Chapter 2: Sensation and Perception

Question 1

List the Functions of the various parts of the eye
Cornea:
Pupil:
Iris:
Ciliary Body:
Canal od Schlem:
Lens:
Retina:
Sclera:

Answer 1

Cornea: Gathers and focuses incoming light
Pupil: Allows passage of light from anterior to posterior chamber
Iris: Controls the size of the pupil
Ciliary Body: Produces aqueous humor; accommodation of lens
Canal of Schlemm: Drains aqueous humor
Lens: Refracts the light to focus it on the retina
Retina: Detects images
Sclera: provides structural support

Question 2

List the structures in the visual pathway; from where light enters the cornea to the casual projection areas in the brain.

Answer 2

Cornea -> Pupil -> Vitreous -> Retina (rod/cones, bipolar cells, ganglion cells) -> Optic Nerve -> Optic Chiasm -> Optic Tract -> LGN -> radiates through parietal and temporal lobes -> Occipital Lobe

Question 3

What is parallel processing?

Define and give example

Answer 3

Ability to simultaneously analyze color, shape, and motion of an object to create an image and recognize it.

Example: People can recognize a moving car very easily from a distance because they are familiar with the usual motions and shapes of cars.

Question 4

What types of cells are responsible for
Color:
Shape:
Motion:

Answer 4

Color: Cones
Shape: Parvocellular
Motion: Magnocellular

Question 5

What structures are used to detect
Linear Acceleration:
Rotational Acceleration:

Answer 5

Linear Acceleration: Utricule and Saccule

Rotational Acceleration: Semicircular Canals

Question 6

List the structures in the auditory pathway, from where sound enters the Pina to the auditory projection areas in the brain.

Answer 6

Pinna, external auditory canal, tympanic membrane, malleus, incus, stapes, oval window, perilymph in cochlea, basilar membrane, hair cells, vestibulocochlear nerve, brain stem, medial geniculate nucleus (MGN) of thalamus, auditory cortex

Question 7

How does the organization of the cochlea indicate the pitch of an incoming sound?

Answer 7

The basilar membrane is tonotopoically organized: high pitched sounds
cause vibrations at the base of the cochlea
low pitched sounds
cause vibrations at the apex of the cochlea.

Question 8

List the structures in the olfactory pathway, from where odor molecules enter the nose to where olfactory signals project in the brain.

Answer 8

Nostril, nasal cavity, olfactory chemoreceptors (olfactory nerves) on olfactory epithelium, olfactory bulb, olfactory tract, higher-order brain regions, including limbic system .

Question 9

Both smell and taste are sensitive to chemicals. What is different about the types of chemicals each one can sense?

Answer 9

Smell is sensitive to volatile or aerosolized compounds; taste is sensitive to dissolved compounds.

Question 10

What are the four main modalities of somatosensation>

Answer 10

Pressure
Vibration
Pain
Temperature

Question 11

How is sensory information integrated in

• Bottom-up processing
• Top-down processing

Answer 11

Bottom-up processing requires each component of an object to be interpreted through parallel processing and then integrated into one cohesive whole.
Top-down processing starts with the whole object and, through memory, create s expectations for the components of the object.

Question 12

Briefly describe the Gestalt Principles 
Proximity:
Similarity:
Good Continuation:
Subjective Contours:
Closure:
Prägnanz

Answer 12

Proximity: Components close to one another tend to be perceived as a unit.
Similarity: Components that are similar (in color, shape, size) tend to be grouped together.
Good Continuation: Components that appear to follow in the same pathway tend to be grouped together; abrupt changes in form are less likely than continuation of the same pattern
Subjective Contours: Edges or shapes that are not actually present can be implied by the surrounding objects (especially if good continuation is present).
Closure: A space is enclosed by a contour tends to be perceived as a complete figure; such figures tend to be perceived as more complete (or closed) than they really are.
Prägnanz: perceptual organization will always be as regular, simple, and symmetric as possible.