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27 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Classical PKU (phenylketouria) is caused by
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a mutated gene for
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phenylalanine hydroxylase (PAH),
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PKU
What does phenylalanine hydroxylase (PAH) do= |
-converts the amino acid phenylalanine to
-other essential amino acids. These compounds compete with each other for entry into the = |
brain
Therefore, an elevation of plasma level of one will inhibit uptake of the others. Here high levels of phenylalanine in plasma reduce brain uptake of other essential amino acids. |
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Pearl Buck and her daughter
PKU develop = |
microcephaly,
progressive impair of cerebral fctn Hyperactivity, seizures, severe learning disabilities "musty or mousy" odor of: skin, hair, sweat urine due to phenylacetate accumulates tendency to: hypopigmentation eczemas |
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Neurotransmitters, Which receptor is directly coupled to an ion channel?
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G-Protein
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There are two types of Neurotransmitter receptors: ligand-gated receptors or ionotropic receptors and G protein-coupled receptors or metabotropic receptors.[2][4] Ligand-gated receptors can be excited by neurotransmitters (ligands) like glutamate and aspartate. These receptors can also be inhibited by neurotransmitters like GABA and glycine. Conversely, G protein-coupled receptors are neither excitatory nor inhibitory. Rather, they modulate the actions of excititory and inhibitory neurotransmitters.[2] Most neurotransmitters receptors are G-protein coupled.[1]
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Nanocircuit: example of feedback inhibition
Neurons in suprachiasmatic nucleus above optic nerve acts on (1) = (2) |
hormonal release (melatonin, cortisol)
autonomic function no neuronal circuit-nano circuit |
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Circadian rhythms
Key: degradation of PER (over 24 hours) cause |
disinhibition of
Gene to start making |
m RNA
circadian rhythms is Feedback inhibition |
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hydrocephalus
obstruction to flow of CSF e.g. congenital malformations 2 Nm - Dz |
(Dandy-Walker,
Arnold-Chiari), Sequele |
masses,
infections, congenital bone defect |
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Normotensive hydrocephalus:
s/s = 3ct |
- abnormal gait,
- urinary incontinence, - dementia |
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Foramen of Monro obstruction may lead to dilation of one or, if large enough (e.g., in Colloid cyst), both lateral ventricles.
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The aqueduct of Sylvius : a number of genetically or acquired lesions (e.g., atresia, ependymitis, hemorrhage, tumor) and lead to dilation of both lateral ventricles as well as the third ventricle.
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Fourth ventricle obstruction will lead to dilatation of the aqueduct as well as the lateral and third ventricles (e.g., Chiari malformation).
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The foramina of Luschka and foramen of Magendie may be obstructed due to congenital failure of opening (e.g., Dandy-Walker malformation).
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The foramina of Luschka and foramen of Magendie may be obstructed due to congenital failure of opening (e.g., Dandy-Walker malformation).
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p
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Non-communicating hydroceph
or obstructive hydrocephalus: involves what structures (its obstructive lol) |
Foramen of Monro
The aqueduct of Sylvius Fourth ventricle The foramina of Luschka and foramen of Magendie |
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Communicating hydrocephalus
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Impaired resorption
- Normal pressure hydrocephalus Hydrocephalus ex vacuo |
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Flow of CSF
11 ct |
Spinal cord
exterior of brain Tentorium to choroid --- (lat-vents) Monro --- 3rd vent-- Sylvias -- 4th vent -- Lucshka -- magendie -- spinal cord |
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The BBB consists of 3 components
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-Tight junctions btw capillary endothelial cells
-thick basement membrane underlying endothelium -astrocytes covering capillaries |
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BBB helps prevent polar chemicals from entering
what enters easily |
small, nonpolar chemicals
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Tight junctions are composed of transmembrane proteins =
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(occludin,
claudins, junctional adhesion molecule (JAM), ESAM) that are anchored to = |
the endothelial cells by another protein complex that includes
zo-1 and associated proteins. |
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blood-brain barrier
Stops large or hydrophilic molecules into the (CSF), while allowing the diffusion of small hydrophobic molecules = 3ct |
O2,
CO2, hormones |
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1. The continuous tight junctions that join the endothelial cells in the brain capillaries limit the diffusion of molecules across the BBB.
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2.The basement (basal) membrane provides structural support for the capillary - specific proteins present in the basement membrane have been proposed to be involved in the development of the BBB.
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3.Astrocytic foot processes release specific factors and are necessary for the development of the BBB. They contain water channels (aquaporin-4) that allow water uptake and contribute to brain swelling.
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4.Transport carriers for glucose and essential amino acids facilitate the movement of these solutes into the brain from the blood.
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5.Secondary transport systems appear to cause efflux of small molecules and nonessential amino acids from the brain to the blood.
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6.Sodium ion transporters on the luminal membrane and Na,K-ATPase on the anti-luminal membrane account for movement of sodium from the blood to the brain. The large number of mitochondrias present in the brain endothelial cells provide energy for the function of this Na,K-ATPase.
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7.The "enzymatic blood-brain-barrier": metabolic processes within the brain capillary endothelial cells , including the control the entry of neurotransmitters into the brain
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Development overview Neurulation
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CNS
Gastrulation (3 germ lyr) Primary neurulation Neural plate Neural folds Neural tube secondary (lwr spine-cord) Neurulation |
: is the stage of organogenesis, during which the neural tube is transformed into the central nervous system
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Shh acts as a morphogen because it induces cell differentiation dependent on its concentration. At low concentrations it forms ventral interneurones, at higher concentrations it induces motor neurone development, and at highest concentrations it induces floor plate differentiation.
Failure of = |
Shh-modulated differentiation causes holoprosencephaly
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