1. Smell, Taste, TOUCH & Hearing
Chapter 7
Smell, Taste, TOUCH & Hearing

2. Sensation and Perception
SENSATION: the psychological experience associated with sound, light, or other simple stimulus and the initial information-processing steps by which sense organs and neural pathways take in stimulus information from the environment
PERCEPTION: the recognition, organization, and meaningful interpretation of sensory stimuli

3. Breakdown of the Sensory Systems
PHYSICAL STIMULUS: that in the environment that activates the sense organs
PHYSIOLOGICAL RESPONSE: pattern of electrical or chemical activity that occurs as a result of the stimulus
SENSORY EXPERIENCE: subjective sensation and perception experienced by the person
Physical stimulus
Physiological response
Sensory experience

4. Each Sensory System Has Distinct Receptors and Neural Pathways
SENSORY RECEPTORS: specialized structures (cells or tips of neurons) that respond to physical stimuli
SENSORY AREAS: areas of the brain’s cerebral cortex that receive and analyze input from the body’s senses

5. Sensory Transduction Concepts
TRANSDUCTION: process by which a receptor cell produces an electrical change in response to the energy of a physical stimulus
RECEPTOR POTENTIAL: the actual electrical charge that occurs in the receptor cell in response to the physical stimulus
SENSORY CODING: process by which information about the quality and quantity of a stimulus is preserved in the pattern of action potentials
SENSORY ADAPTATION: temporary decrease in sensitivity to sensory stimulation that occurs when a sensory system is stimulated for a period of time, and vice versa

6. Transduction and Coding for the Sense of Smell
Physical stimulus: ODORANTS
Sensory Receptors: olfactory receptor cells
Location: mucous membrane of the olfactory epithelium

8. Differences Among People in Olfactory Sensitivity
Women are more sensitive to smells than men
Sensitivity decreases with age
Genetic and environmental influences: ANDROSTENONE & differentiation learning

9. Discriminating Among Individuals by Smell
Smell plays a role in mother-infant bonding
Involved in mate selection (major histocompatibility complex)
PHEROMONES: a chemical that is released by an animal and that acts on other members of the species to promote some specific behavioral or physiological response
Vomeronasal Organ

10. Anatomy and Physiology of Taste
Sensory receptors: taste receptor cells
Location: Tongue (Taste buds), roof of the mouth, entrance of the throat

11. Five Primary Tastes SALTY SOUR BITTER SWEET UMAMI Best stimulus: NaCl
Best stimulus: H+ ions
BITTER
Best stimulus: quinine
SWEET
Best stimulus: glucose/fructose
UMAMI
Best stimulus: Monosodium Glutamate

12. An Evolutionary Account of Taste Quality
What is edible (safe) and what is not (poisonous)?
Sour taste due to bacterial decay; bitter taste due to toxic compounds
Women and children are most sensitive to bitter

13. Neural Pathways for Pain
Physical stimuli:
pressure
vibration (to judge an object’s roughness)
temperature
pain (events that
cause tissue damage)

14. Touch Sensory Receptors
A-delta fibers
C fibers
PIC of skin surface

15. Sound as a Physical Stimulus
AMPLITUDE  LOUDNESS (Decibels)
FREQUENCY  PITCH (Hertz)
High Amplitude
Low Amplitude
Low Frequency
High Frequency

16. How the Ear Works

17. The Inner Ear
Tectorial
membrane

18. Deafness and Hearing Aids
Conduction deafness occurs when the ossicles fail to move and transmit vibrations to the inner ear
Sensorineural deafness results from damage to the hair cells or auditory neurons
A COCHLEAR IMPLANT may be used to transmit electrical impulses directly to the cochlea by means of an implant

19. Von Bekesy (1961)