O nervous tissue it is responsible for various functions of the agency, such as coordinating the activities of different agencies. This tissue is mainly composed of neurons and glial cells (or neuroglia).
Neurons are the cells responsible for the propagation of nerve impulses, whereas glial cells present several functions, but for a long time they were related only to the protection and nutrition function of the neurons.
At glial cells, which were described more than 150 years ago, are a set of several cell types, their main cells being astrocytes, oligodendrocytes, microglia and ependymocytes.
You astrocytes, the most common glial cells, are large star-shaped cells with extensions, large nucleus, loose chromatin, and central nucleolus. They are related to the homeostasis of the Central Nervous System (CNS), performing functions such as: functioning and formation of synapses, nutrition of neurons, release of neurotransmitters, participation in the blood-brain barrier, guide for the migration of neurons and prevention of the disordered propagation of impulses nervous.
Among its functions, nutrition stands out. The ends of the astrocyte extensions (vascular feet) surround the blood vessels and through them the nutrients are carried to the neuron.
We can classify astrocytes into different subtypes, including protoplasmic and fibrous ones. Protoplasmic astrocytes have several short extensions, while fibrous ones have few extensions and these are long. Protoplasmic astrocytes are found in gray matter and fibrous astrocytes in white matter.
You oligodendrocytes they have a spherical nucleus and are smaller than astrocytes. These cells are found in white and gray matter. In the white matter, they are found surrounding the axons of some neurons, thus forming a membrane rich in lipophilic substance called the myelin sheath.
At microglia cells they are also present in the white and gray matter of the central nervous system. These cells are elongated and small, with a rod-shaped nucleus and condensed chromatin. They act in the immune defense of the CNS.
You ependymocytes they are cubic or columnar cells, with an ovoid nucleus and condensed chromatin. Its functions are to line the brain's ventricles and the central channel of the medulla.
by Vanessa dos Santos
Graduated in Biology
