Forebrain Anatomy: Cerebrum, Diencephalon, and Lobes Overview

Forebrain

The large expanded mushroom-like upper part of the brain; it occupies the entire cranium except for the posterior cranial fossa; it consists of the cerebrum and diencephalon.

Cerebrum

Forms the visible part of the forebrain and is by far its larger part.

Gyri or convolutions

Rounded ridges visible on the outer curved surfaces of the cerebrum.

Sulci

Shallow grooves that dip down between adjacent gyri; this arrangement increases the surface area of the cerebrum.

Cerebral cortex

Outer part of the cerebrum; it is composed of several layers of nerve cell bodies and the gray matter.

White matter

Lies inside the cortex and consists of nerve fibers arising from or ending in the cortical cell bodies.

Corpus callosum

Composed of nerve fibers that connect the two halves or hemispheres.

Cerebral hemispheres

Right and left, are the two lateral halves of the cerebrum separated along the median plane by the longitudinal fissure.

Longitudinal fissure

Deep groove that extends from the front to the back of the cerebrum, along the median line.

Transverse fissure

Passes transversely across the upper limit of the posterior cranial fossa.

Central sulcus

Deep groove that begins at the longitudinal fissure at about its midpoint.

Lateral sulcus

A definite groove that begins on the inferior surface of each cerebral hemisphere.

Parietooccipital sulcus

Extends upwards and backwards from the inferior margin of the lateral surface of the hemisphere close to its posterior margin.

Frontal lobe

Lies adjacent to the frontal bone, and anterior to the central sulcus.

Parietal lobe

Lies under the parietal bone, and between the central sulcus in front, and the lateral sulcus and parietooccipital sulcus behind.

Occipital lobe

Lies in contact with the occipital bone posterior to the parietooccipital sulcus.

Temporal lobe

Lies adjacent to the temporal bone and below and behind the lateral sulcus.

Insula (central lobe)

Lies deep within each hemisphere, and deep to the lower part of the lateral sulcus.

Association fibers

Great white nerve fibers that connect the many gyri and the lobes of one hemisphere of the cerebrum.

Projection fibers

Group of fibers that connects the cortex of each hemisphere with parts of the brain below and the spinal cord.

Motor area of the cortex

Located in front of the central sulcus in the adjacent gyrus of the frontal lobe.

Located in the temporal lobe.

Centers of hearing and smell

Located in the parietal lobe.

Center for taste

Located in the posterior part of the occipital lobe.

Visual center

Diencephalon

Located between the cerebrum and the midbrain.

Thalamus

Forms the lateral walls of the third ventricle; it has nuclei that are relay stations for sensory impulses.

Hypothalamus

Forms the floor of the third ventricle; it regulates secretions of the pituitary gland and controls the autonomic nervous system.

Midbrain

Forms a small part of the brain and is less than one inch in length.

Cerebral peduncles

Visible on the ventral surface of the brain as two bulges above the pons.

Corpora quadrigemina

Form relay stations for auditory and visual sensations.

Hindbrain

Lies below the midbrain and extends down the foramen magnum where it becomes the spinal cord.

Pons

Lies immediately below the midbrain and anteriorly forms a definite prominence.

Medulla oblongata

Lies below the pons between it and the spinal cord; it ends at the foramen magnum.

Cerebellum

Lies posterior to the pons and upper part of the medulla oblongata; it coordinates muscular movements.

Brain stem

Term that includes the midbrain, pons, and medulla.

braegen

enkephalos

Anglosaxon and greek term for brain

longitudinal fissure

transverse fissure

central sulcus

lateral sulcus

parietooccipital sulcus

enumerate the components of the fissures and grooves of the brain

frontal lobe

parietal lobe

occipital lobe

temporal lobe

insula

enumerate the lobes of the cerebral hemisphere

hypothalamus

releases the hormone oxytocin and vasopressin

hypothalamus

regulates body temperature

equilibrium and posture

cerebellum is concerned with maintaining <> and <>

ventriculus = small cavity

Ventricles comes from the latin word <>, meaning <>

Ventricles

are the four cavities that lie within the brain

L lateral ventricles

R lateral ventricle

3rd ventricle

4th ventricle

enumerate the four cavities of the brain

L & R lateral ventricles

located in the corresponding cerebral hemisphere; each lies below the corpus collosum and extends from front to back corresponding somewhat in shape to that of the hemisphere within which it lies

posterior horn

central part

anterior horn

inferior horn

interventricular foramen

enumerate the parts of the lateral ventricles

inteventricular foramen - foramen of monro

is the opening between the medial margin of the lateral ventricle and the third ventricle

third ventricle

is a single cavity that lies in the midline of the diencephalon or afterbrain; between the medial margins of the thalami which form the lateral walls

cerebral aqueduct - aqueduct of sylvius

is a canal that passes between the third and fourth ventricles

fourth ventricle

single cavity that lies in the hindbrain; the pons and upper medulla lie in front and the cerebellum lies posterior to it

median foramen - foramen of magendie

an opening between the fourth ventricle and subarachnoid space of the brain in the midline of the roof of the fourth ventricle

lateral aperture - foramen of luschka

2 opening between the fourth ventricle and subarachnoid space of the brain in the midline of the roof of the fourth ventricle

choroid plexus

network of veins in the wall of each ventricle; special cells in this area secrete cerebrospinal fluid into the ventricles

choroid plexus epithelial cells

are cells found in the choroid plexus that secrete csf