Visual Pathway, Smell, Taste, Ear Disorders Flashcards
Where medial optic nerve fibers from each eye cross over
Optic chiasma
Where optic chiasma join with lateral optic nerve fibers and continue
Optic tracts
Sensory information then passes through other structures until it reaches __________
A.k.a occipital lobes
Primary visual cortex
Axons of retinal ganglion cells form ________
Exits eye
Optic nerve
_______ optic tract carries representation of right half of visual field
Left
_______ optic tract carries representation of left half of visual field
Right
Visual cortex of brain fuses slightly different images, resulting in a three-dimensional image
Requires input from both eyes
Depth perception (3D)
Type of vision that many animals have; Eyes are placed more laterally on head, so that the visual fields overlap very little
“Pano”
Panoramic vision
Neural destruction beyond optic chiasma results in partial or loss of vision in opposite _________
Visual field
Sense of smell
Olfaction
Tasting something
Gustation
Complementary senses that let us know whether a substance should be savored or avoided
Smell and taste
Receptors used to smell and taste
Must be dissolved and picked up by receptors
Chemical stimuli
Chemoreceptors
Receptors excited by chemicals dissolved in nasal fluids
Smell receptors
Respond to chemicals dissolved in saliva
Receptors for taste
Taste receptors
Process of smell
Pseudostratified epithelium
Located in roof of nasal cavity
Covers nasal conchae
Olfaction
Neurons that are held in olfactory epithelium
Bipolar neurons with radiating olfactory cilia
Olfactory sensory neurons
Surround and cushion olfactory receptor cells
Produce thin mucous that covers olfactory cilia that airborne chemicals dissolve in
Located around hair cells
Supporting cells
Lie at base of epithelium
Olfactory stem cells
Unmyelinated axons of olfactory sensory neurons gather to form filaments of this nerve
Axons protrude superiorly in openings of cribiform plate of ethmoid bone
Olfactory nerve
Area of interaction between olfactory nerves and mitral cells
Glomeruli
olfactory bulbs —— olfactory tract —– olfactory cortex
Impulse flow
Distinctive smell
Odor
Chemicals that make up odors
Oderants
Some of what we smell is ______
Irritants damage receptors
Pain
In order to smell something, it must be _______
In gaseous state, odorant must dissolve in olfactory epithelium fluid
Volatile
People can’t smell a certain odor after being exposed for a continuous amount of time
Olfactory adaptation
Olfactory disorders; most result from head injuries, inflammation, neurological disorders
Anosmias
Think you smell something but it is not present
Olfactory hallucinations
Sensory organs for taste
Taste buds
Peglike projections of tongue mucosa
Where taste buds are
Papillae
Gives tongue roughness to provide friction
Filiform papillae
Mushroom papillae; house most taste buds
At front of tongue
Fungiform papillae
Form V-shaped row in back of tongue
Vallate papillae
Located on lateral aspects of posterior tongue
Foliate papillae
Type of epithelial cell in taste bud; taste receptor with microvilli that project into taste pores
Gustatory epithelial cells
Type of epithelial cell in taste bud; Dynamic stem cells that divide every 7-10 days
Basal epithelial cells
Sugars, saccharin, alcohol, some amino acids
Sweet
Hydrogen ions in solution
Sour
Metal ions (inorganic salts); sodium chloride tastes saltiest
Salty
Alkaloids such as nicotine, caffeine, and aspirin
Bitter
Amino acids glutamate and aspartate
Beef or cheese
Savory
Umami
Food chemical
Tastant
- Dissolved in saliva
- Diffuse into taste pore
- Contact gustatory hairs
Requirements for taste
Facial nerve, glossopharyngeal nerve, vagus nerve
3 Cranial Nerves of Gustatory Pathway
Are taste disorders more common than smell disorders?
No
