Earthworm Dissection

Earthworms can live in tress, in bark, under rocks, along the river, springs and ponds, they prefer to live in the earth’s rich soil. They get their nutrition from things in the soil such as decaying roots and leaves. Earthworms don’t have lungs, but they breathe through their skin.  

Fun Facts

Earthworms are androgynous, producing both eggs and sperm.

Function of external structures

• clitellum - produces mucous slime during mating
• mouth- where the food goes in
• anus- releases undigested material
• male genital pore- opening where sperm from that worm is released during mating
• setae- bristle-like structures that help the worm grip surfaces and to move
• Prostomium- is a small projection that hangs over the mouth
• female genital pore- releases eggs
• sperm groove- Carries sperm from male genital pore to clitellum
• seminal receptacles- stores sperm received from other worms
• septum- Divides coelom into compartments
• segment- contract during movement
  
  

  

  
  

  

  
  
  
  
  

Function of internal structures

• pharynx- sucks in food
• gizzard - breaks down and grinds the food
• crop-  stores food
• esophagus-  food goes through here before it goes to the crop and after the pharynx
• intestine- food is broken down and absorbed by the blood
• ventral nerve cord- Relays messages between brain and body
• ganglia( brian)- masses of tissue containing many nerve cells
• ventral blood vessel- Transports blood to posterior end of body
• Dorsal blood vessel- Transports blood to anterior end of body
• septa- dividing wall between segments
• nephrida- expel excess water and metabolic waste from the blood
• testes-produces sperm for fertilization
• ovaries- where eggs are laid and stored until they mature
• buccal cavity - Holds for food and opens to Pharynx
• septum- Divides coelom into compartments
• seminal receptacles- stores sperm received from other worms
• central nerve cord-  helps the worm move and feel
• pseudohearts- pumps blood throughout the body
• sperm duct- openings in which sperm can pass through
• oviduct- a tube connecting the ovaries and the uterus
• typhlosole- provide surface area and increase absorption of nutrients
• seminal vesicles- storms sperm made by this worm to give away
  
  
  
  

  

  
  
  Incision Guide-

Cut a slit in the dorsal surface near the posterior pin

 Dissection video