Unit 8 Terms - Annelida Flashcards
Polychaete
- Means many long hair or long bristles
- Have well differentiated head and parapodia on most segments
- Mostly marine
- Examples: Clam Worms, Christmas Tree Worm and Sabellid
Metameres
Repeating similar segments of a body, also known as somite or segment
Annuli
Externally marked circular rings
Metamerism
A division of the body into a series of segments
Setae
Tiny chitinous bristles
Prostomium
- Composes part of the head
- Anterior to the mouth
- First part of head
Peristomium
- Composes part of the head
- Foremost true segment of an annelid, bears the mouth
Pygidium
Posterior end of the worm, bears the anus
Parapodia
- Flaps that may be present on each segment
- Variously modified for locomotion, respiration, or feeding
What type of coelom formation?
Schizocoely
Peritoneum
- A layer of mesodermal epithelium that lines the body wall of each compartment
- Forms dorsal and ventral mesenteries that cover all organs.
Mesenteries
Peritoneal fold serving to hold the organ in position, double layer
Hydrostatic skeleton
A mass of fluid or plastic parenchyma enclosed within a muscular wall to provide the support necessary for antagonistic muscle action
Clitellum
- A reproductive structure found in Clitellata
- Example: Leeches or earthworms
Characteristics of Phylum Annelida
- Means little ring
- 15,000 species
- Triploblastic
Nephridia
- A pair for each segment
- Removes waste from blood as well as from coelom
Nephrostome
- Means kidney mouth
- Opening of nephridia, cilliated funnel
Nephridiopore
- Means kidney hole
- Exit for fluid waste from body
Type of circulatory system
Closed
Complete or incomplete gut?
Complete
Notopodium
Big, thick lobe of the parapodia, closer to the dorsal side
Neuropodium
Smaller lobe, closer to the ventral side
Oligochaetes
- Means few bristles or long hairs
- Mostly freshwater
- Examples: earthworms
Crop
Food storage, moves to the gizzard
Gizzard
Grinds food before it enters the intestine
Typhlosole
Infolding of intestinal wall to increase surface area and absorption
Chlorogogen Tissue
Lines the outside of the intestine, helps form the typhlosole, produces fat and glycogen
Eleocytes
- Fat cells, have been released from chlorogogen tissue
- May accumulate around wounds and regenerating areas
Dorsal Vessel
Functions as the true heart in oligochaetes, pumps to propel blood
Aortic Arches
Helps maintain blood pressure
Ventral Vessel
Carries blood out to all the tissues of the body
Hemoglobin
Pigment in blood, red
Neurosecretory Cells
Make chemicals that regulate reproduction and regeneration
Giant Axons
Nerve cells with high speed transmission, used for rapid escape
