Earthworm Dissection Internal Anatomy

External Features:
- Segmented body with a clitellum.
- Mouth at the anterior end and anus at the posterior end.
- Setae for movement.
Internal Anatomy:
- Digestive System:
  - Mouth leads to the pharynx, esophagus, crop, gizzard, and intestine.
  - Crop stores food, gizzard grinds it.
- Circulatory System:
  - Closed circulatory system with dorsal and ventral blood vessels.
  - Five pairs of aortic arches act as hearts.
- Respiratory System:
  - No specialized respiratory organs.
  - Gas exchange occurs through the skin.
- Excretory System:
  - Consists of nephridia for excretion.
  - Nephridiopores excrete waste.
- Reproductive System:
  - Hermaphroditic with both male and female reproductive organs.
  - Clitellum for reproduction.

Pharynx: Initial part of digestive system for food intake.
Esophagus: Transports food from pharynx to crop.
Crop: Stores food temporarily for digestion.
Gizzard: Grinds food for digestion.
Intestine: Absorbs nutrients from digested food.
Dorsal/Ventral Blood Vessels: Transport nutrients and waste in circulatory system.
Aortic Arches: Pump blood in circulatory system.
Nephridia: Filter waste from blood in excretory system.
Nephridiopores: Excrete waste out of the body.
Reproductive Organs: Produce gametes for reproduction.
Clitellum: Secretes mucus for reproduction.