Please enable JavaScript.
Coggle requires JavaScript to display documents.
Vet and animal bio - Week 5 - Lecture 1 (Echinococcus granolosus (hydatid…
Vet and animal bio - Week 5 - Lecture 1
Bilateria
Bilaterally symmetrical animals
Benefits
Associated with forward, directed movement, motor coordination
Allowed cephalizaton which is the formation of the head region
Resulted in sensor structures, eyes, etc)
Brain development in association with this
Mouth at cephalic end
Triploblastic organsisms
3 germ layers
Endoderm = surrounds gut region
Lining of GI tract, respiratory tubes, liver, pancreas
Mesoderm
kidneys, gonads, circulatory system, muscles, notochord and body cavity
Ectoderm
skin, hair, nails, mouth lining, tooth enamel
Benefits
Greater diversification in body form
correlates with greater body complexity and formation of many different body organs
2 germ layer
Germ layers give rise to specific tissues and organs
Advantage then is development of tissue level of organisation
Lophotrochozoa
Describing features of mouth
Phylum Platyhelminthes
Flat worms basically
use cilliation to walk along
Are acoelomate (no body cavity)
No circulatory system
Have simple gut, no anus, through mouth, out of mouth
Gastrovascular cavity = branches in large form and ramifies through body
Can't distribute nutrients very well = relies on diffusino
Relies on gas exchane
Facilatative anaerobes
Morphology
Organism is covered in Cilia, as it moves, mucus is secreted
Built within a roganism withoutna body cavity = Contains
branched intestine
ventral nervous system
Muscle
More features
Flame cell contain a lot of flagella = drives liquid through network = into excretory pores
Excretory system = very simple, drains directly from body across wall in excretory vessel
Predatory and free living species or parasitic (hence micropredators) many different relationships however
All are motiles - predatory although some parasites secondarily sessile
Sexual/asexual reproduction = parasitic species use asexual reproduction because of constraints of life cycle
4 classes
Class Turbelaria - free living: marine, fresh water, moist terrestrial (some parasites/commensals)
Free living, some commensal some parasitic, ciliated epidermis for locomotion
Class Monogenea = ectoparasites of fish
Class Trematoda - endoparasites (flukes)
Class Cestoda = endoparasitic tapeworms
Turbellaria VS. Other classes
Turbellaria
Mostly free living predatory
Epidermis - cellular and ciliated
Other classes
Always parasitic or always commensalism
Epidermis in larva is cil
Model species
Planaria = Important model for regeneration and stem cell biology
Models for aging = potentially immortal
They have telomeres
Overveiw: with no body cavity (Phylum Platyhelminthes), with body cavity (Phylum Mollusca, Phyum Annelida)
Acoelomate -no body cavity, body is solid.
Coelomate = fluid filled
Other classes in Lophotrochozoa
Monogenea
Always parasites and on fish
Life cycle very simple - eggs laid, fall of host, larva seeks nw host
Live on skin or gills
Posteria attachment devices
High host specificity = same fish
Trematoda (flukes)
Flat leaf-like body
Always parasites
Adults live in intestine of vertebrate hosts
Attach to mucosal wall by suckers
Feed on mucus, tissue fluid, blood
Most hermaphrodite
carry both sexual characteristics (male and female)
complex life cyles with two or more hosts
Live within bile ducts of hosts
Features of typical digenean trematode
Oral sucker = attachment and feeding
Ventral sucke (underneath organism) = attachment, both used for movement
Hermaphroditic reproductive system
Eggs also inside organism and are released to the outside
Fasciola Hepatica
Vet significance - condemnation of livers, disease, death in sheep, cattle, public health concerns
Important parasite of sheep and cattle
Both human and vet pathogen
Life cycle
Fluke lays eggs => eggs pass into host faeces into freshwater => may be in water =>Larval form hatches from eggs => searches of intermediate host (specific snail) begins to develop => asexual reproduction produces larva = exits snail and attaches to plant near water source => Host eats plants and becomes infected.
IMPORTANT
Becoming resistant to drugs and chemicals used to treat it.
Schistosomes
More classes of Lophotrochozoa
Cestoda (tapeworms)
Parasites of small intestine in vertebrates (high nutrient environment)
Tape like body
No mouth, digestive tract or anus - nutrients absorbed across body surface
Reproductive system replicated as chain
Along there body each reproductive units can produce eggs
Features
Scolex = head, so sucker, hook like regions = carries range of attachments devices
Neck = generation of new proglottids
Immature proglottids
with respect to reproductive organs
Mature proglottids
mature male and female organs
Gravid proglottids
egg bearing = Uterus with fertilised eggs, detach and pass out in hosts faeces
Strobila = neck + proglottids
Lifecycle of Beef tapeworm
In humans
Attaches to intestinal mucos
Each proglottids have reproductive system
Last one will break free from tapeworm and pass out into faeces
Eggs may end up in bovine = eat eggs on grass or a whole progloodid
Eating undercooked meat that was an infected cow will infect a human
Humans can be infected by tapeworms
Undercooked meat = if meat is infected
Echinococcus granolosus
hydatid tapewarms
Definitive host = Dog, dingo, fox
Intermediate host = shwwp, cow, marsupials and humans
New final host infected by ingesting contents of hydatid cyst from raw offal of infected intermediate host