The sensory receptors are responsible for the detection of stimuli. The bottom up and top down control are the two important processing that helps in the introductions of sensory information in the body.
Sensation is the process by which the organisms detect the internal as well as external stimuli. The three main process that are involved in sensation are detection of stimuli from the environment, the change of stimuli in electrical signal and then received by the brain for further processing.
.More than likely the arrow is pointing to a LYSOSOME.
Lysosomes are double membrane organelles produced by the Golgi Apparatus that contain enzymes that allow for foreign material to be dissolved when engulfed by the structure
