Sensation and Eye Anatomy

Sensation

• Sensation is the basic experience of stimulating the body's senses (sight, hearing, smell, taste, touch, and balance.)
• Sensation is the process of detecting and encoding physical stimuli from the environment.
• Sensory receptors in sense organs convert physical energy (light, sound) into neural signals sent to the brain.

The Eye

• The eye is the organ of vision.
• The retina is the light-sensitive surface at the back of the eye.
• The cornea is the clear, dome-shaped front surface, focusing light.
• The pupil is a black opening controlled by the iris, regulating light.
• The lens is a transparent structure behind the pupil, focusing light onto the retina.
• The retina contains photoreceptor cells: rods (dim light, peripheral vision) and cones (color vision, bright light).
• The optic nerve transmits visual information from the retina to the brain.

The Visual Process

• Light reflects off objects and enters the eye.
• The cornea helps focus light.
• The pupil adjusts based on light levels.
• The lens focuses light onto the retina.
• The retina converts light into signals.
• The optic nerve sends these signals to the brain.
• The brain interprets the signals to create a visual image.

The Ear

• The ear detects sound.
• The outer ear catches sound waves (pinna, ear canal).
• The middle ear amplifies sound (eardrum, ossicles).
• The inner ear detects sound and balances (cochlea, semicircular canals).
• The cochlea contains hair cells that convert sound waves into signals.
• The auditory nerve transmits these signals to the brain.

Color Vision Theories

• Trichromatic theory: Three types of color receptors (red, green, blue).
• Opponent-process theory: Colors are perceived in opposing pairs (red-green, blue-yellow).

The Nose

• The nose warms and filters air.
• Olfactory organs (in the nose) are responsible for smell.
• The olfactory epithelium contains smell receptor cells.

The Tongue

• The tongue is a muscular organ used for chewing, speaking, and tasting.
• The tongue has different taste buds (filiform, fungiform, circumvallate, foliate).

The Skin

• The skin is the largest sensory organ.
• It is comprised of three main layers: epidermis, dermis, and hypodermis.
• The skin detects pressure, pain, warmth, and cold.

Perception

• Perception is the interpretation of sensory input into meaningful experience.
• Perception is selective and subjective.
• Perception is relatively constant despite changes in sensory input.
• Perception has organizing tendencies (e.g., figure-ground, grouping).

Motion Perception

• Perception of object movement and apparent movement.
• Perceptual illusions, occurring when the same retinal image is perceived differently.

Extrasensory Perception (ESP)

• Perception occurring outside known sensory processes.
• Categories include telepathy, precognition, clairvoyance, and psychokinesis.