Gross/External Morphology of the Brain Flashcards
Tegmentum
Floor of the mesencephalon extending ventrally from the aqueduct to the SN
-Contains PAG, oculomotor nerve complex (at superior colliculus), trochlear nerve (at inferior colliculus), and red nucleus (eye reflexes)
Tectum
Contains the superior and inferior colliculi; involved in visual and auditory reflexes respectively
Cerebral peduncles
consist of the tegmentum and basal midbrain in the mesencephalon
Substantia nigra
nucleus lying immediately dorsal to the crus cerebri; found in the basement midbrain
*Main nucleus which degenerates in Parkinson’s
Crus Cerebri
Contains axons of the descending corticospinal tract that synapse onto anterior horn cells
Vermis
midline of the cerebellum
Sylvian Fissure
“Lateral Sulcus”
Medial border of the temporal lobe
Primary Visual Cortex
Brodmann’s Area 17; also know as the calcarine cortex
- Greatest visual representation given to the fovea
- Small lesion can produce a scotoma or even a hemianopia
Higher Order Visual Cortex
Brodmann’s Area 18, 19
-Lesions produce visual agnosias
Primary Auditory Cortex
Area 41 (transverse temporal gyri of Heschl)
- Disproportionate representation given to human speech sounds
- lesions only produce dimunation of hearing, not deafness due to deep connections
Higher Order Auditory Cortex
Contains Wernicke’s Area (22)
Necessary for the interpretation of spoken language
- Lesions in this area produce aphasia
- Patient’s speak language fluently but what they say is nonsense
Primary Somatosensory Cortex
Areas 3, 1, 2
-Leg is represented medially; hand/face-laterally
- Lesions will produce deficits of fine appreciation of touch, vibration, and proprioception
- Non-specific pain can still be felt at level of thalamus
Higher Order Somatosensory Cortex
Area 2, 5
Part of suprerior parietal lobule; lesions produce somatosensory agnosias
Primary Motor Cortex
Area 4; “Precentral gyrus”
- Necessary for the initiation of voluntary motor movement; leg is represented medially/ hand & face, laterally
- Damage/loss of blood supply to this area will result in contralateral paralysis
Lesion of Area 8
Found on the superior frontal gyrus; controls paired eye movements
-Causes both eyes to deviate to the side of the lesion
Broca’s Area
Areas 44, 45; inferior frontal gyrus
Critically involved in the motor production of language
-Cortical damage results in understanding of language, but inability to speak it
in female children => strong recovery rate
Prefrontal association cortex
Plays rolls in cognitive behavior and making executive decisions
Limbic Association Cortex
Consists of the orbitofrontal cortex and part of the temporal lobe; involved in personality
-Lesions result in impaired personality, behavior, emotional lability
Inferior Parietal lobule
Consists of Area 40(supramarginal) and 39 (angular gyri)
- Important for the perception and interpretation of written language
- Pts. show alexia and agraphia
Pons divisions:
1 Dorsal tegmental zone- contains CN V-VII, ascending and descending fibers
2 Ventral/basal zone- Contains corticospinal tract fibers
Cingulate Gyrus
Medially located cortical gyrus surrounding the corpus collosum; part of the limbic system
First part of the brain to deteriorate in Alzheimer’s
Hippocampus
Divides the diencepahlon into its two major areas
Hypothalamic sulcus
Tumor of pineal gland
Blocks the aqueduct of Sylvius
=>non-communicating hydrocephalus
Pars triangularis Pars opercularis
Located in the frontal lobe
Folia
Folds of the cerebellar cortex
