1. Slides 1 to 106
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2. The General Senses Sensory Basics
Sensory receptors—Specialized cells or cell processes that monitor external or internal conditions. Simplest are free nerve endings.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

3. The General Senses More Sensory Basics
Receptive field—The area monitored by a single receptor cell
Adaptation—Reduction in sensitivity at a receptor or along a sensory pathway in the presence of a constant stimulus.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

4. Receptors and Receptive Fields
The General Senses
Receptors and Receptive Fields
Figure 9-1

5. The General Senses General vs. 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).
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

6. The General Senses Key Note
Stimulation of a receptor produces action potentials that propagate along the axon of a sensory neuron. The frequency or pattern of action potentials contains information about the stimulus. A person’s perception of the nature of that stimulus depends on the path it takes inside the CNS.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

7. The General Senses Pain Definitions
Nociceptors—Receptors for tissue damage lead to the sensation of pain
Referred pain—Perception of pain in a part of the body not actually stimulated
Fast (prickling) pain—Localized pain carried quickly to the CNS on myelinated axons
Slow (burning) pain—Generalized pain carried on slow unmyelinated axons
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

8. The General Senses
Referred Pain
Figure 9-2

9. The General Senses Temperature
Thermoreceptors detect temperature change
Free nerve endings
Found in dermis, skeletal muscle, liver, hypothalamus
Fast adapting
Cold receptors greatly outnumber warm receptors
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

10. The General Senses Touch, Pressure, and Position
Mechanoreceptors—Receptors that respond to physical distortion of their cell membranes.
Tactile receptors—Sense touch, pressure, or vibration
Baroreceptors—Sense pressure changes in walls of blood vessels, digestive organs, bladder, lungs
Proprioceptors—Respond to positions of joints and muscle
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

11. The General Senses Tactile Receptors Fine touch or pressure receptors
Highly detailed information about a stimulus
Crude touch or pressure receptors
Poorly localized information about a stimulus
Important types: root hair plexus, tactile disks, tactile corpuscles, lamellated corpuscles, Ruffini corpuscles
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

12. Tactile Receptors in the Skin
The General Senses
Tactile Receptors in the Skin
Figure 9-3

13. The General Senses Baroreceptors
Provide pressure information essential for autonomic regulation
Arterial blood pressure
Lung inflation
Digestive coordination
Bladder fullness
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

14. Baroreceptors and the Regulation of Autonomic Functions
The General Senses
Baroreceptors and the Regulation of Autonomic Functions
Figure 9-4

15. The General Senses Proprioceptors
Monitor joint angle, tension in tendons and ligaments, state of muscular contraction
Include:
Muscle spindles
Golgi tendon organs
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

16. The General Senses Chemical Detection
Chemoreceptors respond to chemicals dissolved in body fluids that surround them and monitor the chemical composition of blood and tissues
Chemicals that can be sensed include:
Carbon dioxide
Oxygen
Hydrogen ion
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

17. Locations and Functions of Chemoreceptors
The General Senses
Locations and Functions of Chemoreceptors
Figure 9-5

18. The Special Senses—Smell
Sense of smell provided by olfactory organs
Olfactory epithelium
Contains olfactory receptor cells
Neurons sensitive to odorants
Supporting cells
Basal (stem) cells
Olfactory glands
Mucus-secreting cells
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

19. The Special Senses—Smell
The Olfactory Organs
Figure 9-6(a)

20. The Special Senses—Smell
The Olfactory Organs
Figure 9-6(b)

21. The Special Senses—Smell
The Olfactory Pathways
Axons from olfactory receptors penetrate cribriform plate of ethmoid bone
Synapse in olfactory bulb
Olfactory tract projects to:
Olfactory cerebral cortex (not thalamus)
Hypothalamus
Limbic System
Animation
Animation II
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

22. The Special Senses—Taste
Taste (Gustatory) Receptors
Taste buds
Found within papillae on tongue, pharynx, larynx
Contain gustatory cells, supportive cells
Taste hairs (cilia) extend into taste pores
Sense salt, sweet, sour, bitter
Also sense umami, water
Synapse in medulla oblongata
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

24. The Special Senses—Taste
Gustatory Receptors
Figure 9-7(a)

25. The Special Senses—Taste
Gustatory Receptors
Figure 9-7(c)

26. The Special Senses—Taste
Gustatory Receptors
Taste Animation
Taste Animation II
Figure 9-7(b)

27. 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

28. The Special Senses—Vision
Accessory Structures of the Eye
1) Eyelids (palpebra) and exocrine glands
2) Superficial epithelium of eye
Conjunctiva (mucous membrane outer surface of eye)
3) Tear production and removal (lacrimal
apparatus)
4) Extrinsic eye muscles
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

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

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

31. The Special Senses—Vision
Extrinsic Eye Muscles
Move the eye
Six muscles cooperate to control gaze
Superior and inferior rectus
Up and down
Lateral and medial rectus
Lateral and medial
Superior and inferior oblique
Eye rolls, looks down and laterally; eye rolls, looks up and laterally
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

32. The Special Senses—Vision
The Extrinsic Eye Muscles
Figure 9-9(b)

33. The Special Senses—Vision
Layers of the Eye
Fibrous tunic
Outermost layer
Vascular tunic
Intermediate layer
Neural tunic
Innermost layer
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34. The Special Senses—Vision
Layers of the Eye
Fibrous tunic – outermost layer of eye
Provides mechanical support, attachment site for extrinsic eye muscles, assists in focusing
Contains
1) Sclera
Dense fibrous connective tissue
“White of the eye”
2) Cornea
Transparent
Continuous with sclera
Light entrance
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

36. The Special Senses—Vision
The Sectional Anatomy of the Eye
Figure 9-10(a)

37. The Special Senses—Vision
Layers of the Eye
Vascular tunic – middle layer includes blood vessels, lymphatic vessels and intrinsic eye muscles
Provides blood vessels to support eye tissue, regulates light, secrets and absorbs aqueous humor, controls the shape of the lens.
Contains
Iris (colored part of eye)
Ciliary body (mostly muscles)
Choroid (contains capillaries that supply oxygen to eye).
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

39. Vascular tunic (cont).
Pupillary muscles (intrinsic smooth muscle fibers) in this layer contract, changing the diameter of the central opening, or pupil.
When dilators contract, the pupil dilates (enlarges). When constrictors contract, the pupil constricts (gets smaller).

40. The Special Senses—Vision
The Pupillary Muscles
Figure 9-11

41. The Special Senses—Vision
Layers of the Eye
Neural tunic or retina is the innermost layer
Contains
Pigmented part
Absorbs light after passing through neural part
Neural part
Contains photoreceptors, supporting cells, blood vessels.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

42. The Special Senses—Vision
The Sectional Anatomy of the Eye
Figure 9-10(b)

43. The Special Senses—Vision
The Sectional Anatomy of the Eye
Figure 9-10 (c)

44. The Special Senses—Vision
Organization of the Retina
Photoreceptor layer
Rods – light sensitive receptors that allow us to see in dimly lit rooms, twilight, etc.
Cones – provide color vision
Sensitive to green, red, and blue
Combinations of stimulation provide different colors.
Bipolar cells
Ganglion cells
Optic nerve (CN II)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

45. The Special Senses—Vision
Retinal Organization
Figure 9-12(a)

46. The Special Senses—Vision
Retinal Organization
Figure 9-12(b)

47. The Special Senses—Vision
Retinal Organization
Fovea – portion of retina providing sharpest vision with highest concentration of cones.
Blind spot – area of no photoreceptors
Figure 9-12(c)

48. The Special Senses - Vision
Chambers of the eye
Anterior cavity
Anterior chamber (space between iris and cornea)
Posterior chamber (space between suspensory ligaments and iris)
Both filled with aqueous humor (watery)
Posterior cavity
Also filled with vitreous humor (clear gelatinous)
Maintains shape of eye and holds retina against choroid.

49. The Special Senses—Vision
The Sectional Anatomy of the Eye
Figure 9-10 (c)

50. The Special Senses—Vision
The Lens
Supported by suspensory ligaments
Built from transparent cells
Lens and cornea focus light on retina
Bend light (refraction)
Accommodation changes lens shape
Loss of transparency leads to a cataract.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

51. The Special Senses—Vision
Focal Point, Focal Distance, and Visual Accommodation
Figure 9-15(a)

52. The Special Senses—Vision
Focal Point, Focal Distance, and Visual Accommodation
Figure 9-15(b)

53. The Special Senses—Vision
Focal Point, Focal Distance, and Visual Accommodation
Figure 9-15(d)

54. The Special Senses—Vision
Focal Point, Focal Distance, and Visual Accommodation
Figure 9-15(e)

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

56. The Special Senses—Vision
Visual Abnormalities
(Normal vision)
Figure 9-17(a)

57. The Special Senses—Vision
Visual Abnormalities
Eyeball is too big
(near sighted)
Figure 9-17(b)

58. The Special Senses—Vision
Visual Abnormalities
Figure 9-17(c)

59. The Special Senses—Vision
Visual Abnormalities
Eyeball is too small
(far sighted)
Figure 9-17(d)

60. The Special Senses—Vision
Visual Abnormalities
Figure 9-17(e)

61. 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
In peripheral retina
Contain pigment rhodopsin
Cones
Less sensitive, color vision
Include blue, green, and red
Site of sharpest vision
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

62. Equilibrium and Hearing
Anatomy of the Ear
External ear
Visible portion
Collects sound waves toward middle ear
Ends at tympanic membrane (eardrum).
Middle ear
Chamber located in temporal bone
Collect and amplify sound waves and transmit to inner ear
Contains auditory ossicles (malleus, incus, stapes)
Inner ear
Contains sensory organs for hearing and equilibrium (cochlea).
Filled with endolymph and perilymph (fluids).

63. Equilibrium and Hearing
The Anatomy of the Ear
Figure 9-22

65. Equilibrium and Hearing
Anatomy of the Ear
External ear
Pinna (auricle)
External acoustic canal
Tympanic membrane (eardrum)
Middle ear
Auditory ossicles
Malleus, incus, stapes (smallest bone)
Connect tympanic membrane to inner ear
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

66. Equilibrium and Hearing
The Structure of the Middle Ear
Figure 9-23

67. Equilibrium and Hearing
Inner Ear – provides sense of equilibrium and hearing.
Vestibule
Semicircular canals
Cochlea
Includes organ of Corti – contains inner and outer hair cells
Site of equilibrium sensations and structure that provides information to the CNS.
Receptors include:
Hair cells
Mechanoreceptors
Stereocilia on cell surface
Bending excites/inhibits hair cell
Information on direction and strength of mechanical stimuli
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

69. External acoustic canal Cochlear branch of cranial nerve VIII Incus
Oval
window
Malleus
Stapes
Vestibular duct
(perilymph)
Movement
of sound
waves
Vestibular membrane
Cochlear duct
(endolymph)
Basilar membrane
Tympanic duct
(perilymph)
Tympanic
membrane
Round
window
Sound waves arrive at tympanic membrane.
Movement of tympanic membrane causes displacement of the auditory ossicles.
Movement of the stapes at the oval window establishes pressure waves in the perilymph of the vestibular duct.
The pressure waves distort the basilar membrane on their way to the round window of the tympanic duct.
Vibrations of the basilar membrane causes vibration of hair cells against the tectorial membrane.
Information about the region and the intensity of stimulation is relayed to the CNS over the cochlear branch of cranial nerve VIII.
Figure 9-27
1 of 7
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70. Equilibrium and Hearing
Sensory Functions of the Inner Ear
Dynamic equilibrium – maintains balance when moved suddenly.
Static equilibrium – maintains posture when motionless.
Hearing
Amplitude measured in decibels (intensity or power of sound).
Frequency measured in Hertz (cycles of wave per second).
Range of human is ear is 20 – 20,000 Hertz.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

71. Head in horizontal position
Gravity
Head tilted posteriorly
Gravity
Otolith
moves
“downhill,”
distorting
hair cell
processes
Receptor
output increases
Figure 9-25(e)
1 of 4
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72. Aging and the Senses Impact of Aging on Sensory Ability
Gradual reduction in smell and taste sensitivity as receptors are lost
Lens changes lead to presbyopia (loss of near vision due to stiffening of lens)
Chance of cataract increases
Progressive loss of hearing sensitivity as receptors are lost (presbycusis)
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings