/**
 * file: karbytes_28_may_2024.txt
 * type: plain-text
 * date: 28_MAY_2024
 * author: karbytes
 * license: PUBLIC_DOMAIN
 */

The following text was copy-pasted from a conversation which karbytes had with ChatGPT-4o (which is newer version of ChatGPT than is ChatGPT-4) on 28_MAY_2024 at approximately 2:10PM Pacific Standard Time.

(Note that the chat user handle which did not appear on the ChatGPT web page chat interface appears as “karbytes” in this plain-text note).

* * *

karbytes

What are the longest living cells in the human body? What are the shortest?

ChatGPT

The longest living cells in the human body are neurons in the brain, which can last a lifetime. Some neurons in the cerebral cortex are present from birth until death. The shortest living cells are white blood cells (leukocytes) called neutrophils, which typically live for only a few hours to a few days. Neutrophils are constantly produced and replaced to maintain the body’s immune response.

karbytes

Why do those neurons live for so long?

ChatGPT

Neurons live for so long primarily because they are not easily replaceable. The human body has limited capacity to regenerate neurons, especially in the central nervous system. Consequently, neurons are designed to be highly durable and resilient, capable of maintaining their function for decades. They have robust repair mechanisms, efficient metabolic processes, and protective features like the blood-brain barrier to minimize damage and ensure longevity. This allows neurons to preserve crucial functions like memory and cognitive abilities throughout a person’s life.

karbytes

Do such cells ever divide?

ChatGPT

Neurons in the human body generally do not divide. Most neurons are post-mitotic, meaning they exit the cell cycle after their final division during development and do not undergo further division. This is because neurons are highly specialized cells with complex structures like axons and dendrites, making cell division impractical. Instead of dividing, neurons rely on maintenance and repair mechanisms to ensure their longevity and functionality throughout a person’s life. In some brain regions, like the hippocampus, a limited amount of neurogenesis (the creation of new neurons) can occur, but this is an exception rather than the rule.