Foundations of Genetics, Sensation, and Motor Systems

Vocabulary terms covering genetics, visual and auditory systems, somatosensory receptors, motor control, and language processing.

DNA

The blueprint for making and maintaining an organism.

Genes

A small section of DNA used to code for making a protein.

Genotype

The allele formation in the chromosome.

Phenotype

The physical expression of the gene.

Epigenetics

The study of how environmental factors influence whether a genotype expresses into a particular phenotype.

Punnett Square

A diagram that predicts the genotypes and phenotypes of a genetic cross and determines how alleles can be distributed among descendants.

Knockout Mice

Animals used to understand different neurodegenerative diseases and how neurotransmitters affect behavior.

Monozygotic twins

Identical twins resulting from a single egg fertilized by a single sperm.

Dizygotic twins

Fraternal twins resulting from separate eggs fertilized by separate sperm.

Concordance Rates

The risk of developing a disorder between relatives.

Optogenetics

The use of light to control gene neurons in living tissue.

Eugenics

A term meaning “well born”; can be positive (focused on “good” traits) or negative (focused on “bad” traits).

Sensory Transduction

The process by which sensory stimuli are transferred into electrical signals sent to the CNS.

Sclera

The supporting wall of the eye structures.

Iris

The part of the eye that controls the size of the pupil.

Pupil

The opening that allows amounts of light into the eye.

Cornea

The part of the eye that controls and focuses/bends light.

Lens

The eye structure that focuses light; changes shape during accommodation to focus on near or distant objects.

Retina

The part of the eye that contains photoreceptors.

Rods

Photoreceptors responsible for night vision, motion, black-and-white vision, and peripheral vision.

Cones

Photoreceptors responsible for color vision, detail, and visual acuity.

Scotopic Vision

Vision under low-intensity light, movement, and night vision conditions.

Photopic Vision

Vision under bright light, daytime, color, and detail conditions.

Myopia

Nearsightedness where distant objects are blurry due to an elongated eyeball.

Hyperopia

Farsightedness where close objects are blurry due to a shorter eyeball.

Cataracts

Cloudy visual perception that may cause blindness.

Retinitis Pigmentosa

Condition where the peripheral retina becomes dark, causing tunnel vision.

Macular Degeneration

The loss of central vision.

Trichromatic Theory

Theory of color vision identifying three cone types: Red, Green, and Blue (RGB).

Opponent Process Theory

Theory of color vision involving pairings of Red/Green, Blue/Yellow, and Black/White; explains negative after-images.

Ventral Stream

The "What is it?" visual pathway involving objects, faces, colors, and the temporal lobe.

Dorsal Stream

The "Where is it?" visual pathway involving location, movement, spatial awareness, and the parietal lobe.

Prosopagnosia

The inability to recognize faces.

Olfactory Pathway

Odor → Olfactory Receptors → Olfactory Bulb → Glomeruli → Mitral Cells → Piriform Cortex.

Papillae

Structures on the tongue that contain taste buds.

Taste Buds

Structures that contain taste receptor cells.

Taste Pathway

Taste Receptors → Cranial Nerves $VII$, $IX$, $X$ → Thalamus → Insula & Frontal Operculum.

Pinna

The external part of the ear that collects sound.

Auditory Canal

The passage that funnels sound toward the tympanic membrane.

Tympanic Membrane

The ear structure that vibrates in response to sound waves.

Ossicles

The Malleus, Incus, and Stapes which amplify sound.

Oval Window

The structure that transfers vibration from the ossicles to the cochlea.

Cochlea

The structure responsible for hearing transduction.

Hair Cells

Auditory receptors located between the basilar membrane and tectorial membrane.

The auditory relay center of the thalamus

Medial Geniculate Nucleus (MGN)

Pitch

The frequency of sound.

Loudness

The amplitude or intensity of sound.

Timbre

The quality of sound.

McGurk Effect

A phenomenon where visual information changes auditory perception.

Synesthesia

A condition where stimulation of one sense produces experiences in another sense.

Aphasia

Language impairment caused by brain damage.

Broca's Area

Region of the brain responsible for speech production.

Wernicke's Area

Region of the brain responsible for language comprehension.

Wada Test

A procedure that temporarily anesthetizes one hemisphere to determine language dominance.

Split-Brain Outcomes

Results demonstrating hemispheric specialization where hemispheres function independently after the corpus callosum is severed.

Hemispatial Neglect

The neglect of the left side of space, usually caused by right parietal lobe damage.

Semicircular Canals

Part of the vestibular apparatus that detects spinning and rotation.

Utricle

Part of the vestibular apparatus that detects horizontal acceleration and gravity.

Saccule

Part of the vestibular apparatus that detects vertical acceleration and gravity.

Vestibulo-Ocular Reflex (VOR)

Reflex that stabilizes vision during head movement.

Meissner Corpuscles

Highly sensitive skin receptors found in fingertips that detect light touch.

Merkel Cells

Highly sensitive skin receptors found in fingertips that detect fine touch, texture, and detail.

Pacinian Corpuscles

Skin receptors that detect deep pressure and vibration.

Ruffini Endings

Skin receptors that detect skin stretch.

Free Nerve Endings

Skin receptors that detect pain and temperature.

Proprioception

The awareness of body position and movement.

Nociception

The detection of painful stimuli.

Primary Somatosensory Cortex

Located in the postcentral gyrus; processes touch, pressure, pain, temperature, and proprioception in a somatotopic arrangement.

Homunculus

A body map in the sensory and motor cortex where larger regions represent parts requiring more sensitivity or control.

Primary Motor Cortex

Brain region that executes voluntary movement.

Secondary Motor Cortex

Brain region that plans and organizes movement.

Mirror Neurons

Neurons that fire when performing an action and when observing another individual perform the same action.

Basal Ganglia

A group of structures involved in movement initiation, regulation, habit learning, and motor planning.

Parkinson's Disease

A disorder characterized by tremor, rigidity, and bradykinesia caused by the loss of dopamine neurons in the substantia nigra.

Substantia Nigra

A region containing dopamine-producing neurons that project to the striatum.

Cerebellum

A structure involved in balance, coordination, timing of movement, motor learning, and error correction.

Ataxia

Poor coordination and balance problems resulting from cerebellum damage.

Neuromuscular Junction

The connection between a motor neuron and a muscle fiber where Acetylcholine (ACh) is the neurotransmitter.

Actin

A thin muscle filament attached to Z-discs.

Myosin

A thick muscle filament with globular heads.

Periaqueductal Gray (PAG)

Structure responsible for descending pain control and inhibition.

Enkephalins

Endogenous opiate neurotransmitters that inhibit the release of Substance P.

Dorsal Column-Medial Lemniscus

The somatosensory pathway for fine touch, vibration, and proprioception.

Spinothalamic Tract

The somatosensory pathway for pain and temperature.

Betz Cells

Large pyramidal upper motor neurons located in layer $V$ of the primary motor cortex.

CRISPR-Cas9

A technology used for genetic engineering.

SNP (Single Nucleotide Polymorphism)

A location on DNA where a nucleotide differs among individuals.

Fovea

The area of highest visual acuity with a dense concentration of cones.

Blind Spot (Optic Disc)

The area where the optic nerve exits the eye; no photoreceptors are present.

LGN (Lateral Geniculate Nucleus)

The visual relay nucleus of the thalamus.

Arcuate Fasciculus

The fiber tract connecting Broca's Area and Wernicke's Area.