Neuro Exam 2 (without popular media)

Sensation

The detection of environmental stimuli

Perception

Awareness of senses

Sensory system flowing along functional pathways in a precise way

Sensory receptor cells→Thalamus→Primary Sensory Sensory Cortex

Sensory Receptor Cells

sensations through transduction

Thalamus

relay that can modulate attention, relay station

Primary Sensory Cortex

Where perception happens

Sound

pressure waves in the air

Hair Cell Function

stimuli are transduced by these sensory receptors

Pinna

is the visible, external part of the ear made mostly of elastic cartilage, and its main role is to collect and funnel sound into the ear canal.

Auditory canal

a tube that runs from the outer ear to the eardrum

Ossicles

the three tiny bones in your middle ear that help you hear, malleus, incus, and stapes.

Tympanic Membrane

a thin layer of skin that helps with hearing and protects the middle ear from germs and debris.

Cochlea

a spiral cavity filled with fluid and lined with specialized sensory cells called hair cells. Situated within the inner ear's labyrinth, it plays a crucial role in translating sound waves into neural signals.

Auditory Vestibular Nerve

a cranial nerve that transmits sound and equilibrium (balance) information from the inner ear to the brain

Oval Window

• Acts as the interface between air vibrations in the middle ear and fluid vibrations in the inner ear, a small, membrane-covered opening between the middle ear and the inner ear.

three parts of the ear

outer ear, middle ear, and inner ear

Stapes

transmits and amplifies sound vibrations from the middle ear into the inner ear by pushing on the oval window, enabling the fluid movement that starts the hearing process.

Round Window

allows the fluid inside the cochlea to move when sound vibrations enter the inner ear, making normal hearing possible

Scala Tympani

helps transmit sound‑induced pressure waves through the cochlea and provides a pressure‑relief pathway that allows the basilar membrane to move, making hearing possible

Basilar Membrane

converts sound vibrations into neural signals by separating frequencies along its length and triggering hair‑cell activation that the brain interprets as pitch and loudness

Scale Vestibuli

carries sound vibrations from the oval window into the cochlea and helps transmit them through the inner ear’s fluid system to enable hearing.

Helicotrema

allows low‑frequency sound waves to pass between the cochlear chambers and equalizes fluid pressure, enabling the ear to detect very low‑pitched sounds

Apex

specializes in detecting low‑frequency (bass) sounds because its basilar membrane is wide, flexible, and tuned for slow, large‑amplitude vibrations

Stereocilia

Converts mechanical sound vibrations into electrical signals by bending in response to fluid motion, opening ion channels, and triggering the neural activity that the brain interprets as sound.

Tectorial Membrane

a specialized extracellular structure in the cochlea that helps convert sound-induced vibrations into neural signals by mechanically interacting with hair cell stereocilia to enable precise frequency tuning and amplification

Reticular Lamina

a rigid barrier at the top of the organ of Corti that keeps endolymph separate from hair cell bodies and stabilizes stereocilia so they can transduce sound vibrations into electrical signals

Modiolus

the central bony core of the cochlea that houses and protects the auditory nerve fibers and blood vessels, providing the structural and neural support essential for hearing

Outer hair cells

amplify and fine‑tune sound vibrations in the cochlea, making hearing more sensitive and sharply tuned to specific frequencies

Rods of Corti

a stiff, supportive inner framework in the organ of Corti that helps maintain its architecture and transmit mechanical sound vibrations to the sensory hair cells

Inner Hair Cells

convert sound-induced vibrations into electrical signals that the auditory nerve carries to the brain, making them the primary sensory receptors for hearing

TRPA 1 Channel

on the tips of stereocilia, cation channel, movement of the stereocilia can alternately open and close the channels.

Medial Geniculate Nucleus (MGN)

is the thalamic relay center for auditory information, transmitting and shaping sound signals from the inferior colliculus to the auditory cortex

Superior Olivary Nucleus

a brainstem auditory center that enables binaural hearing, especially sound localization, and helps regulate cochlear sensitivity through efferent pathways

Cochlear Nucleus

is the brain’s first processing center for auditory information, where sound signals from the cochlea are decoded into timing, intensity, and frequency features that the rest of the auditory system can interpret

Primary Auditory Cortex

the brain’s first cortical region for processing sound, responsible for decoding basic acoustic features such as pitch, loudness, and sound location before passing information to higher auditory areas for interpretation

Secondary Auditory Cortex

supports higher‑order sound processing, including speech comprehension, music perception, sound recognition, and integration of auditory information with memory and meaning

Light

Electromagnetic energy made out of particles called photons

Photons

different amounts of energy, can be measured as waves

Visual System

allows us to detect photons of particular energies in our environment. These stimuli are transduced by sensory receptor cells called photoreceptors.

Cornea

eye’s clear front surface that provides most of its focusing power while also protecting internal structures from injury, infection, and environmental damage

Ciliary Muscle

controls the eye’s ability to focus by changing the shape of the lens, allowing you to shift between near and distant vision

Pupil

how the eye’s pupil shapes and modulates incoming light, determining the wavefront that reaches the retina and ultimately controlling image quality

Iris

controls the amount of light entering the eye by adjusting the size of the pupil, helping you see clearly in both bright and dim conditions.

Lens

focuses incoming light onto the retina by changing its shape to adjust focus for near and far objects

Sclera

the tough, white outer layer of the eye that provides structural support, protection, and a stable shape necessary for proper vision

Choroid

the eye’s vascular layer that nourishes the retina, regulates temperature, and absorbs excess light to maintain clear, stable vision

Retina

the light‑sensing tissue at the back of the eye that converts incoming light into electrical signals and sends them to the brain, enabling vision

Fovea

the small central region of the retina responsible for sharp, detailed, and color-rich vision, especially for tasks like reading, recognizing faces, and focusing on fine detail

Optic Disc

is the point where retinal nerve fibers exit the eye to form the optic nerve, and because it lacks photoreceptors, it creates the eye’s natural blind spot

Optic Nerve

carries visual information from the retina to the brain, allowing the brain to interpret light signals as sight

Cortical Cell

Sensitive to orientation and direction of motion; only responds when the stimulus moves up and down.

Order of the Visual System

Retina→Optic Nerve→Thalamus→Primary Visual Cortex→Secondary Visual Areas (V2, V3, V4)

Inferior Temporal Cortex

Ventral Pathway (what), carries visual information from the retina to the brain, allowing the brain to interpret light signals as sight

Posterior Parietal Cortex

Dorsal Pathway (where), carries visual information from the retina to the brain, allowing the brain to interpret light signals as sight

Myofilament

support neuronal shape change, synaptic plasticity, and intracellular tension in the visual system and cortex, even though neurons lack the sarcomeric myofilaments found in muscle

Myosin

sensory signaling in the visual system through specialized isoforms, powers muscle mechanics by generating force through ATP‑driven interactions

Myosin Heads

the motor domain of myosin that binds actin, hydrolyzes ATP, and produces force and movement through conformational changes in its lever arm

Contraction

tension generated in muscle fibers in response to neural activation, which may or may not involve the muscle physically shortening.

Mixed Spinal Nerve

formed at the junction of dorsal (sensory) and ventral (motor) roots, and they carry both sensory and motor fibers before branching into peripheral nerves

Peripheral Nerves

communication lines that connect the brain and spinal cord to the rest of the body, carrying signals that allow you to move, feel, and regulate automatic body functions

Motor Neurons

specialized nerve cells whose primary function is to send signals from the nervous system to muscles and glands, enabling voluntary movement, reflexes, and essential bodily functions

Ventral Root

carries motor (efferent) signals from the spinal cord to muscles and glands, enabling voluntary movement and autonomic responses.

Lower motor neurons

the final pathway that directly activate skeletal muscle fibers, producing voluntary and reflexive movement

Ventral Horn

contains the motor neurons that send signals to skeletal muscles, making it essential for voluntary movement and reflex motor output

Motor end plate

the specialized region of a skeletal muscle fiber that converts a motor neuron’s chemical signal into an electrical impulse that initiates muscle contraction

Skeletal Muscles

produce voluntary movement, maintain posture, and generate heat, while also stabilizing joints and supporting overall body mechanics

Axon terminal branch

distribute signals across widely spaced functional columns and release neurotransmitters that integrate complex visual information for object recognition, in the inferior temporal cortex

Muscle Fiber Nucleus

coordinates the high-volume production of proteins needed for contraction, growth, and repair, with each nucleus regulating a specific region of the cell

Muscle Fiber

produce force and movement by contracting, and different fiber types specialize in either quick, powerful actions or sustained, endurance-based activity

Neuromuscular Junction

the specialized connection where a motor neuron communicates with a muscle fiber to trigger muscle contraction

Premotor Cortex

responsible for planning, selecting, and preparing movements, integrating sensory information to guide actions before they are executed

Supplementary Motor Area

a frontal‑lobe motor region responsible for planning, initiating, and coordinating internally generated and complex movements, especially sequences and bimanual actions

Primary Motor Cortex

the brain region that initiates and controls voluntary movement by sending precise motor commands to the muscles of the body

Pyramid of Medulla

carry voluntary motor signals from the brain to the spinal cord and are the site where most of these fibers cross to the opposite side

Decussation of the pyramidal tract

in the lower medulla where most corticospinal motor fibers cross to the opposite side, explaining why each cerebral hemisphere controls the contralateral side of the body

Ventral corticospinal tract

primarily controls voluntary movements of the axial (midline) muscles, especially those involved in posture and trunk stabilization

Lateral corticospinal tract

the major pathway that enables voluntary, precise, skilled movements of the limbs, especially the hands and fingers

Upper Medulla

pyramid of medulla

Lower Medulla

Decussation of pyramidal tract, ventral corticospinal tract

Spinal Cord

Lateral Corticospinal tract

Ventral Premotor Cortex

integrates sensory information to shape and guide action, especially grasping, peripersonal-space responses, action understanding, and speech-related motor codes

Striatum

Caudate nucleus, putamen; a major hub in the basal ganglia that integrates movement, motivation, and reward signals to help the brain select, initiate, and reinforce actions

Caudate Nucleus

a major basal ganglia structure that helps regulate movement, learning, habit formation, motivation, and decision-making

Putamen

helps regulate movement execution, habit learning, and automatic motor patterns by serving as a major input hub of the basal ganglia

Basal Ganglia

deep brain structures that help initiate movement, suppress unwanted actions, shape habits, and regulate motivation and reward

Subthalamic Nucleus

basal ganglia structure that helps regulate movement by providing excitatory signals that suppress unwanted motor activity

Substantia Nigra

a midbrain structure that helps regulate movement, reward processing, and learning, primarily through its dopamine-producing neurons

Vermis

the midline, worm‑shaped structure of the cerebellum that connects its two hemispheres and is essential for posture, balance, gait, and coordination of trunk and axial muscles

Folia

folds of the cerebellar cortex located on the surface of the cerebellum, and they function to greatly increase cortical surface area to support the cerebellum’s role in motor coordination, balance, and certain cognitive processes

Cerebellar Cortex

layered outer surface of the cerebellum, located in the posterior cranial fossa behind the brainstem, and it functions primarily to coordinate movement, maintain balance, and support motor learning

Deep Cerebellar Nuclei

in the white matter at the center of the cerebellum and serve as the primary output channels for cerebellar processing, coordinating movement, posture, and motor planning

Pontine Nuclei

clusters of neurons in the ventral pons that relay information from the cerebral cortex to the cerebellum

Fourth Ventricle

a key cerebrospinal fluid (CSF) chamber that circulates, protects, and regulates CSF flow between the brain and spinal cord

Extension

increasing joint angle (straightening),

Flexion

decreasing joint angle (bending)