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T-tubules (transverse tubules) are extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells.With membranes that contain large concentrations of ion channels, transporters, and pumps, T-tubules permit rapid transmission of the action potential into the cell, and also play an important role in regulating cellular calcium concentration.
T tubule: transverse intracellular tubules invaginating from the cell membrane and surrounding the myofibrils of the T system of skeletal and cardiac muscle, serving as a pathway for the spread of electrical excitation within a muscle cell; Trachea: tubules forming the respiratory system of most insects and many arachnids
A T-tubule surrounded by two terminal cisternae is called a triad. The terminal cisternae, along with the transverse tubules, are the mechanisms of transduction from a nervous impulse to an actual muscle contraction .
An example of analysis of phloem through sieve elements was conducted in the study of Arabidopsis leaves. By studying the phloem of the leaves in vivo through laser microscopy and the usage of fluorescent markers (placed in both companion cells and sieve elements), the network of companion cells with the compact sieve tubes was highlighted.
Plant anatomy or phytotomy is the general term for the study of the internal structure of plants.Originally, it included plant morphology, the description of the physical form and external structure of plants, but since the mid-20th century, plant anatomy has been considered a separate field referring only to internal plant structure.
Examples of molecules that follow this process are potassium K +, sodium Na +, and calcium Ca 2+. A place in the human body where this occurs is in the intestines with the uptake of glucose . Secondary active transport is when one solute moves down the electrochemical gradient to produce enough energy to force the transport of another solute ...
Another example is the depolarization of cardiac muscle cells, which is accompanied by a large increase in the intracellular sodium concentration that causes NCX to work in reverse. Because the concentration of calcium is carefully regulated during the cardiac action potential, this is only a temporary effect as calcium is pumped out of the cell.
In plants, sucrose transport is distributed throughout the plant by the proton-pump where the pump, as discussed above, creates a gradient of protons so that there are many more on one side of the membrane than the other. As the protons diffuse back across the membrane, the free energy liberated by this diffusion is used to co-transport sucrose ...