T-tubules or transverse tubules are a part of the skeletal and cardiac muscle membrane systems. They are the cell membrane extensions that can penetrate into the center of those muscles.
It contains a large amount of on channels, transporters, and pumps. It allows the transmission of the action potential, frequently. T-tubules also regulates the cellular calcium concentration.
Kidneys for transplant can come from a living or a cadaver. Nephrectomy is the surgical removal of one or both kidneys. It is done by removing a healthy kidney from what you call a donor.They are usually to treat kidney diseases and injuries.