the INTERACTIVE GUIDE to FUNCTIONAL NEUROANATOMY

MENINGES : the meninges of the sheep brain are a series of membranes that encase the Central Nervous System. There are three membranes, each structurally different. The dura mater and pia mater are the two meninges visible during sheep brain dissection. The middle membrane, the arachnoid mater ("spider mother") is a delicate, spiderweb-like structure between the dura and pia mater. Highlight the name of the membrane below to highlight it on the corresponding photo.

<-- Dura Mater : dura mater ("tough mother") is the outermost layer of the meninges. It is hard and inflexible; it is a protective coating for the brain. The dura mater was removed from the sheep brains for ease of dissection.

Pia Mater : pia mater ("little mother") is the innermost layer of the meninges. It encases the entire cerebral surface of the brain and is very delicate. During dissection, the pia mater can be seen easiest by gently pulling at the delicate layer that rests in the sulci.

When the dura mater is removed, some structures of the sheep brain are removed with it. In particular, the pituitary gland and a large portion of the optic nerves come off with the removal of the outermost meninge. These structures can be seen on the ventral surface of a sheep brain with dura mater still attached.

Pituitary Gland : one of the major endocrine glands in the brain; releases hormones controlling many different activities, such as growth, blood pressure, and the sex organ function. It connects to the hypothalamus.

Optic Nerves : the optic chiasm and optic tracts are clearly visible on the ventral surface of the sheep brain, however portions of the optic tract often come off with the dura. The optic tracts are involved in transmitting visual stimuli from the eyes to the brain.

© Gravinity Designs 2010
created according to the curriculum of the Skidmore College Introductory Neuroscience course