What are protoplasmic astrocytes?

What are protoplasmic astrocytes?

Protoplasmic astrocytes posses highly branched bushy processes and are widely distributed in the gray matter. They extend endfeet to blood vessels and enwrap them to form the glial limiting membrane, which is the outermost wall of the blood brain barrier (BBB).

Why do astrocytes become reactive?

Astrocyte reactivity is triggered by any alteration in brain homeostasis. Astrocytes are equipped with many receptors and intracellular signaling cascades to respond quickly to changes in their environment (Buffo et al., 2010; Burda and Sofroniew, 2014).

How do astrocytes become reactive?

(A) Astrocyte reactivity can be triggered by a wide variety of molecules from diverse sources, including any cell type in CNS tissue, as well as from microbial pathogens, circulating inflammatory cells, serum proteins, peripheral metabolic disorders, or environmental toxins.

What are protoplasmic processes?

Protoplasmic processes occupy the canaliculi. The osteocytes remain alive in the calcified matrix and secrete alkaline phosphatase to maintain calcification.

What is the difference between protoplasmic and fibrous astrocytes?

Unlike fibrous astrocytes, protoplasmic astrocytes occur in the gray matter of the central nervous system. They have fewer fibrils within their cytoplasm, and cytoplasmic organelles are sparse, so that the somata are shaped by surrounding neurons and fibres.

Are astrocytes glial cells?

Astrocytes are specialized glial cells that outnumber neurons by over fivefold. They contiguously tile the entire central nervous system (CNS) and exert many essential complex functions in the healthy CNS.

What is glial cells and their function?

Glial cells, also called glial cells or neuroglia, are cell which are non-neuronal and are located within the central nervous system and the peripheral nervous system that provides physical and metabolic support to neurons, including neuronal insulation and communication, and nutrient and waste transport.

What are astrocytes functions?

Astrocytes are the most numerous cell type within the central nervous system (CNS) and perform a variety of tasks, from axon guidance and synaptic support, to the control of the blood brain barrier and blood flow. To perform these roles, there is a great variety of astrocytes.

What is the definition of A gemistocyte cell?

ge·mis·to·cyt·ic as·tro·cyte. a round to oval astrocyte cell with abundant cytoplasm containing glial filaments and an eccentric nucleus; may contain two nuclei in the cell; hypertrophy of astrocytes. Synonym(s): gemistocyte, gemistocytic cell, reactive astrocyte, reactive cell.

How are gemistocytes used to diagnose astrocytoma?

Gemistocytes are round to oval astrocytes with abundant, glassy, non-fibrillary cytoplasm which appears to displace the dark, angulated nucleus to the periphery of the cell. To make the diagnosis of gemistocytic astrocytoma, gemistocytes should amount to more than approximately 20% of all tumor cells.

Why are gemistocytic astrocytes an intensely active cell?

It had been assumed that gemistocytic astrocytes were intensely active cells, because those astrocytomas in which they constituted the main cell form often evolved into frank glioblastomas. In morphology too, these cells appeared, by analogy with nonneural neoplasms, to be rapidly dividing ones.

How are vacuolated tumor cells similar to gemistocytes?

Gemistocytes are polygonal cells with peripherally displaced nuclei and glassy cytoplasm, as well as coarse processes. The combination of gemistocytes and vacuolated tumor cells somewhat resembles the reactive astrocyte-macrophage mixture of demyelinating disease, but the sheer number of gemistocytes is greater than in reactive gliosis.