Chapter 3 - Sensation Flashcards
What is the difference between sensation and perception?
Sensation is the activation of sensory receptors in various sense organs. Perception is the way that sensations are interpreted and organized into some meaningful fashion. You can sense something, but not know what it is, meaning you lack the perception to interpret the sensation.
What are sensory receptors?
Specialized forms of neurons that, instead of receiving neurotransmitters, respond to energy.
- Light (eyes)
- Vibrations (ears)
- Pressure/temp (touch)
- Chemicals (taste and smell)
What is transduction?
The process the sense organs use to transform physical energy into electrical signals. These impulses are then sent to the brain for processing.
What is habituation?
The tendency of the brain to stop attending to constant, unchanging information.
What is sensory adaptation?
Decreasing response of sense organs from exposure to continuous levels of stimulation.
Who was Uncle Bob?
Uncle Bob was a man who smoked 5 packs of Marlboros a day, and lived with 28 cats. He couldn’t detect the smell of smoke, his truck and tools all smelled like cigarette smoke. House smelled overwhelmingly like pets and cigarette smoke but neither he, nor his wife could smell it. Their senses had adapted.
What is the visible spectrum?
The wavelength of electromagnetic energy we can see, the waves are the right length to stimulate receptors in our eye. Other wavelengths are invisible to the eye.
What are the parts of the eye?
Cornea: Bends light waves so the image can be focused on the retina.
Iris: Its muscles control the size of the pupil. This is where the color in your eyes is.
Pupil: Iris opening that changes size depending on the amount of light in the environment (the black part inside the iris)
Lens: Changes shape to bring objects into focus.
Retina: Contains photoreceptor cells
Fovea: Central area of retina, greatest density of photoreceptor cells.
Optic Nerve: Sends visual information to the brain
Blind Spot (optic disc): Where the optic nerve leaves the eye, there are no photoreceptor cells here.
What are rods?
Rods are located in the periphery of the retina (about 120 million rods). They are very light sensitive, and allow vision in dim light. Vision in rods is only black, white and shades of grey.
What are cones?
Cones are located in the Fovea (about 6 million cones). They are activated in bright light, and are responsible for adding color and fine details to vision.
What are dark and light adaptation?
Dark adaptation is the recovery of sensitivity to visual stimuli in darkness after exposure to bright light.
Light adaptation is the recovery of sensitivity to visual stimuli in light after exposure to darkness. Light adaptation is responsible for the deer-in-headlights effect. When a deer is hit with high-beams they are essentially blinded while they wait for their eyes to adapting to the light.
What are the theories of color vision?
Trichromatic theory states that there are three types of cones: red, blue, and green. The different shades of color result from the amount of light received by each cone. Combination of cones and rate of firing determines the color seen.
The Opponent-Process theory states that there are four primary colors with cones in pairs, red-green pairs, and blue-yellow pairs. If one member of the pair is over-stimulated, the other can’t work. This is the leading color vision theory.
What is an afterimage?
Visual sensation persists for a brief time after original stimulus is removed. Afterimages support the Opponent-Process theory because after looking away from a stimulus, the over-stimulated member is too weak to inhibit the other member, leading to an afterimage. The flag example we did in class is an example of an afterimage. (The yellow parts turned blue, and the green parts turned red, leading to an American flag)
What are the types of colorblindness?
Monochrome - No cones, or cones not working. Can only see shades of gray.
Red-Green (Dichromatic) - Red or green cones not working, can only see in blue, yellow and gray. This is inherited genetically, mostly in males.
What are sound waves?
Sound waves are vibrations of air molecules, and they are measured in Hertz (Hz).
What is auditory localization?
This is the brains way of determining where a sound is coming from. The brain will calculate the difference in time it takes sound waves to reach the two ears. For example if it reaches the left ear first, then the right ear, the brain will know the sound came from the left hand side.
What are the types of hearing impairment?
Conduction Hearing Impairment is due to a damaged eardrum or bones in the middle ear. Hearing aids can help.
Nerve hearing impairment is due to damage to the inner ear or nerves/brain. Results from aging or exposure to loud noise. Hearing aids can’t help.
How does taste work?
Also referred to as gustation, a person will have about 500-10,000 taste buds, or receptor cells in the mouth. These taste buds can detect sweet, sour, salty, bitter, and Umami (brothy) tastes. Your taste receptors are replaced every 10-14 days. The 5 tastes work together with smell, texture, temperature and heat of food to produce taste sensations.
How does smell work?
Also referred to as olfaction, a person has olfactory receptor cells in their nose. There are over 1000 types of olfactory receptor cells, and over 10 million in total. The hair cells on the receptors are stimulated by chemical molecules in the air.
What are the Olfactory Bulbs?
Areas in the brain that receive signals from the olfactory receptor cells.
What is the Vestibular System?
The vestibular system fluid located in the ear canal that moves in response to movements of the head. The canals have hair cells that respond to fluid movement. The Vestibular system is responsible for sensing the position of your head, keeping your head upright, and maintaining balance.
What is the benefit of pain?
Pain is essential to survival because it motivates you to avoid/escape danger, and recover from injuries.
How is pain different from other senses?
Pain results from different stimuli than the other senses. The intensity of pain depends on physical stimulus and social/psychological factors. The treatment depends on physical injury and reducing psychological/emotional distress.
What is the Gate Control Theory?
When non-painful nerve impulses compete with pain impulses in trying to reach the brain. Creates a bottleneck or neutral gate. Shifting attention or rubbing an injured area decreases the passage of painful impulses.
