Week 8

Question 1

Light has the properties of?

Answer 1

A particle (color change) and wavelength (types of color: yellow, red etc.)

Question 2

The human eye can detect light operating on wavelengths of?

Answer 2

• 380 through 760 nanometers (one billionth of a meter). This is a small part of the electromagnetic spectrum, which includes x-rays, radar waves, cell phone waves, etc.

Question 3

Where is the cornea and what is its function?

Answer 3

The cornea is the outermost layer of the eye, and it helps focus light.

Question 4

Where is the pupil and iris and what is their collective function?

Answer 4

The pupil is the black center of the eye, the iris is the colored part of the eye, and they work together to control the amount of light that enters the eye.

Question 5

What is the function of the lens and where is it?

Answer 5

Behind the front part of the eye is the lens, which through stretching of muscles, changes its shape to focus on incoming visual images.

Question 6

Where is the retina and its importance?

Answer 6

The retina is in the back of the eye and is covered with photoreceptors: rods and cones.

Question 7

How do rods and cones work?

Answer 7

When light hits either a rod or a cone, it causes a chemical change in a chemical that leads to a change in receptor potential. This then leads to action potentials, which travel through a series of intermediate cells before passing on to the brain through the optic nerve.

Question 8

How do we have a blind spot and how do we make up for it?

Answer 8

The blind spot is primarily due to the absence of photoreceptors (specifically, rods and cones) in the area where the optic nerve exits the retina. It’s not a physical hole but a region lacking the light-sensitive cells necessary for processing visual information, perceptual areas in the brain make up for it so we don’t notice it.

Question 9

Rods:

Answer 9

Rods are active in dim light, responsible for low-light conditions and detecting motion.

Question 10

Cones:

Answer 10

Cones are active with color, greater activity, responsible for color in well-lit conditions.

Question 11

What do we have more of cones or rods?

Answer 11

We have more rods than cones, so color is easier to lose than brightness.

Question 12

What is sensory adaptation and habituation?

Answer 12

Sensory adaptation in the eye, involving rods and cones, describes the decreased responsiveness of these photoreceptors to a constant stimulus, while habituation refers to the brain’s reduced attention or response to repetitive visual stimuli processed by these receptors.

Question 13

Are cones and rods sensitive to color or not sensitive to color?

Answer 13

Cones are not sensitive to color, while rods are.

Question 14

We see objects as having color because of what reasons?

Answer 14

Colors absorb certain frequencies of light and reflect others (via their pigments).

Question 15

What are additive colors?

Answer 15

When two colors are added together make white, they are known as complementary colors (law of complementary).

Question 16

What’s trichromatic theory of color perception?

Answer 16

Trichromatic theory is that there are three different types of cones, one for each primary color, and they each respond maximally to red, blue, or green. (Each cone responds somewhat to all colors, but maximally to its own color).

Question 17

How is the brain able to determine the color of light?

Answer 17

By analyzing the response of different cones, permitting the visual areas of the brain to determine the color of a light or an object.

Question 18

Some individuals lack a certain type of cone, what’s the result of this?

Answer 18

They are unable to perceive certain colors making them color blind: About 1-50 people are color blind.

Question 19

What is the opponent-process theory?

Answer 19

The opponent-process is color theory. Stating the trichromatic theory does not explain the law of complementarity (relationship). Heiring says there are three opposing receptors for light: red-green, blue-yellow another, and bright-dark. If these colors above are mixed, they make white light.

Question 20

What else does the opposing-process theory suggest?

Answer 20

It also explains complementary negative afterimages, where the opposing color appears after looking at a color for a long period of time. For example, if you stare at something red for a long time your cones get tired, and you will begin to see green.

Question 21

How do the Trichromatic & opponent process theory relate to each other?

Answer 21

The trichromatic theory is correct at the level of the rods and cones, while the opponent process theory is correct at the level of the ganglion cells.

Question 22

What is frequency?

Answer 22

Frequency is the number of sound waves per second (Hertz), higher means louder.

Question 23

What is amplitude?

Answer 23

Amplitude is the number of molecules displaced by the vibration measured in decibels (dB)

Question 24

How is the auditory cortex significant?

Answer 24

The auditory cortex allows us to hear, and it is in the temporal lobe.

Question 25

What is the stimulus of audition and the receptors involved?

Answer 25

The stimulus of hearing are sound waves and the receptors involved are hair cells.

Question 26

What is the stimulus of gustation and the receptors involved?

Answer 26

The stimulus of gustation is tastants (chemicals dissolved in saliva) and the receptors involved are chemoreceptors that respond to bitter, sour, salty, sweet and savory.

Question 27

What is the stimulus of olfaction and the receptors involved?

Answer 27

The stimulus of olfaction is gaseous chemicals and the receptors involved are chemical receptors that bind groups of molecules called odors.

Question 28

The experience of sound has a couple of aspects, what are they?

Answer 28

• Or the frequency of the sound wave.

Question 29

Auditory perception and loudness, describe the process of the action potential?

Answer 29

• Sound waves of hair amplification bend the hair cells to a greater degree, triggering an action potential that results in release of a neurotransmitter into the synapse they share with nerve cells. Therefore, there is an increase in the firing rate of the auditory nerve. (This is a common mechanism, whereby a stimulus of higher intensity causes higher firing rates).

Question 30

What is Interaural time difference (ITD)?

Answer 30

• The difference in arrival time of a sound between the two ears. For example, a sound presented on the right side of the body will reach the right ear first and vice versa.

Question 31

What is the Interaural level difference (ILD)?

Answer 31

• A sound presented at the right side of the body will be more intense at the right ear than the left ear.

Question 32

Somatosensation

Answer 32

How we sense and feel touch, pain and temperature.

Question 33

What does somatosensation provide us with and what are they

Answer 33

Information about our own body (interception) and information about stimuli outside of the body (exteroception)

Question 34

We have 4 different types of information sent to the brain: cutaneous sense, proprioception, kinesthesis and nociception and where do they come from?

Answer 34

Cutaneous sense- from the skin, proprioception- about our body positioning, kinesthesis- about our bodily movement and nociception- about our pain.

Question 35

What does gustatory relate to?

Answer 35

Taste

Question 36

What does olfactory relate to?

Answer 36

Smell

Question 37

What does more cortex in an area say about the area?

Answer 37

More sensitive

Question 38

What are phantom limbs?

Answer 38

Phantom limbs are where you feel a sensation from the missing limb, shown to disappear with the use of an artificial limb.

Question 39

For which reasons is pain important for organisms?

Answer 39

• Pain alerts the organisms to damage or dangerous stimuli. For example, touching a hot stove.

Question 40

How are organisms able to identify these dangerous stimuli?

Answer 40

• Free nerves located under the skin or in the internal organs respond to painful stimuli by sending nerve impulses to the spinal cord, from which sensory neurons carry the signal to the thalamus, from which it is sent to the somatosensory and frontal areas of the cortex.

Question 41

The thalamus sends a nerve impulse to where?

Answer 41

• The limbic system, which involves emotion.

Question 42

What are endorphins and how do they work?

Answer 42

• Endorphins are natural opiates: they work by inhibiting the neurotransmitter release involved in the firing of the synapses involved in pain signaling from the spinal cord to the brain.

Question 43

Where are somatosensory receptors located

Answer 43

• They are located all over the body.

Question 44

One somatosensory receptor is the nociceptor, what is its process of pain?

Answer 44

• The nociceptor activates the experience of pain by firing in response to damaging stimuli. The response than leads to mechanical stimulation, which is chemoreceptors responding to chemicals released to tissue damage (inflammation in the ear). The sensory information is carried to the brain via the ascending pathway (up the spinal cord) while the nerves from the brain to the reflex organs travel via the descending pathway (down the spinal cord). Which then leads to the immediate feeling of pain when you are injured due to the A-fibers (which travel to the somatosensory cortex). The long-lasting feeling of pain is due to the C-fibers sending signals to the brain that process emotion and interoception.