Lots and lots and lots! If you look just at red blood cells, which live about 120 days, and are made at a rate of 2.4 million per second(!), then in a lifetime of 80 years (which I think will be seen as short in the near future) then a person will go through make about 6,054,912,000,000,000 or 6.054912 quadrillion red blood cells cells! So if you look at the whole body, which contains about 30 trillion cells, then you have to be looking at septillions of cells at least (10 with 24 zeroes after it!).
That’s a difficult question, but I can try to give a rough guess!
Apparently about 50 billion cells die and are replaced every day in the average adult. That means we go through about 18 trillion cells each year. These numbers will be less during childhood because we’re smaller and then made up of fewer cells, but this is just a rough guess anyway. If we work with the rough life expectancy of 80, then we will go through 1,460,000,000,000,000 cells in our life times – that is 1.46 quadrillion cells!
The average adult is made up of about 40 trillion cells (as a rough guess). This would then suggest that we remake ourselves about 35 times through our lives. This isn’t actually really true because some cell types die and are replaced a lot faster than others – particularly red blood cells where apparently 2.4 million are made every second!
Oh wow. Our answers are quite different and I think I might have messed up some of my calculations!
I think the main thing you can see here is that us scientists really don’t have all of the answers and don’t really have a good idea of how many cells we have or how many die each day!
Hey Matt, we two girls are from the Warwick Secondary School and are egar to ask you this simple question, if you were to count each stem cell in your body how many stem cells are their in each arm, leg, face e.t.c
That’s quite a difficult simple question! My guess is that there are between 10 and 100 million stem cells in the body, there will be more in the legs I think because there is more bone marrow which contains a lot of stem cells. Sorry I can’t give a clearer answer!
Comments
Dave commented on :
Oh wow. Our answers are quite different and I think I might have messed up some of my calculations!
I think the main thing you can see here is that us scientists really don’t have all of the answers and don’t really have a good idea of how many cells we have or how many die each day!
Girl Power!! commented on :
Hey Matt, we two girls are from the Warwick Secondary School and are egar to ask you this simple question, if you were to count each stem cell in your body how many stem cells are their in each arm, leg, face e.t.c
Matt commented on :
That’s quite a difficult simple question! My guess is that there are between 10 and 100 million stem cells in the body, there will be more in the legs I think because there is more bone marrow which contains a lot of stem cells. Sorry I can’t give a clearer answer!
13ymag commented on :
hi dave I am here at the warwick school and just wanted to ask how many stem cells do I make in a year ?