THE SENSES by MikeJenny


									                       The Senses                                        Touch and Feeling
• Specialized organs translate a stimulus and                  • Receptors in skin for heat, cold, pain,
  send it to the brain via an electrical nerve                   pressure
  impulse                                                      • Specialized pattern on hands and feet (as we
• General: touch- heat, pain, hot/cold in skin                   studied in the skin unit!)
• Special: smell, taste, sight, hearing                        • Receptors also in muscles and joints
• What we “feel” is a blend of effects

                                                                               THE EYE
                                                               • Photoreceptors translate light into a nerve
                                                                 impulse, which is received and “viewed” in
                                                                 the occipital lobe

                   EYE Protection
•   Eyebrows
•   Eyelashes
•   Eyelids
•   Glands secreting oil, sweat, and tears
    – Conjunctiva: membrane secreting mucus
        • Pinkeye: conjunctivitis- infected membrane
    – Lacrimal glands and ducts for tears- connects to nasal
        • Salty solution contains lysozyme (kills bac)
        • Crying: clean out eye? Emotional release?

                   The Eyeball                                            STRUCTURES
• A vehicle to capture light and focus it on the         •   10- Sclera
  cells that can create a nerve impulse (image)          •   A thick white tissue (white of the eye)
• (Think of this as we label structures and              •   6- Cornea “clear window”
  discuss functions)                                     •   A clear/transparent part of the sclera
• We will label from the outermost structure             •   4- Aqueous Humor
  to the innermost structure
                                                         •   Liquid/squishy cushions lens

• 3- Iris                                                • 5- Lens
• Colored portion of eye attached to lens
                                                         • Focuses the light (able to change shape and
• Able to regulate the amount of light that enters the
  eye through the pupil (add to diagram)                   position) Also FLIPS the image
    – Controls light: bright light? Dim light? Why?      • 7- Vitreous Humor
• 1- Cillary body: holds lens and produces pigment       • Jelly like substance- makes the eye round
  for iris
• 2- Suspensory Ligaments: holds and suspends
  lens- helps lens focus the light

                                                                                The Retina
• 12- Retina                                             • Nerve impulse sent along optic nerve to occipital
• The layer of nerve cells (photoreceptors)                lobe (criss cross at optic chiasma in brain)
• 9- Fovea Centralis                                     • Photoreceptors: 2 Types
                                                             – RODS: can detect shape and movement
• The spot on the retina where the light                        • Adapted for vision in dim light
  should be focused for a perfect image to be                – CONES: detect sharp details and color
  transferred                                                   • Adapted for vision in bright light
• 8- Optic Disk- the “blind spot”                               • Red, blue, and green cones: can “blend” to see all colors

    – No photoreceptors in this spot

                                                  •   Blindness
                                                  •   Color blindness
                                                  •   Night blindness
                                                  •   Glaucoma
                                                  •   Cataract
                                                  •   Retinal Disorders
                                                  •   Farsighted/Nearsighted/Astigmatism
                                                      – Affects ½ of the population

              THIS WEEK                                                 The EAR
• Today==Finish lab (watch video)                 • Fxn: hearing and balance
                                                  • Three Parts
                                                      – 1. Outer ear (transfer sound)
• HW= lab due THURSDAY                                – 2. Middle ear (transfer and amplify sound)
  – 1-2 sentences on purpose of EACH test             – 3. Inner ear (sound and balance receptors here)
  – 1-2 sentences on your results for EACH test   • Sound waves nerve signals to temporal lobes
                                                    where we “hear”
                                                  • Receptors (inner ear) sense position and
• QUIZ= ear, taste, smell on FRIDAY                 movement for balance

                                                                                OUTER EAR
                                                              • 1. Auricle (Pinna)
                                                                  – Funnel sound waves
                                                              • 2. External auditory canal (ear canal)
                                                                  – Narrow cavity that funnels sound
                                                                  – Wax produced to fight infection/hairs protect
                                                              • 3. Tympanic membrane (eardrum)
                                                                  – End of canal: vibrates when sounds strike it

                MIDDLE EAR                                                       INNER EAR
•    3 small bones: ossicles – they magnify gentle            • Where it all goes down……
     sounds and soften loud ones                              • 8. Oval window
    – 4. Malleus “hammer”                                         – Stapes hits to transfer sound   sound vibrations
    – 5. Incus “anvil”                                              transferred to the cochlea
    – 6. Stapes “stirrup”                                     • 9. Cochlea- tubes filled with fluid
    Ear POP: when middle ear pressure is different from           – Vibrations cause fluid to move stimulates “hair cells”
        environment                                                   creates nerve impulse temporal lobes we hear!
    10. Eustacian tube: connects middle ear to throat         • 7. Semicircular canals- 3 tubes filled with fluid
        -when opened (coughing, swallowing) the pressure is       – Movement causes hair cells to detect message to
        released                                                    cerebellum compensates with muscle movement to
        -sickness spreads easily…kids more horizontal               restore balance (MOTION SICKNESS!!)

                                                              •   Infection
                                                              •   Ruptured eardrum
                                                              •   Cochlear damage
                                                              •   Auditory nerve damage
                                                              •   Vertigo

    TASTE and SMELL: The
       Chemical Senses
• Nose and Mouth have chemoreceptors:      • Olfactory receptors (cells) on roof of nasal cavity
  chemicals bind cells transfer to nerve     detect chemicals dissolved in air
  impulse temporal lobe in brain we        • Transferred to impulse olfactory bulb
  taste and smell!                           olfactory nerve thalamus temporal lobe
                                               – *VERY sensitive but quickly adapt
                                               – * closely tied to the EMOTIONAL brain
                                               – DAMAGE? Head injury, cold, allergies, aging,
                                                 smoking, cocaine

                                           •   “to judge”
                                           •   Taste buds: receptors- gustatory cells
                                           •   10,000 of them on tongue, palate, cheeks
                                           •   Chemicals must be dissolved in saliva 1st
                                           •   RECEPTORS:
                                               –   Sweet: sugars
                                               –   Sour: acidity
                                               –   Bitter: alkaloids
                                               –   Salty: metal ions Na,K

                                           • Tastes have homeostatic value
                                               – Crave sugar?
                                               – Crave sour?
                                               – Bitter taste?
                                               Affected by…aromas, temperature, texture
                                                 EX: coffee?
                                                 Hot and Spicy foods?


To top