Sheep for Brains: November 2011

Corpus callosum (Internal view):

Sagittal section/view of Corpus callosum. The Corpus callosum is the "roof" of the Lateral ventricles (1st and 2nd ventricles).

Rostrum (of Corpus Callosum):

Rostrum forms the "anterior wall" of the Lateral ventricles ("1st and 2nd ventricles").

Lateral ventricles (aka "1st and 2nd ventricles"):

Sagittal section/view of Lateral ventricles (only 1 side shown here); Lateral ventricles are the 1st and 2nd "cavities" in the cerebrum.

Alternate photos for the lateral ventricles (1 per lobe in the cerebral hemisphere).

Septum pellucidum: no picture because this structure is not visible in the sheep brain; it is the "flap" of tissue that separates the Lateral ventricles internally.

Fornix:

Fornix is the "floor" of the Lateral ventricles (aka 1st and 2nd ventricles) of the Cerebrum.

Pineal gland:

Pineal gland is a round piece of tissue that sits (approximately) in the center of the brain, located underneath the Fornix. Here is a link to a clearer Sagittal section that shows the location of the Pineal gland.

Thalamus:

Thalamus is the big "bump" of brain tissue indicated by probe. Thalamus is located immediately anterior to the Pineal gland and immediately inferior to (below) the Fornix.

Third (3rd) ventricle: no clear picture from class. Here is a link to a clear Sagittal section/view of the 3rd ventricle in the sheep brain.

Cerebral (Mesencephalic) Aqueduct:

Sagittal section/view of Cerebral aqueduct ("of the midbrain") of Specimen 1.

Sagittal section/view of Cerebral aqueduct of Specimen 2.

Fourth (4th) ventricle:

Sagittal section/view of the 4th ventricle of Specimen A; 4th ventricle is the thin cavity located immediately adjacent and posterior to the 3rd ventricle, and immediately inferior to the cerebellum of the sheep brain.

Sagittal section/view of the 4th ventricle of Specimen B.

Here's a link to a nice pdf of sheep brain dissections.

Meninges (Dura mater, Arachnoid mater, Pia mater) - no sheep pictures (not visible); identification on human brain for lab exam 2 of Dura Mater & Arachnoid mater.

Falx cerebri (of Dura mater):

Falx cerebri is not directly pictured: it is the vertical "shelf" of Dura Mater (outermost/superficial layer of the 3 meninges) between the 2 Cerebral Hemispheres (i.e. forms the lining of the Longitudinal Fissure).

Tentorium cerebelli (of Dura mater):

Tentorium cerebelli is the "strip" of Dura Mater between the Cerebrum and Cerebellum; more specifically, Tentorium cerebelli lines the Transverse fissure.

Cerebral Hemispheres (2) - aka Cerebrum/Telencephalon:

Longitudinal fissure (of Telencephalon/Cerebrum):

pic 1

pic 2

Gyrus:

Gyri are "hills" of brain tissue.

Sulcus:

Sulci are "valleys" in brain tissue.

Corpus callosum:

Internal view 1 of Corpus callosum ("roof" of the lateral ventricles, aka 1st and 2nd ventricles).

External view 1 of Corpus callosum.

Internal view 2 of Corpus Callosum.

External view 2 of Corpus callosum.

Gray matter (non-myelinated axons):

Gray matter of Cerebellum/arbor vitae.

White matter (myelinated axons, Oligodendrocytes):

White matter of Cerebellum/arbor vitae.

Frontal lobe (of Telencephalon/Cerebrum):

Olfactory bulbs (of Frontal lobe):

Probe is pointing to the left Olfactory bulb (brain is shown from an anterior view, held upside down); Olfactory bulb is the bulb-like expansion of the Olfactory tract on the inferior surface of the Frontal Lobe portion of each cerebral hemisphere.

Olfactory tract (of Frontal lobe):

Probe is pointing to the left Olfactory tract (anterior view of brain, held upside down); Olfactory tract is a bundle of axons located on the inferior surface of the Frontal lobe portion of each cerebral hemisphere.

Parietal lobes (of Telencephalon/Cerebrum):

Temporal lobes (of Telencephalon/Cerebrum):

Probe is pointing to the left Temporal lobe.

Occipital lobes (of Telencephalon/Cerebrum):

Diencephalon:

Diencephalon includes the following areas/structures: 3rd ventricle, Thalamus (wall of 3rd ventricle), Hypothalamus (floor of 3rd ventricle), Optic chiasm(a), Tuber cinereum, Infundibulum (stalk of pituitary gland), Pituitary gland, and Mammillary body.

Optic chiasm(a):

Optic chiasma (fully "X" shaped, normally) has been cut; Optic chiasma is where the optic nerves partially decussate (cross). The Optic chiasma is located at the bottom of the brain, immediately inferior to (below) the Hypothalamus.

Sagittal section/view of Optic chiasma.

Pituitary gland: (cut off in all specimens, no class picture available for sheep brain).

Infundibulum (aka "Pituitary stalk" of Pituitary gland):

Probe is pointing through the hole where the Infundibulum would normally emerge, had it not been cut off. Infundibulum is the "stalk"/small tube that the Pituitary gland hangs from.

Tuber cinereum (of Pituitary gland):

Tuber cinereum is the tan-colored circle surrounding the hole where the Infundibulum would normally be.

Mammillary body:

Mammillary body is the structure located opposite the Optic chiasma. Function of Mammillary body has to do with linking emotion with olfactory (sense of smell) memory.

Cerebellum (Latin for "little brain", part of Metencephalon):

Sagittal section/view of Cerebellum.

Bird's Eye view of Cerebellum.

Side view of Cerebellum.

Transverse fissure (of Cerebellum):

Transverse Fissure of the Cerebellum is where the Tentorium cerebelli (made of the Dura mater meninx) would normally be located.

Cerebellar hemispheres (of Cerebellum):

Arbor vitae (of Cerebellum):

Sagittal section of Cerebellum reveals Arbor vitae ("Tree of Life" pattern of white matter).

Midbrain (aka "Mesencephalon")- structures of the Midbrain are: Pineal gland, Corpora quadrigemina, Cerebral aqueduct, Cerebral peduncles.

Cerebral peduncles (part of Midbrain or Mesencephalon; of Brainstem):

Probes are pointing to the left and right Cerebral peduncles, respectively, on the inferior surface of the brain.

Lateral/side view of a Cerebral peduncle.

Corpora quadrigemina (aka "tectum"; of Brainstem):

Probe is pointing to the Superior colliculi, but this is the general area of the Corpora quadrigemina of the Brainstem, tucked between the Cerebrum and Cerebellum.

Superior colliculi (of Corpora quadrigemina; of Brainstem):

Probe is pointing to the Right Superior colliculus (bigger "butt cheek").

Inferior colliculi (of Corpora quadrigemina; of Brainstem:

Probe is pointing to the Right Inferior colliculus (smaller "butt cheek") of the Corpora quadrigemina, which is part of the Brainstem; In general, the Brainstem consists of the following structures/areas: Midbrain (Mesencephalon), Pons (Myelencephalong), and Medulla oblongata (also Myelencephalon).