2. Helminth Phyla Phylum _____________________________ - Phylum _____________________________ - Phylum _____________________________ - (of little economic importance – we will not study them) ______________________________ - study of parasitic worms.
3. Phylum Platyhelminthes – Chapter 13 The flatworms are the planarians, trematodes, and tapeworms. Forms present in the phylum? ____________________________________________ ____________________________________________ ____________________________________________
6. Characteristics of the Phylum Platyhelminthes cont. 7. ________________________________________ ________________________________________ - absent in the tapeworms 8. _______________________________________ _______________________________________ - limits size so most flatworms are small and soft-bodied. 9. ________________________________________ - most flatworms are _________________ - both male and female organs occur in an individual
7. Taxonomy of the Phylum Platyhelminthes We will use the traditional taxonomy: Phylum Platyhelminthes Class Turbellaria – planarians Class Monogenea – monogenetic flukes Class Trematoda – digenetic flukes Class Cestoidea – tapeworms As in the Protozoa, a new taxonomic scheme has been proposed which divides the Turbellaria into several taxa. However, we will not use the new scheme and use the traditional taxonomy.
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11. Representative Turbellaria Dugesia – freshwater planarian It is a free-living scavenger. Bdelloura – commensal on the __________________________
17. 2 members of Class Monogenea Polystomoidella – parasite in the urinary bladder of the snapping turtle Microcotyle – parasite on the gills of the sheepshead fish. Note numerous clamplike structure on the opisthaptor.
18. Class Trematoda Trematodes are __________________________________ in all classes of vertebrates. These worms have become structurally adapted for a parasitic existance: 1. possess ___________________for attachment to host 2. have many types of ____________________to produce secretions for ___________________________________ or to produce a ___________________________ 3. have high _________________________(reproductive capacity) to increase chances of completing complex life cycles
19. Subclasses of the Class Trematoda Of the 3 subclasses in the Class Trematoda, we will examine 2 of them: Subclass Aspidobothrea (= Aspidogastrea) Subclass Digenea
20. Subclass Aspidobothrea Most are parasites in the viscera of ____________________ A few are parasitic in the intestines of ________________________________________________ Cotylogaster - a parasite in the small intestine of the sheepshead fish- is a representative of this subclass.
21. Subclass Aspidobothrea - Cotylogaster Characteristic structure is ______________________ composed of numerous shallow depressions called ____________________ (this sucker resembles bottom of tennis shoe)
23. Subclass Aspidobothrea - Cotylogaster Adults are monoecious: Male and female reproductive organs are similar to those of digenetic trematodes (I will discuss these shortly) Importance?
24. Life cycle of Cotylogaster Life Cycle – Addition of fish host: Adult in fish intestine clam eaten by fish Adult in clam viscera egg released into water hatches enters clam via free-swimming _______________________ incurrent siphon - has tufts of cilia - eyespots - long unbranched intestine
32. Trematode Digestive Tract ___________________________ is contained in oral sucker Muscular ___________________ creates sucking action Short esophagus leads into 2 long blind-ending _________________ (= intestinal ceca) No anus so ______________________________________________________
33. Digestion and the Parenchyma Food taken into the digestive tract consists of ______________________________ ______________________________ Proteins are digested in the lumen of the intestine and _______________________________are absorbed through the intestinal epithelium.
34. Parenchyma PARENCHYMA - loosely arranged cells filling space between internal organs. Major function is:
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36. Trematode Nervous System Ladder-type system consisting of anterior ganglionic mass, lateral nerve trunks, and connecting commissures. Sense organs of adults are at the cellular level within the tegument - ______________________________________________________________ Sense organs of free-swimming larval stages (miracidium & cercaria) are well developed: ______________________________________________________________
37. Trematode Reproductive Systems Reproductive systems are extremely elaborate and specialized Digenetic trematodes have ___________________________ - some produce as many as 25,000 eggs per day. Most digenetic trematodes are _________________________ - schistosomes are only dioecious group - monoecious forms commonly cross-fertilize but self-fertilization is possible
39. Male reproductive system Trematode sperm are unusual for 2 reasons: 1. ________________________________________________________ 2. ________________________________________________________ nucleus 2 flagella mitochondrion
40. Male reproductive system Shape and position of the 2 testes are important taxonomic characters Shape: Position: Combination of shape/position: branched tandem testes; lobed opposite testes, etc.
41. Male reproductive system Sperm ducts consist of 2 ____________________________ which join to form a single _______________________ Vas deferens leads into the cirrus sac (= cirrus pouch) that contains: - ____________________________ - sperm-storage area - _____________________________- produces fluids to maintain sperm - _____________________________- male copulatory organ which can be everted through the ______________________________ for copulation
42. Female reproductive system Single ovary produces ___________________________ which pass along the oviduct to the ___________________________ Taxonomic importance?
43. Female reproductive system Shape and position of the ovary in relationship to testes important in identification Shape: oval lobed branched
44. Female reproductive system Ootype is region of female system where: (1) ____________________________ (2) ____________________________
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46. Female reproductive system Vitellaria (= vitelline glands) - occur in _____________________ which generally stain intensely - secrete ______________________ which will coalesce in the ootype to form the _______________________ - vitelline cells containing this protein pass along vitelline ducts which join and lead into the ootype
47. Female reproductive system Mehlis' gland - surrounds the ootype - produces secretions that ______________________________ ______________________________in the ootype - stains a light pink
48. Female reproductive system ___________________________ leaves from the ootype and consists of a long, often highly coiled duct containing eggs and sperm As the eggs pass through the uterus, 2 processes occur: 1. 2. Uterus function -
49. Female reproductive system Anteriorly, the uterus leads into a strongly muscularized duct called the __________________________ - this functions as an ovijector, forcing eggs out the common genital pore - metraterm joins the cirrus sac at the __________________________
50. Trematode Anatomy – Representives We will examine the anatomy of Prosthogonimus macrorchis, the chicken and duck oviduct fluke, in lab.
51. Trematode Anatomy – Representatives We will examine the anatomy of Quinqueserialis , the muskrat cecal fluke, in lab.
52. Trematode Anatomy – Representatives We will also examine the anatomy of the immature adult of Leucochloridiomorpha from a snail. We’ll examine living specimens to see excretory system and beating of the protonephridia. We will compare living specimen to stained whole mount.