Question

Describe the nervous system in Planaria with a well-labeled diagram.

Hint:

Planaria has the simplest bilaterally symmetrical nervous system, which is a precursor to more complex nervous systems in higher organisms.

Answer 1

Planaria, a type of flatworm, has a ladder-like nervous system with a simple cephalized structure. 
- Planaria has a bilaterally symmetrical body. 
- The cerebral ganglia (primitive brain) is present at the anterior end. 
- Two ventral nerve cords run longitudinally along the body. 
- Transverse nerve branches connect the ventral nerve cords, forming a ladder-like structure. 
- Ocelli (eyespots) on the head help in light detection. 

Functions of the Planarian Nervous System: 
1. Sensory Reception: Ocelli detect light, and auricles sense touch and chemicals. 
2. Motor Coordination: The nerve cords coordinate body movement. 
3. Reflex Actions: Planaria exhibits simple reflex movements in response to stimuli.