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25 Cards in this Set
- Front
- Back
Describe the capillary endothelium of the brain.
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-not support vesicular transport
-histamine, 5HT, and NE do not inc. its permeability -no contractile proteins -enzymes regulating transport of AA, amines and hexoses |
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Where else is capillary endothelium of the brain found?
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pia and arachnoid, retina
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How many membranes must CNS drugs cross?
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2 lipid membranes: the basement membrane from the glial cells and the endothelium layer that is connected by tight junctions
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What is the choroid plexus? type of cells?
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secretes the CSF and lines the ventricles.
CILIATED CUBOIDAL EPITHELIUM |
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Areas with fenestrated epithelial linings of the CNS? (i.e. no BBB)
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pineal gland
pituitary gland median eminence area postrema wall of the optic recess (suprachaismatic and supraoptic nuclei of the hypothalamus-control bio rhythms and pit. control) |
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Areas with fenestrated epithelial linings of the PNS?
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*olfactory receptor cells
*terminal endings of *peripheral nerves (site entry for virus) *sensory ganglia of SC and CN *part of the optic nerve (P scleral foramen) *Dura |
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What impairs the BBB?
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*infarction
*heavy metals (Pb, Hg, Mn) *degenerative, inflammatory and autoimmune dz *HTN (>200) *hypercapnia *convulsions (electroshock, hypoglycemia) |
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Factors that facilitate diffusion rate across BBB?
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*lipid/water partition coefficeint
*Carrier-mediated facilitated diffusion |
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Factors that impede diffusion rate across BBB?
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*level of ionization of the drug in plasma (ionic not cross)
*binding to plasma proteins *Hydrogen bonding with H20 *enzymatic degradation within endothelial cells |
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General description of CNS drugs.
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*high lipid solubility
*large Vd,extensively redistributed *duration of action << half-life *Cleared by hepatic metabolism *no diffusion barrier between CSF and ECF, intrathecal admin |
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Only CNS drug that is not highly lipid soluble?
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L-dopa
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Which class of drugs produces a life threatening withdrawal?
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Sedative hypnotics:
Benzos, barbituates, and alcohol |
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Name the catecholamines
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NE, epinephrine, dopamine
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What are the neurotransmitters of the CNS?
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NE, Epi, Dopamine, serotonin, histamine
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Name the types of NE receptors and what they are coupled to?
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B-receptors: inc. CAMP--excites
A1R: inc. neuronal excitability A2R: neuronal inhibition (pre and post-synaptic)--sedation, analgesia, hypotension |
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Describe the Locus coeruleus.
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*NE cell bodies
*collaterals to entire brain *stress, nociceptive stimuli, maintenance of waking state. *Part of Reticular Activating System |
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Parts of the brain richly innervated by NE neurons
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*dorsal horn-snesory modulation
*intermediolateral cell column- BP and other sympath. funct. *most autonomic medularry nuclei *hypothalamic nuclei (some) *limbi system |
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Role of adrenergic neurons in the CNS
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FEW
*central regulation of stress *autonomic functions *BP |
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Location of dopamine cell bodies
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*mesencephalon (ventral tegmental area (VTA), substantia nigra)
*diencephalon (thalamus, hypothatlamus) |
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Location of Dopamingergic neurons and their role/function
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* Midbrain (substantia nigra)-motor function
*Basal forebrain-personality and affects/motivation and reward *Hypothalamus- endocrine- inhibit prolactin release |
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Location of serotonergic cell bodies in CNS
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midline series of brainstem nuclei: raphe nuclei
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Projections of Serotonergic neurons and their function?
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*limbic system-mood
*hypothalamus-appetite and hormone production *dorsal horn-pain *intermediolateral column and ventral horn-inc. sympathetic and somatic motor outflows *brainstem-breathing [infant-respiration; adult-airway diameter] |
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Describe the cycle of sertonergic neuron action.
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active during waking, less so during SWS and not active in REM.
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Location of Serotonin in the periphery?
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*In platelets-not produced here;absorbed from blood
*Enterochromaffin cells of the GI tract |
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Location of histamingeric neurons in the CNS
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Not produced in CNS; except for a cluster in the hypothalamus
Receptors H1 and H2 located in a cluster in the hypothalamus regulation of sleep-waking cycle |