olfaction the special sensescf.linnbenton.edu/mathsci/bio/waitea/upload/lecture_12... ·...
TRANSCRIPT
1/18/2016
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Olfaction
Gustation
The Special Senses
Olfaction
Figure 15.21a
Olfactory tract
Olfactory bulb
(a)
Nasal
conchae
Route of
inhaled air
Olfactory
epithelium Olfaction
Cilia
Olfactory epithelium of
nasal cavity
Olfactory bulb
Neurons in olfactory tract
Temporal lobe
Cribriform plate
Olfactory neuron
Figure 15.21a
Mitral cell (output cell)
Olfactory
gland
Olfactory
tract
Olfactory
epithelium
Filaments of olfactory nerve
Cribriform plate of ethmoid bone
Lamina propria connective tissue
Basal cell
Supporting cell
Dendrite
Olfactory cilia
Olfactory bulb
Glomeruli
Axon
Olfactory receptor cell
Mucus
Route of inhaled air
containing odor molecules(b)
Gustation
• Taste buds are receptors
– Chemical stimulation nerve impulse to parietal lobe
– Salty, sweet, bitter, sour and umami
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Gustation
• Most of our sense of taste comes from smell
• Let’s do an experiment…
Figure 15.23a
(a) Taste buds are associated with fungiform,
foliate, and circumvallate (vallate) papillae.
Fungiform papillae
Epiglottis
Palatine tonsil
Foliate papillae
Lingual tonsil
Circumvallate papillae
Figure 15.23b
(b) Enlarged section of a
circumvallate papilla.
Taste bud
Circumvallate papilla
Figure 15.23c
Taste fibers
of cranial
nerve
Connective
tissue
Gustatory
(taste) cells
Taste
pore
Gustatory
hair
Stratified
squamous
epithelium
of tongue
(c) Enlarged view of a taste bud.
Basal
cells
1) Encapsulated nerve endings
a) Tactile (Meissner’s) corpuscles
- Mechanoreceptor that senses fine touch
- Concentrated in fingertips, tongue, lips
b) Lamellated (Pacinian) corpuscles
- Respond to heavier degrees of pressure
- Deep within skin, some visceral organs
c) Ruffini’s corpuscles
- Stretch in connective tissue
d) Muscle spindles and Golgi tendon organs
- Tension and position of muscles and joints
More Special Senses:
Cutaneous ReceptorsReceptors
Lamellated/Pacinian
Ruffini’s
Golgi Tendon
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2) Free nerve endings
- Neurons that branch between other cells
throughout the body
- Pain and temperature
Cutaneous Receptors
• Visceral and somatic pain
– Visceral pain is difficult to localize referred pain
• Somatosensory cortex doesn’t know where the heart is,
so it produces shoulder pain
– Phantom pain
• Intact sensory neurons
produce pain in amputated
limbs
Pain