Ch. 10.1 The Retina Transduces Light into Neuronal Activity Flashcards
What is visible light?
It is a narrow band of electromagnetic radiation.
What is a wavelength?
The distance between two peaks in a repeated stimulus such as a wave, light, or sound.
What is a cornea
The outer layer of the eye
What is the lens?
A structure in the eye that help focus an image on the retina.
What is refraction?
The bending of light rays due to a change in density of a medium (air to the cornea or lens)
What is the name of the muscles which adjust the shape of the eye lens in order to focus?
Ciliary muscles
The process of focusing by the ciliary muscles and the lens to form a sharp image on the retina.
Accommodation
What controls the amount of light let into the eye?
The pupil (black part)
What muscles control the rotational movements of the eye?
Extraocular muscles
Where does the first stages of visual information processing occur?
The retina
What are the receptor cells that detect light called?
photoreceptors
What are the two kinds of photoreceptor cells?
- rods (long and narrow and most active at low levels of light)
- cones (responsible for color vision)
What is a bipolar cell?
A class of interneurons of the retina that receive information from rods and cones and pass the information to retinal ganglion cells.
What are ganglion cells?
A class of cells in the retina whose axons form the optic nerve.
What is the optic nerve?
Cranial nerve ll; the collection of ganglion cell axons that extended from the retina to the optic chiasm.
Do rod and cone photoreceptors release neurotransmitter molecules?
Yes
What are horizontal cells?
Specialized neurons that contact both the receptor cells and the bipolar cells.
What are amacrine cells
Specialized neurons that contact both the bipolar cells and the ganglion cells.
Rods, cones, bipolar cells, horizontal cells and ganglion cells : of these which produce action potentials or graded local potentials
Rods, cones, bipolar cells, horizontal cells produce graded local potentials (using neurotransmitters)
Ganglion cells produce action potentials
How do photoreceptors transduce light into chemical reactions?
- The photons that strike the discs are captured by special photopigment receptor molecules (called rhodopsin) in the rods.
- RETINAL dissociates from the opsin molecule revealing an enzymatic site.
- a bunch of chemical stuff happens resulting in hyperpolarization
Where are photons detected?
the rods and cones
What is a photon?
A quantum of electromagnetic energy in the range of wavelengths we call light
The rod and cone photopigments in the eye consist of two parts
A. RETINAL
B. opsin
What is the scotopic system
A system in the retina that operates at low levels of light and involves the rods. It does not respond to colors
What is the photopic system?
A system in the retina that operates at high levels of light, show sensitivity to color, and involves the cones.
