How big is a human egg?
The human egg (or ovum or oocyte) is probably the largest single cell in the human body. Sperm cells, the other half of the reproductive equation, are much, much smaller (in fact, sperm cells are the smallest cells in the human body).
The human egg is about 0.12 mm in diameter. That is about the size of a period (.) or a single strand of human hair. Therefore the human egg is just visible to the naked eye.
Although the egg itself is only the size of a full-stop, the whole ovary (which contains many immature eggs) is about 5 cm long.
Can I see the egg in my menstrual blood?
If the egg is unfertilized it will break down before a person starts their period. Therefore its very unlikely that someone would be able to find the egg (or bits of it) in their menstrual blood.
Do human eggs have yolks?
Yes. The yolk (“ooplasm“) is found at the centre of the human egg cell. It contains the cell’s nucleus (“germinal vesicle”) and nucleolus (“germinal spot”). Unlike the yolk sac in reptilian and bird eggs, the human yolk sac (“ooplasm”) is small and contains only a tiny amount of nutrition, just enough for nourishing the embryo in the early stages of its development. The placenta and umbilical cord begin to form 7-8 days after fertilization, and once fully developed they provide the embryo with all of its nutrition.
What does a human egg look like?
Under the microscope, the egg cell is a sphere surrounded by a radiant corona. It is translucent in appearance. Pictures of it are below.