The five general senses are hearing, sight, touch, smell, and taste. Taste is detected by taste buds on the tongue that contain receptor cells. Smell occurs when chemicals dissolve in mucus in the nasal cavity and bind to odor receptors. Sight involves light refraction through the eyes and photoreception by retinal rods and cones. Hearing detects sound waves that vibrate the eardrum and small bones of the middle ear and cause fluid motions in the inner ear. Touch has no single organ but comes from receptors throughout the body, especially skin, that provide information on pressure, vibration, position, pain, and heat.

1. SPECIAL
SENSES

2. Five General Senses:
Hearing
Sight
Touc
Smell
Tast
e
h

3. TASTE
Physiology of Taste Activation
Taste buds
-located inTaste
oral cavity (most in tongue in saliva,
To be tasted, first must be dissolvedpapillae) each
taste bud has 40-100 epithelial cells made of 3 major
diffuseSensations make contact with
types.into the pore and
gustatory hairs which trigger
Sweet at tip of tongue
1. Supporting Cells:to elicit action potentials in
neurotransmitters separate and insulate
Salty & sour on the
2. Receptor Cells: deal with taste seconds &
these fibers. Adapt rapidly 3-5
sides stem cells, they give rise to new
3. Basal cells: 1-5 minutes
completely in like
cellsBitter in the back
Taste Transduction Process in which
stimulus energy is converted into a nerve

4. SMEL
L
STRUCTURE
Pathway
PHYSIOLOGY
- In order to smell the substance must be in a
- Detects chemicals infrom bulb down tract
gaseous state
- Send impulses solution
- Olfactory Epithelium: soluble to dissolve in olfactory
-Must be water Located on roof
-Thalmus -> Frontal Lobe or Hypothalmus
of nasal cavity and elicit emotional responses
toepithelium
interpret
- Contain olfactory receptor cells with open ion
Bind
to-odor to protein receptors which
columnar supporting cellsanosmias (without
channels that send
- Imablances include action potentials to
- Covered byfrom head injuries; unicinate fits
olfactory bulb
smells) mucous to trap air born
molecules
(olfactory hallucinations)

5. SIGHT
Accessory Structures
Eyebrows -Shade the eyes; Prevent
perspiration into eye
Eyelids
Palpabrae- protects eye; Levatorpal pebrae
superioris raises eyelid; Eyelashes trigger
blinking
Conjunctiva- Mucous membrane over eyelids
and anterior surface of eyeball (white part);
Vascular, when irritated eyes are blood shot

6. VISION
PHYSIOLOGY
Photoreception
Wavelength & Color- Eyes respond to visible light spectrum;
Progresses from red to violet
Photoreceptors are modified neurons; Outer
segment connected to inner, in straight lines and blocked by
Refraction & lenses- Light travelsinner connects to
cell body which has synaptic endings.
non transparent objects Light reflects or bounces off a surface;
Rods- Sensitive to low of light reaching our
Reflection accounts for most light, best at night eyes; as light
Cones- Require high light, provides color
changes mediums it can bend or refract.
Focus- Your lens refracts the light to your focal point which
projects on your retina Images are upside down & reversed
Myopia (near sighted) Hyperopia (farsighted) Astigmatism
(unequal curvature of lens leading to blur)

7. HEARIN
G
Middle Ear
Outer
Inner EarEar (tympanic cavity)
Auricle or Pinna: ear composed of elastic
Three areas: direct sound waves to
-Small air filled mucus lined cavity
cartilage & skin to
-Behind eye socket & contains receptor information
Outer ear
-Between eardrum & bony
external auditory
2 Major divisions canal wall with two openings
oval (vestibular) ) round (cochlear) curved
External auditory meatus:
middle ear
-Bony (osseous & labyrinth Short window
-Contains pharyngotympanic (auditory tube) running
tube from ear to ear Series
-Membranous Labyrinth-drum. of sacs and ducts
inner auricle nasopharynx & helps equalize
from middle ear to
Tympanic membrane ( to drum ) boundary
containing endolymph fluidear help conduct sound
pressure
between
vibrations. outer & middle ear
-Otitis Media – middle ear inflammation

8. SOUND & MECHANISM HEARING
Sound – a disturbance of pressure
Transmission
Frequency – measurement of offurrences of a
Sound waves unit of time
repeated event per move through the air,
membranes, bones, fluids is a wavelength
- Distance between two crests to reach
receptor is expressed in hertz
- Frequencycells in the organ of corti.
Vibrations excite is 20-20,000 Hz
- Range for humans hair cells which
send messages to cochlear related
- Amplitude or height of wave is nerve to
and brings the impulses to the brain
intensity
for processing
- Loudness is measured in decibles.

9. IMBALANCES OF HEARING
Deafness – any hearing loss
Conduction deafness- When something hampers sound
conduction to fluids of inner ear
Sensorinerual- Damage to neural structures of cochlear hair
cells.
Tinnitus- Ringing of ear; Symptom of pathology and not
disease1st symptom of cochlear nerve degeneration.
Meniere’s Syndrome- Affects semicircular & cochlear canals.
Causes vertigo, nausea, vomiting.

10. EQUILIBRIUM
-Responds to head movement without awareness
-Receptors of inner ear are divided into two parts:
Static Sensory receptors for static are the maculae Found in saccules
and utricle Monitor position of head in space, control posture
Dynamic Receptor for dynamic are the crista ampullaris; Excited by
head movement but major stimuli are rotatory. These areas are at
work when twirling or feeling ill on a boat

11. TOUCH
In contrast, the other sense, touch, is a somatic
sense which
does not have a specialized organ but comes from all
over the body, most noticeably the skin but also the
internal organs.
Touch includes mechanoreception (pressure, vibration
and proprioception), pain (nociception) and heat
(thermoception), and such information is carried in
GSA and GVE.