Pineal gland- lives anterior to the superior colliculi near the center of the brain
where the two halves of the thalamus join.
Interpeduncular cistern:
Caudal (posterior) to the mammillary bodies and between the cerebral peduncles
is a substantial indentation called the interpeduncular cistern (p. 13 dissection).
This is part of the network of ventricles that circulates CSF through the brain.
Cerebrospinal fluid/cerebrospinal fluid: is a fluid that is derived from blood. It's
made specifically by cells in tissues called choroid plexus --we're going to see that
each one of the brain ventricles actually has a colloid plexus.
Colloid plexus: These are clusters of cells that take blood (arterial blood). The
basically selectively take certain parts of the blood and move it into the ventricles
as a new fluid called cerebrospinal fluid.
The interpeduncular cistern is a cone-shaped cistern situated between the
cerebral peduncles and the mesencephalic and diencephalic leaflets of the LM at
the confluence of the supra- and infratentorial compartments of the subarachnoid
space
Circulation of CSF Written Out
The brain’s cerebral cortex is the outermost layer that gives the brain its characteristic wrinkly
appearance. The cerebral cortex is divided lengthways into two cerebral hemispheres connected
by the corpus callosum. Traditionally, each of the hemispheres has been divided into four lobes:
frontal, parietal, temporal and occipital.
Although we now know that most brain functions rely on many different regions across the
entire brain working in conjunction, it is still true that each lobe carries out the bulk of certain
functions.
In humans, the lobes of the brain are divided by a number of bumps and grooves. These are
known as gyri (bumps) and sulci (groves or fissures). The folding of the brain, and the
resulting gyri and sulci, increases its surface area and enables more cerebral cortex matter to fit
inside the skull.
Two major sulci located on the lateral, or side, surface of each hemisphere distinguish
these lobes. The central sulcus, or fissure of Rolando, separates the frontal and parietal
lobes, and the deeper lateral sulcus, or fissure of Sylvius, forms the boundary between
the temporal lobe and the frontal and parietal lobes.
The frontal lobe, the largest of the cerebral lobes, lies rostral to the central sulcus (that
is, toward the nose from the sulcus). One important structure in the frontal lobe is the
precentral gyrus, which constitutes the primary motor region of the brain.
When parts of the gyrus are electrically stimulated in conscious patients (under local
anesthesia), they produce localized movements on the opposite side of the body that are
interpreted by the patients as voluntary. Injury to parts of the precentral gyrus results in
paralysis on the contralateral half of the body. Parts of the inferior frontal lobe (close to
the lateral sulcus) constitute the Broca area, a region involved with speech (see
below Functions of the human nervous system: Language).
The parietal lobe, posterior to the central sulcus, is divided into three parts:
(1) the postcentral gyrus
(2) the superior parietal lobule
(3) the inferior parietal lobule.
The postcentral gyrus (middle ?) receives sensory input from the contralateral half of
the body. The sequential representation is the same as in the primary motor area, with
sensations from the head being represented in inferior parts of the gyrus and impulses
from the lower extremities being represented in superior portions.
The superior parietal lobule, located caudal to (that is, below and behind) the
postcentral gyrus, lies above the intraparietal sulcus. This lobule is regarded as an
association cortex, an area that is not involved in either sensory or motor processing,
although part of the superior parietal lobule may be concerned with motor function.
The inferior parietal lobule (composed of the angular and supramarginal gyri) is a
cortical region involved with the integration of multiple sensory signals.
In both the parietal and frontal lobes, each primary sensory or motor area is close to, or
surrounded by, a smaller secondary area. The primary sensory area receives input only
from the thalamus, while the secondary sensory area receives input from the thalamus,
the primary sensory area, or both. The motor areas receive input from the thalamus as
well as the sensory areas of the cerebral cortex.
The temporal lobe, inferior to the lateral sulcus, fills the middle fossa, or hollow area, of
the skull. The outer surface of the temporal lobe is an association area made up of the
superior, middle, and inferior temporal gyri. Near the margin of the lateral sulcus, two
transverse temporal gyri constitute the primary auditory area of the brain. The
sensation of hearing is represented here in a tonotopic fashion—that is, with different
frequencies represented on different parts of the area. The transverse gyri are
surrounded by a less finely tuned secondary auditory area. A medial, or inner,
protrusion near the ventral surface of the temporal lobe, known as the uncus,
constitutes a large part of the primary olfactory area.
The occipital lobe lies caudal to the parieto-occipital sulcus, which joins the calcarine
sulcus in a Y-shaped formation. Cortex on both banks of the calcarine sulcus constitutes
the primary visual area, which receives input from the contralateral visual field via the
optic radiation. The visual field is represented near the calcarine sulcus in a retinotopic
fashion—that is, with upper quadrants of the visual field laid out along the inferior bank
of the sulcus and lower quadrants of the visual field represented on the upper bank.
Central vision is represented mostly caudally and peripheral vision rostrally.
Not visible from the surface of the cerebrum is the insular, or central, lobe, an
invaginated triangular area on the medial surface of the lateral sulcus; it can be seen in
the intact brain only by separating the frontal and parietal lobes from the temporal lobe.
The insular lobe is thought to be involved in sensory and motor visceral functions as
well as taste perception.
The limbic lobe is a synthetic lobe located on the medial margin (or limbus) of the
hemisphere. Composed of adjacent portions of the frontal, parietal, and temporal lobes
that surround the corpus callosum, the limbic lobe is involved with autonomic and
related somatic behavioral activities. The limbic lobe receives input from thalamic nuclei
that are connected with parts of the hypothalamus and with the hippocampal formation,
a primitive cortical structure within the inferior horn of the lateral ventricle.
Cerebral ventricles
Deep within the white matter of the cerebral hemispheres are cavities filled
with cerebrospinal fluid that form the ventricular system. These cavities include a pair of
C-shaped lateral ventricles with anterior, inferior, and posterior “horns” protruding into
the frontal, temporal, and occipital lobes, respectively. Most of the cerebrospinal fluid is
produced in the ventricles, and about 70 percent of it is secreted by the choroid plexus, a
collection of blood vessels in the walls of the lateral ventricles. The fluid drains via
interventricular foramina, or openings, into a slitlike third ventricle, which, situated
along the midline of the brain, separates the symmetrical halves of
the thalamus and hypothalamus. From there the fluid passes through the cerebral
aqueduct in the midbrain and into the fourth ventricle in the hindbrain. Openings in the
fourth ventricle permit cerebrospinal fluid to enter subarachnoid spaces surrounding
both the brain and the spinal cord.