Week 4

Question 1

Describe the key path elements of a sensory system

Answer 1

• Stimulus
• Accessory structure modifies stimulus (lens of eye focuses)
• Receptor transduces energy into neural activity
• Sensory nerves transfer neural activity to CNS
• Thalamus processes and relays neural activity to cerebral cortex
• Cerebral cortex receives input and produces the sensation and perception.

Question 2

Explain transduction

Answer 2

Converting external stimuli into neural signals

Question 3

Explain encoding

Answer 3

process of acquiring information and entering it into memory

Question 4

Describe physical stimulus, accessory structure, receptor cells and psychological correlates for VISION

Answer 4

Physical stimulus – visible light
Accessory structure – cornea (protective outer layer), pupil (light passes through here), iris (contracts or relaxes to increase or decrease light), lens (focus)
Receptor cells – transduction occurs at the retina
Psychological correlates – Light to lens to retina to optic nerve to thalamus to visual cortex

Question 5

Describe physical stimulus, accessory structure, receptor cells and psychological correlates for HEARING

Answer 5

Physical stimulus - sound
Accessory structure – Pinna, tympanic membrane, cochlea, basilar membrane
Receptor cells – transduction mechanism – hair cells of the organ of Corti.
Psychological correlates – Stimulus to accessory structure (pinna) to acoustic nerve to thalamus to primary auditory cortex

Question 6

Describe physical stimulus, accessory structure, receptor cells and psychological correlates for TASTE

Answer 6

Physical stimulus - food
Accessory structure - tongue
Receptor cells – inside papillae/tastebuds (around 10,000 in mouth)
Psychological correlates – stimulus to tongue to papillae to orbital frontal cortex

Question 7

Describe physical stimulus, accessory structure, receptor cells and psychological correlates for SMELL

Answer 7

Physical stimulus - perfume
Accessory structure - nose, mouth, upper part of throat, lungs
Receptor cells – transduction at mucous membrane (moist inner lining of nose)
Psychological correlates – stimulus to nose to olfactory bulb to hypothalamus and amygdala (emotion)

Question 8

Describe physical stimulus, accessory structure, receptor cells and psychological correlates for TOUCH/TEMPERATURE

Answer 8

Physical stimulus – hot surface
Accessory structure – fingertips, hands
Receptor cells - nerves
Psychological correlates – stimulus to fingertips to nerves to spinal cord to thalamus to cerebral cortex

Question 9

Outline the Trichromatic theory of colour perception

Answer 9

3 types of visual elements (cones), each of which is most sensitive to different wavelengths of light. (E.g. TV screen with red, blue and green pixels)

Question 10

Outline Opponent process theory of colour perception

Answer 10

Red vs green
Blue vs yellow
Black vs white
One colour of the pair suppresses the other

Question 11

How does the auditory system detect how far away a sound is?

Answer 11

Tympanic membrane – in the middle of the ear that vibrates to match sound waves (closer together waves the closer the sound origin, further apart waves the further away sound origin)
Neuron firing - The more intense (close) the sound is the more rapid the firing of a given neuron.

Question 12

Explain the gate theory of pain

Answer 12

The ‘gate’ in spinal cord can be open or shut allowing, or not, pain to travel to brain (e.g. rubbing a bumped elbow used the pathways the pain sensations would have used)

Question 13

What is the effects of culture, expectation and analgesics on pain

Answer 13

Some cultures are predisposed via experience to deal better with pain.
Patients who have operations, and expectations of pain explained prior object less to pain and heal faster.
Analgesics are drugs that induce analgesia (the absence of pain sensation).