Nam lacinia pulvinar tortor nec facilisis. Lorem ipsum dolor sit asectetur adipiscing elit. Fusce dui lectus, congue vel laoreet ac, dictum vitae odio. Nam risus ante, dapibus a molestie consequat, ultrices ac magna. ![]() Lorem ipsum dolor sit amet, consectetur adipiscing elit. Based on the response of the underlying neurons, you can identify which of the above cell types are present in the ganglion. Then you will virtually probe the ganglion by stimulating the skin of the leech with mild, moderate, or strong stimulation. In this lab you will observe the dissection of a leech to reveal a ganglion. Another type of neuron, the annulus erector neuron (X) causes bumps to form on the skin as leech contracts. Two large R cells in the center of ganglia may secrete serotonin and control the activity level of the leech. These are attached to the body wall and appear to control the secretion of mucus from the skin of the leech. The leech also has a cell type in its CNS called Retzius cells (R)a. The sensory input component consists of three different types of neuron cells [touch (T), pressure (P), and nociceptive (pain) (N) cells. ![]() Inside each ganglion are about 400 neurons which constitute a sensory input, motor output system, and allow the leech to have a large number of complex behaviors. Instead it has a number of small brains called ganglia. Some leeches can survive up to 10 years.Unlike humans and most other vertebrates, a leech does not have a large brain in its central nervous system (CNS). ![]() They can survive loss of 9/10 of their body weight and exposure to heavy chemicals.ĭifferent species of leeches have different lifespan. They produce large number of eggs and lay them either in a cocoon or store them in their own body. Leeches are able for self-reproductions (they do not require partner for reproduction). Leeches are hermaphrodites which mean they have both male and female reproductive organs. Leeches have several natural predators: large mouth brass, larvae of a dragonfly, catfish… This method is very old, dating back from 1000 years B.C. Leeches are used for bloodletting in medicine. Also, leech releases anticoagulant, called hirudin, which prevents blood coagulation.īoth anticoagulant and anesthetic produced by leech are used in medicine for the production of drugs. Leech produces anesthetic which reduces the pain and allows undisturbed extraction of blood. Since they are able to eat a lot in a single meal, leeches can survive without food period of one year.Īlthough leech pierces skin and sucks a huge amount of blood, process is not painful at all. Once they are full, leeches will detach from the victim. They can ingest amount of blood that is five times bigger than their own weight. They eat blood of mammals, birds, reptiles and fish. ![]() Certain species of leeches consume decaying plant material or various worms and insects.īlood-eating leeches use their suckers to attach to the skin of various animals. Due to similarity with the nervous system of humans, leeches are often used in the investigations of brain disorders. Their teeth are even able to pierce thick skin of a hippo. Most species have three jaws equipped with small, sharp teeth. Leeches have suckers on both ends of their body. Most leeches are usually 0.3 to 3 inches long.īody of leeches is composed of 34 segments. Some species can reach 16 inches in length. Unfortunately, number of medical leech in the wild is decreased due to habitat loss (as a result of increased agriculture), water pollution and introduction of invasive species. It is used for several medical procedures. The most popular species of leeches is Hirudo medicinalis, better known as medical leech. One fifth of all leeches live in the sea, while certain species live attached to the forest vegetation. Leeches usually inhabit marshes, rivers and ponds. They differ in size, type of diet and habitat.
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