The bottom surface of the brain are well discernible structure of the midbrain (mesencephalon): Brain stem and fibers of the oculomotor nerve (III pair). The first crossing from the front edge of the bridge, the second out of the interpeduncular fossa and sent to the striated muscles of the eyeball.
The rear portion of the midbrain called the lamina quadrigemina or midbrain roof (lamina tecti mesencephali). It is distinguishable only by removal of the cerebellum and occipital lobes of the cerebral hemispheres. Mounds separated by transverse groove at the top and bottom. The top two are the hills of subcortical centers in the lower - the subcortical centers of hearing.
In transverse section seen subcortical motor center, called the black substance (substantia nigra), as the body of the cells contain pigment. Black substance has a crescent-shaped legs, and shares in the ventral part of the brain - the dorsal and the base - the tire (tegmentum). At the bottom are fibers connecting the cortex of the cerebral hemispheres with the cerebellum, as well as pass through the wires of conscious motor impulses. In the lid contains the neurons of the reticular formation. The lid is removed from the roof of the midbrain (tectum mesencephali) cavity of the midbrain called the plumbing of the midbrain (aqueductus mesencephali).
|In Fig. 264.
The brain stem, rear view
1 - the roof of the midbrain;
2 - the central gray matter;
3 - aqueduct of the brain;
4 - tire;
5 - red nucleus;
6 - black substance;
7 - foot cord;
8 - oculomotor nerve
In the oculomotor nucleus are plumbing (III pair) and block (IV pair) nerves. Water around the central gray matter is responsible for autonomic functions. Above the black substance in the lateral section tires, wires lie joint-muscular sense, conscious tactile, thermal and pain sensitivity, which are fibers medial loop (lemniscus medialis). The lateral loop (lemniscus lateralis), formed by the auditory fibers located dorsally. In the very center of the lid is subcortical, known as the red nucleus (nucleus ruber). Red nucleus is responsible for motor activity, automation such as walking, jogging, etc.
a., aa. — arteria, arteriae (artery, the artery)
lig., ligg. — ligamentum, ligamenta (ligament, the ligaments)
m., mm. — musculus, musculi (muscle, the muscle)
n., nn. — nervus, nervi (nerve, the nerve)
r., rr. — ramus, rami (branch)
s. — seu (or)
v., vv. — vena, venae (vienna)