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Astrocytes (green) in the context of neurons (red) in a mouse cortex cell culture 23-week-old fetal brain culture human astrocyte Astrocytes (red-yellow) among neurons (green) in the living cerebral cortex. Astrocytes are a sub-type of glial cells in the central nervous system. They are also known as astrocytic glial cells.
Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart .
The action potential passes along the cell membrane causing the cell to contract, therefore the activity of the sinoatrial node results in a resting heart rate of roughly 60–100 beats per minute. All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the ...
This evidence is supported by an increased amount of MCT shuttle proteins in the heart and muscle in direct proportion to exertion as measured through muscular contraction. [11] Furthermore, both neurons and astrocytes have been shown to express MCT proteins, suggesting that the lactate shuttle may be involved in brain metabolism. Astrocytes ...
The Purkinje fibers are further specialized to rapidly conduct impulses (having numerous fast voltage-gated sodium channels and mitochondria, and fewer myofibrils, than the surrounding muscle tissue). Purkinje fibers take up stain differently from the surrounding muscle cells because of having relatively fewer myofibrils than other cardiac cells.
Various cell types play a role in HR, including astrocytes, smooth muscle cells, endothelial cells of blood vessels, and pericytes. These cells control whether the vessels are constricted or dilated, which dictates the amount of oxygen and glucose that is able to reach the neuronal tissue.
Within cardiac muscle cell and smooth muscle cells voltage-gated calcium channel activation initiates contraction directly by allowing the cytosolic concentration to increase. Not only are T-type calcium channels known to be present within cardiac and smooth muscle, but they also are present in many neuronal cells within the central nervous system.
The neurovascular unit consists of neurons, astrocytes, vasculature (endothelial and vascular mural cells), the vasomotor apparatus (smooth muscle cells and pericytes), and microglia. [1] Together these function in the homeostatic haemodynamic response of cerebral hyperaemia. [3]