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Nervous tissue, also called neural tissue, is the main tissue component of the nervous system.The nervous system regulates and controls body functions and activity. It consists of two parts: the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the branching peripheral nerves.
Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges , blood vessels , and ducts. The two main types of cells in the brain are neurons , also known as nerve cells, and glial cells , also known as neuroglia. [ 1 ]
During early development, cell migration plays a crucial role in neuronal tissue organization. Although still largely under investigation, networks of highly ordered neurons are known to be a vital component of the nervous systems communication with the body.
Induction of neural tissues causes formation of neural precursor cells, called neuroblasts. [78] In Drosophila, neuroblasts divide asymmetrically, so that one product is a "ganglion mother cell" (GMC), and the other is a neuroblast. A GMC divides once, to give rise to either a pair of neurons or a pair of glial cells.
Neuroanatomy is the study of the structure and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defined nervous systems. Their neuroanatomy is therefore better understood.
The cell is named after its characteristic triangular-shaped soma. Since there is a broad range of functions performed by different types of neurons in diverse parts of the nervous system, there is a wide variety in the size, shape, and electrochemical properties of neurons. Neurons can be found in different shapes and sizes and can be ...
Neural induction is often studied in Xenopus embryos since they have a simple body plan and there are good markers to distinguish between neural and non-neural tissue. Examples of neural inducers are the molecules noggin and chordin. When embryonic ectodermal cells are cultured at low density in the absence of mesodermal cells they undergo ...
Moreover, the distinctions based on function between neurons and other cells such as cardiac and muscle cells are not helpful. Thus, the fundamental difference between a neuron and a nonneuronal cell is a matter of degree. Another major class of cells found in the nervous system are glial cells. These cells are only recently beginning to ...