Ento Key

Retinal rods and cones are highly specialized neurons that transform light into an electrical signal (see Chapter 18 ) and provide the sensory input for vision. In contrast to most…

Introduction The electroretinogram (ERG) is a useful tool for objective, noninvasive assessment of retinal function both in the clinic and the laboratory. It is a mass electrical potential that represents…

Overview Phototransduction is the series of biochemical events that leads from photon capture by a photoreceptor cell to its hyperpolarization and slowing of neurotransmitter release at the synapse. This overall…

Introduction The outermost, fibrous tunic of the human eye consists of the cornea and the sclera ( Fig. 4.1A,B ). Both are soft connective tissues that provide structural integrity to…

Introduction The cranium protects the brain and provides scaffolding for facial structures. During primate evolution, the orbits were enlarged and reoriented toward the front of the face. This, along with…

Tear film overview The tear film overlays the ocular surface, which is comprised of the corneal and conjunctival epithelia and provides the interface between these epithelia and the external environment….

Introduction Rod and cone photoreceptors transduce light, and they operate over different levels of illumination and chromatic ranges. In the vertebrate retina, there is a single type of rod and…

Vision from starlight to sunlight The human visual system operates effectively over an enormously wide range of intensities, of at least a billion-fold, from around 10 −4 cd m −2…

The basic architecture, signal flow, and neurochemistry of signaling through the vertebrate retina is well understood: photoreceptors, bipolar cells (BCs), and retinal ganglion cells (RGCs) are all thought to be…

Introduction Somatosensory innervation of the eye is provided by the peripheral axons of a small number of primary sensory neurons located in the trigeminal ganglion (TG). Most sensory axons enter…