Ch.5 Sensation Flashcards
Adaptation
Refers to the decreasing response of the sense organs, the more they are exposed to a continuous level of stimulation
Transduction
Refers to the process in which a sense organ changes, or transforms, physical energy into electrical signals that become neural impulses, which may be sent to the brain for processing
Sensations
Relatively meaningless less bits of information that result when the brain processes electric signals that come from the sense organs
Perceptions
Meaningful sensory experiences that result after the brain combines hundreds of sensations
When you see an object, the eye
Reverses the image so it’s upside down in the eye but the brain turns objects we see right side up so we see the world as it is
Cornea
The rounded transparent covering over the front of your eye
The curved surface of the cornea focuses and bends light waves into a narrower beam
Pupil
- Light passes through pupil after passing through the cornea
- A round opening at the front of hour eye that allows light waves to pass into the eye’a interior
- Grows larger or smaller because of iris
Iris
- A circular muscle that surrounds the pupil and controls the amount of light entering the eye
- iris contains pigment which gives eyes the color
What does an iris do in dim light? In bright light?
Dim light-iris relaxes, allowing more light to enter and the pupil dilates
Bright light-iris constricts, allowing less light to enter, pupil constricts
Lens
- A transparent, oval structure whose curved surface bends and focuses light waves into an even narrower beam
- the lens is adjusted to muscles that adjust the curve of the lens which adjusts the focusing
Retina
- located at the very back of the eyeball
- a thin film that contains cells that are extremely light sensitive (photoreceptors) and begin the process of transduction by absorbing light waves
Nearsightedness occurs when
The eyeball is too long so that objects are focused at a point in front of the retina
Farsightedness (hyperopia) occurs when
The eyeball is too short and objects are focused slightly behind the retina
How many layers does the retina have
3 layers of cells
Fovea
Location of many cones in the eye and is in the center of the retina
Rods have.
Rhodopsin
Cones have…
Opsins
Rods allow us to see
In dim light but only in black and white with shades of gray
Cones allow us to see
Color and fine details
Transduction in the eye occurs when:
- Rods and cones breakdown after absorbing light waves
- Breakdown of the cells generates a tiny electrical force which will
- trigger nerve impulses in neighboring ganglion cells
Blind spot in the eye
The point where the optic nerve exits the eye and goes to the brain
Layers of the retina
Back layer:rods and cones (where transduction occurs)
Middle layer: ganglion cells which is where impulses begin
Front layer: contains nerve fibers which carry impulses to brain
Impulses go to which brain parts
Optic nerve ➡️thalamus➡️primary visual cortex➡️visual association areas
Thalamus role in vision
Does some initial processing then relays the impulses to the occipital lobe
Function of primary visual cortex in vision
Turns impulses into basic lines and shadows
Visual agnosia
Having difficulty in assembling simple visual sensations into more complex meaningful images
Visual association area
Turns meaningless info from the primary visual cortex into meaningful images
Red wavelength
The longest of all the colors we can see
Trichromatic theory
Says that there are three different kinds of cones in the retina and each cone contains one of three opsins
Three opsins show colors of red, blue, or green
Creator of the trichromatic theory
Thomas young
Afterimage
A visual sensation that continues after the original stimulus is removed
Creator of opponent-process theory
Ewald Hering
Opponent-process theory
Says that ganglion cells in the retina and cells in the thalamus of the brain respond to two pairs of colors red-green and yellow-blue
According to opponent process theory, when cells are excited they use this color of this color
Red (green when inhibited)
Blue (yellow when inhibited)
Color blindness
The inability to extinguish two or more shades in the color spectrum
Monochromats
People with total color blindness and can only see black and white
Dichromats
Have trouble extinguishing red from green because they only have two kinds of cones instead of three
High amplitude of sound waves means
Loud sounds
High frequency of sound waves means
A high pitch
Loudness
Your subjunctive experience of a sounds intensity
Pitch
Our subjunctive experience of a sound being high or low which the brain calculated from specific stimuli
The outer ear: consists of three structures
- External ear-an oval shaped structure
- the auditory canal-a long tube that funnels sound waves down it’s length so that the waves but the eardrum
- tympanic membrane-a taunt, thin structure, sound waves hit it and cause it to vibrate (aka the eardrum)
Middle ear:one key structure
The ossicles; hammer, anvil, and stirrup
Greatly amplify the vibrations and on turn cause the oval window to vibrate
Cochlea
- inner ear
- Contains the receptors for hearing and it’s function is transduction
Hair cells
Stick up from the cochlea’s bottom membrane (the basilar membrane), the cells are bent by vibrations which creates an electrical force and triggers a nerve impulse
Auditory nerve
A band of fibers that carry nerve impulses to the auditory complex for processing
Primary auditory cortex
- located at the top edge of the temporal lobe
- transforms nerve impulses into basic auditory sensations, such as meaningless tones of various pitches and loudness
Auditory association area
Receives meaningless auditory sensations in the form of neural impulses and combines them into meaningful songs, words, melodies, or sentences
How does the brain figure out the direction a sound comes from?
Calculates the slight difference in time for the sound waves to get to each ear
Frequency theory
Applies to low pitches sounds, says that the rate at which nerve impulses reach the brain determines how low a pitch is
Place theory
Says that the brain determines medium to higher pitched sounds on the basis of the place on the basilar membrane where maximum vibration occurs
Vestibular system
- Located above the cochlea in the inner ear
- filled with fluid that loves in response to your head
- functions are to keep the head upright, maintain balance, and sense the position of your head
Motion sickness
Consists of feeling discomfort, nausea, and dizziness in a moving vehicle
Cause of motion sickness
A sensory mismatch between the information from the vestibular system and eyes- vestibular system tells you your heads bouncing but your eyes tell you things in the distance look steady
Ménière’s disease
Results from a malfunction of the semicircular canals of the vestibular system; includes sudden dizziness, nausea, vomiting, spinning, and head splitting buzzing sounds
Vertigo
Symptoms are dizziness and nausea, results from malfunction of the semicircular canals of the vestibular system
Five basic tastes
Sweet, salty, sour, bitter, umami
Taste buds
Shapes like mini onions, chemicals dissolve in saliva and activate taste buds which produce nerve impulses that go to the parietal lobe
How often are taste buds replaced?
About every 10 days
About 25% of people are
Supertasters a genetic trait
Flavor
We experience flavor when taste and smell are combined
Olfaction
- is called a chemical sense because it’s stimuli are various chemicals that are carried by the air
- sense of smell
Olfactory cells
Receptors for smell and are located in two 1 inch square patches of tissue in the uppermost part of the basal passages
The sense of touch includes
Pressure, temperature, and pain
The skin has how many layers?
3
Outermost layer of skin contains
A thin layer of dead cells with no receptors
Hair receptors
- respond when hairs are bent
- when hairs are bent for a while, the receptors stop firing-sensory adaptation
- in the middle and fatty layer of the skin
Free nerve endings
- near the Bottom of the outer layer of skin
- transmits information on both temperature and pain
Pacinian corpuscle
- in the fatty layer of the skin
- has distinctive layers
- highly sensitive to touch
- only type of receptor that responds to vibrations
Somatosensory cortex
- located in the parietal lobe
- transforms nerve impulses into sensations of touch, temp, and pain
Gate control theory
Says that non painful impulses compete with pain impulses in trying to reach the brain. This competition creates a bottle neck or neural gate through which only a limited number of impulses can be transmitted
Endorphins
Chemicals produced by the brain and secreted in response to injury or sever physical or psychological stress
Dread affects
A persons perception of pain
Cochlear implant
A miniature electronic device that is surgically implanted into the cochlea
Conduction deafness
Can be caused by wax in the auditory canal, injury to the eardrum, or malfunction of the ossicles. These conditions interfere with the transmission of vibrations. Can be treated with hearing aids often
Neural deafness
Can be caused by damage to the auditory receptors (hair cells), which prevents nerve impulses from reaching the brain. Cochlear implant helps treat it
Decibel
Way of measuring loudness of sounds
