Visual Perception - Sensation and The Eye Flashcards
What is the difference between sensation and perception?
Sensation is a physiological process in which sense organs detect and respond to sensory information; no meaning has been given and it is the same for everyone
Perception is giving meaning to sensory information by organisation and interpretation, resulting in a perception unique to each individual; includes sensation BUT IT INCLUDES SENSATION
Name the five sensory systems
Vision (eyes) hearing (ears) touch (skin) smell (nose) taste (tongue)
List the steps light goes through to reach the brain.
Light ➡️ source ➡️ Cornea ➡️ Aqueous humour ➡️ Pupil ➡️ Lens ➡️ Vitreous humour ➡️ Retina ➡️ Optic nerve ➡️ Brain
What are the two types of photoreceptors (specialised neurons in the retina)?
Rods and cones
What are rods responsible for and how many are there?
125 million Low levels of light/night vision No colour vision Not details Peripheral vision
What are cones responsible for and how many are there?
6.5 million High levels of light Colour Detail Central vision
What are the five processes of visual perception? RTTOI
Reception Transduction Transmission Organisation Interpretation
What is reception?
Process of receiving electromagnetic energy and taking it through the eye to the retina
What is transduction?
The process in which rods and cones convert electromagnetic energy to electrochemical energy - a form which can be recognised by the brain
What is transmission?
Process of sending converted electrochemical energy to the visual cortex via the optic nerve
What is organisation?
The process of arranging visual information in a meaningful way, using Gestalt and Depth principles.
What is interpretation?
The process in which the image is given meaning to and interpreted, resulting in a unique perspective
Define: cornea, aqueous humour, iris, pupil
Cornea: transparent, convex shaped membrane which helps protect the eye focus light through the eye
Aqueous humour: watery liquid at front of the eye with 3 functions: jell hold its shape, providing eye with water and oxygen, flushing out toxins
Iris: ring of muscles which changes size of pupil depending on light
Pupil: circular aperture in iris which lets light enter the eye
Define: lens, ciliary muscle, vitreous humour
Lens: convex structure which focuses light onto the retina
Ciliary muscle: muscle which controls the size and shape of the pupil; contracts to zoom in and elongates to zoom out
Vitreous humour: jelly like liquid in the eye which helps it hold its shape
Define: retina, blind spot, optic nerve
Retina: membrane made of photoreceptors which convert light into electrochemical energy
Blind spot: area in front of optic nerve with no photoreceptors, resulting in a gap in field of vision
Optic nerve: bundle of nerve fibres which send electrochemical energy to the visual cortex
