About
Community
Bad Ideas
Drugs
Ego
Erotica
Fringe
Abductees / Contactees
Area 51 / Groom Lake / Roswell
Crop Circles and Cattle Mutilations
Cydonia and Moon Mountains
Dreams / Auras / Astral Projection
Flying Saucers from Andromeda
Free Energy
Fringe Science
Government UFO Coverups
Gravity / Anti-gravity
Life Extension
MJ-12 - The Alien-Government Conspiracy
Men In Black
Tesla
Society
Technology
register | bbs | search | rss | faq | about
meet up | add to del.icio.us | digg it

The Hayflick Limit

In the early 60's, Dr. Leonard Hayflick carried out research at the Wistar Institute in Philadelphia which led to the discovery of the "Hayflick Limit".

Hayflick found that lung tissue appeared to die out after the cells had divided a certain number of times (roughly 50). Cell cultures were also frozen after dividing 25 times. On revival, the cells would continue until the 50 division limit was reached, then die.

As the cells approached the end of their division limit, the cells would take on the appearance of old tissue. This appearance included age pigments (lipofuscin) which is also found in aged hearts and brain cells.

The discovery of the Hayflick Limit led to theories speculating on the existence of a cellular "clock". These clocks could be internally regulated for each individual cell (accounting for variations below and above the 50 limit) or controlled systemically by the hypothalamus of the brain.

Another possibility is that control is exerted by the DNA since DNA is known to contain our genetic blueprints. Dr. James Fries and Dr. Lawrence Crapo write,

"Probably, aging just happens, as the result of cumulative, random, and inevitable errors in translation of DNA into protein. The errors may even be a crucial part of a process that allows variation among individuals and thus allows natural selection."

Mistakes in cell division tend to accumulate from the actions of viruses, free radicals, radiation and chemicals to affect the healthy replication of DNA. As the system ages and the DNA becomes more damaged, the DNA repair mechanism can no longer perform to its optimum level.

Organisms and animals which have better DNA repair mechanisms tend to live longer than those who don't.

One technique used by lower life forms is to minimize cell replication during daylight hours to prevent radiation damage from ionizing rays such as UV.

Cell division is encouraged during the night to allow the best possible replication with a minimum of interfering radiation.

 
To the best of our knowledge, the text on this page may be freely reproduced and distributed.
If you have any questions about this, please check out our Copyright Policy.

 

totse.com certificate signatures
 
 
About | Advertise | Bad Ideas | Community | Contact Us | Copyright Policy | Drugs | Ego | Erotica
FAQ | Fringe | Link to totse.com | Search | Society | Submissions | Technology
Hot Topics
here is a fun question to think about...
Miscibility
Possible proof that we came from apes.
speed of light problem
Absolute Zero: Why won't it work?
Why did love evolve?
Capacitators
Intersection of two quads
 
Sponsored Links
 
Ads presented by the
AdBrite Ad Network

 

TSHIRT HELL T-SHIRTS