Definition of demurrer 1: a response in a court proceeding in which the defendant does not dispute the truth of the allegation but claims it is not sufficient grounds to justify legal action 2: objection
blind spot. The beginning of the optic nerve in the retina is called the optic nerve head or optic disc. Since there are no photoreceptors (cones and rods) in the optic nerve head, this area of the retina cannot respond to light stimulation.As a result, it is known as the blind spot, and everybody has one in each eye.he beginning of the optic nerve in the retina is called the optic nerve head or optic disc. Since there are no photoreceptors (cones and rods) in the optic nerve head, this area of the retina cannot respond to light stimulation.
Developmentally, both the optic nerve & retina are outgrowths of brain. Optic nerve fibers from the retina converge on the optic disc, pierce near the posterior pole of the eyeball where four recti and ciliary vessels & nerves surround it. In the optic canal, it is related superomedially to the ophthalmic artery & nasociliary nerve.