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Encyclopedia > Tegmentum
Brain: Tegmentum
Transverse section of mid-brain at level of superior colliculi. ("Tegmentum" visible center right.)
Section through superior colliculus showing path of oculomotor nerve. (Tegmentum not labeled, but surrounding structures more clearly defined.)
Latin Tegmentum

The tegmentum (from Latin for "floor") is a general area within the brainstem. It is located between the ventricular system and distinctive basal or ventral structures at each level. It is a multisynaptic network of neurons that is involved in many unconscious homeostatic and reflexive pathways. Image File history File links Gray712. ... 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. ... The Superior collici is an area in the mesencephalon of vertebrate brains. ... Image File history File links Cn3nucleus. ... The superior colliculus is part of the brain that sits below the thalamus and surrounds the pineal gland in the mesencephalon of vertebrate brains. ... The oculomotor nerve () is the third of twelve paired cranial nerves. ... For other uses, see Latins and Latin (disambiguation). ... For other uses, see Latins and Latin (disambiguation). ... The brain stem is the stalk of the brain below the cerebral hemispheres. ... The ventricular system is a set of structures in the brain continuous with the central canal of the spinal cord. ... The basal ganglia (or basal nuclei) are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... Neurons (also called nerve cells) are the primary cells of the nervous system. ... Homeostasis or homoeostasis is the property of an open system, especially living organisms, to regulate its internal environment so as to maintain a stable condition, by means of multiple dynamic equilibrium adjustments controlled by interrelated regulation mechanisms. ... The Ouroboros something reflexive refers to itself. ...

Contents

Development

In embryos the tegmentum is the anterior half of the neural tube. However, for fetuses to adults, tegmentum only refers to the parts of the brain that remains relatively unchanged after development is complete, i.e. at the brain stem and midbrain. Other parts, on the other hand, develop further, through folding and thickening, and have different names. Still, it is considered a continuous central region through all levels of the brainstem. Categories: Biology stubs | Developmental biology ... In the developing vertebrate nervous system, the neural tube is the precursor of the central nervous system, which comprises the brain and spinal cord. ... Fetus at eight weeks A fetus (alternatively foetus or fœtus) is an embryo in later stages of development, from the third month of pregnancy until birth in humans. ... The brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. ... 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. ...


Structures that develop to grow ventral or lateral outside this primitive tube as add-ons (e.g. the crus cerebri in the anterior of the midbrain) are not considered part of the 'tegmentum' as they are not part of the primitive neural tube but grow as projections from the cerebral cortex. Whereas, parts that were inside the primitive neural tube and remained an integral part of it after complete development (e.g. the red nucleus) are considered part of the tegmentum. The cerebral peduncle, by most classifications, is everything in the mesencephalon except the tectum. ... For other uses, see Cortex. ... The red nucleus is a structure in the rostral midbrain involved in motor coordination. ...


Divisions

The tegmentum forms distinguished divisions in the midbrain, pons and medulla 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. ... For other uses, see Pons (disambiguation). ... Medulla in general means the inner part, and derives from the Latin word for marrow. In medicine it is contrasted to the cortex. ...


Midbrain tegmentum

Main article: Midbrain tegmentum

The midbrain tegmentum is the part of the midbrain extending from the substantia nigra to the cerebral aqueduct in a horizontal section of the midbrain. The midbrain tegmentum is part of the midbrain extending from the substantia nigra to the cerebral aqueduct. ... 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. ... The substantia nigra, (Latin for black substance, Soemering) or locus niger is a heterogeneous portion of the midbrain, separating the pes (foot) from the tegmentum (covering), and a major element of the basal ganglia system. ... The mesencephalic duct, also known as the aqueduct of Sylvius or the cerebral aqueduct, contains cerebrospinal fluid (CSF), is within the mesencephalon (or midbrain) and connects the third ventricle in the diencephalon to the fourth ventricle, which is between the pons and cerebellum. ...


Pontine tegmentum

Main article: pontine tegmentum

The pontine tegmentum is a part of the pons of the brain involved in the initiation of REM sleep. ...

Lateral tegmental field

The lateral tegmental field (LTF) [1] is the source of several neurons of the noradrenaline system of the brain


Other

Other pertinent areas of the tegmentum are:

Periaqueductal gray (purple) can be seen surrounding the cerebral aqueduct in the midbrain. ... The red nucleus is a structure in the rostral midbrain involved in motor coordination. ...

References

  1. ^ Lateral Tegmental Field Neurons of Cat Medulla: A Source of Basal ...

  Results from FactBites:
 
Gray, Henry. 1918. Anatomy of the Human Body. Page 802 (748 words)
It is semilunar on transverse section, its concavity being directed toward the tegmentum; from its convexity, prolongations extend between the fibers of the base of the peduncle.
Bechterew is of the opinion that the fibers from the motor area of the cerebral cortex form synapses with cells whose axons pass to the motor nucleus of the trigeminal nerve and serve for the coördination of the muscles of mastication.
The principal gray masses of the tegmentum are the red nucleus and the interpeduncular ganglion; of its fibers the chief longitudinal tracts are the superior peduncle, the medial longitudinal fasciculus, and the lemniscus.
  More results at FactBites »

 
 

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