MCAT Biology Sensation and Perception Part 1 Flashcards
___ is the act of organizing, assimilating, and interpreting the sensory input into useful and meaningful information
Perception
How does the brain know the difference between stimulation of visual receptors andd olfactory receptors?
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
___are pressure sensors located deep in the skin
Pacinian corpuscles
Pacinian corpuscles, auditory hair cells, and vestibular hair cells are all___
mechanoreceptors, responding to mechanical disturbances
This is a specialized cell found in the cochlea of the inner ear that detects vibrations caused by sound waves (mechanoreceptor)
Auditory hair cell
____ are mechanoreceptors located inside semicircular canals in the inner ear
Vestibular hair cells
___ is a mechanoreceptor that detects acceleration and position relative to gravity
Vestibular hair cell
____ is found in the cochlea of the inner ear
Auditory hair cells
__detect airborne chemicals and allow us to smell things
Olfactory receptors
____ are chemoreceptors for taste buds
Gustatory receptors
___are stimulated by tissue injury
Nociceptors
___ is the phenomenon of illusionary pain on the skin when nerve ends of nociceptors cross paths with somatic afferents from the skin
Referred pain
____ are stimulated by electromagnetic waves
Electromagnetic receptors
The four properties of all sensory receptors that need to be communicated to the CNS are
- stimulus modality (what type of stimulus)
- Location
- Intensity is coded by the frequency of action potentials
- Duration of stimulus
How is the stimulus modality determined by the CNS?
CNS determines the modality (what type) of stimulus based on which type of receptor fires
How is stimulus location determined by the CNS
The stimulus location is communicated by the receptive field of the receptor sending the signal.
How is stimulus intensity determined by the CNS?
Intensity is coded by the frequency of action potentials.
___ is a decrease in firing frequency when the intensity of a stimulus remains constant
Adaptation
___ is an important proprioceptor (mechanoreceptor) that detects muscle stretch
Muscle spindle
__is a proprioceptor (mechanoreceptor) that monitors tension in the tendons
Golgi tendon organs
___ is a proprioceptor that detects pressure, tension, and movement in the joints
Joint capsule receptors
What portion of the CNS would require input from proprioceptors?
The cerebellum which is responsible for motor coordination
Olfaction is accomplished by olfactory receptors in the roof of the __
nasopharynx
A thin watery fluid found in the anterior segment of the eye (between the lens and the cornea)
Aqueous humor
The tube that connects the middle ear cavity with the pharynx; also known as the Eustachian tube
Auditory tube
___ functions to equalize middle ear pressure with atmospheric pressure so that pressure is equal on both sides of the tympanic membrane
Auditory tube
The flexible membrane in the cochlea that supports the organ of Corti (the structure that contains the hearing receptors)
Basilar membrane
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
Basilar membrane
A cell in the retina of the eye that receives input from photoreceptors and subsequently synapses on the ganglion cells.
Bipolar cells
__ belong to a class of neurons that have a single dendrite and single axo extending from opposite sides of the cell body
Bipolar cells
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
Bottom-up processing
The darkly pigmented middle layer of the eyeball, found between the sclera (outer layer) and the retina (inner layer)
Choroid
The curled structure in the inner ear that contains the membranes and hair cells used to transduce sound waves into action potentials
Cochlea
Photoreceptors in the retina of the eye that respond to bright light and provide color vision
Cones
The clear portion of the tough outer layer of the eyeball, found over the iris and pupil
Cornea
The minimum noticeable difference between any two sensory stimuli, 50% of the time
Difference threshold
Inhibitory neurotransmitter released onto bipolar cells in the retina by rods and cones.
Glutamate
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
Glutamate
___respond to vibrations in the cochlea caused by sound waves
Cochlear hair cells
____respond to changes in position and acceleration
Vestibular hair cells
A pigmented membrane found just in front of the lens of the eye
Iris
The ___ regulates the diameter of the pupil in response to the brightness of the light
Iris
The “blind spot” of the eye, this is where the axons of the ganglion cells exit the retina to form the optic nerve
Optic disk
The nerve extending from the back of the eyeball to the brain that carries visual information
Optic nerve
The optic nerve is made up of the axons of the _____
ganglion cells of the retina
The structure in the cochlea of the inner ear made up of the basilar membrane, the auditory hair cells, and the tectorial membrane
Organ of Corti
The __ is the site where auditory sensation is detected and transduced to action potentials
Organ of Corti
The three small bones found in the middle ear are __,___,and___
Malleus
Incus
Stapes
The malleus, incus, and stapes (small bones found in the middle ear) are called___
Ossicles
The ___ help to amplify the vibrations from sound waves
Ossicles (malleus, incus, and stapes)
The ___ is attached to the tympanic membrane
Malleus
The ___ is attached to the oval window of the cochlea
Stapes
The portion of the ear consisting of the pinna and external auditory canal
Outer ear
The outer ear is separated from the middle ear by the ___
Tympanic membrane (the ear drum)
A hole in the center of the iris of the eye that allows light to enter the eyeball
Pupil
The diameter of the __ is controlled by the iris in response to the brightness of light
Pupil
The innermost layer of the eyeball
Retina
The ___ is made up of a layer of photoreceptors, a layer of bipolar cells, and a layer of ganglion cells
Retina
A chemical derived from vitamin A found in the pigment proteins of the rod photoreceptors of the retina
Retinal
Photoreceptors in the retina of the eye that respond to dim light and provide us with black and white vision
Rods
The white portion of the tough outer layer of the eyeball
Sclera
Three loop-like structures in the ear that contain sensory receptors to monitor balance
Semicircular canals
The integration of single muscle twitches into a sustained contraction (tetany)
Summation
A tenet of Gestalt psychology where the brain applies experience and expectations to interpret sensory information
Top-Down processing
The membrane that separates the outer ear from the middle ear.
Tympanic membrane
A thick gelatinous fluid found in the posterior segment of the eye (between the lens and the retina)
Vitreous humor
The ___ is only produced during fetal development and helps maintain intraocular pressure (the pressure inside the eyeball)
Vitreous humor
____states that two stimuli must differ by a constant proportion in order for their difference to be perceptible
Weber’s Law
The __ is a membrane that divides the middle and the inner ear
Oval window
The semicircular canals together with the __ and __ are important to the sense of balance
Utricle and saccule
The ___ is a membrane covered hole in the cochlea near the oval window that releases excess pressure
Round window
The __ is a passageway from the back of the throat to the middle ear
Eustachian tube
__ functions to equalize pressure on both sides of the eardum and is the cause of “ear popping” at high altitudes or underwater
Eustachian tube / auditory tube
Vibration of the oval window creates pressure waves in the ___ and ____ the fluids in the cochlea
Perilymph and endolymph
The pressure waves in the ___ cause vibration of the basilar membrane
Endolymph
___ of sound is distinguished by which regions of the basilar membrane vibrate, stimulating different auditory neurons
Pitch (frequency)
Low frequency (long wavelength) sound stimulate hair cells at the ___
apex of the cochlear duct, farthest away from the oval window
High pitched sounds stimulate hair cells at the__
base of the cochlea, near the oval window
Loundness of a sound is distinguished by the __
amplitude of vibration
Larger vibrations cause more ___
frequent action potentials in auditory neurons
If a sensory neuron leading from the ear to the brain fires an action potential more rapidly, how will the brain perceive this change?
More rapid firing of a cochlear neuron indicates an increase in volume of sound
If the bones of the middle ear are unable to move, would this impair the detection of sound by conductance through bone?
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
