Development/ROS Flashcards
embryonic bilaminar disc
when implantation is occuring, the embyoblast develops a bilaminar embryonic disc –> epiblast and hydpoblast
completes at the end of week 2
prechordal plate
by day 14 -> thickening of the hypoblast, forms within the bilaminar disc, marking the cranial region of the embryo
important for oranganizing the dev of head region
general gastrulation def
the convserion of the bilaminar embryonic disc to a trilaminar which gives rise to the 3 germ layers – endo, meso, and ectoderm
tissues derived from the ectoderm
epidermis, nervous system, eye, innner ear, neualr crest cell –> connective tissues of the head
tissues derived from the mesoderm
skeletal muclses, blood cells, lining of blood vessles, viercerl small muscular caots, serosal linings, ducts and organs of the reporductive and exretory systems, most of cardiovascualr system, connective tissue of the trunk
tissues derived from the endodererm
epithelila lining of resp, digestive, reporductive and uriniary systems
glandular cells of assocaited organis (liver, pancreas, thymus, thyroid, and parathyroid glands)
gastrulation steps
e appearance of the primitive streak on the caudal end of of the epiblast
this streak is the thickening of the epiblast caused by the proliferation of epiblast between the epiblast and hypoblast –> organizing into the mesoderm
signaling moelcules like bone morphogenetic proteins (BMPs), Wnt and fibroblast growth factors (FGFs)
general neurlation
the process of the neural tube formation and closure
neuralation general steps
the CNA is formed form the neuroectoderm of the neural plate while the peripheral nevous sytem is derived fom the neuarl crest cells, the nural tube and mesoderm
1st 2nd and 3rd tirmester correlates to which daysin rodetns
1st- 1-10/11
2nd- 12- 21/22
3rd- PND 1-10
brian brain developemnt grows rapidly from week 25-38 weeks
teratogenesis and windows of suseptability
certain periods of embryonic or fetal development are more suseptiable to distruption than others
firt 2 weeks-> no effect or in utero death
emrbyonic period -> humans 4-8 weeks, mice GD 5-14 will result in strucutral birth defects, the specific type depend on the organ being developing
fetal period -> humnad week 9- birth, mice GD 14-19, results in functional defects like cognitive or motor defets, metabolic diseases like diabetes
reactive intermediate mediated mechanisms -> electrophili reactive intermediates bvs.
ex. benzo[a]pyrene
electrophillic reactive intermedaite-> structures have electron defient centers; ex. epxosides, bioactivation is usually catalzed by P450 CYPs
embryo has low levels of detoxifiying enzymes
reactive intermediate mediated mechanisms – free radical reactive intermediates
ex. phenyotin, methamphetamine, thalidomide, Etoh
bioactivation of xenobiotics to free radical intermediates
embryo expresses high levels of PHS and lipoxygenases but low levels of CYP enzymes
ROS types - superoxide anion
one electron reduction of O2
can react with nitric oxide to make peroxynitire
can be converted to H2O2 enzymatically by SOD
ROS types: H2O2
non radical
can easily cross biological membranes,
removed by catalase or by glutathione peroxidases
fenton reaction –> reacts with iron or copper metals to make hydroxy radicals
ROS types
hydroxyal radical
3 electron reduction of oxygen
very short half life 10^-9 and dose not diffuse from the site of generation
damage to protins leads to loss of activity, damage to lipids can lead to lipid peroxidation
endogenous sources of ROS
MTC - oxidative phosphorylation, ROS can be formed through the electron transfers, 5% of electrons that go through complex 1 and 3 ae diverted to superoxide, but the mitochondria have high levels of SOD
ER contains CYP enzymes
peroxisomes
NADPH oxidases
xanthine oxidases
auto oxidation of small molecules liek dopamine
mouse brain development - neurulation
neural tube formation -> finished GD 10-11
○ PAE specifically effects the neurulation
mouse brain development - neurogenesis
Neuogenesis and cell migration for forebrain, midbrain and hindbrain -> starts GD 5-11
mouse brain development - GD 11-21
most CNS areas have distinct differentiation processes and several neuronal cell types emerge and migrate to specific parts of the brain
PAE effect prolication and migration processes of the neocortex, cerebellum, hippocampus and basal ganglia
mouse brain development - GD 18- PND 9
prolifation of astroglia and oligofendroglial cells, synaptogenesis, and dendritic arborization
○ Alochol exposure results in sever nuronal loss, reactive fliosis, impaired myelination and damage to prefrontal cortex, hippocampal and cerebellar regions
• What is the definition of oxidative stress
o Oxidative stress was originally defined as an imbalance between ROS and antioxidant defence mechanisms, but the definition has been recently modified, recent version –> imbalance between oxidant and antioxidants in faou of the oxidants, leading to a disruption of redox singling and control and or molecular damage
