Invertebrate Morphology (EarthWorm) Flashcards
To understand parts of a Earthworm and it's functions
What is thickened band called?
Clitellum
What are the 2 segments called? Where are these found.
Peristomium an Prostomium, they are found near the anterior half of the worm.
What is the part of the worm that aids in the movement of the worm?
These little brown bristles are known as Chaetae. Which aid aid sensory and locomotion. There are usually 8 on each segment.
What are the male gonopores functions?
The male gonopores acts as an exit for the sperms. A sperm groove extends posteriorly to the clitellum and transfers the sperm to the female genital.
Where are the male gonopores located?
They are located near the edge of the transverse ridges.
What is the function of the seminal receptors ?
These receptors are pouch like structures located in the female reproductive system, and their function is to receive and store the sperm.
What are coelomic pores and where are they found ?
Coelomic pores are located on the dorsal midline in the groove between the segments. They open into the coelom and release coelomic fluids onto the animal to keep it moist. Each of these pores have a sphincter to prevent excessive fluid loss.
What is the function of the nephridiopore ?
Nephridiopores are an external opening to the kidney and they aid to excrete metabolic waste and fluid.
What are the 2 muscles called in an earthworm
Circular muscle and longitudinal muscle
What is the type of movement for an earthworm?
Peristalsis
What is the order of layers for an earthworm
Cuticle, epidermis, circular muscle, longitudinal muscle, stomatic peritoneum
What are the features of the longitudinal muscle and the circular muscle.
The Circular muscle lies inside the epidermis, and is reddish-brown in fresh preparations, these muscles are divided into rings in each segment.
The Longitudinal muscle is a thick white layered band that runs longitudinally without interruptions across the segments.
What are some features of the inner most layer of the Earthworm?
The stomatic peritoneum is a thin glistening layer that covers the inner surface of the longitudinal muscles.
What is the annelids gut composed of ?
It is composed of the Hindgut, the Midgut and the Foregut,
What are the functions and features of an Earthworm’s foregut system?
When food is present, the mouth of the earthworm opens into the buccal cavity, and the pharynx extends out of the mouth and pulls the food in. Once the food is inside the pharynx, the radial muscles contract and grind up the food into smaller pieces.
posterior to the Pharynx is the Esophagus, which serves as a passageway for the food to be transported down to the crop of the earthworm.
Posterior to the esophagus is the esophageal glands which are white lateral bludges from the esophagus into the coelom and contain fine parallel red blood cells. These glands aid in the removal of excess calcium and carbon dioxide from the blood by secreting white crystals of calcium carbonate into the gut.
Posteriorly to the last pair of calciferous glands lies the large, bulbous thin walled crop which acts as a place for food storage.
Posterior to that is the gizzard. This part of the gut is a large expansion that have thick heavy muscular walls used for mechanical digestion.
