In which parts of the body are cells not replaced when they die?
485659
I know at least in the Brain.
1107106
Our bodies die when our bodies die.\n\nYet most of our souls are much older, and may live on to be born into another body, or be trapped between existances as a ghost, or perhaps go to some sort of afterlife.\n\nBasically, no one knows for SURE.  It's simply impossible for an ordinary human being to know.
921540
It's different for each tissue in the body... some examples are: epithelial (skin) cells: 1 month, or neurons (brain cells) : 50 years.
931582
Stem cells are primal cells that retain the ability to renew themselves through cell division and can differentiate into a wide range of specialized cell types\n\nBone marrow (or medulla ossea) is the soft tissue found in the hollow interior of bones. It is the place where most new blood cells are produced.
243571
Your liver was meant to regenerate. Cells are constantly being createds and constanly dying, like your skin. But limbs are more complex. There are bones, nerves, veins, and muscle that would have to grow in. Your body is controlled by chromosomes that tell it how and what to grow, and most of us only grow two arms and two legs.
1082766
This is a remarkably good question and one we have been pondering for centuries.\n\nOne of the best answers we have now is that cells lose their ability to reproduce, to divide. They seem to have a limited number of times each cell may make a copy of itself. This is known as the Hayflick's Hypothesis (after the scientist who first figured it out). I think the current number is about 20 divisions for most end-line cells.\n\nYour chromosomes have a tiny bit called a telomere on the end of them. The telomere shortens with each cell division. It is sort of a score keeper.\n\nWhen a cell can no longer divide, the wear and tear bit becomes the problem. Just like your shoes, you wear them out and you cannot afford new ones. Same thing with your lungs and heart and liver and kidneys. Sooner or later, one or all malfunction. \n\nSome cells do not seem to mind the telomeres shortening and are immortal. Unfortunately those cells are cancers. We have a cancer line living in the lab, the HeLa line, that came from the cervix of a woman (Helen Lane or Lang, no one remembers for sure). Helen died probably 30 years ago but her cervical cancer is still alive. Strange immortality.
1180880
Death is defined differently depending on what institution or book you are accessing. Usually though, death is the complete and irreversible sesation of a heart beat and the death of brain activity (along with these, the lungs and other vital organs follow).\n\nIf our life solemnly depended on the functioning of cells, then you are right, it would not make sense to see people dying. But the human body, composed of several trillions of cells, needs to maintin certain levels of oxygen in order to keep these cells alive and in constant reproduction. So consider the following case, a person starts drowning, therefore he starts lacking oxygen. The lack of oxygen will eventaully lead to cells dying and thus the failure of the organ systems. After that, if the person isnt rescued, the whole body dies, thus the person dies. See how the human body doesn not only depend on cells in order to live? Thats why we die. \n\nAlso, as we age, the funcion of our cells becomes less and less productive. As we get old, so do our cells and guess what, they die too and are not always replaced. Eventually, the replacement of cells stops at some point.\n\nSo what gives us the strenght to do things? Its cells yes, but from a bigger point of view, its the nutrition that we give these cells. Cells run on ATP just like cars run on gas. If we eat the appropiate things, our cells will be stronger, and our bodies will too. Thus ATP is actual energy, energy that our cells provide to our tissues, to our organs, to our organ systems and to  us, as organisms-humans.\n\nThe reason why doctors cannot prevent death is simple, they cannot reverse the course of nature that our primary parents, Adam and Eve left for us to inheret. They sinned, inhereted death and illnesses and so did we. Although medical doctors can often make things better and help us feel that way too, expecting them to come up for a solution to death is a little to off, perhaps out of their league.
83068
people dont die form "old age" theres always a body part/organ/function that goes causing death.
779752
A living cell (like a cell from the liver, lungs, brain, etc...) will die soon after it was removed from its original "place" (liver, lungs, brain, etc.) as it has no more nutrients-supply (by blood venes, for example!) except it is kept in an artificial environment, a culture medium, which is suited to it's very specific needs.\n\nA living cell that is an organism needs a special suited environment, too (a diatom won't survive in the desert...). But it is not depending on an EXTERNAL supply of nutrients, as it "searches" its nutrients on its own. Bacteria, for example, don't need blood venes to grow in order to make cell division, they just need an environment which supplies all the needed nutrients. That's why bacteria can grow nearly everywhere, while lung cells  would die short after you dispersed them on an old dank sponge.\n\nHope I helped you. Excuse my English, please, it's not my first language. Good luck for tomorrow! ;-)
846449
the cell would not be able to grow or repair it self...the cell would most likely die.
795294
organelles perform a specific function for the cell (respiration, transportation, etc.) much like organs perform a specific function for an organism (circulation, respiration, etc.).  animal cells and plant cells have some organelles that are the same, but some are different (plants have cell walls and vacuoles, while most animal cells do not).
946598
The blood woudn't be circulating in the body anymore. The cell wouldn't get their oxygen, and they would die.  So would you.
1173651
Usually death is caused by the body organs failing or shutting down.   This is caused by increased growth of the cancer cells that spread to other organs other than where the cancer is and and cause them not to function properly.  Sometimes this growing or spreading of cancer cells and be slowed down or stopped with medication called CHEMO or by radiation.  Other times CHEMO and radiation are not sucessful  and the disease gets worse and leads to death.
1163429
New body parts grow by division of stem cells at the base. They divide, differentiate into the correct cells and grow larger. The bulk of cells dividing and growing larger provides the "pushing" out of new tissue.
710159
As the time goes by our cells decay and we loose them, some of them cells are never replaced and the process of aging starts to cave in, the skin begin to wrinkle and our organs start to slow down functions..☺
1027259
Hello Summerspirit,\n\nThanks for your question. I think this question deserved a better reponse than what it has received till now. Anyways, I'll try to compensate: \n\nFirst of all, neurons don't usually die at all. The neurons are the cells with the least regenerative powers in our body. Once killed, they cannot be replaced! But, as we grow older, some wear and tear is unavoidable and brain cells too are no exception to the wear and tear of ageing. \n\nStill, the brain cells are the last to die in our bodies as they are kept well oxygenated by an abundant blood supply.\n\nNow, the neuroglia cells that support the neurons are not as sustainable as the neurons and thus, are subject to regular wear and tear. So, there must be a path for them and other metabolic wastes to leave the brain, right? \n\nOur brain as opposed to popular conception is not a lump of matter floating in blood. It is floating alright but, not directly in blood. The brain floats in a colorless, transparent, plasma-like fluid called Cerebro-Spinal Fluid or CSF. The fluid provides a one way traffic from the cavities and membranes of the brain to the vein carrying used blood.\n\nSo, the CSF takes the dead brain-cells and flows towards a blood stream, then the waste matter is transferred to the blood.\n\nThe blood then takes the stuff to the kidneys which is known as the sieve of the human body. Kidney filters the metabolic waste from the blood to urine from where it is passed from the body.\n\nHope it helped to keep your summer spirit alive! Bye!
377948
Even the blood inside your body has to be replaced regularly, so it only makes sense that it doesn't last forever outside of your body!!