal gyrus, cingulate gyrus, precuneus, lunate, arcus gyrus, supp occipital gyrus, inf occipital gyrus parolfactory gyrus
OR
the 1st superior occipital. the middle 2nd occipital.the lower 3rd occipital. the 4th and 5th occipital are located on the underside the 6th occipital, called cuneus, occupies the internal face
sulci and gyri of inferior surface: (orbital + tentorial parts)
sulci: orbital, olfactory, lateral, occipito-temporal (med + lat), uncus, collateral sulcus, rhinal
gyri: lat occipital gyrus, lingual gyrus, lat orbital gyrus, medial orbital gyrus, gyrus rectus, ant orbital gyrus, post orbital gyrus, medial occipital gyrus, lat occipital gyrus,
Cerebrum = Separated from the cerebellum by
the tentorium of the cerebellum.
cerebrum = separated from brainstem by:
transverse fissure of BICHAT: space delimited between the brainstem inside and the cerebral hemisphere outside
Diencephalon encloses the:
3rd ventricle + thalamus + hypothalamus
what is the diencephalon?
Posterior part of of the forebrain that connects midbrain with cerebral hemispheres
cerebrum infrastructure: (united by?, separated incompletely by?)
*United by the interhemispheric commissures
*Separated incompletely by the longitudinal fissure of the brain: falx cerebri.
Falx cerebri
crescent-shaped invagination of the dura mater which separates the left and right cerebral hemisphere
foramen of Pachionni
orifice delimited by the small circumference of the tentorium cerebelli, where the junction between the diencephalon and the mid brain is located
cerebral cortex =
surface of the brain (with the lobes)
The parieto-occipital sulcus:
separates occipital and parietal lobes
The pre-occipital notch:
inconstant, limiting the occipital lobe in front, marks the boundary between the temporal and occipital lobes of the brain. It is an anatomical landmark
insular lobe:
folded deep within the lateral sulcus
The calloso-marginal fissure:
parallel to the corpus callosum
The calcarine fissure: (slide 23)
a long horizontal groove extending from the occipital pole of the brain to the lower end of the internal perpendicular fissure, on the internal face of the hemisphere, and separating the fifth occipital gyrus from the sixth.
(1; 2 et 3 c’est supp, middle et inf occipital gyri et les autres sont à côté)
Insula lobe:
*located at the bottom of the Sylvian fissure.
*It is divided into two lobules by a deep groove.
*The anterior has 3 convolutions and the posterior has 2.
corpus callosum:
forward: the genu which ends in the beak (rostrum)
Backward: the splenium
Fornix =
under corpus callosum (ac les balles)
represents the largest single pathway of the hippocampus, connecting it to various subcortical structures.
*located in the concavity of the corpus callosum
*Anteriorly, it bifurcates into two anterior columns which join the mammillary bodies.
*backward, we have the two posterior columns which end at the hippocampus
telencephalic commissures: (c’est quoi + anterior et posterior + functions):
(papillon devant fornix): *The commissures are bundles of white matter that unite the two cerebral hemispheres
- The anterior white commissure: in front of the fornix and the knee of the corpus callosum
- The posterior white commissure: passes under the epiphysis in the posterior wall of the third ventricle
- Functions: Cognition, memory, emotions
grey matter location:
➢Peripheral cerebral cortex
➢The deep basal ganglia
white matter location:
centrium ovale+ capsules
what ventricles communicate with the 3rd ventricule through the foramen of M…
The lateral ventricles which communicate with the third ventricle through the foramens of MONRO
gray matter function:
Production of thoughts, Behavoral control. Perception of the outside world, interprets sensory info from various parts of the body
cerebral cortex functions:
Interprets sensory
information from various
parts of the body
➢Production of thoughts.
➢Behavoral control.
➢Perception of the outside worl
basal ganglia: (slide 43)
*Three pairs of main nuclei: The caudate nucleus
lenticular nucleus The tonsillar nucleus
*Two pairs of accessory nucleus: locus niger Subthalamic nucleus
basal ganglia nuclei:
- The basal ganglia consist of five pairs
of nuclei:
➢ caudate nucleus
➢ Putamen
➢ globus pallidus
➢ subthalamic nucleus (diencephalon)
➢ and substantia nigra (mesencephalon) - Striatum, which further consists of
the:
– Dorsal striatum, made by the caudate
nucleus and putamen
– Ventral striatum, composed of nucleus
accumbens and olfactory tubercle (this
part of the striatum is considered part
of the limbic system)
caudate nuclei relationships: (slide 47)
- The head of the nucleus
contributes to the lateral wall of
the lateral ventricle. - The tail of the caudate nucleus
forms the roof of the inferior horn
of the lateral ventricle. - It arches over the ventral surface
of the thalamus, enters
the temporal lobe and terminates
by connecting with the amygdala. - The rostral portion of the caudate
nucleus is continuous with the
putamen, and inferiorly it’s
bordered by nucleus accumbens.
putamens relationships:
- It is the most lateral of the
basal ganglia on the axial
section of the brain. - The putamen lies laterally to
the globus pallidus and
medially to the external
capsule, covering it like a
shell and extending both
rostrally and caudally. - It is encircled by the caudate nucleus, from which it is separated by the internal capsule.
globulus pallidus relationships: (slide 49)
- The globus pallidus is a paired
subcortical structure, situated
medially to the putamen - It is divided by a vertically
placed sheet of white matter,
the medial (internal) medullary
lamina, into external (GPe) and
internal (GPi) segments
subthalamic nucleus relationships:
- The subthalamic nucleus lies at
the junction of
the diencephalon and midbrain - ventral to the thalamus and
ventro-lateral to the red nucleus. - Anteriorly its bordered by the
substantia nigra and medially by
the internal capsule. - It’s a neurostimulation target in
parkinson’s disease
substancia nigra relationships:
within the
anterior part of the midbrain,
between the cerebral peduncle
and tegmentum of the midbrain.
* Despite its location in the
midbrain, function-wise it is
considered part of basal ganglia.
* The substantia nigra consists of
two parts with very different
connections and functions:
the pars compacta (SNc) and
the pars reticulata (SNr)
* It divides the cerebral
peduncles from the
tegmentum within both sides
of the midbrain.
* Dorso-medially it is bordered
by the subthalamic and red
nuclei, and laterally by
the medial lemniscus and
the geniculate bodies.
basal ganglia functions: (+ what it functions with etc…)
- responsible primarily for motor
control, as well as other roles such as motor learning, executive functions and
behaviors, and emotions. - They form a part of the extrapyramidal motor system and work with the pyramidal and limbic systems.
- Their proper functioning requires dopamine to be released at the input nuclei.
- It divides the cerebral
peduncles from the
tegmentum within both sides
of the midbrain. - Dorso-medially it is bordered
by the subthalamic and red
nuclei, and laterally by
the medial lemniscus and
the geniculate bodies.
pyramidal tract:
*The corticospinal tract or the pyramidal tract, is the major neuronal pathway providing voluntary motor function.
*The corticospinal tract originates primarily from the primary motor cortex
*The corticospinal tracts come together travel through the internal capsule and cerebral peduncles. The bundles then travel down to the brainstem.
*A majority of its fibers decussate to the contralateral side within the medulla then continues to travel down the spinal cord to provide innervation to the distal extremities and muscle groups.
hemispheres control: (R + L hemispheres functions)
Each hemisphere controls the opposite side of the body. If a stroke occurs on the right side of the brain, your left arm or leg may be weak or paralyzed.
the left hemisphere controls speech, comprehension, arithmetic, and writing.
The right hemisphere controls creativity, spatial ability, artistic, and musical skills.
*The left hemisphere is dominant in hand use and language in about 92% of people.
frontal lobe functions:
Personality, behavior, emotionsJudgment, planning, problem solving
Speech: speaking and writing (Broca’s area)
Body movement (motor strip)
Intelligence, concentration, self awareness
temporal lobe functions:
Understanding language (Wernicke’s area)
Memory
Hearing
Sequencing and organization
parietal lobe functions:
Interprets language, words
Sense of touch, pain, temperature (sensory strip)
Interprets signals from vision, hearing, motor, sensory and memory
Spatial and visual perception
occipital lobe functions:
Interprets vision (color, light, movement)
cerebrellum = connected to brainstem by:
by three fibre tracts known as cerebellar peduncles
role of cerebrellum:
motor movement regulation,
tonus and balance control
location of cerebellum: (inferior to truc lalala)
in the posterior cerebral
fossa
- inferior to the tentorium cerebelli
- behind the pons and medulla oblongata
- separated from these structures by cavity
of fourth ventricle
PS: two large lobes called cerebellar hemispheres. They are
united to each other by a median portion, vermis.
fissures that divide the cerebellum:
*The primary fissure divides the
smaller anterior and larger posterior lobes
*The posterolateral fissure demarcates the flocculonodular lobe
*The horizontal fissure divides the cerebellum into superior and inferior portions
the lobes of the cerebellum
➢The anterior lobe
➢The posterior lobe
➢The flocculonodular lobe. It is the oldest part of the brain in evolutionary terms (archicerebellum) and participates mainly in balance and spatial orientation. (the little one internally)
grey + white matter locations:
➢on the surface of the cerebellum. It is tightly folded,
forming the cerebellar cortex.
➢the four cerebellar nuclei (the dentate, emboliform,
globose, and fastigi nuclei).
* White matter: located underneath the cerebellar
cortex and between the cerebellar nuclei, it called
cerebellum tree of life
* Ependymal canal: fourth ventricle
relationships of cerebellum
- Superior
➢ the great cerebral vein of Galen
➢ the straight sinus (in the midline of the tentorium cerebelli)
➢ the occipital lobe is also superior to the cerebellum. - Anterior
➢ the brainstem
➢ the fourth ventricle.
➢ the distal end of the cerebral aqueduct of Sylvius, and the corpora
quadrigemini - Downward:
➢ the foramen magnum
➢ the cisterns - Posterior and lateral
➢ the occipital bone and its overlying layer of dura mater
➢ The sigmoid sinuses are also found inferiorly
➢ the occipital sinus (if present) and the confluence of sinuses are
both posteriorly related.
cerebellum vasculature
three paired arteries:
* Superior cerebellar artery (SCA)
* Anterior inferior cerebellar artery (AICA)
* Posterior inferior cerebellar artery (PICA)
* The SCA and AICA are branches of the basilar
artery, which wraps around the anterior aspect
of the pons before reaching the cerebellum.
The PICA is a branch of the vertebral artery.
* Venous drainage of the cerebellum is by
the superior and inferior cerebellar veins. They
drain into the superior petrosal, transverse and
straight dural venous sinuses.
functional subdivisions of cerebellum:
- Vestibulocerebellum. The vestibulocerebellum comprises
the flocculonodular lobe and its connections with the lateral vestibular nuclei: postural maintenance. - Spinocerebellum. The spinocerebellum comprises the vermis and the intermediate zones of the cerebellar cortex, it receives major inputs from the spinocerebellar tract. It is involved in the integration of sensory
input with motor commands to produce adaptive motor coordination. - Cerebrocerebellum. its extensive connections with the cerebral cortex. It is involved in the planning and timing of movements
cerebral hemispheres (what it is composed of + embryological unfolding):
telencephalon: cortex, subcortical structures, lateral ventricles
what is the tentorium cerebelli ?
is a thick, dura mater (outermost membrane covering the brain) fold that separates the cerebellum (located in the lower part of the brain) from the occipital lobes of the cerebrum (upper brain)
which sulci is the parietal lobe located between:
central, lateral and parieto-occipital
AREA OF WERNICKE = (what makes 2nd temporal furrow):
- responsible for the
understanding of language. - Wernicke’s area is a critical language
area in the posterior superior temporal
lobe connects to Broca’s area via a
neural pathway. - located in the posterior part of the superior temporal gyrus in the dominant cerebral hemisphere
temporal lobe location:
below the frontal and parietal lobes and forward of the occipital lobe
cerebellum relationships:
➢inferior to the tentorium cerebelli
➢behind the pons and medulla oblongata
➢separated from these structures by cavity of fourth ventricle.
cerebellum functions:
➢Motor mouvement control
➢Balance regulation
➢muscle tone control
Some of the fissures are used as
landmarks to divide the cerebellum
into lobes:
*The primary fissure divides the
smaller anterior and larger posterior
lobes
*The posterolateral fissure demarcates the flocculonodular lobe
*The horizontal fissure divides the
cerebellum into superior and inferior
portions
cerebellum 3 lobes:
➢The anterior lobe
➢The posterior lobe
➢The flocculonodular lobe. It is the oldest part of the brain in evolutionary terms (archicerebellum) and participates mainly in balance and spatial orientation
(Each lobe is deviated by secondary furrows into lobules, then into lamellae by tertiary furrows)
the 3 cerebellar peduncles that connect cerebellum to brainstem:
➢Superior peduncle connects cerebellum with midbrain
➢middle with pons
➢inferior with medulla oblongata
grey VS white VS ependymal of cerebellum (location):
- Grey matter located:
➢on the surface of the cerebellum. It is tightly folded, forming the cerebellar cortex.
➢the four cerebellar nuclei (the dentate, emboliform,
globose, and fastigi nuclei). - White matter: located underneath the cerebellar cortex and between the cerebellar nuclei, it called cerebellum tree of life
- Ependymal canal: fourth ventricle
cerebellum relationships (part2):
- Superior
➢ the great cerebral vein of Galen
➢ the straight sinus (in the midline of the tentorium cerebelli)
➢ the occipital lobe is also superior to the cerebellum. - Anterior
➢ the brainstem
➢ the fourth ventricle.
➢ the distal end of the cerebral aqueduct of Sylvius, and the corpora quadrigemini - Downward:
➢ the foramen magnum
➢ the cisterns - Posterior and lateral
➢ the occipital bone and its overlying layer of dura mater
➢ The sigmoid sinuses are also found inferiorly
➢ the occipital sinus (if present) and the confluence of sinuses are both posteriorly related.
cerebellum vasculature (part 2):
Superior cerebellar artery (SCA)
* Anterior inferior cerebellar artery (AICA)
* Posterior inferior cerebellar artery (PICA)
* The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum.
The PICA is a branch of the vertebral artery.
* Venous drainage of the cerebellum is by the superior and inferior cerebellar veins. They drain into the superior petrosal, transverse and straight dural venous sinuses. (go all into jugular vein (pr l’endroit))
centrum semioval:
is a paired mass of white matter superior to the lateral ventricles and corpus callosum, present in each of
the cerebralhemispheres, subjacent to the cerebral cortex
location of capsules (white matter) (slide 41):
✓ Internal: between the thalamus and
cap of caudate nucleus medially
and the lenticular nucleus laterally
✓ external: between the lenticular
nucleus medialy and the claustrum
laterally
✓ Extreme : outside the claustrum
functions of each lobe:
slide 56
R + L hemisphere functions:
slide 57
