Cnidocytes and Nematocysts
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
A cnidarian's defining structure is the cnidocyte, a cell housing a coiled, harpoon-like nematocyst that fires on contact to capture prey.
Show
A jellyfish's tentacle fires thousands of nematocysts on contact, injecting venom that can subdue small prey or harm a larger animal.
Watch for
Nematocyst discharge is a one-time event — a fired nematocyst cannot retract or fire again without being replaced.