Cardiac myocytes (heart muscle cells) do not regenerate. They can get bigger (hypertrophy), but new cells are not made under normal circumstances. This means that when you have a heart attack or another injury to the heart and cardiac cells die, they are replaced by fibrous scar tissue which does not contract like normal heart tissue does.
Stem cells can repair a damaged heart by turning into new cardiac cells to replace the damaged tissue.
Cardiac tissue has limited regenerative capacity primarily due to the low proliferation rate of cardiomyocytes, the heart muscle cells. After injury, such as a heart attack, the damaged cells are replaced by scar tissue rather than new muscle cells, which impairs the heart's function. Additionally, the complex structure and specialized functions of cardiac tissue require precise cellular organization that is difficult to restore. Factors like the lack of stem cell presence and the inhibitory environment created by inflammation further hinder regeneration.
In postnatal muscle, skeletal muscle precursors (myoblasts) can be derived from satellite cells (reserve cells located on the surface of mature myofibers) or from cells lying beyond the myofiber, e.g., interstitial connective tissue or bone marrow. Both of these classes of cells may have stem cell properties. In addition, the heretical idea that postmitotic myonuclei lying within mature myofibers might be able to re-form myoblasts or stem cells is examined and related to recent observations for similar post-mitotic cardiomyocytes. In adult hearts (which previously were not considered capable of repair), the role of replicating endogenous cardiomyocytes and the recruitment of other (stem) cells into cardiomyocytes for new cardiac muscle formation has recently attracted much attention. The relative contribution of these various sources of precursor cells in postnatal muscles and the factors that may enhance stem cell participation in the formation of new skeletal and cardiac muscle in vivo are the focus of this review. We concluded that, although many endogenous cell types can be converted to skeletal muscle, the contribution of non-myogenic cells to the formation of new postnatal skeletal muscle in vivo appears to be negligible. Whether the recruitment of such cells to the myogenic lineage can be significantly enhanced by specific inducers and the appropriate microenvironment is a current topic of intense interest. However, dermal fibroblasts appear promising as a realistic alternative source of exogenous myoblasts for transplantation purposes. For heart muscle, experiments showing the participation of bone marrow-derived stem cells and endothelial cells in the repair of damaged cardiac muscle are encouraging.
That's correct. Nerve and muscle cells are examples of cells that are incapable of undergoing mitosis to generate new cells once they have matured. This is due to their specialized functions and structures that make it challenging for them to divide and replicate. Instead, these cells are typically replaced through repair processes, such as tissue regeneration or repair by stem cells.
It contracts, so the blood flows into the arteries. Then, the cardiac muscle relaxes, so the blood flows back. The backflowing blood fills the valves in the arteries, so it cannot flow back into the heart itself. While the cardiac muscle relaxes, new blood flows into the ventricles and atriums from other veins.
new cells can be made for three reasons To replace damage tissue. To replace old cells to use for growth
probably by adding fat cells.
Muscle cells are produced during development in the embryo from stem cells called myoblasts. Muscle growth can also occur through exercise or injury, where satellite cells are activated to differentiate into new muscle cells.
Old cells make new cells so that when the old ones die there are new ones to replace them.
The principle that states cells arise from pre-existing cells supports the idea that new cells will replace damaged cells in a scraped knee. When skin cells are damaged, nearby cells will divide to produce new cells to replace the damaged ones, adhering to the principle that new cells come from existing cells in the body.
Skeletal muscle cells containing a single nucleus, called satellite cells, are believed to play a crucial role in muscle hypertrophy. These cells are involved in muscle repair and growth by contributing new nuclei to muscle fibers, aiding in protein synthesis, and increasing muscle mass in response to resistance training.
It contracts, so the blood flows into the arteries. Then, the cardiac muscle relaxes, so the blood flows back. The backflowing blood fills the valves in the arteries, so it cannot flow back into the heart itself. While the cardiac muscle relaxes, new blood flows into the ventricles and atriums from other veins.