Lab 3: Gross And Internal CNS III Flashcards
Lateral Fissue
A deep groove that separates the temporal lobe from the frontal and parietal lobes
Central Sulcus
A relatively unbroken vertical sulcus that separates the frontal and parietal lobes
Corpus Callosum
The major cortical commissure
Central Sulcus (medial view of cerebral cortex)
It’s superior end forms a small notch that makes the boundary between the frontal and parietal lobes
Cingulate Sulcus
Encircles the corpus callosum and ends posteriorly as 2 vertical branches that surround the central sulcus; anterior (paracentral sulcus) and posterior (marginal sulcus)
Parietooccipital Sulcus
Posterior angled sulcus that separates parietal and occipital lobes
Calcarine Sulcus
Horizontal sulcus within the occipital cortex; it’s walls contain the primary visual cortex
Insular Lobe (insula)
Deep lobe on the lateral surface. Gently spread margins of lateral fissure to observe. Contains short vertical gyri
Basal Surface of Forebrain
Examine the frontal lobe that rests on the roof of the orbit
Temporal lobe that’s lateral to the floor of the hypothalamus (contains the mammillary bodies)
Occipital gyri: posterior pole
Frontal Lobe Gyri
Precentral gyrus: vertical gyrus immediately anterior to the central sulcus. Contains most of the primary motor cortex that sends voluntary movement to the opposite side of the body above the knee
Anterior to this: there are 3 named gyri that are relatively horizontal
Subdivide these into: Superior frontal gyrus
Middle frontal gyrus (looks like 2 gyri)- contain areas for thinking and decision making
Inferior frontal gyrus
Inferior frontal gyrus
Subdivided into orbital (anterior)
Triangular (middle)
Opercular (posterior)
Broca’s Area
Usually in the left hemisphere (language dominant)
Triangular and opercular parts
Involved with selection of words for voluntary speech
Paracentral lobule
Surrounds the central sulcus on the medial view of the cerebral cortex (u-shaped). In between paracentral and marginal sulcus
Contains:
Anterior paracentral lobule that contains primary motor cortex for leg/foot (frontal lobe)
Posterior paracentral lobule that contains somatosensory cortex for leg/foot (parietal lobe)
Orbital frontal cortex
Basal surface of the cerebral cortex
Component of the limbic or emotional system
postcentral gyrus (parietal lobe)
Contains primary somatosensory cortex which receives impulses from receptors on the opposite side of the body above the knee
Superior parietal lobule and Inferior parietal lobule
Areas involved with memory storage of internal and environmental spatial info
3-D CNS info
Temporal Lobe Gyrus
Superior Temporal Gyrus: upper lateral gyrus
Middle Temporal Gyrus: intermediate lateral gyrus separated from the superior Temporal Gyrus by a superior temporal sulcus
Inferior Temporal Gyrus: lower gyrus that borders the basal surface
Transverse Temporal Gyri
2-3 gyri that extend horizontally inward from the superior Temporal gyrus to the depths of the lateral fissure
Contain primary auditory cortex for perception of sound stimuli
Continuous with the superior Temporal gyrus
Planum Temporale
Posterior to the transverse temporal gyri
Upper surface of the superior Temporal gyrus
Continuous with cortex of the inferior parietal lobule
High level sensory processing
Wernicke’s Area (receptive speech)
Language dominant hemisphere (usually the left)
Planum Temporale and adjacent areas of the inferior parietal lobule
Processing for the comprehension of spoken, written or sign language
Parahippocampal gyrus
Medial gyrus of the basal surface of the temporal lobe
Uncus
Medial fold of the rostrum end of the parahippocampal gyrus
Clinically: during increased intracranial pressures above the tentorium cerebellum, it can herniated through the opening formed by the free edge of the tentorium and compress structures of the midbrain
Gyri of Insula
Lateral surface, deep in the lateral fissure
Function in taste, visceral sensation and possibly paths linked to addiction
Lateral Occipital Lobe Gyri
A small number of broken gyri at the posterior pole
Occipital Lobe (medial view)
Cortex posterior to the parietal-occipital sulcus
Cuneus (these are gyri)
Upper occipital cortex on the medial side
Calcarine Fissure
Separates the cuneus above from lingual gyrus below
Lingual Gyrus
Below calcarine fissure
Extending to posterior pole
Limbic Lobe
Concerned with emotional tone and memory
Encircles the corpus callosum q
Cingulate gyrus (limbic lobe)
Encircling most of the corpus callosum
Parahippocampal gyrus and uncus
Difficult to see except on the basal surface
Medial view of the Corpus Callosum and its components
It’s a major cortical commissure that includes:
rostrum-thinned anteroventral area
Genu-anterior bending part
Body-large intermediate part
Splenium-caudal part
Lamina Terminalis
Vertical membrane that descends from the rostrum of the corpus callosum. It was the roster all end of the medial forebrain during development
Anterior Commissure
Posterior to the lamina terminalis; connects parts of left and right Temporal lobe
Septum Pellucidum
Midline membrane that separates the lateral ventricles
Diencephalon
This part of the forebrain surrounds the third ventricle and is deep to the cerebral hemispheres. It has several components including the thalamus, hypothalamus and pineal gland
Hypothalamic Sulcus
Groove along the wall of the third ventricle that marks the boundary between the thalamus (above) and hypothalamus (below)
Thalamus
Superior to hypothalamic sulcus
Massa intermedia or interthalamic adhesion
Thalamic nuclei that variably fuse in the midline
Hypothalamus
Below hypothalamic sulcus
Optic Chiasm
Crossing of optic nerve fibers
Falx Cerebri and Tentorium Cerebelli
Supportive partitions between parts of the brain
Internal Capsule
Boomerang-shaped sheet of white matter that is seen on an axial slice of the forebrain
Subcortical nuclei called Basal ganglia
Seen on axial slice of the forebrain
Longitudinal cerebral fissure and lateral fissure
External landmarks on an axial slice of the forebrain
Subdivisions of Telencephalon on an Axial Scan
Cortex
White matter including subcortical white matter: core of white matter in each cortical gyrus that consists of fibers traveling to and from its cortical neurons
And Deep white matter: located deep to the subcortical area; contains many tracts traveling in different directions
Internal capsule: boomerang-shaped bundle of axons that connect the cerebral cortex and lower CNS areas; has subdivisions three of which are landmarks that can be seen together ONLY IN THE HORIZONTAL PLANE
Three parts of internal capsule
Can only bee seen together in the HORIZONTAL PLANE
Anterior limb: located between 2 subcortical nuclei or basal ganglion
Genu (bend): lateral to the interventricular foramen (part of ventricular system that connects the lateral and third ventricle)
Posterior limb: area between the thalamus medially and a subcortical nucleus called the lentiform nucleus laterally
Subcortical Nuclei or Basal Ganglion on an Axial Image
Include several individual nuclei, including the caudate nucleus (anterior) and a group of nuclei described collectively as the lentiform nucleus; involved in movement planning
Coronal Section of the Forebrain (structures seen)
Thalamus (diencephalon)
Telencephalon: that includes:
Cortex: peripheral sheet of gray matter
Subcortical white matter: finger-like white matter projections that consist of axons bringing info to and from cortical neurons
Deep White Matter: mass of bundles of fibers passing in different directions
Posterior Limb of internal capsule: bundle of fibers traveling between the thalamus and the lentiform nucleus en route to the cortex or lower structures
Subcortical nuclei (basal ganglion): including the lentiform nucleus (putamen and globus pallidus) that are located lateral to the internal capsule
Also can see: longitudinal and lateral fissures, cerebral peduncles of the midbrain and the base of the pons
