1. Senses

2. Touch proprioceptors & cutaneous receptors

3. Proprioceptors
In skin, muscles and tendons. They detect the amount of stretch and tension

4. Cutaneous In the skin Pain, touch, heat, cold, pressure
Free nerve ending = pain
Meissner = touch
Pacinian = pressure
Ruffini = heat
Krause = cold

5. Vision- Eye

7. Structures-external:
Muscle- movement
Lacrimal- washes, disinfects

9. Pupil – the hole formed in the center of the pigmented iris
Pupil – the hole formed in the center of the pigmented iris. Contracts or dilates depending on the amount of light

11. Eyelids - protection
Meibomian gland- lubricates eyelid (blockage causes a “sty”)
Canal of Schlemm – drains aqueous fluid (blockage can increase eye pressure and lead to glaucoma)
Conjunctiva- mucus membrane covering= lubricates (conjunctivitis =pink eye)

12. 3 internal covers- tunics
Sclera
Choroid
Retina

13. Sclera
Outermost, tough
The anterior is clear= cornea

14. Middle layer, nutrition (blood vessels)
Choroid
Middle layer, nutrition (blood vessels)
Contains muscles- iris and ciliary body

15. Retina Inner layer, sensory Contains rods and cones
Rods – sensitive, respond to dim light and found in the peripheral; gray tones
Cones- need bright light; see color

18. Blind spot Point where optic nerve leaves eye No rods, no cones
Fovea Centralis – pit with a concentration of cones; this is your best vision

21. Lens- convex, light bending, refractory
Anterior is aqueous humor provides reinforcement and nutrition to lens & cornea
Posterior vitreous fluid reinforces the eye

23. Errors of refraction Myopia- nearsightedness Hyperopia- farsightedness
Astigmatism- problem in the curvature of part of the lens or cornea
Cataract- cloudy lens
Presbyopia-as you age, lenses become harder and cannot bend as much

27. Eye reflexes: Photopupillary- protects retina from bright light
Accomodation- allows close reading by bending lens
Convergence- movement of eye medially when close

28. Pathway of Light
Cornea  aqueous humor  pupil (hole) lens  vitreous fluid  retina

29. Pathway of Nerve Impulse
Retina  receptors (rods and cones)  optic nerve  optic chiasma  optic tract  thalmus  optic radiation  visual cortex of the occipital lobe

31. Nerve impulse pathway continued
Vision from the medial eye is interpreted on the opposite side of the brain
Vision from the peripheral eye is interpreted on the same side of the brain

32. Ear- hearing & balance

34. 3 areas: External ear- sound transmission, pinna (auricle)
external auditory canal
tympanic membrane

35. Middle Ear Sound transmission Ossicles
Auditory tube also called: (eustachian tube or pharygotympanic tube)

36. Internal ear- Equilibrium receptors, hearing receptors
bony labyrinth (cochlea, vestibule, semicircular canals) contains fluid

37. Receptors of the semicircular canal-
Cristae are dynamic equilibrium receptors- angular/ motion
Receptors of the vestibule-
Maculae- static equilibrium gravity up or down

41. Hearing Receptors in the cochlea
Organ of Corti- within the cochlea is stimulated by sound vibration- moves hair cells

44. Deafness is hearing loss in any degree

45. Conduction deafness- transmission to inner ear is disrupted
Sensineural deafness- damage to receptors, nerve, or cortex

46. Equilibrium problems- nausea, dizziness, vertigo

47. Chemical senses- Smell and Taste
Smell & taste chemicals must be dissolved in water to excite receptors

48. Smell
Olfactory receptors are located at the superior part of each nasal cavity- closely linked to limbic systems-memories
Can stimulate the autonomic nervous system (salivation)

50. Taste
Gustatory cells are located in the taste buds primarily on the tongue, 4 sensations:
Sweet (-OH)
Sour (H+)
Salty (metal ions)
Bitter (alkaloids)

52. Taste is influenced by smell, texture, temperature