7. Is the epithelium
vascularized? How do
nutrients and oxygen reach
the epithelium? Why is this
feature an important
evolutionary acquisition?

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
Epithelia are not
(capillaries do not reach their
cells). epithelium exchanges
substances diffusion with the
tissue situated under .

Since the epithelia not vascularized
minuscule injuries or scratches
happen all the donot trigger
bleeding do not expose blood to
contamination external agents.
This an important protective
discovered by evolution.