Vision Flashcards
(42 cards)
The Transformation of sensory information into neural signals.
Transduction
The process of obtaining information about the environment and transmitting it to the brain for processing
Sensation
The process of interpreting sensory signals sent to the brain
Perception
A narrow focus of conciousness
Attention
The combining of simpler meanings to construct more complex meanings
Bottom-up processing
The use of knowledge and expectation to interpret meanings
Top-down processing
Most important sensory systems in humans with about 50 percent of our cerebral cortex responding to visual information but only 3 for hearing and 11 percent for touch and pain
Visual Stimulus: Light
The energy that we can see and is one of the forms of electromagnetic radiation produced by the sun.
Visible light
Radiation emitted in the form of energy waves
Electromagnetic Radiation
The distance between successive peaks of a wave; determines color in visible light
Wavelength
Individual, indivisible , very small particles that form waves of electromagnetic energy.
Photons
A unit of measurement equaling 10-m used to measure light wave frequency
Nanometers
light that is visible to humans occupies a small part of the _______ (appears white in teh human eye)
•The range of electromagnetic energy visible to humans falls between 400 and 700 nanometers (nm). A nanometer is 10-9 meters, or one billionth of a meter.
When we say a light has a wavelength of 400 nanometers, this means that the peaks of the wave are 400 nanometers apart. Shorter wavelengths, approaching 400 nm, are perceived by humans as violet and blue, whereas longer wavelengths, approaching 700 nm, are perceived as red.
The Electromagnetic Spectrum
The 3 Light that Interacts with objects
Absorption
Reflection
Refraction
The ability to retain something rather than reflect or transmit it to another location
Absorption
The bending back of light toward its source
Reflection
The deflection, or changing of direction of light at a boundary such as that between air and water
Refraction
produced in the lacrimal gland at the outer corner of each eye. The fluid not only is composed primarily of water and salt but also contains proteins, glucose, and substances that kill bacteria.
Tears
flush away dust and debris and moisten the eye so that the eyelids don’t scratch the surface during blinks.
Basal tears
share a similar composition to basal tears but are released in large quantities in response to chemicals, bright lights, or debris in the eye.
Reflexive tears
Contain more hormones than basal or reflex tears, including leu-enkephalin, which acts as a natural painkiller
Emotional Tears
A rapid closing of the eyelids
Blink/blinking
Is roughly a sphere with a diameter of about 24mm, just under one inch, and individual variations are very small, no more than 1 or 2 mm.
Eye
-The white outer covering of the eye
- helps the fluid-filled eyeball maintain its shape
Sclera