CNS (central nervous system)

Originates from the neural tube.

Normal function dependent upon maintaining the neuronal microenvironment with regulation of the extracellular ionic composition, osmolarity, pH, prevention of the accumulation of synaptic space neurotransmitters, provision of adequate blood flow to maintain oxidative metabolism.

Astrocytes have a critical role in regulating the microenvironment of the CNS.

Astrocytes are the major neuroglia in the CNS.

Astrocytes influence all the synapses in a given volumetric space and regulate extracellular potassium concentration, volume, osmolarity, pH and concentration of neurotransmitters.

Excitatory synaptic transmitter is L-glutamate and the inhibitory transmitter at the synaptic space is gamma-aminobutyric acid (GABA).

Neurons and astrocytes are 2 interactive and intermingled networks with the neurons connected by synapses and the astrocytes a syncytium interconnected by gap junctions.

The astrocyte membrane facing synapses contain ion channel pumps, transmitters and receptors.

Astrocyte end-foot domains enwrap cerebral micro vessels and contributes to the induction and an maintenance of the blood brain barrier, uptakes capillary nutrients and transport potassium and water.

The relationship between astrocyte and brain capillaries allows the delivery of glucose to neurons in their proximity.

Neuronal-astrocyte interactions are bidirectional and essential for the normal function of the CNS.

Transport of immune cells from blood into the CNS restricted by the blood-brain barrier formed by CNS parenchyma microvessel and the blood-CSF barrier formed by the choroid plexus.

Cerebral microvessel are positioned along the interfaces between astrocytic domains.

Astrocytes typically extend processes in a 3-dimensional space and are polarized into 2 functional domains, the largest part of the astrocyte membrane faces the synapses and the remainder abut capillaries forming astrocytic foot processes.

Lacks draining lymphatic vessels.

Immune responses may develop in the CNS and cervical lymph nodes are considered a major sites of antigen presentation from the draining neuroinflammatory diseases.

Antigens drain from the CNS to cervical lymph nodes along the axons of craniofacial peripheral nerves.

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