Unit 1.6 All Flashcards

Sensation definition

The process by which our sensory receptors and nervous system receive and represent stimuli from our environment

Detection of a stimulus

Sensation begins when a stimulus (like light, sound, or a smell) is detected by sensory receptors

Absolute Threshold

The minimum intensity of a stimulus that can be detected 50% of the time

Just-Noticeable Difference (JND/Difference Threshold)

The smallest detectable change in a stimulus

Weber’s Law

The principle that the size of the JND is proportional to the intensity of the stimulus

Sensory Adaptation

When constant exposure to a stimulus leads to decreased sensitivity over time

Sensory Interaction

The idea that one sense may influence another, like how smell can affect taste

Synesthesia

A rare condition where stimulation of one sensory pathway leads to involuntary experiences in second sensory pathway

(e.g., seeing colors when hearing music)

Priming

Exposure to one stimulus can influence how we perceive a subsequent stimulus

Transduction in the Retina

The retina converts light into neural signals through photoreceptors

Cornea

The clear, outer layer at the front of the eye. It helps focus light coming into the eye

Pupil

The black circle in the middle of your eye. It controls how much light enters the eye by getting bigger or smaller

Iris

The colored part of your eye (blue, brown, etc.) that surrounds the pupil. It changes the size of the pupil to regulate light entry

Lens

A clear, flexible structure behind the pupil. It bends (accommodates) to focus light onto the retina

Retina

The back of the eye where light is turned into signals. It contains special cells (rods and cones) that help us see

Fovea

A small area in the center of the retina where vision is the sharpest, used for detailing tasks like reading

Optic Nerve

The nerve that sends visual information from the eye to the brain for processing

Rods

Detect light and are used in low-light conditions

Cones

Detect color and are concentrated in the fovea, the center of the retina

Nearsightedness and Farsightedness (Myopic/Hyperopic)

Conditions where the image doesn’t focus correctly on the retina, leading to blurry vision

Trichromatic Theory (Young-Helmholtz)

The retina contains three types of color receptors (red, green, blue), and their combination allows us to perceive the full color spectrum

Opponent-Process Theory

Certain cells in the brain are stimulated by some colors and inhibited by others (e.g., red-green or blue-yellow), helping to explain afterimages

Color Vision Deficiencies

Dichromatism (two types of cones) and Monochromatism (only one type of cone or none), leading to color blindness

Sound Waves

Bands of compressed and expanded air. Our ears detect these brief changes in air pressure

Pitch

Pertains to frequency/pitch sounds. Measured in hertz (Hz). Can be determined based on length of the wave (side-to-side)

Loudness

Pertains to amplitude/sound. Measured in decibels. Can be determined based on width of the wave (up-and-down)

Pinna

The visible part of the ear that collects sound waves and funnels them into the ear canal. It helps to capture sound from the environment

Part of the outer ear

Ear Canal (Auditory Canal)

A tube that channels sound waves from the pinna to the eardrum. It amplified the sound waves as they travel towards the middle ear

Part of the outer ear

Eardrum (Tympanic Membrane)

A thin, flexible membrane that vibrates when the sound waves hit it. These vibrations mark the transition from the outer ear to the middle ear and start the process of turning sound waves into mechanical energy

Part of the outer ear

Ossicles

Three tiny bones — the malleus (hammer), incus (anvil), and stapes (stirrup) — that amplify the vibrations from the eardrum and transfer them to the inner ear

Part of the middle ear

Eustachian Tube

A canal that connects the middle ear to the throat. It helps to equalize air pressure on both sides of the eardrum, which is important for normal hearing (like when your ears “pop” during a flight)

Part of the middle ear

Cochlea

A snail-shaped, fluid-filled structure that converts the mechanical vibrations from the ossicles into electrical signals. Inside the cochlea is the basilar membrane, lined with hair cells

Part of the inner ear

Auditory Nerve (Cochlear Nerve)

Carries the electrical signals generated by the hair cells in the cochlea to the brain, where they are interpreted as sound

Place Theory definition

How we hear high-pitched sounds

Place Theory key idea

Different frequencies of sound waves stimulate different places or locations along the basilar membrane in the cochlea. Essentially, the cochlea acts like a piano, where each location along the membrane corresponds to a particular pitch

Frequency Theory definition

How we hear low-pitched sounds

Frequency Theory key idea

The rate (frequency) at which the auditory nerve sends electrical signals to the brain matches the frequency of the sound wave, helping us detect lower-pitched sounds. So, the entire basilar membrane vibrates at the same frequency as the sound wave

Frequency Theory how it works

For example, if a sound wave has a frequency of 100 Hz (which is a low pitch), the auditory nerve will fire at 100 times per second, matching the frequency of the sound wave

Volley Theory definition

How we hear higher-pitched sounds (especially between 1,000 Hz and 4,000 Hz)

Volley Theory key ideas

Individual neurons can’t fire fast enough on their own to keep up with high-frequency sound waves (like a 2,000 Hz tone). Instead, groups of neurons work together by taking turns firing in a rapid succession, a process known as “volleying”. Together, these groups of neurons can handle higher frequencies

Sound Localization

Helps us determine where sounds are coming from

If a car to your right honks, your right ear will receive a more intense sound, and it will receive the sound slightly sooner than your left ear

Conduction Deafness

Problems with conducting sound waves to the cochlea

Sensorineural Deafness

Damage to the cochlea or auditory nerve

Cochlear Implants

Devices that can help restore hearing by stimulating the auditory nerve

Olfactory System definition

Responsible for our sense of smell (olfaction)

Olfactory System how it works

Molecules from scents in the air enter the nose and dissolve in the mucus of the olfactory epithelium

These molecules stimulate olfactory receptors on specialized neurons, which then send signals to the olfactory bulb in the brain

Bypasses the thalamus and goes to the limbic system and olfactory cortex (linked to emotion and memory)

Epithelium

A tissue at the top of the nasal cavity

Gustation

Scientific word for taste

Taste Buds

Specialized structures located on the tongue that contain taste receptors

Primary Taste Categories

Sweet: Sugar, which signals energy-rich foods

Sour: Acidic foods, which may indicate spoilage

Salty: Sodium, essential for body functions

Bitter: Can signal toxins, leading to aversion

Umami: A savory taste, often linked to proteins

Oleogustus: A newer term for the taste of fat, which plays a role in food preferences

Taste Receptors

Located within taste buds, these detect chemicals dissolved in saliva and send signals to the brain via the gustatory pathway

Types of Tasters

Supertasters, Medium Tasters, and Nontasters

Supertasters

People with more taste buds than average, making them highly sensitive to certain flavors, especially bitter ones

Medium Tasters

Most people fall into this category, having a moderate number of taste buds

Nontasters

People with fewer taste buds, meaning they have a reduced sensitivity to tastes, especially bitterness

Skin receptors

The skin contains specialized receptors that detect pressure, temperature, and pain. These receptors send signals to the brain for processing

Mechanoreceptors

Detect pressure and texture (e.g., when touching a smooth surface)

A type of skin receptor

Thermoreceptors

Detect change in temperature

A type of skin receptor

Nociceptors

Detect pain (damage to tissues)

A type of skin receptor

Somatosensory Cortex

Located in the parietal lobe of the brain, this area processes touch sensations. The body is mapped onto the cortex in a way that reflects the sensitivity of different areas (e.g., hands and lips have more representation due to their high sensitivity)

Thalamus

Acts as a relay station, sending touch information from the body to the somatosensory cortex

What is pain?

The body’s way of signaling potential harm and encouraging protective behaviors. It is processed through both physical and emotional pathways.

Gate Control Theory

Suggests that the spinal cord contains a neurological “gate” that either blocks or allows pain signals to pass to the brain

Phantom Limb Sensation

Refers to the experience of feeling sensations, including pain, in a limb that has been amputated

Occurs because the brain’s sensory map still includes the missing limb, and sometimes misfires

Vestibular Sense

This sense allows us to detect the movement of our head and helps us keep our balance. It is essential for everyday actions, such as walking, standing upright, and maintaining coordination

Semicircular Canals

The semicircular canals are three fluid-filled tubes located in the inner ear. Each canal id oriented in a different plane (horizontal, vertical, diagonal) to detect different types of head movements

When does dizziness occur?

When the fluid in the canals keeps moving after you stop spinning, creating a sensation that you’re still moving

Vertigo

A common issue related to the vestibular system, occurs when the brain receives conflicting signals from the vestibular system and other senses, leading to a spinning sensation