The information about the image via the eye is transmitted to the brain along the optic nerve. Different populations of ganglion cells in the retina send information to the brain through the optic nerve. About 90% of the axons in the optic nerve go to the lateral geniculate nucleus in the thalamus.
a 'Male' is a biological term and a Man is more of a gender based term which associates with many 'manly' behaviors in different contexts.
The difference between a man and a guy is also a difference of opinion in the eyes of the person who has a specific perception about men. In regular language, a guy and a man are not very different, but ask people individually, and each one has their own opinion.