The Branchiobdellida are sister to the leech clade Hirudinida, which approximately corresponds to the traditional subclass Hirudinea. The main subdivision of leeches is into the Rhynchobdellida and the Arhynchobdellida, though the Acanthobdella are sister to the clade that contains these two groups.
Lumbriculidae blackworms. The most ancient annelid group consists of the free-living polychaetes that evolved in the Cambrian period, being plentiful in the Burgess Shale about million years ago. Oligochaetes evolved from polychaetes and the leeches branched off from the oligochaetes.
Both the oligochaetes and the leeches, having no hard parts, do not fossilise well. Leeches show a remarkable similarity to each other in morphology, very different from typical annelids which are basically cylindrical, with a fluid-filled space, the coelom body cavity. In leeches, the coelom is reduced to four slender longitudinal channels, and the interior of the body is filled with a solid dermis in between the various organs.
Typically, the body is dorso-ventrally flattened and tapers at both ends. Longitudinal and circular muscles in the body wall are supplemented by diagonal muscles, giving the leech the ability to adopt a large range of body shapes and show great flexibility.
Most leeches have a sucker at both the anterior front and posterior back ends, but some primitive leeches have a single sucker at the back. Like other annelids, the leech is a segmented animal, but unlike other annelids, the segmentation is masked by external ring markings annulations.
Of these segments, the first five are designated as the head and include the anterior brain, several ocelli eyespots dorsally and the sucker ventrally.
The following 21 mid-body segments each contain a nerve ganglion , and between them contain two reproductive organs, a single female gonopore and nine pairs of testes. The last seven segments contain the posterior brain and are fused to form the animal's tail sucker. The body wall consists of a cuticle , an epidermis and a thick layer of fibrous connective tissue in which are embedded the circular muscles, the diagonal muscles and the powerful longitudinal muscles.
There are also dorso-ventral muscles. The coelomic channels run the full length of the body, the two main ones being on either side; these have taken over the function of the hemal system blood vessels in other annelids. Part of the lining epithelium consists of chloragogen cells which are used for the storage of nutrients and in excretion. There are 10 to 17 pairs of metanephridia excretory organs in the mid-region of the leech.
From these, ducts typically lead to a urinary bladder , which empties to the outside at a nephridiopore. Leeches are protandric hermaphrodites, with the male reproductive organs , the testes , maturing first and the ovaries later. In hirudinids, a pair will line up with the clitellar regions in contact, with the anterior end of one leech pointing towards the posterior end of the other; this results in the male gonopore of one leech being in contact with the female gonopore of the other.
The penis passes a spermatophore into the female gonopore and sperm is transferred to, and probably stored in, the vagina. Some jawless leeches Rhynchobdellida and proboscisless leeches Arhynchobdellida lack a penis, and in these, sperm is passed from one individual to another by hypodermic injection. The leeches intertwine and grasp each other with their suckers. A spermatophore is pushed by one through the integument of the other, usually into the clitellar region.
The sperm is liberated and passes to the ovisacs, either through the coelomic channels or interstitially through specialist "target tissue" pathways.
Some time after copulation, the small, relatively yolkless eggs are laid. In most species, an albumin -filled cocoon is secreted by the clitellum and receives one or more eggs as it passes over the female gonopore. The cocoon of Hemibdella soleae is attached to a suitable fish host. When breeding, most marine leeches leave their hosts and become free-living in estuaries. Here they produce their cocoons, after which the adults of most species die.
When the eggs hatch, the juveniles seek out potential hosts when these approach the shore. However, veins which return oxygen-depleted blood to the heart are thin-walled and difficult to suture, particularly if the surrounding tissue is damaged.
If blood flow is restored through the arteries but not the veins, blood to the attached body part may become congested and stagnant. The reattached part will eventually turn blue and become lifeless and at serious risk of being lost.
In such cases one or two leeches can be applied to the area. A single leech feeds for approximately 30 minutes, during which time it ingests about 15 grams 0. After becoming fully engorged, the leech detaches naturally, and the appendage continues to bleed for an average of 10 hours, resulting in a blood loss of about grams.
When bleeding has almost ceased, another leech is applied to the appendage, and the process continues until the body has had time to reestablish its own working circulation network—usually within three to five days. On rare occasions a patient may develop an infection from microorganisms that live in the leech gut. For a comparison of the speeds of all creatures, see Base Creature Speeds.
While leeched, both the host's Health and Stamina will slowly drop. Italics denote creatures that have not yet been released! See also Gallery of Dossiers. Categories : Invertebrates Sanguinivores Creatures released in v Creatures released in Creatures released in v Creatures released in v Creatures released in v1 Creatures released in v Tameable creatures Unbreedable creatures Creatures that are immune to torpor Creatures that don't drop feces Creatures Aquatic Extant creatures.
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Frank still lives with his mother , while Rick leeches off his father. That was the only time that I have truly felt like a parasite because I felt I was leeching from people. Translations of leech in Chinese Traditional. Need a translator? Translator tool. Since the time of ancient Egypt, leeches have been used in medicine to treat nervous system abnormalities, dental problems, skin diseases, and infections.
This is because leeches secrete peptides and proteins that work to prevent blood clots. These secretions are also known as anticoagulants. This keeps blood flowing to wounds to help them heal.
Currently, leech therapy is seeing a revival due to its simple and inexpensive means of preventing complications. Medicinal leeches have three jaws with tiny rows of teeth.
The leeches are then allowed to extract blood, for 20 to 45 minutes at a time, from the person undergoing treatment. This equates to a relatively small amount of blood, up to 15 milliliters per leech.
Medicinal leeches most often come from Hungary or Sweden. There are several situations in which leech therapy may be used. People who may benefit include those who risk limb amputation due to the side effects of diabetes, those who have been diagnosed with heart disease, and those who are undergoing cosmetic surgery in which they risk the loss of some of their soft tissue. The therapy has also been recommended to treat blood clots and varicose veins.
People with anemia, blood clotting conditions, or compromised arteries are not candidates for leech therapy.2. To remove from a substance by the action of a percolating liquid: acids in groundwater that leach calcium out of the bedrock.