Cerebral Hemispheres Flashcards
Largest part of the brain, with two hemispheres
Cerebrum
2 parts of cerebrum
Diencephalon and telencephalon
Forms the central core
Diencephelon
Forms the cerebral hemispheres
Telencephalon
Folds or convolutions that increases surface area of the brain
Gyrus
Shallow groove that separate each gyrus from each other
Sulcus
Deeper groove that separate each gyrus from each other
Fissures
Forms largest part of the brain
Cerebral hemisphere
2 cerebral hemispheres
Right and left hemispheres
Composed of gray matter; Forms a complete covering for the cerebral hemisphere
Cerebral cortex
Separates the two cerebral hemispheres containing the falx cerebri which is a sickled-shaped fold of dura mater
Longitudinal Cerebral Fissure
Connects the hemispheres across the midline;
Also known as the callosal commissure
Corpus callosum
Sulci of the cerebral hemisphere
Central Sulcus / Sulcus of Rolando
Lateral Sulcus / Fissure of Sylvius
Parieto-occipital Sulcus
Calcarine Sulcus
Only sulcus of any length on this surface of the hemisphere that indents the supermodial border and lies between two parallel gyri.
Central sulcus
Separates the frontal lobe (anterior) and parietal lobe (posterior)
Central sulcus
Gyrus that lies anterior to it contains motor cells that initiate the movements of the opposite side of the body;
Gyrus posterior to it lies the general sensory cortex and receives information from the opposite side of the body
Central sulcus
Separates the frontal (superior) and parietal lobes from the temporal lobe (inferior)
Lateral sulcus
Branches into 3 rami, which divides the inferior frontal gyrus into 3 parts (Opercular, Triangular and Orbital)
Lateral sulcus
3 rami of Lateral sulcus
Anterior Horizontal Ramus
Anterior Ascending Ramus
Posterior Ramus
Separates the parietal lobe from the occipital lobe;
Begins on the superior medial margin of the hemisphere about 2 inches anterior to the occipital pole;
Passes downward and anteriorly on the medial surface to meet the calcarine sulcus.
Parieto-occipital Sulcus
Separates the occipital lobe medially from Cuneus and Lingual gyrus
Found on the medial surface of the hemisphere
Joined at an acute angle by the parieto-occipital sulcus about halfway along its length
Calcarine sulcus
Lobes of the cerebrum
Frontal Parietal Temporal Occipital Insula or Island of Reil/Insular Cortex
Lobe:
Contains the primary motor area which carries out the individual movements of the different parts of the body
Frontal lobe
Lobe:
Contains the areas for sensory reception and integration of sensory information
Parietal lobe
Lobe:
Plays a role in person’s feeling and social judgment
Frontal lobe
Lobe:
Anterior to the central sulcus and superior to the lateral sulcus
Frontal lobe
Lobe:
Associated with movement, orientation, recognition, perception of stimuli
Parietal lobe
Lobe:
Extends posteriorly as far as the parieto-occipital sulcus
Parietal lobe
Lobe:
Occupies the area posterior to the central sulcus and superior to the lateral sulcus
Parietal lobe
Sulci and Gyri of the Frontal Lobe
Pre-central sulcus Pre-centrul gyrus Superior Frontal sulcus Interior Frontal sulcus Superior frontal gyrus Middle frontal gyrus Inferior frontal gyrus
Gyrus:
Lies superior to the superior frontal sulcus, contains the supplementary motor area/prefrontal cortex/pre-motor area
Superior frontal gyrus
Gyrus:
Lies between the superior and inferior frontal sulci, contains the frontal eye field responsible for eyeball movement
Middle frontal gyrus
Gyrus:
Lies inferior to the interior frontal sulcus, contains the Broca’s Area linked to speech production
Inferior frontal gyrus
Divisions of inferior frontal gyrus
Opercular, Triangular and Orbital parts of the Inferior Frontal Gyrus
Sulci and Gyri of the Parietal Lobe
Postcentral sulcus
Postcentral gyrus
Intraparietal sulcus
Gyrus:
lies between the postcentral sulcus and central sulcus, represents the primary somesthetic area
Postcentral gyrus
Intraparietal sulcus divides the parietal lobe into:
Superior and inferior parietal lobule
Gyrus:
Somatosensory, auditory and visual inputs
Supramarginal gyrus
Gyrus:
Inputs from primary visual cortex
Angular gyrus
Lobe:
Contains the primary auditory area or cortexand is associated with perception and recognition of auditory stimuli, memory and speech
Temporal lobe
Lobe:
Contains primary visual area
Occipital lobe
2 structures of occipital lobe
Cuneus and Lingual gyrus
Considered as fifth lobe; An area in coordinating movements responsible for speech
Insula or Island of Reil/
Insular Cortex
Triangular area of cortex bounded by the parieto-occipital and calcarine sulci and the superior medial margin
Cuneus
Gyrus:
Between the lateral sulcus and superior temporal sulcus; contains primary auditory cortex and Wernicke’s area associated with speech comprehension
Superior temporal gyrus
Gyrus:
Between the superior and middle temporal sulci; contains hippocampus associated with memory
Middle temporal gyrus
Gyrus:
Inferior to the middle temporal sulcus
Inferior temporal gyrus
Sulci of Temporal lobe
Superior Temporal Sulci
Middle Temporal Sulci
Knows what he or she wants to say, but is unable to accurately produce the correct word or sentence
Broca’s aphasia
Unaware that the words they are producing are incorrect and nonsensical. May have severe comprehension difficulties and be unable to grasp the meaning of spoken words, yet may be able to produce fluent and connected speech.
Wernicke’s aphasia
Broca’s aphasia
Brodmann area 44 and 45
Wernicke’s aphasia
BA 22
Primary auditory area
BA 41, 42
Primary somesthetic area
BA 3, 1, 2
Primary motor area
BA 4
T or F: Our hemispheres are identical, but in terms of function they are different.
T
Hemisphere:
Language, Math, Logic
Left
Hemisphere:
Visual and Spatial Skills, Emotions, Artistic Skills
Right
Band of nerve fibers that connect the two cerebral hemispheres at the midline; Also known as callosal commissure
Corpus callosum
4 parts of corpus callosum
Rostrum, genu, body, and the spleni
Top of corpus callosum; part of the limbic system
Cingulate Gyrus
Between corpus callosum and cingulate gyrus
Callosal Sulcus
Top of cingulate gyrus
CIngulate sulcus
Anterior part of the lobule is continuation of precentral gyrus, while
posterior part is continuation of postcentral gyrus that is why thrombosis of an artery supplying paracentral
lobule may result to BOTH motor and sensory deficits
Paracentral lobule
Surrounds the indentation produced by the central sulcus on the
superior border
Paracentral lobule
Anterior to the Precuneus
Parieto-Occipital Sulcus
Area bounded by the cingulate sulcus and parieto-occipital sulcus
Precuneus
A triangular area cortex found between parieto-occipital sulcus and
calcarine sulcus; Involved in basic visual processing together with the precuneus
Cuneus
Parallel to the calcarine sulcus
Collateral sulcus
Between Calcarine sulcus and collateral sulcus; Visual processing
Lingual gyrus
Continuing anteriorly from the collateral sulcus
Rhinal sulcus
Separates median occipitotemporal gyrus into medial and lateral
occipitotemporal gyrus; Also seen in inferior view
Occipitotemporal Sulcus
Anterior to lingual gyrus; Terminates in a hook-like uncus (Uncus: Constitutes primary
olfactory area)
Parahippocampal Gyrus
Some authors consider this as the sixth lobe;
Ring of structures on the medial side of the cerebral hemisphere,
encircling the corpus callosum (cingulate gyrus, parahippocampal
gyrus, uncus)
Limbic lobe
Extends from the occipital pole to the temporal.;
Bounded medially by the rhinal and collateral sulci sulci, laterally by
the occipitotemporal sulcus
Medial Occipitotemporal Gyrus
Located on the inferior surface of the frontal lobe, olfactory bulb and
olfactory tract;
Overlain by the olfactory bulb and olfactory tract
Olfactory Sulcus
Straight Gyrus; Medial to olfactory sulcus
Gyrus Rectus
Lateral to the olfactory sulcus
Orbital gyri
T or F: Our brain has a bend which refers to Diencephalic-Midbrain Junction.
T
T or F: In the brain: Gray matter is on the outside, while white matter is on the inside
T
In the spinal cord, where is the white and gray matter located?
White matter - outer
Gray matter - inner
fluid-filled cavities in the brain
Ventricles
No. of ventricles in the brain
4
What fluid is found in the ventricles?
CSF
Shape of lateral ventricles
C-shaped
Examples of structures that are c-shaped:
Lateral ventricles
Corpus callosum
Fornix
Caudate nucleus
collection of masses of gray matter situated within each hemisphere
Basal nuclei
A thin sheet of gray matter that is separated from the lateral surface of the lentiform; Function in human is unknown
Claustrum
Situated in the temporal lobe close to the uncus; Considered as a part of the limbic system that plays an important role in the control of posture and voluntary movement
Amygdaloid nucleus
T or F: Lesions in the basal nuclei do not cause paralysis. Damage in this area will cause abnormalities in movement
T
Composed of myelinated nerve fibers of different diameters supported by neuroglia
Cerebral white matter
3 groups of cerebral white matter
Commissural, Association, and Projection Fibers
Commissural Fibers
Corpus callosum Anterior commissure Posterior commissure Fornix Habenular commissure
The largest commissure connecting the 2 hemispheres. It lies at the bottom of the longitudinal fissure.
Corpus callosum
3 parts of corpus callosum
Rostrum
Genu
Body
The thin part of the anterior end of the corpus callosum.
Rostrum
The curved anterior end of the corpus callosum that bends inferiorly in front of the septum pellucidum.
Genu
It arches posteriorly and ends as the thickened portion called the splenium
Body
when fibers of the genu curve forward into frontal lobe.
forceps minor
when fibers in the splenium arch backward into the occipital lobe.
Forceps major
when fibers of the body extend laterally.
Radiation of the corpus callosum
fibers of the corpus callosum that form the roof and walls of the lateral ventricle
Tapetum
A small bundle of nerve fibers that crosses the midline in the anterior portion
Anterior commissure
Bundle of nerve fibers that cross the midline immediately above the opening of the cerebral aqueduct into the third ventricle.
Posterior commissure
Composed of myelinated nerve fibers which connect the hippocampal formation of the two sides; C-shaped and part of the limbic system.
Fornix
Is a small bundle of nerve fibers associated with the habenular nuclei which receive many afferents from the amygdaloid nuclei and the hippocampus. The function of this is still unknown.
Habenular commissure
Nerve fibers that essentially connect various cortical regions within the same hemisphere
Association fibers
Lie immediately beneath the cortex and connect adjacent gyri; these fibers run transversely to the long axis of the sulci.
Short association fibers
Collected into named bundles that can be dissected in a formalin-hardened brain
Long association fibers
Different association fibers
Uncinate fasciculus Cingulum Superior longitudinal fasciculus Arcuate fasciculus Inferior longitudinal fasciculus Fronto-occipital fasciculus
Association fiber:
Connects the first motor speech area and the gyri on the inferior surface of the frontal lobe with the cortex of the pole of the temporal lobe.
Uncinate fasciculus
Association fiber:
Is a long, curved fasciculus lying within the white matter of the cingulate gyrus. It connects the frontal and parietal lobes with parahippocampal and adjacent temporal cortical regions.
Cingulum
Association fiber:
The largest bundle of nerve fibers connecting the anterior part of the frontal lobe to the occipital and temporal lobes.
Superior longitudinal fasciculus
Association fiber:
Runs anteriorly from the occipital lobe, passing lateral to the optic radiation, and is distributed to the temporal lobe.
Inferior longitudinal Fasciculus
Association fiber:
Connects the frontal lobe to the occipital and temporal lobes
Fronto-occipital fasciculus
Association fiber:
part of the superior longitudinal fasciculus that bridges the Broca’s and Wernicke’s Area
Arcuate fasciculus
Projection fibers that radiate in all directions to the cerebral cortex
Corona radiata
The nerve fibers lying within the most posterior part of the posterior limb of the internal capsule radiate toward the calcarine sulcus and are known as the ______
optic radiation
Example of projection fiber
Internal capsule
Different areas of the Temporal lobe
Primary Auditory Area
Secondary Auditory Area
Sensory Speech Area of Wernicke’s
Area of temporal lobe:
Hearing without giving meaning to what the ears perceive
Primary Auditory Area
Area of temporal lobe:
Gives meaning to what the ears perceive
Secondary auditory area
Area of temporal lobe:
Responsible for receptive speech
Sensory Speech Area of Wernicke’s
Different Areas of the Frontal Lobe
Pre-central Area Posterior Region Anterior Region Supplementary Motor Area Frontal Eye Field Motor Speech Area of Broca
Area of the frontal lobe:
Movement of the parts of the body
Pre-central Area
Area of the frontal lobe:
Associated with memories of past experiences
Posterior Region
Area of the frontal lobe:
For storage of motor movements
Anterior Region
Area of the frontal lobe:
Needs high intensity stimuli to excite the part of the body; found in the medial side of frontal lobe
Supplementary Motor Area
Area of the frontal lobe:
For visual tracking
Frontal Eye Field
Area of the frontal lobe:
Located in the inferior frontal gyrus; Responsible for expressive speech
Motor Speech Area of Broca
Area of the frontal lobe:
For executive functioning, imagination and memory.
Prefrontal cortex
Different areas of Parietal lobe
Primary Somasthetic Area Secondary Somasthetic Area Somasthetic Association Area Vestibular Area Taste Area
Area of parietal lobe:
Taste area; sensation
Primary Somasthetic Area
Area of parietal lobe:
Gives meaning to different body sensations
Secondary Somasthetic Area
Area of parietal lobe:
Responsible for naming objects that are unseen but felt
Somasthetic Association Area
Area of parietal lobe:
Associated with balance
Vestibular Area
Area of parietal lobe:
Associated with sense of taste.
Taste area