1. Unit 8:  The Senses

2. The Senses DB
Explain why the smell of a doctor�s office or the smell of turkey cooking on Thanksgiving can easily generate an emotional response. Hint: there is a concept called sense memory that should be referenced here. OR The ear is important in not only hearing, but balance. Explain how the ear functions, and how it can be easily damaged by loud noises, and result in hearing loss. OR How do we perceive color? Why does the color wash out when we look at a bright light, or are out in the sun?

3. Responsibilites for the week
Work on APT project. Writing paper!! 
Lesson 1: Sense Organs
Lesson 2: The Eye
Lesson 3: The Ear
The Senses: Quick Wrap-Up
Unit 8 Practice Quiz
Discussion
Seminar
The Senses Module Exam

4. LEARNING OUTCOMES
HS120-U8-1    Classify sense organs as special or general.     HS120-U8-2    Describe the general sense organs and their functions.     HS120-U8-3    Identify the structures and functions of the eye.     HS120-U8-4    Identify the structures functions of the ear. HS120-U8-5    Discuss the physiology of hearing.

5. Classify sense organs as special or general
Eye
Taste buds
Ear
Nose
General:
Microscopic receptors
Pacinian corpuscles
Meissner’s corpuscles
Muscle spindles

6. .
What is the difference between special and general sense organs?

7. The differences
Special = they have large and complex organs or localized groupings of specialized receptors like taste buds on tongue.
These are the senses that you typically think of; except for perhaps touch!

8. A very special sense

9. The differences
General = made of microscopic receptors widely distributed throughout the body.
Pacinian corpuscles = pressure and high frequency
Meissner’s corpuscles = fine touch and low frequency
Muscle spindles = propriocetors (muscle length and location)

11. Sense organ functions
Vision
Hearing
Smell
Taste
Balance

12. How is a stimulus converted into a sensation?
Stimulus detected [sound]
Stimulus converted to electrical signal or nerve impulse= [middle ear]
Signal transmitted over nervous system “pathway” = [VIII cranial nerve]
Sensation perceived in brain = [music]

13. music
Sound is:
A pressure disturbance (alternating areas of high and low pressure) originating from a vibrating object

14. Eye anatomy Sclera = white of the eye (cornea)
Choroid = contains a dark pigment to prevent scattering of light rays
Retina = innermost layer of eyeball (rods and comes)
Iris = circular colored part of eye
Conjunctiva = mucous membrane that lines eyelids and covers the sclera
Lacrimal gland = tear duct
Pupil = black center of iris; a hole
Lens = ciliary muscles contract the lens for focusing

17. Posterior wall of Rods only right eye Pg 563 Less cones cones Disc
Macula Lutea
Mostly Cones
Fovea Centralis
ONLY Cones
Detailed color vision
Optic
Disc
Lateral to ML. Radiates Blood V.

18. The Retina: Photoreceptors
Rods:
Respond to dim light
Are used for peripheral vision
Ex. Best to see moonlit evening when you don’t look directly at object. Recognize best when they move. Peripheral.
Cones:
Respond to bright light
Have high-acuity color vision
Are found in the macula lutea
Are concentrated in the fovea centralis

20. The Retina: Ganglion Cells and the Optic Disc

21. Focusing Light on the Retina; Pathway of light entering the eye:
Light is Refracted
cornea
Refracted again
aqueous humor
Lens
vitreous humor
the neural layer of the retina to the photoreceptors

22. Major visual disorders
Refraction disorders
Myopia = nearsightedness
Astigmatism = irregularity in cornea or lens
Conjunctivitis = pink eye
Strabismus = convergent
Cataracts=?
Macular Degeneration=?
Glaucoma=?

24. Eye anatomy Sclera Choroid Retina Iris Conjunctiva Lacrimal gland
Pupil
Lens
Ciliary Muscles

25. Ear anatomy External ear External auditory canal Tympanic membrane
eardrum

29. Ear anatomy Middle ear Ear bones = ossicles
Malleus
Incus
stapes
Auditory or Eustachian tube

31. Ear anatomy Inner ear Bony labrinth Perilymph Vestibule
Semicircular canals
Cochlea
Crista ampullaris
Organ of Corti

32. PATH: Transmission of Sound to the Inner Ear

33. Sound and Mechanisms of Hearing
Sound vibrations beat against the eardrum
The eardrum pushes against the ossicles, which presses fluid in the inner ear against the oval and round windows
This movement sets up shearing forces that pull on hair cells
Moving hair cells stimulates the cochlear nerve that sends impulses to the brain

35. Deafness
Conduction deafness – something hampers sound conduction to the fluids of the inner ear (e.g., impacted earwax, perforated eardrum, osteosclerosis of the ossicles)
Sensorineural deafness – results from damage to the neural structures at any point from the cochlear hair cells to the auditory cortical cells

36. Hearing impairment Blockage of external auditory canal
Otosclerosis = structural irregularities in stapes
Tinnitus = ringing in ears (may be symptom of otosclerosis)
Otitis = ear infection
Meniere’s disease = chronic inner ear disease, resulting in vertigo

37. areas for taste receptors
Sour Bitter
POSTERIOR TONGUE
salty
Sweet -tip
ANTERIOR TONGUE

38. Taste Sensations There are five basic taste sensations
Sweet – sugars, saccharin, alcohol, and some amino acids
Salt – metal ions
Sour – hydrogen ions
Bitter – alkaloids such as quinine and nicotine
Umami – elicited by the amino acid glutamate

39. Influence of Other Sensations on Taste
Taste is 80% smell
Thermoreceptors, mechanoreceptors, nociceptors also influence tastes
Temperature and texture enhance or detract from taste

40. Which one would be
the worst to lose?

41. Have you any questions. Do you have any questions
Have you any questions? Do you have any questions? Are there any questions? Can I answer anything? Can I answer anything for anybody? Is anything unclear? Is everything clear?
The End…