Week 4

Question 1

Describe the key elements of a sensory system

Answer 1

First step in sensation involves accessory structures which collect and modify sensory stimuli.
Second step is transduction, converting incoming energy into nerve cell activity; accomplished by neural receptors.

Question 2

What is sensory adaptation

Answer 2

Sensory adaptation takes place when the receptors receive unchanging stimulation, nerve cell activity is transferred through the thalamus and onto the cortex.

Question 3

Explain transduction

Answer 3

Transduction is the process of converting incoming energy into nerve cell activity

Question 4

Explain Encoding

Answer 4

Encoding is the translation of a stimulus’ physical properties into a pattern of neural activity.

Question 5

Explain visible light

Answer 5

Visible light is electromagnetic radiation that has a wavelength from just under 400 nanometres to about 750 nanometres (a nanometre is one-billionth of a metre).

Question 6

Explain light intensity

Answer 6

Refers to how much energy the light contains and determines the brightness of light.

Question 7

Explain light wavelength

Answer 7

What colour you see depends mainly on light wavelength, different wavelengths produce sensations of different colours.

Question 8

Explain the eye

Answer 8

Light enters through the cornea.
Light then passes through the pupil.
The iris adjusts the amount of light allowed into the eye by contracting to reduce the size of the pupil/
The lens is directly behind the pupil.
Both cornea and lens are curved so that can bend light rays.
Light rays are focused into an image on the retina

Question 9

Describe photoreceptors

Answer 9

Photoreceptors are specialised cells in the retina that convert light energy into nerve cell activity.

Question 10

Describe the two basic types of photoreceptors

Answer 10

Rods and Cones
Rods use photopigment rhodopsin, which is more light-sensitive than cones
Cones use one of three isospin photopigments each is sensitive to different light wavelengths.

Question 11

Describe sound

Answer 11

Sound is a repetitive fluctuation in the pressure of a medium, such as air. Vibrations of an object produce the fluctuations in pressure that create sound. A wave is a repetitive, rhythmic variation in pressure that spreads out in all directions.

Question 12

Describe amplitude

Answer 12

or intensity is the difference in air pressure from a wave’s baseline to its peak.

Question 13

Describe wavelength

Answer 13

is the distance from one peak to the next.

Question 14

Describe frequency

Answer 14

is the number of complete waveforms, or cycles, that pass by a given point in space every second. One cycle per second is 1 hertz (Hz)

Question 15

Describe Auditory Accessory Structures

Answer 15

The pinna is the crumpled part of the ear visible on the outside of the head that funnels sound down through the ear canal.
At the end of the ear canal, the sound waves reach the middle ear, where they strike a tightly stretched membrane known as the eardrum or tympanic membrane.
The vibrations of the tympanic membrane are transferred through a chain of three tiny bones named for their shapes, the malleus (hammer), incus (anvil) and the stapes (stirrup).

These bones amplify the changes in pressure produced by the original sound waves by focusing the vibrations of the tympanic membrane onto the oval window, a smaller structure.

Question 16

Describe Auditory Transduction

Answer 16

After sound passes through the oval window, it enters the inner ear reaching the cochlea. The cochlea is the structure in which transduction actually occurs.

The cochlea is wrapped into a coiled spiral. A fluid filled ‘tube’ runs the length of it.

The asilar membrane forms the floor of this long tube.

When a sound wave passes through the fluid in the tube, it moves the basilar membrane, and this movement deforms hair cells of the organ of Corti, a group of cells that rests on the membrane.

These hair cells make connections with fibres from the acoustic nerve (auditory nerve), a bundle of axons that go into the brain. When the hair cells bend, they stimulate neurons in the auditory nerve to fire in a pattern that sends the brain a coded message about the amplitude and frequency of the incoming sound waves, senses as loudness and pitch.

Question 17

Describe Psychological Dimensions of Sound

Answer 17

Loudness is determined by the amplitude of the sound wave
Pitch, how ‘low’ or ‘high’ a tone sounds, depends on the frequency of sound waves.
Timbre is sound’s quality. It is caused by complex wave patterns that are added onto the lowest, or fundamental, frequency of a sound. This enables you to tell the difference between a note played on a flute and a note played on a clarinet.

Question 18

Describe taste perception

Answer 18

Taste perception (gustatory perception or sense of taste) is the chemical sense system in the mouth. The receptors for taste are in taste buds, which are grouped together as papillae in the mouth and throat.

Question 19

Describe Olfactory perception

Answer 19

Olfactory perception (or sense of smell) detects chemicals that are airborne, or volatile. Accessory structures include the nose, the mouth and the upper part of the throat. Odour molecules can reach receptors either through the nose or through an opening in the palate at the back of the mouth.

Question 20

Explain cutaneous senses

Answer 20

somatic senses or somatosensory systems) are located throughout the body, rather than in a localised, specific organ. These include the skin senses of touch, temperature, and pain as well as proprioception,

Question 21

Describe stimulus and receptors for touch

Answer 21

Skin, hairs receptors that transduce pressure into neural activity are in or just below the skin.

Question 22

Describe Proprioception

Answer 22

The proprioceptive senses provide information about the position of the body and what each part of the body is doing.

Question 23

Describe the Trichromatic Theory of Colour Vision

Answer 23

The trichromatic theory or Young-Helmholtz theory of colour vision states that there are three types of visual elements in the eye, each most sensitive to a different wavelength, and information from these three elements combines to produce the sensation of colour.

Question 24

Which cones respond most to light in the blue range?

Answer 24

Short-wavelength cones

Question 25

Which cones respond most to light in the green range?

Answer 25

Medium-wavelength cones

Question 26

Describe colour vision

Answer 26

Colour vision is the result of the pattern of activity of the different cones. The trichromatic theory was applied in the creation of colour television screens, which contain microscopic elements of red, green and blue.

Question 27

Describe the Opponent-Process Theory of Colour Vision

Answer 27

The opponent-process theory of colour vision holds that the colour-sensitive elements in the eye are grouped into three pairs, where each pair member opposes or inhibits, the other.

Question 28

What are the three pairs?

Answer 28

The three pairs are a red–green element, a blue–yellow element, and a black–white element. Each element signals one colour or the other, but never both. This theory explains afterimages.

Question 29

What are Complementary colours?

Answer 29

Complementary colours stimulate opposite ‘sides’ of the same opponent-process colour element. Two colours are complementary if grey results from mixing lights of the two colours.

Question 30

How does the brain locate sounds?

Answer 30

The brain analyses the location of sound-based partly on the difference in time the sound takes to reach each ear and on the sound intensity at each ear.

Question 31

Explain Coding Intensity and Frequency

Answer 31

The auditory system generally codes intensity by the speed of the firing of the given neuron. The more intense the sound, the more rapid the firing.

Question 32

Explain The Gate Control Theory of Pain

Answer 32

The gate control theory of pain says that there is a ‘gate’ in the spinal cord that either lets pain impulses travel to the brain or blocks their progress.

Input from other skin senses may ‘take over’ pathways that pain impulses would have used. This may explain why rubbing the area around a wound eases pain.

The brain can close the gate by sending signals down the spinal cord. The result is analgesia, an absence of pain sensation in the presence of a normally painful stimulus.

Question 33

What are natural analgesics?

Answer 33

At least three chemicals that are released by the body during stress play a role in the brain’s ability to block pain signals. They are the neurotransmitter serotonin, natural opiates called endorphins, and endocannabinoids

Question 34

Describe the emotional aspects of pain

Answer 34

All senses can have emotional components, most of which are learned responses. However, pain is more direct. Specific pathways carry an emotional component of the painful stimulus to areas of the hindbrain and reticular formation, as well as the cingulate cortex via the thalamus.

Cognition affects emotional responses to pain. Knowing about the nature of pain and when to expect it seems to make it less aversive even though the sensations are reported to be just as intense.

The use of pain-reducing strategies, such as focusing on distracting thoughts, also affects emotional responses to pain.