Cells, cell division and wound healing

Q: If cells can divide for limited times, does that mean there will come a time when our cells will not divide, meaning if I get a wound it will not heal?

Krishna: Except for labile cells, which act as stem cells, and cancerous ones – cells cannot reproduce forever. However, adult stem cells, which are special cells that can make many other types of cells, can divide much longer, and embryonic stem cells can divide nearly indefinitely and are pluripotent.
These embryonic Stem cells are considered to be immortal in culture and, therefore, of great interest for aging research. This immortality is regulated by increased proteostasis, which controls the quality of proteins. A team of researchers found a link between increased proteostasis and immortality of human embryonic stem cells (5).
So why haven't scientists already turned embryonic stem cells into every type of cell they need to cure disease?

Unfortunately, it's not that easy. In the case of the retina cells needed to cure macular degeneration, researchers have discovered which molecules can coax stem cells to become the correct cell type for transplantation into the eye. However, they have not yet discovered the specific conditions and transplant techniques for all 220 of the cell types in our bodies. Different cell types require different conditions and molecular cues. As well as the technical limitations regarding the cell culture, scientists are held back by the human culture outside the lab because not everyone supports research on embryonic stem cells (4).

The Hayflick Limit is a concept that helps to explain the mechanisms behind cellular aging. The concept states that a normal human cell can only replicate and divide forty to sixty times before it cannot divide anymore, and will break down by programmed cell death or apoptosis.
The conclusion held for many cell types, whether they were adult cells or fetal cells.
The concept of the Hayflick Limit helped scientists study the effects of cellular aging on human populations from embryonic development to death, including the discovery of the effects of shortening repetitive sequences of DNA, called telomeres, on the ends of chromosomes.
In cellular biology, labile cells are cells that continuously multiply and divide throughout life.(2)This continual division of labile cells allows them to reproduce new stem cells and replace functional cells that are lost in the body. Functional cells may be lost through necrosis, which is the premature death of cells caused by environmental disturbances, such as diseases or injuries. Functional cells may also need to be replaced after undergoing apoptosis, which is the programmed death of cells that occurs normally as part of an organism's development (Fink & Cookson, 2005). Labile cells continually regenerate by undergoing mitosis and are one of three types of cells that are involved in cell division, classified by their regenerative capacity. The other two cell types include stable cells and permanent cells. Each of these three cell types respond to injuries to their corresponding tissues differently. Stable cells, unlike labile cells, are typically not dividing and only do so when an injury occurs. Permanent cells are not capable of division after maturing.

Some examples of labile cells, which act as stem cells, include skin cells, cells within the gastrointestinal tract, and some cells found within bone marrow.(3)

Labile cells exhibit a very short G1 phase and never enter G0 phase (the resting phase), as they are continually proliferating throughout their life.

Cells that are constantly dividing have a higher risk of dividing uncontrollably and becoming malignant, or cancerous.
When cells become damaged or die the body makes new cells to replace them through a process called cell division. .Cells make copies by dividing into two cells in a process called mitosis. As the parent cell divides, it passes on its genetic instructions to both copies. The new cells look and function just like the parent. Eventually, each of the new cells will divide, too.
The cells in our bodies live for anything from a few hours, in the case of certain types of white blood cells, to a few weeks, for skin cells, to many decades, in the case of most brain cells. But while most cells are regenerated, the processes involved become progressively unreliable over time. In particular, the DNA carrying the instructions for cell processes becomes damaged, eventually preventing any more cell division. The result is the increasing level of decrepitude we call ageing (6).
Over time, cells age and become damaged, so your body's cells are constantly replicating, creating their own replacements.
Certain cells in some organs and systems in your body are totally replaced in a matter of months, but others remain much the same as they were on the day you were born.
In humans with non-injured tissues, the tissue naturally regenerates over time; by default, new available cells replace expended cells.
Most of the skin and gut are replaced very fast, most likely within months. However, cells in other organs and systems are even slower to replicate and lag behind.
For example, "the human heart renews at a rather low rate, with only 40% of all cardiomyocytes [the cells responsible for the contracting force in the heart] exchanged throughout life. Skeletal cells, meanwhile, need around 10 years to replicate a skeleton in its entirety. In the brain, cell renewal can be even more leisurely. Scientists have uncovered evidence showing that some neurons in the hippocampus are renewed, but only at a rate of 1.75% annually, according to a 2013 study in