mesencephalon (redirected from Midbrain of brain stem)

mesencephalon /mes·en·ceph·a·lon/ (mez″-en-sef´ah-lon) midbrain.

1. the part of the brain developed from the middle of the three primary vesicles of the embryonic neural tube, comprising the tectum and the cerebral peduncles.

2. the middle of the three primary brain vesicles in the embryo, lying between the prosencephalon and the rhombencephalon.mesencephal´ic

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mes·en·ceph·a·lon (mzn-sf-ln)

n.

The portion of the vertebrate brain that develops from the middle section of the embryonic brain. Also called midbrain.

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mesencephalon

[mes′ensef′əlon]

Etymology: Gk, mesos, middle, enkephalos, brain

one of the three parts of the brainstem, lying just below the cerebrum and just above the pons. It consists primarily of white substance with some gray substance around the cerebral aqueduct. Deep within the mesencephalon are nuclei of the third and the fourth cranial nerves and the anterior part of the fifth cranial nerve. The mesencephalon also contains nuclei for certain auditory and visual reflexes. Also called midbrain. mesencephalic [mes′ensifal′ik] , adj.

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mesencephalon [mes″en-sef´ah-lon]

1. the short part of the brainstem just above the pons; it contains the nerve pathways between the cerebral hemispheres and the medulla oblongata, as well as nuclei (relay stations or centers) of the third and fourth cranial nerves. The center for visual reflexes, such as moving the head and eyes, is located here.

The mesencephalon (midbrain). From Applegate, 2000.

2. the middle of the three primary brain vesicles of the embryo; called also midbrain. adj., adj mesencephal´ic.

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mesencephalon

1. the midbrain, including the colliculi of the tectum, the cerebral crura, the Edinger-Westphal nucleus, internal capsule, lemniscal trigone, pallidum, putamen and substantia nigra.

2. the middle of the three primary brain vesicles of the embryo. See also midbrain syndrome.