What is the transport system of cnidarians?
Cnidaria do not have a circulatory system simply because it is not needed; all cells are in contact with the water, which contains oxygen and nutrients. The cells undertake a process of diffusion to transport the oxygen, nutrients and waste in and out of the organism.
Are cnidarians motile?
Medusa forms are motile, with the mouth and tentacles hanging down from an umbrella-shaped bell. Cnidarian morphology: Cnidarians have two distinct body plans, the medusa (a) and the polyp (b). Some cnidarians are polymorphic, having two body plans during their life cycle.
How do cnidarians move and respond to their environment?
Cnidarians respond to their environment using sensory cells and a simple, non-centralized nerve net. There is no cephalization (no head). Remember, they have radial symmetry! This nerve net is spread throughout the body rather than centralized.
What do cnidarians use to support their body?
In addition to a primitive digestive cavity, cnidarians have a decentralized nervous system, muscle tissue, reproductive tissues, and a hydrostatic skeleton. A hydrostatic skeleton is maintained by the internal pressure of fluids within the organism.
How do cnidarians excrete waste?
Cnidarians take in food through their mouths, which is then digested in the coelenteron. Nutrients are then passed to other areas of the body for use, and waste products are expelled either through the mouth or through surface cells via water circulation.
Why do cnidarians have nematocysts?
Nematocysts or cnidocysts represent the common feature of all cnidarians. They are large organelles produced from the Golgi apparatus as a secretory product within a specialized cell, the nematocyte or cnidocyte. Nematocysts are predominantly used for prey capture and defense, but also for locomotion.
Do cnidarians have a Coelom?
A coelom is a fully-encased, fluid-filled body cavity (gut) lined with mesodermic tissue. Cnidarians are not considered to have a coelom because they are diploblastic, so they don’t have any mesodermic tissue. Cnidaria are a phylum consisting of aquatic animals like jellyfish, anemones, and corals.
How do cnidarians defend themselves?
Cnidarians defend themselves and catch prey using their tentacles, which have cells called cnidocytes at their tips.
Do cnidarians have Coelom?
How do cnidarians maintain homeostasis?
Cnidarians secrete hormones from glands that allow them to maintain homeostasis. They use direct diffusion in order to circulate the necessary nutrients through its body.
How do nematocysts work for cnidarians?
The nematocyst is a coiled thread-like stinger. When the nematocyst is called upon to fire, the thread is uncoiled, and springs straight. The harpoon-like thread punctures through the cnidocyte wall and into the prey. Most Cnidarians also have a toxin in their stinger which helps to disable the prey.