MCAT Sensory Systems Flashcards

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Questions and Answers

What is sensory adaptation?

Strengthening of a stimulus
Diminishing sensitivity to an unchanging stimulus (correct)
Response to variable stimuli
The ability to detect changes in stimulus quickly

What does amplification refer to in sensory processes?

Filtering incoming stimuli
The strengthening or increase in sensitivity of the stimulus energy (correct)
Decreasing response to stimuli
Diminishing sensitivity

What is the primary function of the cornea?

Gathers and filters incoming light

What are sensory receptors?

Sensory nerves that respond to stimuli (D) Signup and view all the answers

Where does sensory processing occur?

In the projection areas of the lobes of the brain Signup and view all the answers

Define absolute threshold.

The minimum stimulus energy needed to activate a sensory system. Signup and view all the answers

What is the threshold of conscious perception?

The minimum stimulus energy that creates a signal large enough to be brought into awareness. Signup and view all the answers

What does Difference Threshold (Just Noticeable Difference) refer to?

The minimum difference in magnitude between two stimuli before one can perceive this difference. Signup and view all the answers

State Weber's Law.

The just-noticeable difference for a stimulus is proportional to the magnitude of the stimulus. Signup and view all the answers

What is the signal detection theory?

It accounts for non-sensory factors affecting perception of stimuli. Signup and view all the answers

What is aqueous humor?

Clear watery fluid filling the space between the cornea and lens. Signup and view all the answers

What are sensory ganglia?

Enlargements along peripheral nerves that transmit signals to the CNS. Signup and view all the answers

What is the function of the retina?

To line the back of the eye and contains rods and cones. Signup and view all the answers

What do rods detect?

Light and dark (black and white). Signup and view all the answers

What is the function of cones?

To detect color. Signup and view all the answers

What is retinal disparity?

Provides a binocular cue that facilitates depth perception. Signup and view all the answers

What is the role of horizontal and amacrine cells?

To integrate signals from ganglion cells and perform edge sharpening. Signup and view all the answers

What do magnocellular cells process?

Motion. Signup and view all the answers

What do parvocellular cells process?

Shape. Signup and view all the answers

What is parallel processing in vision?

The idea that our eyes process color, form, and motion at the same time. Signup and view all the answers

What is the visual pathway?

Retina -> Optic Nerve -> Optic Chiasm -> Optic Tracts -> LGN of Thalamus -> Visual Radiations -> Visual Cortex. Signup and view all the answers

What are the three main divisions of the ear?

Outer ear, middle ear, inner ear (A) Signup and view all the answers

What does the outer ear comprise?

Pinna (auricle), external auditory canal, and the tympanic membrane. Signup and view all the answers

What is included in the middle ear?

Malleus, incus, and stapes. Signup and view all the answers

What is the shape of the malleus?

Like a hammer. Signup and view all the answers

What shape does the incus resemble?

Like an anvil. Signup and view all the answers

What shape is the stapes?

Like stirrups. Signup and view all the answers

What does the inner ear contain?

Cochlea, semicircular canals, and vestibular sacs. Signup and view all the answers

What is the iris?

A ring of muscle tissue that forms the colored portion of the eye. Signup and view all the answers

What is the function of the pinna (auricle)?

Acts as a funnel to direct sound into the ear. Signup and view all the answers

What does the external auditory canal do?

Transmits sound waves from the pinna to the tympanic membrane. Signup and view all the answers

What is the tympanic membrane?

A thin flap of skin that vibrates when sound hits it. Signup and view all the answers

What is the function of the cochlea?

Translates sound into nerve impulses to be sent to the brain. Signup and view all the answers

What does the vestibular system do?

Provides information about motion to the brain. Signup and view all the answers

What is the role of the semicircular canals?

Responsible for balance. Signup and view all the answers

What is the function of the superior olive?

Localize sound. Signup and view all the answers

What does the inferior colliculus do?

Responsible for the startle reflex and vestibulo-ocular reflex. Signup and view all the answers

What does the vestibuloocular reflex help with?

Keeps the eyes fixed on a single point as the head rotates. Signup and view all the answers

What is the auditory pathway?

Cochlea -> Vestibulocochlear Nerve -> MGN of Thalamus -> Auditory Cortex. Signup and view all the answers

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Study Notes

Sensory Processes

Sensory Adaptation: Decreased sensitivity to a constant stimulus over time.
Amplification: Increase in sensitivity of stimulus energy during transduction.
Sensory Receptors: Nerve cells that respond to stimuli, essential for sensory input.

Eye Anatomy

Cornea: The outermost layer of the eye; gathers and filters light.
Aqueous Humor: Clear fluid between the cornea and lens; maintains eyeball shape through pressure.
Retina: Sensory membrane at the back of the eye; contains photoreceptors (rods and cones).
Rods: Detect light and dark (black and white).
Cones: Detect color and are responsible for color vision.
Iris: Colored muscle tissue controlling the pupil's size for light regulation.

Sensory Thresholds

Absolute Threshold: Minimum stimulus energy required to detect a stimulus 50% of the time.
Difference Threshold (Just Noticeable Difference): Smallest difference between two stimuli that can be perceived.
Threshold of Conscious Perception: Minimum energy for a stimulus to be consciously perceived.

Sensory Processing in the Brain

Sensory Processing: Occurs in the projection areas of various lobes: frontal, parietal, temporal, and occipital.
Weber's Law: The just-noticeable difference is proportional to the magnitude of the stimulus; this ratio remains constant.

Visual Processing

Signal Detection Theory: Effects of non-sensory factors (motives, experiences, expectations) on stimulus perception.
Parallel Processing: Simultaneous processing of color, form, and motion in visual perception.
Visual Pathway: Sequence of structures from the retina to the visual cortex: Retina → Optic Nerve → Optic Chiasm → Optic Tracts → LGN of Thalamus → Visual Radiations → Visual Cortex.

Ear Anatomy

Three Divisions of the Ear: Outer ear, middle ear, and inner ear.
Outer Ear: Composed of the pinna (auricle), external auditory canal, and tympanic membrane.
Middle Ear: Contains auditory ossicles: malleus (hammer), incus (anvil), and stapes (stirrup).
Inner Ear: Houses cochlea (sound processing), semicircular canals (balance), and vestibular sacs.

Auditory Processing

Tympanic Membrane: Vibrates in response to sound waves, transmitting sound to the inner ear.
Cochlea: Converts sound waves into nerve impulses for the brain.
Auditory Pathway: Path of sound signals from the cochlea to the auditory cortex: Cochlea → Vestibulocochlear Nerve → MGN of Thalamus → Auditory Cortex.

Balance and Localization

Vestibular System: Provides the brain with information about motion; integral for balance.
Semicircular Canals: Structures within the inner ear that help maintain balance.
Superior Olive: Brain stem structure involved in sound localization.
Inferior Colliculus: Involved in startle reflex and vestibulo-ocular reflex, maintaining visual focus during head movement.

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