The Cerebrum Flashcards
lateral sulcus
aka Sylvian fissure; separates frontal and parietal lobe from temporal lobe below
central sulcus of Rolando
separates frontal and parietal lobes, bordered by precentral gyrus (motor) and postcentral gyrus (sensory)
function of precentral vs postcentral gyrus
precentral gyrus = motor
postcentral gyrus = sensory
the primary visual cortex is subdivided by the horizontally oriented ____ sulcus
calcarine sulcus
parts of which lobes make up the limbic lobe
frontal, parietal, temporal
the limbic lobe makes a rim around the…
diencephalon (lying in lateral wall of third ventricle)
the anterior end of each temporal lobe is formed by a rounded projection called the ___, lies above the almond shaped ____
uncus lies above amygdala
the cortex that sweeps over top of the limbic lobe is the
cingulate gyrus, aka limbic system cortex
what are the parts of the corpus collosum
rostrum (most inferior)
genu (most anterior)
body
splenium (most posterior)
the large area in front of the primary motor cortex is the
pre-motor or supplemental motor cortex
how does histological structure of association cortex differ from the restricted areas of the cerebrum?
association cortexes are homotypical- all 6 layers of neuronal structure are similar in thickness
restricted areas have varying thicknesses (heterotypical)- primary sensory cortex is “granular” cortex, motor cortex is “pyramidal” cortex
what layer is thickest in the primary sensory cortex
granular cells (layers 2 and 4)
what layer is thickest in primary motor cortex
pyramidal cells (layers 3 and 5)- give rise to axons of corticospinal and corticobulbar tracts
Brodmann areas 3, 1, 2
three regions of primary somatosensory cortex (in order 3, 1, 2 from anterior to posterior)
Brodmann area 4
primary motor cortex
Brodmann area 17
primary visual cortex
Brodmann areas 41 and 42
primary auditory cortex
Brodmann areas 44 and 45
Broca’s area
Brodmann area 22
Wernicke’s area
Brodmann area 6
premotor cortex
on the medial extension of both the primary somatosensory and motor cortexes is control for what body area?
lower limb (contralateral)
the most inferior portion of the homunculus for both the primary somatosensory and motor cortexes is for what body area
face
virtually all of the lateral aspect of each brain hemisphere is in the vascular territory of branches of the…
middle cerebral artery
supplying blood to the upper half of both the motor and somatosensory homunculus (primary cortexes) is that
middle cerebral artery branches
the medial aspect of the primary motor and somatosensory cortexes (where lower limb is controlled) is supplied with blood via the…
anterior cerebral artery
the motor and somatosensory homunculus have a dual arterial blood supply… describe
most of vascular supply is middle cerebral artery, except for medial aspect which is supplied by anterior cerebral artery
effect of vascular injury or blockage of middle cerebral artery on the motor and somatosensory homunculus’?
motor- contralateral upper body, upper limb, and lower face (not upper face because of bilateral motor innervation via cranial nerves) spastic weakness
sensory- contralateral face and upper body loss of sensation
effect of vascular injury or blockage of anterior cerebral artery on motor and somatosensory homunculus’?
anterior cerebral artery only supplies medial portion- some trunk and lower limb
motor-contralateral lower limb spastic weakness (hyperactive muscle stretch reflex, upgoing toes- lost inhibition)
sensory- contralateral lower trunk/ limb loss of sensation
the distal ends of the middle cerebral artery and the anterior cerebral artery come together in a…
watershed zone- found at distal ends of 2 circulations
watershed zone
found at distal ends of 2 circulations
what part of the motor and somatosensory homunculus are in the watershed zone (of middle cerebral and anterior cerebral arteries)?
trunk portion
watershed infarct
sudden drop in overall arterial blood pressure
effect of watershed infarct on the motor and somatosensory primary cortexes?
watershed zone at distal ends of middle cerebral and anterior cerebral arteries, trunk area of both homunculus is in the watershed zone
infarct results in person in a barrel syndrome- bilateral trunk weakness and bilateral trunk sensory loss
person in a barrel syndrome
bilateral trunk weakness and bilateral trunk sensory loss due to watershed infarct affecting trunk area of both motor and somatosensory homunculus
how are the large purkinje cells of the cerebellum affected by global ischemia, resulting from sudden drop in arterial pressure (such as watershed infarct)?
purkinje cells of cerebellum are very sensitive to disruption in blood supply (consume large amounts of oxygen). these are involved in memory processing with hippocampus, so patients with temporal lobe watershed infarct have negative effect on memory processing