Here's why:

* Sensory organs are responsible for detecting stimuli. This includes sight, sound, touch, taste, smell, and even things like balance and temperature.

* The nervous system is responsible for receiving, processing, and responding to stimuli. Sensory organs act as the "input" for this process.

Here's a breakdown:

1. Sensory receptors within the organs detect stimuli. For example, light hitting the retina of your eye.

2. This information is converted into electrical signals. These signals travel along nerves.

3. The signals reach the brain or spinal cord. The brain then processes the information and determines an appropriate response.

4. The brain sends out signals to muscles or glands. This results in a reaction, like moving your hand away from a hot object.

So, while the sensory organs themselves are not the entire nervous system, they are a crucial component of it.