Azoospermia is the medical condition of a man whose semen contains no sperm. It is associated with infertility, but many forms are amenable to medical treatment. In humans, azoospermia affects about 1% of the male population and may be seen in up to 20% of male infertility situations. 1 Classification 1.1 Pretesticular.
Nematocysts are the stinging cells on tentacles of a cnidarian, like a jellyfish. Since jellyfish don't have any teeth, and their body consists of gelatin, it's hard to captur â¦ e prey.Nematocysts help jellyfish with feeding by stinging the prey in an attempt at trying to immobilizing the prey.hat is a Cnidarian? cnidarians, such as jelly fish, sea anemones, hydra, and corals, have tentacles surrounding their mouth. they are a hollow-bodied animal with two celled layers that are organ â¦ ized into tissues. the inner layer forms a digestive cavity where food is broken down.
The phylum Cnidaria (pronounced nid-AIR-ee-ah) contains approximately 9000 living species worldwide. They are among the simplest of the so-called higher organisms, but are also among the most beautiful. The creatures in this phylum are radially symmetrical. This means that the parts of the body extend outward from the center like the spokes on a bicycle wheel. A common example of radial symmetry is the sea star (a member of the Echinoderm phylum) or the anemone, a Cnidarian (seen below). 1  The Cnidarians include the hydroids, jellyfish, anemones, and corals. All Cnidarians have tentacles with stinging cells in their tips which are used to capture and subdue prey. In fact, the phylum name Cnidarian literally means stinging creature.. The stinging cells are called cnidocytes and contain a structure called a nematocyst. The nematocyst is a coiled thread-like stinger.