Psych 101 Ch. 3

Sensory receptors

All sensation is a result of the stimulation of specialized cells.

Perception

Occurs when we integrate, organize, and interpret sensory information in a way that is meaningful.

Smell

(airborne chemical molecules) This is also called olfaction. Odors such as smoldering fire, leaking gas, or spoiled food, alert us to potential dangers. Molecules in the air and these molecules encounter millions of olfactory receptor cells located high in the nasal cavity. Bundles of these molecules make up the olfactory nerve. There is not a separate receptor for each of the estimated 10,000 different odors that we can detect. The brain identifies an odor by interpreting the pattern of olfactory receptors that are stimulated. (Shepherd, 2006) Olfactory function tends to decline with age. (80 and above)

Taste buds

(dissolvable chemicals in your mouth) This is also called gustation. It helps us determine whether a particular substance is to be savored or spat out. When activated special receptor cells in these send neural messages along pathways to the thalamus in the brain. There is salty, sour, bitter, and sweet. Bitter or sour taste warn us to avoid many toxic or poisonous substances. Sensitivity to salty tasting substances help us regulated the balance of electrolytes in our diets.

Touch

(pressure, warmth, or cold) Skin senses which provide essential information about your physical status and your physical interaction with objects in your environment. Body senses keep you informed as to your position and orientation in space. The skin of an average adult covers about 20 square feet of surface area and weighs about six pounds. Sensory receptors are distributed unevenly among different areas of the body, which is why sensitivity to touch and temperature varies from one area of the body to another. Your hands, face, and lips for example are much more sensitive to touch than are your backs, arms, and legs. Thats because your hands, face, and lips are much more densely packed with sensory receptors.

Hearing

(sound waves) Or audition is capable of responding to a wide range of sounds, from faint to blaring, simple to complex, harmonious to discordant. The ability to sense and perceive very subtle differences in sound is important to physical survival, social interactions, and language development. Most of the time, all of us use this.

Rods

125 million of these; much more sensitive to light than cones. Fully adapted to the dark, they are about a thousand times better than cones at detecting weak visual stimuli.

Cones

7 million of these; Are sensitive to the different wavelengths that produce the sensation of color. Also specialized for seeing fine details for visioning bright light. Most of these are concentrated in the center of retina.

top-down processing

Also referred to as conceptually driven processing. Occurs when we draw on our knowledge, experiences, expectations and other cognitive processes to arrive arrive at meaningful perceptions, such as people or objects in a particular text. Cultural experiences also effect this.

Basilar membrane

As the fluid in the cochlea ripples, the vibration in turn is transmitted to this.

Integrated Explanation of Color Vision

Both the trichromatic theory and opponent process theory are both right because it turns out each theory correctly describes color vision at a different level of visual processing.

Pain

Can be defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage.

Vision

Consists of four things: Color, motion, form, & water.

Gate control theory of pain

Depending on how the brain interprets the pain experience, it regulates pain by sending signals down the spinal cord that either open or close pain"gates," or pathways.

Cilia Hair Cells

Embedded in the basilar membrane are the sensory receptors for sounds, which have tiny, projecting fibers that look like hair. These cells bend as the basilar membrane ripples.

Bipolar cells

Information from the sensory receptors, the rods and cones, is the first collected by specialized neurons.

Difference threshold

Is the smallest possible difference between two stimuli that can be detected half the time.

bottom-up processing

Psychologists sometimes refer to this flow of sensory data from the sensory receptors to the brain. Also called data-driven processing, and is usually at work when we're confronted with an ambiguous stimulus.

Sensation

Refers to the detection and basic sensory experience of environmental stimuli, such as sounds, images, and odors. How are sensory receptors respond to stimulation and transmit that information in usable form to the brain. No clear boundary line between this and perception.

Frequency

Refers to the rate of vibration or number of waves per second, and is measure in a unit called hertz. Hertz simply refers to the number of waves per second.

Pitch

Refers to the relative "highness" or "lowness" of a sound.

Absolute threshold

Refers to the smallest possible strength of stimulus that can be detected half the time.

Sensitization

Sensory adaptation is were sensory receptors become gradually less responsive to steady stimulation over time. Sensitization is the opposite of adaptation. In sensitization, pain pathways in the brain become increasingly more responsive over time. In the case of phantom limb pain, sensitization has occurred in the pain transmission pathways from the site of amputation.

Sensory Adaptation

Sensory receptor cells become less responsive to a constant stimulus. This gradual decline in sensitivity to a constant stimulus is called....

Photoreceptors

Sensory receptor cells that respond to light.

Substance P

Stimulates free nerve endings at the site of the injury and also increases pain messages within the spinal cord.

Perceptual Set

The tendency to perceive objects or situations from a particular frame of reference. Lead us to reasonably accurate conclusions.

Blind spot

The tiny hole that appears in our field of vision due to their being no photoreceptors in the optic disk.

Opponent Process Theory

There are four basic colors, which are divided into two pairs of color-sensitive neurons: red-green and blue-yellow. Ex: if red is stimulated, green is inhibited. (green stimulated then red is inhibited) In addition black and white act as an opposing pair.

Trichromatic Theory

There are three varieties of cones. Red light (long wavelengths), green light (medium wavelengths), or blue light (short wavelengths). red-sensitive, green-senstitive, and blue-sensitive. When a color other than red, green, or blue strikes the retina, it stimulates a combination of cones.

Dogs

These animals have about 200 million olfactory receptor cells compared with the 12 million receptors that humans have.

Ganglion cells

These cells combines, analyzes, and encodes the information from the photoreceptors in its receptive field before transmitting the information to the brain.

Smell & Taste

These two things are closely linked. They're both called the "chemical senses."

White light

This type of light contains all wavelengths thus all colors.

Perceptual Illusion

When we misperceive the true characteristics of an object or an image.

Figure ground relationship

When we view a scene, we automatically separate the elements of that scene into the figure, which is the main element of the scene, and the ground, which is its background. coffee cup-main element and table-ground.

Optic nerve

The optic disk, the point at which fibers make up this...leave the back of the eye and project to the brain. Is a thick nerve that exits from the back of the eye at the optic disk and extends to the brain.

Threshold

The point at which a stimulus is strong enough to be detected because it activates a sensory receptor cell.

Transduction

The process by which a form of physical energy is converted into a coded neural signal that can be processed by the nervous system.