Week 4: Brain & Spinal Cord, Blood supply/venous drainage, cranial nerves Flashcards
features of the cerebrum
separated intocerebral hemispheres R and L - this is marked by thelongitudinal cerebral fissure
Superficial surface of the brain, which constitutes the cerebral cortex, is characterised by
sulci (grooves)
glyri (ridges)
these increase SA
features of the cerebellum
consist of two lateral hemispheres that are united the vermis
what are the ridges of the cerebellum called
folia
what are the parts of the brainstem
Medulla Oblongata
Pons
Midbrain
what forms the central core of the brain.
thediencephalon - composed of the epithalamus, thalamus, and hypothalamus,
features of the frontal lobe
It’s divided from the parietal lobe by thecentral sulcus
areas include the prefrontal cortex, the motor cortex – which is the area corresponding to the precentral gyrus -, and Broca’s area.
features of the parietal lobe
processes sensory information
he primary somatosensory cortex is located in the postcentral gyrus
features of the occipital lobe
it is posterior the parieto-occipital sulcus.
It is the visual processing centre of the brain and the location of the visual cortex
features of the temporal lobe
processes sensory information (hearing, smell, visual memories)
what and where is the Wernicke’s area
it is responsible for language comprehension and it is located in the temporal lobe
what is the role of the insula
The anterior insula, thought to be involved in language
The posterior insula is thought to be involved in integrating information relating to touch, vision and hearing
It also has connections with olfactory cortex
where is the insula
deep to the lateral sulcus
what is the importance of corpus callosum
provides a horizontal pathway for myelinated axons
it connects the two brain hemispheres, permitting communication between the right and left sides of the brain.
what important feature can be seen on a transverse section through the brain
the internal capsule
where is thebasal nuclei/ basal ganglia, are located
deep between the corona radiata and brainst
what are the 5 basal nuclei
caudate nucleus
putamen
globus pallidus
subthalamic nucleus
substantia nigra.
what basal ganglia form the Corpus Striatum
caudate nucleus and putamen.
what basal ganglia form the Lentiform nucleus
globus pallidus and the putamen
where do the basal ganglia project to to rely information to the cerebral cortex
thalamus
what is the role of the hypothalamus
maintaining homeostasis
by monitoring internal environment (eg blood glucose and body temperature) and controlling autonomic systems
how is the hypothalamus control release of hormones from the pituitary gland
via the pituitary stalk/ infundibulum
what is the importance of the pituitary gland
regulate hormone release through releasing or inhibiting hormones
what is acromegaly
over production of growth hormone by the pituitary gland
what does the ventricular system of the brain consists of
two lateral ventricles and
the midline 3rd and 4th ventricles (connected by the cerebral aqueduct)
where are the lateral ventricles located
sit in the hemispheres, one in each, and are separated by the thin septum pellucidum
connected via interventricular foramen
where is the 4th ventricle located
between the brainstem and the cerebellum
where is the CSF secreted
by the choroid plexuses of the ventricles
role of the CSF
protects the brain by providing a cushion against blows to the head
what connects lateral ventricles to 3rd ventricle in midline
Interventricular foramen (foramen of Munro)
where does the spinal cord begin and end
Begins at foramen magnum of skull as continuation of medulla
Ends at L1/L2 vertebrae in adults
what makes spinal nerves
Ventral (motor, efferent) & dorsal (sensory, afferent) roots converge to become a spinal nerve (mixed, motor & sensory)
where do all spinal nerves emerge from (which is the exception)
All spinal nerves emerge between adjacent vertebrae
except C1 which emerges between the occipital bone of the skull & C1 (atlas)
The unilateral area of skin supplied by a single (right or left member of a pair of) spinal nerves is called
dermatome
define myotome
The unilateral mass of muscle supplied by a single spinal nerve
which pinal nerve does not have a dermatome
spinal nerve C1
what are the structural features of spinal nerves
ventral root - is the efferent motor root and carries motor information from the brain.
dorsal root - afferent sensory root and carries sensory information to the brain
what are the 5 cerebral lobes
frontal
parietal
occipital
insula
temporal
what is the blood supply to the brain
the internal carotid arteries
the vertebral arteries
arteries which comprise the cerebral arterial circle (of Willis)
basilar
posterior communicating
middle cerebral
internal carotid
anterior communicating
anterior cerebral
posterior cerebral
vertebral
the impact of an ANTERIOR cerebral artery occlusion (stroke) on thebrain
= Contralateral hemiparesis and hemisensory loss involving mainly the leg and foot
= Inability to identify objects correctly, apathy, and personality changes (frontal and parietal lobes)
the impact of a MIDDLE cerebral artery occlusion (stroke) on thebrain
=Contralateral hemiparesis and hemisensory loss involving mainly the face and arm (precentral and postcentral gyri)
= Aphasia if the left hemisphere is affected (rarely if the right hemisphere is affected)
=Contralateral homonymous hemianopia (damage to the optic radiation)
=Anosognosia if the right hemisphere is affected (rarely if the left hemisphere is affected)
the impact of a POSTERIOR cerebral artery occlusion (stroke) on thebrain
= Contralateral homonymous hemianopia with some degree of macular sparing (damage to the calcarine cortex, macular sparing due to the occipital pole receiving collateral blood supply from the middle cerebral artery)
=Visual agnosia (ischemia of the left occipital lobe)
=Impairment of memory (possible damage to the medial aspect of the temporal lobe)
venous drainage of the brain
dura venous sinuses
then into the IJV
functions of the dura venous sinuses
They receive blood from the cerebral veins
receive CSF from the subarachnoid space via arachnoid granulations, and mainly empty into the internal jugular vein.
what are the dural septa
dural folds to limit the rotational displacement of the brain
tentorium cerebellli
falx cerebri
falx cerebelli
What are the major dural venous sinuses
the superior and inferior sagittal sinuses
the straight sinus
the superior and inferior petrosal sinuses
the occipital sinus
the transverse sinus
the sigmoid sinuses
what are the cavernous sinuses
hollow spaces located under the brain, behind each eye socket.
danger triangle drain in
sits next to sella turcica
function of the cavernous sinuses
drain the blood from the orbits through the ophthalmic veins and from the anterior part of the base of the brain by the sphenoparietal sinus and the middle cerebral veins.
what are the 4 types of intracranial haemorrhage
epidural hemorrhage
subdural hemorrhage
subarachnoid hemorrhage
intraparenchymal hemorrhage
what are the major foramina of the craniofacial skeleton.
cribiform foramina
optic canal
superior orbital fissure
foramen rotundum
foramen ovale
internal acoustic meatus
jugular foramen
hypoglossall canal
what passes through the cribriform foramina
CN 1 olfactory
what passes through the optic canal
CN II optic
opthalamic artery
what passes through the foramen rotundum
CN V2 trigeminal maxillary division
what passes through the internal acoustic meatus
CN VII, VIII ( facial, vestibulatrochlear)
what passes through the jugular foramen
CN IX, X, XI (glossopharyngeal, vagus, spinal accessory)
IJV
what passes through the hypoglossal canal
CN XII hypoglossal
what passes through the superior orbital fissure
CN III, IV, V(1,2), VI (opthalamic, trochlear, trigeminal, abducens)
what passes through the foramen ovale
CN V3 trigeminal mandibular division
origin of cranial nerves
cerebrum - CNI, II
midbrain-pontine junction - CN III
midbrain - CN IV
Pons - CN V
pons-medulla junction - CNVI, VII, VIII
medulla oblongata - IX, X, XI, XII
what are the 7 paired dural venous sinuses
transverse
cavernous
greater & lesser petrosal
sphenoparietal
sigmoid
basilar
what are the 5 unpaired dural venous sinuses
superior & inferior sagittal
straight
occipital
intercavernous
what artery supplies the motor cortex of the head and neck
middle meningeal artery
what/where is the Tentorium Cerebelli
horizontal projection of the meningeal dura mater. extends over the posterior cranial fossa.
It separates the occipital and temporal lobes of the cerebrum from the cerebellum and brainstem
divides the cranial cavity into supratentorial and infratentorial spaces
what/where is the falx cerebri
fold of dura mater that descends vertically into the longitudinal fissure between the cerebral hemispheres
what/where is the falx cerebelli
small midline fold of dura mater
begins anteriorly at the crista galli and winds around the corpus callosum
Located below the tentorium cerebelli on the middle of the occipital bone
what connects the lateral and 3rd ventricle
interventricular foramina
