Metencephalon
Encyclopedia
The metencephalon is a developmental
categorization of portions of the central nervous system
. The metencephalon is composed of the pons
and the cerebellum
; contains a portion of the fourth ventricle
; and the trigeminal nerve
(CN V), abducens nerve (CN VI), facial nerve
(CN VII), and a portion of the vestibulocochlear nerve
(CN VIII).
, and is differentiated from the myelencephalon
in the embryo by approximately 5 weeks of age. By the third month, the metencephalon differentiates into its two main structures, the pons and the cerebellum.
. The cerebellum
works to coordinate muscle movements, maintain posture, and integrate sensory information from the inner ear
and proprioceptors in the muscles and joints.
Morphogenesis
Morphogenesis , is the biological process that causes an organism to develop its shape...
categorization of portions of the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
. The metencephalon is composed of the pons
Pons
The pons is a structure located on the brain stem, named after the Latin word for "bridge" or the 16th-century Italian anatomist and surgeon Costanzo Varolio . It is superior to the medulla oblongata, inferior to the midbrain, and ventral to the cerebellum. In humans and other bipeds this means it...
and the cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
; contains a portion of the fourth ventricle
Fourth ventricle
The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle...
; and the trigeminal nerve
Trigeminal nerve
The trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
(CN V), abducens nerve (CN VI), facial nerve
Facial nerve
The facial nerve is the seventh of twelve paired cranial nerves. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity...
(CN VII), and a portion of the vestibulocochlear nerve
Vestibulocochlear nerve
The vestibulocochlear nerve is the eighth of twelve cranial nerves, and is responsible for transmitting sound and equilibrium information from the inner ear to the brain...
(CN VIII).
Embryology
The metencephalon develops from the higher/rostral half of the embryonic rhombencephalonRhombencephalon
The rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates.The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomeres...
, and is differentiated from the myelencephalon
Myelencephalon
The myelencephalon is categorized as a secondary vesicle in the development of the central nervous system. The prefix "myelen" is derived from Greek for medulla...
in the embryo by approximately 5 weeks of age. By the third month, the metencephalon differentiates into its two main structures, the pons and the cerebellum.
Functions
The pons regulates breathing through particular nuclei that regulate the breathing center of the medulla oblongataMedulla oblongata
The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...
. The cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
works to coordinate muscle movements, maintain posture, and integrate sensory information from the inner ear
Inner ear
The inner ear is the innermost part of the vertebrate ear. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:...
and proprioceptors in the muscles and joints.