Cerebrum Anatomy and Features

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Questions and Answers

What is the primary structural feature that separates the two hemispheres of the cerebrum?

Longitudinal cerebral fissure (correct)

Basal ganglia

Falx cerebri

Corpus callosum

Which layer of the cerebrum contains large masses of grey matter embedded in the basal part of white matter?

White matter

Basal ganglia (correct)

Lateral ventricle

Cerebral cortex

What is the function of the corpus callosum in the cerebrum?

Separates the frontal and occipital poles

Connects the temporal lobes

Lodges the falx cerebri

Joins the two cerebral hemispheres (correct)

Which surface of the cerebral hemisphere is described as being most convex and extensive?

Superolateral surface Signup and view all the answers

Which pole of the cerebral hemisphere is located at its anterior end?

Frontal pole Signup and view all the answers

What is the name of the grooves between the gyri in the cerebral cortex?

Sulci Signup and view all the answers

Which surface of the cerebral hemisphere adapts to the floors of the anterior and middle cranial fossae?

Inferior surface Signup and view all the answers

What separates the superolateral surface from the medial surface of the cerebral hemisphere?

Superomedial border Signup and view all the answers

What is the area between the central sulcus and precentral sulcus called in the frontal lobe?

Precentral gyrus Signup and view all the answers

Which sulcus separates the parietal lobe into superior and inferior parietal lobules?

Intraparietal sulcus Signup and view all the answers

What is the role of the cingulate sulcus?

Lies above the corpus callosum Signup and view all the answers

Which gyri are found in the temporal lobe?

Superior, middle, and inferior temporal gyri Signup and view all the answers

Which sulcus extends below the splenium of the corpus callosum towards the occipital pole?

Calcarine sulcus Signup and view all the answers

What is the area called that lies between the parieto-occipital sulcus and the precuneus?

Precuneus Signup and view all the answers

What distinguishes the precentral sulcus from the postcentral sulcus?

Their orientation and position relative to the central sulcus Signup and view all the answers

What structures does the term opercula refer to?

Cortex covering the insula Signup and view all the answers

What is the function of the convolutions in the cerebral cortex?

They increase the surface area of the cortex. Signup and view all the answers

Which part of the lateral sulcus arises first from the inferior surface of the cerebral hemisphere?

Stem of the sulcus Signup and view all the answers

Where does the central sulcus end?

Above the posterior ramus of the lateral sulcus Signup and view all the answers

Which lobe lies behind the central sulcus?

Parietal lobe Signup and view all the answers

What is the shape of the insula in the cerebral cortex?

Triangular Signup and view all the answers

Which sulcus separates the occipital lobe from the temporal lobe?

Parieto-occipital sulcus Signup and view all the answers

What does the parieto-occipital sulcus extend in front of?

The occipital pole Signup and view all the answers

Which part of the brain is defined as the submerged portion of the cerebral cortex in the floor of the lateral sulcus?

Insula Signup and view all the answers

Study Notes

Cerebrum

The cerebrum is the largest part of the brain, filling the majority of the cranial cavity.
It has a convoluted bilobed structure.
The longitudinal cerebral fissure separates the cerebrum into two hemispheres.
The falx cerebri, a dura mater fold, is housed within the fissure.
The corpus callosum, a white fiber mass, connects the two hemispheres.
Each hemisphere comprises:
- Cerebral cortex (outer grey matter layer)
- White matter
- Basal ganglia/basal nuclei (embedded grey matter masses)
- Lateral ventricle (internal cavity)

External Features

Poles:
- Frontal pole: Anterior end of the hemisphere
- Occipital pole: Posterior end of the hemisphere
- Temporal pole: Between frontal and temporal lobes
Surfaces:
- Superolateral surface: Most convex and extensive, facing upwards and laterally
- Medial surface: Flat and vertical
- Inferior surface: Irregular, adopting the floors of cranial fossae, divided into orbital and tentorial parts by the stem of the lateral sulcus
Borders:
- Superomedial border: Separates superolateral and medial surfaces
- Superciliary border: Junction of superolateral and orbital surfaces
- Inferolateral border: Separates superolateral and tentorial surfaces
- Medial orbital border: Separates medial and orbital surfaces
- Medial occipital border: Separates medial and tentorial surfaces

Sulci & Gyri

Sulci: Grooves between gyri
Gyri (Convolutions): Folds of the cerebral cortex, increasing its surface area
Each gyrus contains a core of white matter covered by grey matter

Main Cerebral Sulci

Lateral Sulcus (of Sylvius):
- Stem originates on the inferior surface and extends laterally to the superolateral surface
- Divides into anterior horizontal, anterior ascending, and posterior rami
Central Sulcus (of Rolando):
- Begins on the superomedial border, runs downwards and forwards
- Ends above the posterior ramus of the lateral sulcus
- Extends into the medial surface
Parieto-occipital Sulcus:
- Present on the medial surface, extending 5 cm in front of the occipital pole
- May extend slightly onto the superolateral surface

Lobes

The superolateral surface is divided into four lobes: frontal, parietal, temporal, and occipital, defined by:
- Three main sulci: central, lateral, and parieto-occipital
- Two imaginary lines:
  - Vertical line joining the parieto-occipital sulcus to the preoccipital notch
  - Backward continuation of the lateral sulcus' posterior horizontal ramus
Frontal Lobe: Anterior to the central sulcus and above the lateral sulcus' posterior ramus
Parietal Lobe: Behind the central sulcus, in front of the first imaginary line's upper part, bounded below by the lateral sulcus' posterior ramus and the second imaginary line
Temporal Lobe: Below the lateral sulcus' posterior ramus and the second imaginary line, separated from the occipital lobe by the first imaginary line's lower part
Occipital Lobe: Behind the vertical line joining the parieto-occipital sulcus and preoccipital notch

Insula/Island of Reil (Central Lobe)

Submerged portion in the lateral sulcus floor, triangular in shape
Surrounded by the circular sulcus, except at its anteroinferior apex (limen insulae)
Hidden from view by the frontal, frontoparietal, and temporal opercula

Sulci and Gyri on Superolateral Surface

Frontal Lobe:
- Precentral sulcus: Runs downwards and forwards, parallel and anterior to the central sulcus
- Precentral gyrus: Area between the central and precentral sulci
- Superior and inferior frontal sulci: Run horizontally, dividing the frontal lobe into superior, middle, and inferior frontal gyri
Parietal Lobe:
- Postcentral sulcus: Runs downwards and forwards, behind and parallel to the central sulcus
- Postcentral gyrus: Area between the central and postcentral sulci
- Intraparietal sulcus: Divides the rest of the parietal lobe into superior and inferior parietal lobules
Temporal Lobe:
- Superior temporal sulci
- Inferior temporal sulci: Run parallel to the lateral sulcus' posterior ramus, dividing the temporal lobe into superior, middle, and inferior temporal gyri
- Heschl's gyrus: Present on the superior surface of the superior temporal gyrus
Occipital Lobe:
- Three short sulci: lateral, transverse occipital sulci, and lunate sulcus

Sulci and Gyri on Medial Surface

Callosal Sulcus: Above the corpus callosum
Cingulate Sulcus: Curved trajectory above and parallel to the corpus callosum's upper margin
Cingulate Gyrus: Area between the cingulate and callosal sulci
Paracentral Lobule: Small region around the central sulcus' upper part
Medial Frontal Gyrus: In front of the central sulcus
Calcarine Sulcus: Extends below the corpus callosum's splenium, backwards towards the occipital pole
Isthmus: Small region between the splenium and calcarine sulcus
Parieto-occipital Sulcus
Cuneus: Triangular area between the posterior part of the calcarine sulcus and the parieto-occipital sulcus
Precuneus: Quadrangular area between the parieto-occipital sulcus and paracentral lobule

Sulci and Gyri on Inferior Surface

Orbital Surface:
Tentorial Surface:

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Description

This quiz covers the anatomy of the cerebrum, including its structure, external features, and the functions of its various parts. Test your knowledge on the cerebral cortex, white matter, and the connections between the two hemispheres. Explore the significance of the poles and surfaces of the cerebrum in brain function.