Transcript Special Sensesx

Special Senses
Olfactory (Smell)
 Receptors
 Pathways
 Discrimination
Gustation (taste)

Papillae
 Receptors
 Taste buds

Basal cells (stem cells)

Gustatory cells
 Taste pore
 Survive 10 days

Discrimination

Primary taste sensations
 Bitter
 Sour
 Salty
 Sweet

Secondary taste sensation
 Umami
 Water

Aging
Vision

Accessory structures

Palpebrae (eyelids)

Medial/lateral canthus


Eyelashes

Tarsal glands

Lacrimal caruncle


Thick fluid
Conjunctiva



(corners of your eye)
Conjunctivitis
Palpebral conjuctiva
Cornea
 Lacrimal
apparatus
 Lacrimal gland
 Lysozyme
 Orbital
fat
Eye

Iris

Pupil (opening)
 Constrictor muscles
 Dilator muscles

Retina
 Photoreceptors
 Rods
 Cones
 Optic disc
 Blind spot

Chamber of the eye

Anterior

Posterior

Lens
 Cataracts

Refraction (light is bent)
 Focal point

Accommodation
 Astigmatism

Image reversal

Visual acuity
Visual
Physiology

Recovery after stimulation
 Bleaching
 Night blindness

Color vision
 Blue cones
 Green cones
 Red cones
 Color blindness
 http://colorvisiontesting.com/ishihara.htm
 http://www.color-blindness.com/ishihara38-plates-cvd-test/#prettyPhoto
 http://kids.niehs.nih.gov/games/illusions/l
ots_of_illusions.htm

Visual pathway
Visual
Physiology
 Central
processing of
visual information
 Field of vision
 Depth perception
 Brain stem and visual
processing
 Circadian rhythm
Which sphere is bigger?
Left facing or right facing?
Lines straight or curved?
How many triangles?
Standing up or lying down?
How many legs?
Equilibrium and Hearing

External ear
 Auricle
 Acoustic canal
 Tympanic membrane
 Ceruminous glands
 Cerumen

Middle ear
 Tympanic cavity
 Auditory tube
 Auditory ossicles
 Malleus, incus, stapes

Inner ear
 Bony labyrinth
 Cochlea
Cochlear Implant
Equilibrium

Semicircular ducts


Utricle and saccule


Hair cells
Receptors for gravity and
balance
Pathways for sensations

vestibular
Hearing

Cochlear Duct

Introduction to sound
 Amplitude: how high
the wave travels
 Wavelength: top of one
wave to the next


Frequency/Pitch: how
many times the
wavelength repeats in a
second
Decibels (amt of
energy)
Hearing

Hearing Process
 Spiral ganglion
 http://www.youtube.com/watch?v=tkPj4IGbmQQ&featur
e=related

Auditory pathways
 Cochlear branch

Auditory sensitivity
Hearing Process

Step 1: Sound waves arrive at the tympanic membrane.

Step 2: Movement of the tympanic membrane causes displacement of the
auditory ossicles. In this way, sound is amplified.

Step 3: Movement of the stapes at the oval window establishes pressure waves of
the vestibular duct.

Step 4: The pressure waves distort the basilar membrane on their way to the round
window of the tympanic duct. Information about frequency is translated into
information about position along the basilar membrane.

Step 5: Vibration of the basilar membrane causes vibration of hair cells leading to
the release of neurotransmitters and thus to the stimulation of sensory neurons.
The number of hair cells responding provides information on the intensity of the
sound.

Step 6: Information about the region and intensity of stimulation is relayed to the
CNS over the cochlear branch of the vestibulocochlear nerve (VIII).
Equilibrium

Hair cells in the inner ear

Vestibulocochlear nerve

Cranial nerve VIII

Balance and hearing rely on the
same basic types of sensory
receptors (hair cells). The
anatomical structure of the
associated sense organ
determines what stimuli affect
the hair cells.