BIOL 2001 Lecture Notes - Lecture 6: Mucous Gland, Flatworm, Symmetry In Biology
12 Nov 2018
School
Department
Course
Professor
Document Summary
They have a bilateral symmetry, are triploblastic acoelomates, have a tissue-organ level of organization. 4-cestoda: are internal parasitic and do not have a digestive tract. 1-rhabdites: small rod-shaped structures formed from the golgi body inside mucous gland cells. They swell to produce a viscous mucous once mixed with water. 2-dual-gland adhesive organs: organs composed of three cell types that allow the epidermis to attach and detach from substrate quickly. Paired viscid cells (glands): produce adhesive secretions that attach the microvilli of anchor cells to substrate. Anchor cells: produce subtle muscular contractions to pull the animal forward. Releasing cell (gland): produce secretions that release anchor cell attachment. Most platyhelminthes have a mouth, pharynx and central intestine with branching diverticula. Most have no anus (regurgitate undigested material), some have a single anus, some have many ani. 1-beating agella inside the ame cells (bundle into protonephridium) create a negative pressure that draws uid in through the mesh.
