Search results
Results from the WOW.Com Content Network
Along with the brain, it develops from the dorsal nerve cord in the embryonic stage. The spinal cord consists of such segmental enlargements called ganglia. These ganglia form the basis for the peripheral nervous system’s (PNS) sensory and motor neurons that innervate various parts of the body.
Megalencephaly (or macrencephaly; abbreviated MEG) is a growth development disorder in which the brain is abnormally large. It is characterized by a brain with an average weight that is 2.5 standard deviations above the mean of the general population. [2]
The brain is small and simple in some species, such as the nematode worm, where the body plan is quite simple: a tube with a hollow gut cavity running from the mouth to the anus, and a nerve cord with an enlargement (a ganglion) for each body segment, with an especially large ganglion at the front, called the brain.
While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a vesicular enlargement at the rostral end of the neural tube, with centralized control over all body segments.
Nervous system of a bilaterian animal, in the form of a nerve cord with segmental enlargements, and a "brain" at the front. The vast majority of existing animals are bilaterians, meaning animals with left and right sides that are approximate mirror images of each other.
Embryonic vertebrate subdivisions of the developing human brain hindbrain or rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates. It includes the medulla , pons , and cerebellum .
An experimental nasal spray has helped clear toxic protein buildups in the brains of mouse models of Alzheimer's. Its developers believe the spray may help delay Alzheimer's by at least a decade.
Many people with abnormally large heads or large skulls are healthy, but macrocephaly may be pathological. Pathologic macrocephaly may be due to megalencephaly (enlarged brain), hydrocephalus (abnormally increased cerebrospinal fluid), cranial hyperostosis (bone overgrowth), and other conditions. Pathologic macrocephaly is called "syndromic ...