| Brain: Mesencephalon | ||
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| Inferior view mesencephalon (2), above (3) | ||
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| Human brainstem mesencephalon (B) | ||
| Latin | mesencephalon | |
| Gray's | subject #188 800 | |
| NeuroNames | hier-445 | |
| MeSH | Mesencephalon | |
In biological anatomy, the mesencephalon (or midbrain) is the middle of three vesicles that arise from the neural tube that forms the brain of developing animals. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. This is a list of the subjects in Gray's Anatomy: IX Neurology NeuroNames is a system of nomenclature for the human and/or macaque Brain. Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books In the developing vertebrate the neural tube is the Embryo 's precursor to the Central nervous system, which comprises the Brain and Spinal cord The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain Caudally the mesencephalon adjoins the pons (metencephalon) and rostrally it adjoins the diencephalon (Thalamus, hypothalamus, et al). The pons (sometimes pons Varolii after Costanzo Varolio) is a structure located on the Brain stem. The diencephalon (or interbrain is the region of the Brain that includes the Thalamus, Hypothalamus, Epithalamus, Prethalamus or
In mature human brains, the mesencephalon becomes the least differentiated, from both its developmental form and within its own structure, among the three vesicles. The mesencephalon is considered part of the brain stem. The brain stem (or brainstem) is the lower part of the Brain, adjoining and structurally continuous with the Spinal cord. Its substantia nigra is closely associated with motor system pathways of the basal ganglia. The substantia nigra ( Latin for "black substance" Sömmering) or locus niger is a heterogeneous portion of the midbrain, separating The motor system is the part of the peripheral nervous system that is involved to movement The basal ganglia (or basal nuclei) are a group of nuclei in the Brain interconnected with the Cerebral cortex, Thalamus and
The human mesencephalon is archipallian in origin, meaning its general architecture is shared with the most ancient of vertebrates. In Anatomy of Animals the archipallium is the oldest region of the brain's pallium. Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes Dopamine produced in the substantia nigra plays a role in motivation and habituation of species from humans to the most elementary animals such as insects. Dopamine is a Hormone and Neurotransmitter occurring in a wide variety of animals including both vertebrates and invertebrates
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Corpora Quadrigemina
The corpora quadrigemina ("quadruplet bodies") are four solid optic lobes on the dorsal side of cerebral aqueduct, where the superior anterior pair are called the superior colliculi and the inferior posterior pair are called the inferior colliculi. In the Brain, the corpora quadrigemina ( Latin for "quadruplet bodies" are the four colliculi—two inferior, two superior —located The superior colliculus ( Latin, higher hill) is a paired structure that is part of the Brain 's tectal area. The inferior colliculi ( Latin, lower hills) together with the superior colliculi form the eminences of the Corpora quadrigemina, and also part The four solid optic lobes help to decussate several fibres of the optic nerve. However some fibers also show ipsilateral arrangement (i. e. they run parallel on the same side without decussating. ) The superior colliculus is involved with saccadic eye movements; while the inferior is a synapsing point for sound information. The trochlear nerve comes out of the posterior surface of the midbrain, below the inferior colliculus. The trochlear nerve (the fourth cranial nerve, also called the fourth nerve or simply IV) is a motor nerve (a “somatic efferent” nerve that innervates
Cerebral Peduncle
The cerebral peduncles are paired structures, present on the ventral side of cerebral aqueduct, and they further carry tegmentum on the dorsal side and cresta or pes on the ventral side, and both of them accommodate the corticospinal tract fibres, from the internal capsule (i. The cerebral peduncle, by most classifications is everything in the Mesencephalon except the Tectum. The tegmentum (from Latin for "covering" is a general area within the Brainstem. The corticospinal or pyramidal tract is a massive collection of Axons that travel between the Cerebral cortex of the Brain and the Spinal The internal capsule is an area of White matter in the Brain that separates the Caudate nucleus and the Thalamus from the Lenticular nucleus e ascending + descending tracts = longitudinal tract. ) the middle part of cerebral peduncles carry substantia nigra (also called "Black Matter") which is a type of basal nucleus. The substantia nigra ( Latin for "black substance" Sömmering) or locus niger is a heterogeneous portion of the midbrain, separating It is the only part of the brain that carries melanin pigment.
Between the peduncles is the interpeduncular fossa, which is a cistern filled with cerebrospinal fluid. Cerebrospinal fluid ( CSF) Liquor cerebrospinalis, is a clear Bodily fluid that occupies the Subarachnoid space and the Ventricular system The occulomotor nerve comes out between the peduncles, and the trochlear nerve is visible wrapping around the outside of the peduncles. The oculomotor nerve is the third of twelve paired Cranial nerves.
Cross-Section Through the Midbrain
The midbrain is usually sectioned at the level of the superior and inferior colliculi.
A cross-section at the level of the superior colliculus shows the red nucleus, the nuclei of the oculomotor nerve (and associated Edinger-Westphal nucleus), as well as the substantia nigra. The red nucleus is a structure in the Rostral Midbrain involved in Motor coordination. The oculomotor nerve is the third of twelve paired Cranial nerves. The Edinger-Westphal nucleus (also known as the accessory oculomotor nucleus) is the accessory parasympathetic Cranial nerve nucleus of the Oculomotor The substantia nigra ( Latin for "black substance" Sömmering) or locus niger is a heterogeneous portion of the midbrain, separating
The substantia nigra is still present at inferior colliculus level. Also apparent are the trochlear nerve nucleus, and the decussation of the superior cerebellar peduncles. The trochlear nerve (the fourth cranial nerve, also called the fourth nerve or simply IV) is a motor nerve (a “somatic efferent” nerve that innervates
The cerebral aqueduct runs through the midbrain, and is the communication between the third and fourth ventricle. The mesencephalic duct, also known as the aqueductus mesencephali, aqueduct of Sylvius or the cerebral aqueduct, contains Cerebrospinal The third ventricle ( ventriculus tertius) is one of four connected fluid-filled cavities comprising the Ventricular system within the human Brain. The fourth ventricle is one of the four connected fluid-filled cavities within the human Brain.
As a mnemonic the mesencephalic cross-section resembles a bear (or teddybear) upside down with the two red nuclei as the eyes and the crus cerebri as the ears. A mnemonic device (nəˈmɒnɪk is a Memory aid Commonly met mnemonics are often verbal something such as a very short poem or a special word used to help a person remember
Organization
- mesencephalon
Additional images
 Ventral midbrain |
 Diagram of the midbrain, sectioned at the level of the superior colliculus |
 Chick embryo of thirty-three hours’ incubation, viewed from the dorsal aspect. The tectum (Latin roof) is a region of the Brain, specifically the dorsal part of the Mesencephalon (midbrain The inferior colliculi ( Latin, lower hills) together with the superior colliculi form the eminences of the Corpora quadrigemina, and also part The superior colliculus ( Latin, higher hill) is a paired structure that is part of the Brain 's tectal area. The cerebral peduncle, by most classifications is everything in the Mesencephalon except the Tectum. The midbrain Tegmentum is the part of the Midbrain extending from the Substantia nigra to the Cerebral aqueduct in a horizontal section The cerebral crus is the anterior portion of the Cerebral peduncle which contains the motor tracts the plural of which is cerebral crura. The substantia nigra ( Latin for "black substance" Sömmering) or locus niger is a heterogeneous portion of the midbrain, separating The superior colliculus ( Latin, higher hill) is a paired structure that is part of the Brain 's tectal area. X 30. |
 Embryo between eighteen and twenty-one days. |
 Transverse section of mid-brain at level of inferior colliculi. |
 Transverse section of mid-brain at level of superior colliculi. |
 Embryonic brain |
 Human cerebrum lateral view |
_section_description.JPG/120px-Human_brain_frontal_(coronal)_section_description.JPG) Human brain frontal (coronal) section |