Test 3-Platyhelminthes Flashcards
Helminth
worm
Environment or Habitat
parasitic or free-living (water: lakes, streams, damp soil)
Common representatives
planaria, flukes, tapeworms
Planaria
free living fresh water example: turbellaria eyespots gray, brown, black regenerate lost body parts
Flukes
parasitic short and flat male and female live anywhere digestive system
Tapeworms
long and flat
cestoda: from uncooked meat that is infected, also fecal contamination
live in intestines
no digestive systems
Symmetry
bilateral not segmented
Muscular system
use cilia to move
Skin
3 layers
gas is exchanged across skin
avoids white blood cell detection-so it can get into humans
Digestive system
primitive
1 opening
branch digestive system
excretion by special cells and canals
Other organ systems
no respiratory, circulatory, or skeletal systems
Size
some less than 1 mm
others are several meters long
Nervous system
nerve endings come together at the anterior or head to form what is almost a brain
Organs
simple sense organs
simple muscles
Parasitic Characteristics
have special suckers for holding onto host
special skin to help avoid detection by host
can be harmful to humans
