Brain Facts Chapter 2 - Important Topics

Transduction

This is the process of environmental stimuli like light waves, sound waves, and food molecules being turned into sensory experiences by the brain.

Cornea

This structure is the outermost layer of the eye. It protects the interior of the eye from debris and begins to focus the light that enters.

Lens

This transparent structure is located just behind the pupil in the eye, bending to focus light onto the retina.

Pupil

This structure in the eye is the hole that light passes through before it is focused onto the retina. The size of this structure changes to let different amounts of light into the eye.

Iris

This structure in the eye is a ring around the pupil. It dictates the size of the pupil by expanding and contracting to let more or less light into the eye. It is known for its variety of colors.

Retina

This structure covers the back of the eye. It receives light as a reversed and flipped image via specialized receptors, and then it passes the visual information to the brain to be processed.

Optic Nerves

These structures are large nerve bundles that carry information from the retina of the eye to different parts of the brain to be processed.

Photo Receptors

These are light sensitive cells called rods and cones located at the back of the retina. They are how the eye collects brightness and color information from the environment.

Ganglion Cells

This is a specialized type of photo receptor neuron that transports light information from the retina to the brain; its axons make up the optic nerve.

Rods

These make up about 95 percent of the photo receptor cells in the retina. They are very sensitive, detecting shades of darkness and allowing sight in dim light.

Cones

These are photo receptor cells in the retina that detect color. There are three different types that pick up red, green, and blue light, respectively.

Interneurons

These are an abundant type of neuron that connects motor and sensory neurons. They do not have a specialized purpose, but allow communication between specialized parts of the brain. They play a large role in processing and analyzing sensory data to decide how to respond, making them essential to reflexes. They also acts as important inhibitory neurons to prevent overactivity.

Fovea

This small structure is at the very center of the retina, and contains densely packed photoreceptors to interpret very fine visual detail.

Macula

This is a central area in the retina that helps pick up on fine visual details in a slightly wider area to help with reading, driving, and other visual precision tasks.

Blind Spot

This is a small spot in the visual field of each eye that doesn’t pick up light information because it is where the optic nerve connects to the retina.

Optic Chiasm

This structure is where both optic nerves cross paths. Visual information from the left side of each retina (the right visual field) is sent to the left hemisphere of the cerebrum for processing, and information from the right side (left visual field) is sent to the right hemisphere.

Lateral Geniculate Nucleus

This is a region of the thalamus in the brain’s limbic system that routes visual information from the optic nerves to be further processed in the primary visual cortex.

Visual Cortex

This is a region of the occipital lobe at the back of your brain. It recognizes specific visual stimuli like edges and shapes.

Cerebrum Hemispheres

Striabismus

This is a condition that causes the eyes no to be aligned, meaning a person wouldn’t be able to overlap the images from both eyes in the brain. They would have to rely on one eye and miss out on depth cues that come from having binocular vision. The unused eye may also become blind.

Sound Waves

These are pressure waves in the air that travel from environmental stimuli into your ear to be translated into hearing.

Eardrum

Also known as the tympanic membrane, this ear structure physically vibrates in response to sound waves, beginning a chain of events that allows the brain to hear.

Hammer, Anvil, and Stirrup

These are three very small bones in the inner ear that translate and amplify vibrations of the eardrum to the cochlea.

Cochlea

This is a snail shell-shaped structure in your inner ear. It is filled with fluid that vibrates in response to different sound frequencies from the hammer, anvil, and stirrup bones. This structure also contains hair cells that begin the process of translating these vibrations into signals to the brain.

Hair Cells

These are tiny, differently sized hairs on the inside of the cochlea in the ear that respond to different frequencies of sound. They convert the vibrations into electrical signals that begin travelling to the brain for auditory processing. These cells can never be grown back, so their damage is a common reason for hearing loss.

Auditory Nerve

This nerve is activated by hair cell activity in the inner ear. It sends auditory information (and vestibular information but that’s not important yet) from the cochlea to the brain for processing.

Primary Auditory Cortex

This is a region in the temporal lobes that processes sound. It contains many different specialized neurons that are trained to recognize different sounds like pitch, intensity, frequency, and even combinations of tones.

Wernicke’s Area

This is an area in your brain (left cerebral hemisphere) that processes auditory information related to language. If a person has this area in their brain damaged, they may not be able to recognize speech.

Gustation

This is a fancy word for the sense of taste.

Olfaction

This is a fancy word for the sense of smell.

Taste Buds

These are small groups of receptor cells mainly located on the tongue, as well as the roof and back of your mouth. They pick up on five different taste profiles: sweet, sour, salty, bitter, and umami (savory).

Cranial Nerves

Vagus Nerves

Glossopharyngeal Nerves

Facial Nerves

Olfactory Bulbs

Cilia

Neurogenesis

Somatosensory Cortex

A-beta Fibers

C-fibers

Two-point Discrimination

Nociceptors

Neuropathic Pain

Analgesic

Adrenaline

Cognitive Behavioral Therapy