HeLa cells, development and human life spans of cells

Human cells that keep dividing To study cell division for medical and other purposes, biologists need human cells that continue to divide in culture in the laboratory. In 1951, researchers at Johns Hopkins University tried to culture a line of cells that would continue to live and multiply. Every cell sample they tried died out in a few weeks, because normal mammalian cells will divide only 20-50 times in culture before they die. Finally, cells from one sample kept dividing week after week, and eventually, year after year. These were called HeLa cells after their original source, a young Baltimore woman named Henrietta Lacks. The sample had been taken from a malignant tumor in her body. Unfortunately, she died a few months later, but HeLa cells have been grown since that time in laboratories around the world.

Sea Urchin Embryo Cell Division

Zebrafish development from 1 cell to hatching – 48 hours

Life Spans of Human Cells Cell Type

Life Span

Cell Division

Lining of esophagus

2-3 days

Can divide

Lining of small intestine

1-2 days

Can divide

Lining of large intestine

6 days

Can divide

Red blood cells

Less than 120 days

Cannot divide

White blood cells

10 hours to decades

Many do not divide

Smooth muscle

Long-lived

Can divide

Cardiac (heart) muscle

Long-lived

Cannot divide

Skeletal muscle

Long-lived

Cannot divide

Neuron (nerve cell)

Long-lived

Most do not divide

1. White blood cells help protect the body from infection and diseaseproducing organisms. How might their function relate to their life span? 2. Based on the data, how are the consequences of injuries to the heart and spinal cord similar to each other? How are they different from the consequences of injuries to smooth muscle?