Perch Anatomy: Complete List of Biological Structures

External Anatomy of the Perch

• 1. Head: Structurally supportive and protective.
• 2. Eye: Visual stimuli.
• 3. Nares: Avenue for water to enter the oral cavity.
• 4. Mouth: Made up of the mandible and maxilla.
• 5. Operculum: Covers and protects soft gills.
• 6. Pectoral fin: Used like paddles; assist in direction change.
• 7. Anterior dorsal fin: Serves as a rudder for stability.
• 8. Posterior dorsal fin: Supported by rays; serves as a rudder for stability.
• 9. Caudal fin: Propels the fish through the water.
• 10. Pelvic fin: Assists in stability when swimming.
• 11. Anal fin: Assists in stability when swimming.
• 12. Lateral line: Sensory organ that allows the perch to detect changes in pressure, movement, and vibration.

Internal Skeletal and Sensory Structures

• 13. Gills: Organs for respiration.
• 14. Skull: Protects and supports the sensory structures and brain.
• 15. Vertebrae: Provides support to the spinal cord.
• 16. Spines: Assist in warding off predators.
• 39. Brain: Social learning, memory retention, and processing.
• 40. Olfactory nerve: Senses smell.
• 41. Olfactory bulb: Senses smell.
• 42. Spinal Cord: Carries impulses from the brain to the remainder of the body.

Digestive and Excretory Systems

• 17. Teeth: Help grasp prey during feeding and ensure food holds to the esophagus.
• 18. Oral cavity: Area inside the mouth containing teeth and tongue.
• 19. Tongue: Helps to push food toward the esophagus.
• 20. Esophagus: Connects the oral cavity to the stomach.
• 21. Stomach: Food is mechanically and chemically digested.
• 22. Pyloric caeca: Secrete digestive enzymes into the intestine that help in absorption.
• 23. Intestine: Nutrient absorption.
• 24. Rectum: Waste is stored until ready to be released.
• 25. Anus: Exit for digestive waste.
• 28. Liver: Makes bile, which helps in the breakdown of fats.
• 29. Gall Bladder: Stores bile before it is released.
• 30. Kidney: Filters blood of liquid wastes and sends them to the bladder.
• 31. Urinary Bladder: Stores urine.
• 33. Urogenital opening: Exit for both liquid waste and reproductive cells.

Circulatory, Reproductive, and Support Systems

• 26. Spleen: Circulatory and immune function.
• 27. Pancreas: Assists in regulating blood glucose.
• 32. Air bladder: Provides buoyancy when needed.
• 34. Testes: Create sperm.
• 35. Ovary with eggs: Produce and store eggs.
• 36. Atrium: Receives blood returning from the body.
• 37. Bulbous arteriosus: Maintains blood flow to the gills.
• 38. Ventricle: Pumps blood out to the gills.
• 43. Dorsal aorta: Blood travels through the body.
• 44. Ventral aorta: Blood travels through the body.