Question

What is the average life span of a red blood cell (RBC) in the human body?

Hint:

Think of how long a red blood cell survives before the spleen removes it, roughly four months.

Answer 1

Correct answer: About 120 days.

A red blood cell is born in the bone marrow and lives for close to four months before it wears out. As it moves through narrow capillaries again and again, its cell membrane gets damaged over time.

Old and worn out RBCs are removed by the spleen and liver. The body keeps making new RBCs to replace the ones that die, so the total count stays fairly steady in a healthy person.