Brain II Flashcards
what marks the location of the visual cortex
calcarine suture
function of the corpus callosum
to join the two cerebral hemispheres
what is the corpus callosum formed from
myelinated axons thus white matter
how is the corpus callosum subdivided
genu anteriorly, splenium posteriorly which are connected by a body
what does the internal capsule contain
contains fibres running from thalamus to cortex and cortex to thalamus, brainstem and spinal cord
what tract runs through the internal capsule
the corticospinal tract
function of basal ganglia / nuclei
primarily involved in motor control
5 basal nuclei are
- caudate nucleus
- putamen
- globus pallidus
- subthalamic nucleus
- substantia nigra
what forms the lentiform nucleus
caudate nucleus, putamen, globus pallidus
how are basal nuclei involved in motor control
they project neurons into the thalamus which is involved in relying information to the cerebral cortex
where is the hypothalamus in relation to the thalamus
it sits inferior and anterior to the thalamus
function of the hypothalamus
maintains homeostasis by controlling release of hormones from the pituitary gland
where is the pituitary gland found
in the pituitary fossa in the middle cranial fossa and sella turcica
what 4 hormones are released from the pituitary
- growth hormone
- thyroid stimulating hormone
- follicle stimulating hormone
- adrenocorticotrophic hormone
acromegaly
caused by overproduction of growth hormone in the pituitary
ventricular system of the brain consists of
2 lateral ventricles and the midline 3rd and 4th ventricles
what connects the 3rd and 4th ventricles
cerebral aqueduct
where are the 2 lateral ventricles found
1 in each hemisphere
what separates the 2 lateral ventricles
thin septum pellucidum
how do the lateral ventricles connect to the 3rd ventricle
by interventricular foramen
what releases CSF
choroid plexuses of the ventricles
where does the CSF go
it fills the ventricles and subarachnoid space of the brain (which is continuous with the subarachnoid space of the spinal cord)
role of CSF
protection via buoyancy to prevent weight of brain compressing the spinal nerve roots etc
where is the brainstem found
in the posterior cranial fossa
what connection does the brainstem form
the connection between the forebrain and spinal cord
what are the 3 parts of the brainstem
- midbrain
- pons
- medulla oblongata
where does the spinal cord begin and end
begins at foramen magnum
ends at L1/L2
anterior horns of the spinal cord are
efferent motor
posterior horns of the spinal cord are
afferent sensory
rootlets converge to form 2 roots:
ventral (motor efferent)
dorsal (sensory afferent)
the roots converge to form
a spinal nerve (mixed - motor & sensory)
how do spinal nerves divide
into ventral and dorsal rami (mixed - motor & sensory)
when do the spinal nerves divide
after exiting from the intervertebral foramen of the vertebral column
which anterior / posterior; dorsal / ventral
dorsal = posterior
ventral = anterior
spinal dura mater is
continuous with inner meningeal layer of cranial dura mater at the foramen magnum
myotome
unilateral mass of muscle supplied by a single spinal nerve
dermatome
unilateral area of skin supplied by a single spinal nerve (left, right or pair of)
why does C1 have no dermatome
it lacks significant afferent component and does not supply the skin
extra -dural haemorrhage
rupture of middle meningeal artery causing a haematoma which over hours leads to loss of consciousness
cause of extra-dural haemorrhage
small skull fracture tearing the artery
sub-dural haemorrhage
cerebral veins break away from superior sagittal sinus causing blood to build up in the dura mater and arachnoid mater space
sub-arachnoid hamorrhage
where a cerebral artery aneurysm ruptures causing blood to enter CSF. consciousness is lost fast.
dura mater
outside meninge of cranial cavity. tough layer made of collagen
arachnoid granulations / villi
white fluffy granulations present on dura mater that drain CSF from subarachnoid space to superior sagittal sinus
what is the falx cerebri
sickle shaped arched fold of dura mater
function of falx cerebri
separate the 2 hemispheres of the brain and along with CSF helps cushion the brain
superior sagittal sinus
runs through flax cerebri and is the venous drainage of the brain. larger posteriorly than it is anteriorly
pia mater
highly vascular layer on surface of brain
what cranial nerves are present in the cavernous sinus
CN III, IV, V1, V2, VI
