BIOL 371 Lecture Notes - Lecture 16: Elephantiasis, Ascaris Lumbricoides, Kinorhyncha
Document Summary
Some are free-living and eat small organisms like yeast and bacteria. Have an external cuticle which is secreted by hypodermis (epidermis) Cuticle is shed as it grows and is made of collagen. Protects from environmental damage- the host digestive juices or dirt abrasions. The hypodermis is syncytial- all nuclei for cells are collected into 4 cords that run length of body. Hypodermal cords- dorsal and ventral hypodermal cords contain nerve cord and the lateral 2 contain excretory ducts. Muscles are only longitudinal contractile fibers with non-contractile cell body to inside, and. Non-contractile arms extend to the nerve cord (no nerves from the nerve cord) Have a mouth and a muscular pharynx to suck in food. Pass it down through the intestine for digestion. Have a anus which they blast their waste through. Increase pressure inside the body and open up the anus. Nerve ring around the pharynx but no real brain.
