Eukarya Kingdom: Animalia ٍSubkigdom : Metazoa Triploblastic Animal презентация

Characteristics
1. They are soft bodied, unsegmented worms.
2. They show bilateral symmetry and
dorsiventrally flat worms
3. Triploplastic.
4. Exo or Endo skeleton is completely absent.
5. The parasite shows suckers or hooks or both for attachment to the host body.
6. They are the first animals to illustrate the development of organ system.
7. A true body cavity or coelome is absent, and the space between the body organs is filled with loose parenchyma.
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Characteristics cont.
8. Circulatory and respiratory systems are absent.
9. Nervous system and sense organs are poorly developed.
10. Usually hermaphrodite animals.
11. May be free living (Turbellaria), ectoparasitic or endoparasitic. A few may be commensals.
12. The alimentary canal is either absent or highly branched. Anus is absent.(incomplete digestive system)
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Phylum Platyhelminthes is divided into three classes:
Class I:- TURBELLARIA
Ex. Planaria sp.
Class II:- TERMATODA
Order: Diginea
Ex1- Fasciola sp.
Ex2- Schistosoma sp.
Class III:- CESTODA
Ex. Taenia sp.
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CLASS I: TURBELLARIA :
1. Mostly free - living forms found in fresh or sea waters or on land.
2. Body is unsegmented and dorsoventrally flattened.
3. Epidermis is cellular or syncytial.
4 Intestine is either absent (Acoela) or simple and sac like (Rhabdocoela) or branched.
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Class:- Turbellaria
EX. : PLANARIA
.
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CLASS II : TERMATODA :
These are commonly known as flukes.
These are ectoparasitic or endoparasitic forms.
Body is unsegmented and enlongated.
Adhesive organs are, one or two suckers without hooks and spines.
Digestive tract is bifurcated and highly diverticulated. Anus is absent.
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CLASS
Trematoda
ORDER
Digenea
Fasciola sp.
Schistosoma sp.
ORDER
Monogenea
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Ex 1: Fasciola Hepatica
(liver flukes)
An endoparasite
Has 2 hosts(digenea)
Primary host : sheep
Secondary host : snail
Infective stage to
snail:miracidium
Infective stage to
sheep:metacercariae
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Anterior mouth
Has 2 suckers (oral and ventral)
Hermaphrodite
Body surrounded by tough resistant tegument
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1-Digestive system
Incomplete (has no anus)
At the anterior end of the body a mouth opening is present surrounded by oral sucker leading to buccal cavity, which lead to pharynx then into narrow oesophagus.
It opens into intestine which is divided into branches. Each gives side branches. The two branches end near the posterior end of the animal.
The tegument absorbs glucose from the host directly.
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2-Excretory system
In liver fluke the excretion is carried out by flame cells.
It has a longituidnal excretory canal. From it a number of branches will arise.
They branch again. The fine branches end with flame cells.
The longitudinal excretory canal opens at the posterior end through excretory opening.
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3-Reproductive system
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T.S in Fasciola Hepatica
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Testis
Main
excretory canal
Parenchyma
tissue
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Intestinal
caecum
Testis
Parenchyma
tissue
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Branch of
excretory canal
Vitelline gland
P.T.
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T
Sp
TC
LMF
P
T: Tegument
Sp: Spicule
LMF: Longitudinal muscle fiber
TC: Tegument forming cell
P: Parenchyma
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Ex. 2: Schistosoma sp.
Unisexual(dioecious)
Male having a gynecophoral canal
(schisto-soma = split body)
Live inside blood vessels and are commonly known as blood flukes.
Primary host : human
Intermediate hosts : Snails
Eggs excreted with faeces or urine.
Infectice stage of snail : miracidia
Infective stage of human :cercariae.
Vertebrate infected by penetration of the skin.
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CLASS III : Cestoda
Ex. : Taenia sp.
endoparasites
Body covered with thick cuticle.
Mouth , digestive tract and sense organs are absent.
Fertilization is internal.
The tapeworm use the scolex (diagram shown on the right), to attaches itself firmly to the host’ intestinal wall.
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The tip of the scolex is equipped with a retractable hook-bearing rostellum which acts like discs with teeth to hold onto the intestinal wall.
So, the tapeworm will just hang on to the intestinal wall and absorb food through their skin.
tapeworms do not have any digestive tracts and also lack mouths and digestive enzymes, unlike the other classes of platyhelminthes.
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Made up of many segments called proglottids.
Each proglottid is a reproductive unit that produces gametes.
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The neck produces segments called proglottids which make up the body and tail.
Each segment has both male and female reproductive organs.
Segments can produce eggs on their own but sometimes mate with other segments or even other tapeworms.
Segments absorb nutrients through their skin and have the ability to produce eggs.
Over time the segments fill with eggs and detach from the tail. They are then carried out of the body in the feces.
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Has at least 2 hosts
Though they are sexually hermaphroditic, self-fertilization is a rare phenomenon.
To permit hybridization, cross-fertilization between two individuals is often practiced for reproduction.
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Endoparasitic
Primary host : human
Secondary host: pigs or cattle
Infective stage to human : cysticercus
Infective stage to pigs:
eggs or proglottid
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