Development/ROS

Question 1

embryonic bilaminar disc

Answer 1

when implantation is occuring, the embyoblast develops a bilaminar embryonic disc –> epiblast and hydpoblast

completes at the end of week 2

Question 2

prechordal plate

Answer 2

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

Question 3

general gastrulation def

Answer 3

the convserion of the bilaminar embryonic disc to a trilaminar which gives rise to the 3 germ layers – endo, meso, and ectoderm

Question 4

tissues derived from the ectoderm

Answer 4

epidermis, nervous system, eye, innner ear, neualr crest cell –> connective tissues of the head

Question 5

tissues derived from the mesoderm

Answer 5

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

Question 6

tissues derived from the endodererm

Answer 6

epithelila lining of resp, digestive, reporductive and uriniary systems

glandular cells of assocaited organis (liver, pancreas, thymus, thyroid, and parathyroid glands)

Question 7

gastrulation steps

Answer 7

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)

Question 8

general neurlation

Answer 8

the process of the neural tube formation and closure

Question 9

neuralation general steps

Answer 9

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

Question 10

1st 2nd and 3rd tirmester correlates to which daysin rodetns

Answer 10

1st- 1-10/11
2nd- 12- 21/22
3rd- PND 1-10

brian brain developemnt grows rapidly from week 25-38 weeks

Question 11

teratogenesis and windows of suseptability

Answer 11

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

Question 12

reactive intermediate mediated mechanisms -> electrophili reactive intermediates bvs.

Answer 12

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

Question 13

reactive intermediate mediated mechanisms – free radical reactive intermediates

Answer 13

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

Question 14

ROS types - superoxide anion

Answer 14

one electron reduction of O2

can react with nitric oxide to make peroxynitire

can be converted to H2O2 enzymatically by SOD

Question 15

ROS types: H2O2

Answer 15

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

Question 16

ROS types

hydroxyal radical

Answer 16

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

Question 17

endogenous sources of ROS

Answer 17

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

Question 18

mouse brain development - neurulation

Answer 18

neural tube formation -> finished GD 10-11

○ PAE specifically effects the neurulation

Question 19

mouse brain development - neurogenesis

Answer 19

Neuogenesis and cell migration for forebrain, midbrain and hindbrain -> starts GD 5-11

Question 20

mouse brain development - GD 11-21

Answer 20

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

Question 21

mouse brain development - GD 18- PND 9

Answer 21

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

Question 22

• What is the definition of oxidative stress

Answer 22

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