About.com suggests that blind spots have an explanation rather than a function. The explanation is that the part of the eye that the optic nerve exits from does not have rods or cones, thus resulting in a blind spot. Scholarpedia states that blind spots are present only in vertebrates because eyes in vertebrates develop from the brains, as compared to cephalopods, whose eyes develop from the skin and therefore have no blind spots.Continue Reading
Scholarpedia goes on to say that there are a couple of hypotheses on why people do not notice their blind spots, also known as scotomas. The first hypothesis is that the brain fills in these blind regions, which suggests that both memory and imagination affect vision. This filling-in theory postulates that the brain adds objects, patterns and colors to the blind spot. The second hypothesis is that the brain merely ignores the blind spots.
However, Reference.com points out that blind spots beyond those found normally in every eye may be a sign of retinal disease. These pathological scotomata can be any shape or size. If they occur in the periphery of the field of vision, they are more likely to be ignored or to go unnoticed. Diseases that cause this include multiple sclerosis and tumors on the pituitary gland.Learn more about Human Anatomy
According to the New International Standard Medical & Health Encyclopedia, the hardest spot on the human body is the enamel covering the teeth. The next hardest spots are the bones that make up the human skeleton. Specifically, the jaw bone is the hardest bone in the human body, making it the next hardest spot on the body, according to the Chicago Museum of Science and Industry.Full Answer >
Fordyce spots are not caused by any specific condition, they naturally occur in some people. The spots are a type of sebaceous gland.Full Answer >
"Mystery spots" are found in many places around the United States, and are the result of unusual local topography. A mystery spot is typically purported to be a place where some force of nature, usually gravity, behaves in unusual and mysterious ways. Many mystery spots feature houses where visitors can walk at odd angles across the floor or walls and areas where water and dropped balls roll uphill.Full Answer >
Punctate foci are focal points of tiny spots or depressions. Punctate foci are seen in radiology exam results and denote the presence of possible disease. Punctate foci are commonly seen in the spine and brain.Full Answer >