sensations

2. 1. Absolute Threshold: The smallest level of stimulus that can be detected by the senses at least 50% of the time.

3. 2. Just Noticeable Difference (JND): The minimal change in a stimulus that can be detected.

4. 3. Transduction: The process of converting sensory stimuli into neural signals that the brain can interpret.

5. 4. Thalamus: A brain structure that acts as a relay center, sending sensory information (except smell) to appropriate areas of the brain.

Lens: A transparent structure that focuses light on the retina. Accommodation: The process by which the lens changes shape to focus near or far objects.

6. • Retina: The light-sensitive layer of cells at the back of the eye containing rods and cones.

7. • Rods and Cones: Photoreceptor cells; rods detect black, white, and gray, while cones detect color and fine detail.

8. • Blind Spot: The point where the optic nerve exits the eye, creating a spot with no photoreceptors.

9. 6. Occipital Lobe (Visual Cortex): The part of the brain responsible for processing visual information.

10. 7. Opponent-Process Theory: A theory of color vision stating that color is processed in opposing pairs (red-green, blue-yellow, black-white).

11. 8. Trichromatic Theory: A theory of color vision based on three types of cone cells sensitive to red, green, and blue light.

12. 9. Light/Dark Adaptation: The ability of the eyes to adjust to changes in light levels.

13. 10. Prosopagnosia: The inability to recognize faces.

14. 11. Blindsight: A condition where individuals can respond to visual stimuli without consciously perceiving them.

16. • Hair Cells: Sensory receptors in the cochlea that detect sound vibrations.

17. • Ossicles and Tympanic Membrane: The ossicles are tiny bones in the middle ear (malleus, incus, and stapes) that amplify sound; the tympanic membrane is the eardrum.

18. • Temporal Lobes (Auditory Cortex): The brain region responsible for processing auditory information.

19. 13. Sound Waves: Variations in air pressure that travel as waves; characterized by wavelength and amplitude.

20. 14. Sound Localization: The ability to determine the location of a sound in space.

21. 15. Pitch Theories:

22. • Frequency Theory: Suggests that the frequency of auditory nerve impulses corresponds to the frequency of a tone.

23. • Place Theory: Proposes that different areas of the cochlea are activated by different frequencies.

24. 16. Hearing Impairments:

25. • Conduction Deafness: Hearing loss caused by damage to the middle ear structures.

26. • Sensorineural Deafness: Hearing loss caused by damage to the cochlea or auditory nerve.

27. 17. Phantom Pain: The perception of pain in a limb or part of the body that has been amputated.

2. The “Other” Senses

   1. 18. Vestibular Sense: The sense of balance and spatial orientation, controlled by semicircular canals in the inner ear.

   2. 19. Kinesthetic Sense: The awareness of the position and movement of body parts.

   3. 20. Cutaneous (Touch) Senses: Sensations of pressure, temperature, and pain perceived through the skin.

   4. 21. Gate-Control Theory: A theory explaining how the nervous system blocks or allows pain signals to pass to the brain.

   5. 22. Olfactory Sense (Smell):

   6. • Anosmia: The inability to perceive odors.

   7. • Pheromones: Chemicals secreted by organisms that can influence the behavior or physiology of others.

   8. 23. Gustatory Sense (Taste):

   9. • Taste Buds: Sensory organs that detect taste (sweet, sour, salty, bitter, umami).

24.Synesthesia: A condition in which stimulation of one sensory pathway leads to automatic, involuntary experiences in a second sensory pathway.