Light rays passes through the pupil in the eye and activates the neurons in the retina. The light wavers that are from the reflection of the object are transformed into neural impulses or transduction then action potentials are released when electrical charges are sent through the neurons. Excitatory neurotransmitters are supplied when action potential goes to the axon terminal and the thalamus routes the neural message from the retina elsewhere in the brain. Feature detectors organize the visual projection of the object.
The endocrine system or the skin (:
Isotopes are variants of a particular chemical element which differ in neutron number (neutral particle)and all isotopes of a given element have the same number of protons (positive particle) in each atom.So isotope B of the sodium will have 11 protons, 11 electrons but it may have a wide range in its number of neutrons.
Intestine, the intestine digests food involuntary.