MCAT Biology Sensation and Perception Part 1

Question 1

___ is the act of organizing, assimilating, and interpreting the sensory input into useful and meaningful information

Answer 1

Perception

Question 2

How does the brain know the difference between stimulation of visual receptors andd olfactory receptors?

Answer 2

Both signals are received in the brain as action potentials from sensory neurons. The brain distinguishes the sensory stimuli based on which sensory neurons are signaling

Question 3

___are pressure sensors located deep in the skin

Answer 3

Pacinian corpuscles

Question 4

Pacinian corpuscles, auditory hair cells, and vestibular hair cells are all___

Answer 4

mechanoreceptors, responding to mechanical disturbances

Question 5

This is a specialized cell found in the cochlea of the inner ear that detects vibrations caused by sound waves (mechanoreceptor)

Answer 5

Auditory hair cell

Question 6

____ are mechanoreceptors located inside semicircular canals in the inner ear

Answer 6

Vestibular hair cells

Question 7

___ is a mechanoreceptor that detects acceleration and position relative to gravity

Answer 7

Vestibular hair cell

Question 8

____ is found in the cochlea of the inner ear

Answer 8

Auditory hair cells

Question 9

__detect airborne chemicals and allow us to smell things

Answer 9

Olfactory receptors

Question 10

____ are chemoreceptors for taste buds

Answer 10

Gustatory receptors

Question 11

___are stimulated by tissue injury

Answer 11

Nociceptors

Question 12

___ is the phenomenon of illusionary pain on the skin when nerve ends of nociceptors cross paths with somatic afferents from the skin

Answer 12

Referred pain

Question 13

____ are stimulated by electromagnetic waves

Answer 13

Electromagnetic receptors

Question 14

The four properties of all sensory receptors that need to be communicated to the CNS are

Answer 14

1. stimulus modality (what type of stimulus)
2. Location
3. Intensity is coded by the frequency of action potentials
4. Duration of stimulus

Question 15

How is the stimulus modality determined by the CNS?

Answer 15

CNS determines the modality (what type) of stimulus based on which type of receptor fires

Question 16

How is stimulus location determined by the CNS

Answer 16

The stimulus location is communicated by the receptive field of the receptor sending the signal.

Question 17

How is stimulus intensity determined by the CNS?

Answer 17

Intensity is coded by the frequency of action potentials.

Question 18

___ is a decrease in firing frequency when the intensity of a stimulus remains constant

Answer 18

Adaptation

Question 19

___ is an important proprioceptor (mechanoreceptor) that detects muscle stretch

Answer 19

Muscle spindle

Question 20

__is a proprioceptor (mechanoreceptor) that monitors tension in the tendons

Answer 20

Golgi tendon organs

Question 21

___ is a proprioceptor that detects pressure, tension, and movement in the joints

Answer 21

Joint capsule receptors

Question 22

What portion of the CNS would require input from proprioceptors?

Answer 22

The cerebellum which is responsible for motor coordination

Question 23

Olfaction is accomplished by olfactory receptors in the roof of the __

Answer 23

nasopharynx

Question 24

A thin watery fluid found in the anterior segment of the eye (between the lens and the cornea)

Answer 24

Aqueous humor

Question 25

The tube that connects the middle ear cavity with the pharynx; also known as the Eustachian tube

Answer 25

Auditory tube

Question 26

___ functions to equalize middle ear pressure with atmospheric pressure so that pressure is equal on both sides of the tympanic membrane

Answer 26

Auditory tube

Question 27

The flexible membrane in the cochlea that supports the organ of Corti (the structure that contains the hearing receptors)

Answer 27

Basilar membrane

Question 28

The fibers of the __ are short and stiff near the oval window and long and flexible near the apex of the cochlea. This difference in structure allows the basilar membrane to help transduce pitch

Answer 28

Basilar membrane

Question 29

A cell in the retina of the eye that receives input from photoreceptors and subsequently synapses on the ganglion cells.

Answer 29

Bipolar cells

Question 30

__ belong to a class of neurons that have a single dendrite and single axo extending from opposite sides of the cell body

Answer 30

Bipolar cells

Question 31

A tenet of Gestalt psychology wherein the processing of sensory input begins with the sensory receptors and works up to the complex integration of information occurring in the brain

Answer 31

Bottom-up processing

Question 32

The darkly pigmented middle layer of the eyeball, found between the sclera (outer layer) and the retina (inner layer)

Answer 32

Choroid

Question 33

The curled structure in the inner ear that contains the membranes and hair cells used to transduce sound waves into action potentials

Answer 33

Cochlea

Question 34

Photoreceptors in the retina of the eye that respond to bright light and provide color vision

Answer 34

Cones

Question 35

The clear portion of the tough outer layer of the eyeball, found over the iris and pupil

Answer 35

Cornea

Question 36

The minimum noticeable difference between any two sensory stimuli, 50% of the time

Answer 36

Difference threshold

Question 37

Inhibitory neurotransmitter released onto bipolar cells in the retina by rods and cones.

Answer 37

Glutamate

Question 38

The release of __ is stopped when light hits the photoreceptor, and the subsequent cessation in __ releases the inhibition on the bipolar cells, causing it to fire

Answer 38

Glutamate

Question 39

___respond to vibrations in the cochlea caused by sound waves

Answer 39

Cochlear hair cells

Question 40

____respond to changes in position and acceleration

Answer 40

Vestibular hair cells

Question 41

A pigmented membrane found just in front of the lens of the eye

Answer 41

Iris

Question 42

The ___ regulates the diameter of the pupil in response to the brightness of the light

Answer 42

Iris

Question 43

The "blind spot" of the eye, this is where the axons of the ganglion cells exit the retina to form the optic nerve

Answer 43

Optic disk

Question 44

The nerve extending from the back of the eyeball to the brain that carries visual information

Answer 44

Optic nerve

Question 45

The optic nerve is made up of the axons of the _____

Answer 45

ganglion cells of the retina

Question 46

The structure in the cochlea of the inner ear made up of the basilar membrane, the auditory hair cells, and the tectorial membrane

Answer 46

Organ of Corti

Question 47

The __ is the site where auditory sensation is detected and transduced to action potentials

Answer 47

Organ of Corti

Question 48

The three small bones found in the middle ear are __,___,and___

Answer 48

Malleus Incus Stapes

Question 49

The malleus, incus, and stapes (small bones found in the middle ear) are called___

Answer 49

Ossicles

Question 50

The ___ help to amplify the vibrations from sound waves

Answer 50

Ossicles (malleus, incus, and stapes)

Question 51

The ___ is attached to the tympanic membrane

Answer 51

Malleus

Question 52

The ___ is attached to the oval window of the cochlea

Answer 52

Stapes

Question 53

The portion of the ear consisting of the pinna and external auditory canal

Answer 53

Outer ear

Question 54

The outer ear is separated from the middle ear by the ___

Answer 54

Tympanic membrane (the ear drum)

Question 55

A hole in the center of the iris of the eye that allows light to enter the eyeball

Answer 55

Pupil

Question 56

The diameter of the __ is controlled by the iris in response to the brightness of light

Answer 56

Pupil

Question 57

The innermost layer of the eyeball

Answer 57

Retina

Question 58

The ___ is made up of a layer of photoreceptors, a layer of bipolar cells, and a layer of ganglion cells

Answer 58

Retina

Question 59

A chemical derived from vitamin A found in the pigment proteins of the rod photoreceptors of the retina

Answer 59

Retinal

Question 60

Photoreceptors in the retina of the eye that respond to dim light and provide us with black and white vision

Answer 60

Rods

Question 61

The white portion of the tough outer layer of the eyeball

Answer 61

Sclera

Question 62

Three loop-like structures in the ear that contain sensory receptors to monitor balance

Answer 62

Semicircular canals

Question 63

The integration of single muscle twitches into a sustained contraction (tetany)

Answer 63

Summation

Question 64

A tenet of Gestalt psychology where the brain applies experience and expectations to interpret sensory information

Answer 64

Top-Down processing

Question 65

The membrane that separates the outer ear from the middle ear.

Answer 65

Tympanic membrane

Question 66

A thick gelatinous fluid found in the posterior segment of the eye (between the lens and the retina)

Answer 66

Vitreous humor

Question 67

The ___ is only produced during fetal development and helps maintain intraocular pressure (the pressure inside the eyeball)

Answer 67

Vitreous humor

Question 68

____states that two stimuli must differ by a constant proportion in order for their difference to be perceptible

Answer 68

Weber's Law

Question 69

The __ is a membrane that divides the middle and the inner ear

Answer 69

Oval window

Question 70

The semicircular canals together with the __ and __ are important to the sense of balance

Answer 70

Utricle and saccule

Question 71

The ___ is a membrane covered hole in the cochlea near the oval window that releases excess pressure

Answer 71

Round window

Question 72

The __ is a passageway from the back of the throat to the middle ear

Answer 72

Eustachian tube

Question 73

__ functions to equalize pressure on both sides of the eardum and is the cause of "ear popping" at high altitudes or underwater

Answer 73

Eustachian tube / auditory tube

Question 74

Vibration of the oval window creates pressure waves in the ___ and ____ the fluids in the cochlea

Answer 74

Perilymph and endolymph

Question 75

The pressure waves in the ___ cause vibration of the basilar membrane

Answer 75

Endolymph

Question 76

___ of sound is distinguished by which regions of the basilar membrane vibrate, stimulating different auditory neurons

Answer 76

Pitch (frequency)

Question 77

Low frequency (long wavelength) sound stimulate hair cells at the ___

Answer 77

apex of the cochlear duct, farthest away from the oval window

Question 78

High pitched sounds stimulate hair cells at the__

Answer 78

base of the cochlea, near the oval window

Question 79

Loundness of a sound is distinguished by the __

Answer 79

amplitude of vibration

Question 80

Larger vibrations cause more ___

Answer 80

frequent action potentials in auditory neurons

Question 81

If a sensory neuron leading from the ear to the brain fires an action potential more rapidly, how will the brain perceive this change?

Answer 81

More rapid firing of a cochlear neuron indicates an increase in volume of sound

Question 82

If the bones of the middle ear are unable to move, would this impair the detection of sound by conductance through bone?

Answer 82

The bones of the middle ear serve to conduct vibrations from the outer ear to the liquid within the cochlea but are not involved directly in detecting sound. Bond conductance can still stimulate the cochlea and result in hearing if the middle ear is nonfunctional