SAFMEDs Chapter 6: Sensations

Question 1

Sensation

Answer 1

-The process by which our brain and nervous system receive input from the environment through our five senses

Question 2

Transduction

Answer 2

• one form of energy transforms into another
• electromagnetic light waves are received by our sense of vision and transformed into electrochemical energy our brains can understand

Question 3

Wavelength

Answer 3

• the distance from one wave peak to the next

- the brain is able to determine the wavelength by how active each of the color cones is

Question 4

Intensity

Answer 4

• the amount of a wave’s energy

- measured by amplitude or height

Question 5

Photoreceptor

Answer 5

• transduce light energy into electrochemical energy
• light receptor cells
• turns light into nerve impulses

Question 6

Hue

Answer 6

• comes in red, green or blue

- the color we experience

Question 7

Visible spectrum

Answer 7

-the band of wavelengths the human eye can see

Question 8

Cornea

Answer 8

• the outer layer of the eye
• transparent, convex, covers the front of the eye
• bends light toward the center of the eyeball

Question 9

Iris

Answer 9

• the colored part of the eye
• adjusts the dilating and constricting in response to the brightness in the environment to let in more or less light
• muscle

Question 10

Pupil

Answer 10

• the black part at the center of the eye

- the product of the opening the iris creates

Question 11

Lens

Answer 11

• transparent structure behind the pupil
• cureved and flexible
• changes curvature to help focus images
• flips the image and focuses the inverted image

Question 12

Aqueous humor

Answer 12

• chamber behind the pupil and iris

- filled with watery fluid

Question 13

Vitreous humor

Answer 13

-jelly like fluid that light waves pass through before hitting the retina

Question 14

Retina

Answer 14

-light sensitive layer at the back of the eye

Question 15

Visual accommodation

Answer 15

-the process bby which the lens flips an image and focuses the inverted imahe before passing through to the retina

Question 16

Rods

Answer 16

• photoreceptors that detect black/white/grey
• work in very dim light
• “night vision”

Question 17

Cones

Answer 17

• photorecptors that function in bright light
• located in and around the fovea
• three types: red, green, blue
• allow us to perceive color
• the brain is able to determine the wavelength by how active each of the color cones is

Question 18

Fovea

Answer 18

• the central point of the retina
• part of the macula
• cones are located in and around

Question 19

Optic Nerves

Answer 19

-the nerves that send signals from the eyes to the brain

Question 20

Optic chiasm

Answer 20

-where the fibers from each optic nerve crosses into the opposite side of the brain

Question 21

Peripheral vision

Answer 21

• the eye’s ability to see things on the side of our field of vision when looking straight ahead
• not as good as our ability to see things straight on

Question 22

Blind spot

Answer 22

• The disc where the ganglion cells meet at the back of the eye
• Since it is a hole in the retina there are no photoreceptors present
• you cannot see there

Question 23

Saccade

Answer 23

• reflexive rapid eye movement from side to side
• keeps different neurons firing
• fills in the missing information created by the blind spot
• occurs during reading, talking in a scene and certain stages of sleep

Question 24

Dark Adaptation

Answer 24

• the ability to adapt to quickly darkening conditions
• pupil opens quicly to allow for more light waves to enter the eye
• Increased retinal sensitivity in the rods
• going from a bright hallway to a dark movie theater

Question 25

Rhodopsin

Answer 25

• a light-sensitive pigment in the rods that helps the rods deal with low-light conditions
• overexposure to sunlight decreases this chemical

Question 26

Feature Detectors

Answer 26

• react to the strength of visual stimuli
• responds to shapes, angles, edges, lines and movement in our field of vision
• feature detectors in other locations in the brain have specialized functions
• the brain takes the information received from feature detectos and makes a series of interpretations that allow us to see what we see

Question 27

Parallel Processing

Answer 27

• the brain can multitask

- color, motion, shape and depth are processed simultaneously by feature detectors

Question 28

Trichromatic Theory (Young-Helmholtz

Answer 28

• earliest theory about why we can only see color on the visible spectrum
• the three cone types in the retina work together to potray a range of colors, producing only red, green or blue
• we see a specific color by comparing responses from the three types of cones
• color depends on the strength of cone types that are firing
• when all three cones are equally active we see white or gray

Question 29

Opponent-Process Theory

Answer 29

• focuses on brain processes rather than the eye
• three opponent channels (red-or-green, blue-or-yellow, black-or-white)
• light waves will excite one color in a pair that will inhibit the excitation in its opposing color
• black-white are achromatic and detect luminace (light-dark changes)

Question 30

Afterimage

Answer 30

• a visual sensation that remains after the stimulus is removed
• staring at one color fatigues the sensors for that color

Question 31

Color blindness

Answer 31

• the inability to perceive color differences
• caused by a lack of shoty, medium or long wavelength cones in the fovea
• gentic condition caused by the recessive trait on a chromosome
• diagnosed using the Ishihara test (dot test)
• color deficiency occurs in 8% of men and 1% of women
• total color blindness is rare

Question 32

Audition

Answer 32

-the biological proces by which our ears process sound waves

Question 33

Amplitude

Answer 33

-affects the psychological quality of loudness (sound pressure or intensity)

Question 34

Pitch

Answer 34

-affected by the wavelength of sound waves

Question 35

Frequency

Answer 35

• the number of wavelength cycles in a unit of time

- measured in Hz

Question 36

Pinna

Answer 36

-the outer ear

Question 37

Auditory canal

Answer 37

• ear canal

- catches sound waves

Question 38

Tympanic membrane

Answer 38

• eardrum

- is vibrated