1. The Senses

2. Special senses Smell Taste Sight Hearing
“Touch” = temperature + pressure + pain of skin, muscles, & joints
Equilibrium (in the ear)

3. The General Senses What are the Sensory Basics?
Sensory receptors—Specialized cells or cell processes that monitor external or internal conditions. Simplest are free nerve endings.
General versus Special Senses
General senses—Temperature, pain, touch, pressure, vibration, and proprioception. Receptors throughout the body
Special senses—Smell, taste, vision, balance, and hearing. Receptors located in sense organs (e.g., ear, eye).
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4. The General Senses What is a Pain Definition? Temperature
Nociceptors—Receptors for tissue damage to lead to the sensation of pain
Temperature
Thermoreceptors detect temperature change
Cold receptors greatly outnumber warm receptors
Touch, Pressure, and Position
Mechanoreceptors—Receptors that respond to physical distortion of their cell membranes.
What are Baroreceptors?
Provide pressure information essential for autonomic regulation
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5. Baroreceptors and the Regulation of Autonomic Functions
The General Senses
Baroreceptors and the Regulation of Autonomic Functions
Figure 9-4

6. Sensory Receptors Large complex organs (eyes, ears)
Localized clusters of receptors (taste buds, olfactory epithelium)

7. The General Senses
Referred Pain
Figure 9-2

9. Vision Tests

10. The Special Senses—Vision
What are the Accessory Structures of the Eye?
Eyelids (palpebra) and glands
Superficial epithelium of eye
Conjunctiva
Lacrimal apparatus
Tear production and removal
Extrinsic (outer) eye muscles
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11. The Special Senses—Vision
What is the Lacrimal Apparatus?
Lacrimal gland produce tears
Tears drain into nasal cavity
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12. The Special Senses—Vision
The Accessory Structures of the Eye
Figure 9-8(a)

13. The Special Senses—Vision
The Accessory Structures of the Eye
Figure 9-8(b)

14. The Special Senses—Vision
Image Formation
Figure 9-16(a)

15. The Special Senses—Vision
Image Formation
Figure 9-16(b)

16. The Special Senses—Vision
Visual Physiology
Photoreceptors—Cells specialized to respond to photons, packets of light energy
Two types of photoreceptors
Rods
Highly sensitive, non-color vision
Cones
Less sensitive, color vision
Site of sharpest vision
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17. Are the squares inside the blue and yellow squares all the same color?

18. Bezold effect
The smaller squares inside the blue and yellow squares are all the same color.
They seem different (magenta and orange) because a color is perceived differently depending on its relation to adjacent colors (here blue or yellow depending on the outer square).

19. Are the horizontal lines straight or crooked?

20. Café Wall Illusion
The horizontal lines are straight, even though they do not seem straight.  In this illusion, the vertical zigzag patterns disrupt our horizontal perception.

21. Does Lincoln’s face look normal?

22. Some neurons in the brain seem specialized in processing faces
Some neurons in the brain seem specialized in processing faces. Faces are usually seen upright. When presented upside down, the brain no longer recognizes a picture of a face as a face but rather as an object. Neurons processing objects are different from those processing faces and not as specialized. As a consequence these neurons do not respond to face distortions as well. This explains why we miss the weird eyes when the face is inverted.

23. Can you see a baby?

24. Illusory Contour
The baby’s head is on the left, the baby’s feet are against the trunk of the tree on the right. Illusory Contour: a form of visual illusion where contours are perceived without a luminance or color change across the contour

25. How quickly can you say the color of the words below?

28. Taste Tests

30. The Special Senses—Taste
What are Taste (Gustatory) Receptors?
Taste buds
Found within papillae on tongue, pharynx, larynx
Sense salt, sweet, sour, bitter
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31. Flavor = taste + smell

32. 5 Types of Taste Receptors

33. Aging After age 50, ability to smell and taste decrease
Membranes lining nose become thinner & drier  olfactory nerve deteriorate
# taste buds decrease with age  more difficult to detect sweet/salty  foods taste more bitter
As people age, their food tastes more bland  eat less  possible malnutrition

34. The Special Senses—Smell
What are Olfactory Organs?
Olfactory epithelium
Olfactory receptor cells
Neurons sensitive to odorants
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35. The Special Senses—Smell
The Olfactory Organs
Figure 9-6(a)

36. The Special Senses
Key Note
Olfactory information is routed directly to the cerebrum, and olfactory stimuli have powerful effects on mood and behavior. Gustatory sensations are strongest and clearest when integrated with olfactory sensations.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

38. Equilibrium and Hearing
What are Sensory Functions of the Inner Ear?
Dynamic equilibrium
Static equilibrium
Hearing
What is the Anatomy of the Ear?
External ear
Pinna (auricle)
External acoustic canal
Tympanic membrane (eardrum)
Middle ear
Auditory ossicles
Connect tympanic membrane to inner ear
Auditory tube
Connection to nasopharynx
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39. Equilibrium and Hearing
What is the Anatomy of the Inner Ear?
Vestibule
Receptors for linear acceleration, gravity
Semicircular canal with ducts
Receptors for rotation
Cochlea with cochlear duct
Receptors for sound
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40. Equilibrium and Hearing
The Anatomy of the Ear
Figure 9-22

41. Equilibrium and Hearing
Key Note
Balance and hearing both rely on hair cells. Which stimulus excites a particular group depends on the structure of the associated sense organ. In the semicircular ducts, fluid movement due to head rotation is sensed. In the utricle and saccule, shifts in the position of otoliths by gravity is sensed. In the cochlea, sound pressure waves distort the basilar membrane.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings