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32 Cards in this Set
- Front
- Back
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Define microsomatic.
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poorly developed sense of smell
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Which sense do humans use for locating food and communicating with other members of the species?
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Vision
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The CNS structures associated with olfaction are collectively called what?
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Rhinecephalon
("nose brain") |
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Name the structure collectively called the rhinecephalon (4).
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(1) olfactory nerves, bulbs, and tracts
(2) pyriform cortex (3) entorhinal cortex (4) amygdala |
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What do you call the primary olfactory cortex?
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pyriform cortex
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Where is the entorhinal cortex located?
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In the parahippocampal gyrus
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What is the nucleus under the uncus called which is part of the limbic system?
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amygdala
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Where are olfactory receptors located?
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In olfactory epithelium on superior nasal concha + upper part of the nasal septum.
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What type of neurons are olfactory neurons?
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Bipolar
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How often are olfactory neurons replaced?
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Every 4-6 weeks
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What secretes mucus that bathes cilia over the surface of the olfactory mucosa?
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Bowman's glands
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What must happen in order for odors to be smelled (2)?
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1) dissolve in mucus
2) stimulate chemosensitive cilia |
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What forms the olfactory nerve?
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axons of the olfactory cells
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Where does the olfactory nerve pass thru in the cranium?
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cribriform plate
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Where does the olfactory nerve synapse?
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olfactory bulb
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What is the olfactory bulb an outgrowth of?
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telencephalon
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Where would you find the olfactory bulbs?
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cribriform plates of the anterior cranial fossa
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What part of the brain do the olfactory bulbs come in contact with?
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orbital surface of the frontal lobes
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The olfactory bulbs are composed of several types of cells. Which cells are the most common?
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Mitral cells
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What do axons of mitral cells form?
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olfactory tract
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What is a narrow band that continues POSTERIORLY from the olfactory bulb on the undersurface of the frontal lobe?
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olfactory tracts
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What is a point at which the olfactory tracts split into 2 diverging pathways?
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olfactory trigone
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What lies at the end of the olfactory tracts?
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olfactory trigone
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Where is the lateral olfactory stria directed?
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To the olfactory cortex for perception of smell.
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Where do the medial olfactory stria go?
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Enter anterior commisure and go to limbic structures.
DO NOT PLAY A ROLE IN THE PERCEPTION OF OLFACTORY STIMULI. |
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Which lobe of the brain do lateral olfactory stria enter?
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temporal lobe
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Pathway of smell perception from the Lateral olfactory stria?
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Lateral olfactory stria---->enters temporal lobe---->entorhinal cortex (parahippocampal gyrus---->primary olfactory cortex (posterolateral part of orbitofrontal cortex)--->olfactory identification and discrimination
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What indirectly connects the 2 olfactory bulbs?
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fibers of medial olfactory stria enter anterior commissure.
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What are some emotional responses elicited by olfactory stimuli?
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1) memory
2) danger 3) feelings |
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Loss of sensation of smell is called what?
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anosmia
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What are causes of Anosmia (loss of sensation of smell)?
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1) head trauma
2) fracture of cribriform plate 3) nasal infections may damage olfactory receptors 4) gradual loss due to tumor growth at base of anterior cranial foss |
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What can cause olfactory hallucinations?
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Lesion of the uncus.
Commonly occurs in temporal lobe epilepsy. |
