Neuroscience - Block 3 - Part 1

yepezaxi's version from 2016-07-12 22:34

Special Senses

Question Answer
Unmyelinated, bipolar neurons. These pass through the cribriform plate to synapse onOlfactory Receptors
Located in the olfactory bulb, which project via the olfactory tract to the primary olfactory cortex (medial/inferior temporal lobe) and amygdala.Mitral Cells
Projects to mediodorsal thalamus and on to orbitofrontal cortex and hippocampus. Amygdala sends axons to hypothalamusPrimary Olfactory Cortex
Provide support, nourishmentSupporting Cells
These undergo cell division to produce new olfactory receptorsBasal Stem Cells
Also known as Bowman’s gland, secrets mucus which lines the olfactory epithelium. Innervated by CN VIIOlfactory Gland
The olfactory gland is also known as thisBowman's Gland
Where the axons from the olfactory neurons synapse with the mitral cell dendritesGlomerulus
Inhibit other surrounding mitral cells (lateral inhibition). This helps to identify the odor more accuratelyMitral cells
Contains mucopolysaccharides, salts, enzymes and antibodies. Antibodies are good as the 1st order neurons are a direct access pathway to the brain. Mucus flows constantly and is replaced about every ten minutesOlfactory Mucus
Some mitral cells cross over via this and they inhibit the contralateral olfactory bulbAnterior Commissure
Connects the two amygdala, and some neospinothalamic axons cross hereAnterior Commissure
Chemoreceptors that are sensitive to chemicals that dissolve in liquidsOlfactory/Gustatory Receptors
Desensitize quickly; intensity of a drops 50% within seconds of initial stimulationOlfactory/gustatory receptors
Loss of sensation of smellAnosmia
Diminished/enhanced sensation of olfactory acuityHypo-, Hyper-osmia
Distorted olfactory sensationDysosmia
Things smell worse than they should (occurs sometimes during upper respiratory infections)Parosmia
Smelling something when there are no odors present (could be psychiatric i.e. schizophrenia, but also occurs with seizures and migraines)Phantosmia
Composed of three cells - a) Gustatory receptor cells (10 day shelf life), b) Supporting cells, which become gustatory cells, c) Basal cells, which produce supporting cellsTaste Buds
Chemoreceptors; these are not neurons but modified epithelial cellsTaste Receptors
It is amino acid sensitive, activated by tastes like chicken or beef brothUmami
Central process of 1st order neuron goes to solitary nucleus in brainstem, which then projects to VPM of the thalamus, hypothalamus, amygdala, gustatory cortex and hippocampusCentral Tegmental Tract
Three ganglion Nodose ganglion (CN X). Petrosal ganglion (CN IX). Geniculate ganglion (CN VII)Gustatory Ganglion
Loss of sense of tasteAgeusia
Diminished taste sensationHypogeusia
Enhanced sensation of tasteHypergeusia
Distorted sensation of tasteDysgeusia
Persistent abnormal tasteParageusia
Vibrates the narrow portion of the cochlea basilar membraneHigh Frequency Sound
Vibrates the wider portion of the cochlea basilar membraneLow frequency Sounds
Static equilibrium measured by this which is made up of the saccule and utricleMaculae
Rock like substance within a membrane in the inner ear that bend the hairs which senses linear accelerationOtolith
Dynamic equilibrium is measure by these structures as fluid washes over hairsSemicircular Canals
Axons of this tract decussate and ascend contralaterally in the lateral lemniscus to the inferior colliculus and ascend to the medial geniculate bodyDorsal Cochlear
Axons of this tract project to the ipsilateral superior olivary complex. Fibers from there project bilaterally to the inferior colliculi (crossing in the trapezoid body), and from there ascend to the MGN as the lateral lemniscusVentral Cochlear
Keeps the eyes on target when the head moves quicklyVestibulo-Ocular Reflex
Through this the left horizontal canal activates ipsilateral CN III and contralateral CN VI, and the eyes move in the opposite directionMLF
Eyes are showing movements when they are not tracking anythingPathologic Nystagmus
Tilt a comatose patient’s head in one direction; if eyes move in opposite direction, brainstem is intact. If the eyes move with the head movement, indicates brainstem damageDoll's Eye Maneuver
Cool or warm water into the ear canal; in normal persons, cool will result in nystagmus towards the opposite side, warm will result in nystagmus towards same sideCaloric Test
Place vibrating tuning fork on center of foreheadWeber’s Test
Tuning fork placed against mastoid. Normal: Air conduction (AC) better than bone conduction (BC). Conductive: BC better than AC. Sensorineural: Both AC and BC are depreciatedRinne’s Test

Basal Ganglion

Question Answer
A group of internal structures that are involved in voluntary muscle movements and postureBasal Ganglia
Translates the idea of movement into the motor expression of that ideaBasal Ganglia
Caudate nucleusCaudate Nucleus
Globus pallidus + PutamenLentiform Nucleus
Lentiform + CaudateCorpus Striatum
Caudate + PutamenNeostriatum (Striatum)
Amygdaloid bodyAmygdaloid Nucleus
Activation of this pathway disinhibits thalamic motor nuclei (the ventral anterior and ventral lateral or VA and VL), resulting in cortical activation and movement initiationDirect Pathway
Activating of this pathway inhibits the VA and VL, resulting in reduction in cortical activation and movement suppressionIndirect Pathway
Pathway from the striatum to Globus pallidus medialDirect Pathway
Pathway from the striatum to Globus pallidus lateral to Subthalamic nucleus to Globus pallidus medialIndirect Pathway
Direct pathway releases this peptide in addition to neurotransmittersGABA Subtance P
Indirect pathway release this peptide in addition to neurotransmittersGABA Enkephalin
GABA Enkephalin binds to this receptorD2
GABA Substance P bind to this receptorD1
Dopamine is inhibitory when it binds to this receptorD2
Dopamine is excitatory when it binds to this receptorD1
Dopamine receptors D1 and D5Excitatory Dopamine Receptors
Dopamine receptors D2, D3 and D4Inhibitory Dopamine Receptors
Cortex to striatumCorticostriatal
SNpc to various BG structures (and others)Nigrostriatal
Amygdala to ventromedial caudate and putamen (suggests that BG may have limbic and non-limbic components)Amygdalostriatal
From centromedian (and other) thalamic nuclei to striatumThalamostriatal
From striatum (caudate and putamen) to globus pallidusStriatopallidal
From striatum to substantia nigraStriatonigral
Globus pallidus to thalamusAnsa Lenticularis
Globus pallidus to subthalamusFasciculus Lenticularis
Movement disordersDyskinesia
Involuntary spontaneous movementsHyperkinesia
Lack of spontaneous movement, and slowing of voluntary movementHypokinesia
A series of rapid, jerky, involuntary movementsChorea
Continual uncontrolled writhing movementsAthetosis
A severe form of athetosis. Extreme contraction of antagonist muscle groups results in limbs locked in one position for long periods of time. Also may go in and out of muscle spasmsDystonia
Involuntary flinging of limbsBallismus
Bilateral electrodes targeted at the Thalamus - Effective in reducing tremor (resting and essential tremor). Subthalamus - Potentially very effective in reducing tremor and most other PD symptoms. Globus pallidus - Electrodes here may reduce drug-induced side effects in patients who have already received pallidotomyDeep Brain Stimulation
Bilateral electrodes targeted at this structure is effective in reducing tremor (resting and essential tremor)Thalamus
Bilateral electrodes targeted at this structure potentially very effective in reducing tremor and most other PD symptomsSubthalamus
Bilateral electrodes targeted at this structure may reduce drug-induced side effects in patients who have already received pallidotomyGlobus Pallidus
Lesion of the globus pallidus produces that conditionTourettes
Lesion of the striatum/neostriatum produces that conditionHuntington’s
Lesion of the subthalamic nucleus produces that conditionBallismus
Lesion of the substantia nigra produces this conditionParkinson’s Disease
Lesion of various structures due to copper depositionWilson’s Disease
Damage during pregnancy or birth produces that conditionCerebral palsy