Student Presentations Flashcards
what is an endocrine?
hormones secreted by glands throughout the entire body thru the blood stream
what are estrogen and androgens responsible for?
estrogen = implantation, placentation
androgens = male development, sex characterisitics
what is an endocrine disruptor?
something that disrupts normal flow of endocrines
- several things (synthetic & naturally)
- mainly impact endocrine receptors
what is the main endocrine disruptor we talked about? what is it used for?
BPA
- synthetic estrogen
- making plastic
- in 90% of people’s urine
- only 20-400 mg can cause effects
what are the three types of trophoblastic cells? describe them
CTB (Cytotrophoblasts)= progenitor cell
* STB (Syncytiotrophoblast) = form chorion, secrete hormones
* EVT (Extravillious trophoblast) = anchor placenta to uterus
which receptor is BPA an agonist for? what about antagonist?
estrogen ALPHA agonist
estrogen BETA antagonist
describe how BeWo cells were used to see the effects of BPA
BeWo cells function very similarly to EVT cells
- adding BPA to BeWo cells decreased implantation by 50%
what is important for regulating endocrine disruptors?
Classification
- very difficult and expensive to do
- important to prevent manufacturing of harmful substances
what is metamorphosis?
modifications to morphological characteristics of larval tissue to transition an animal to next life stage
- caterpillar to butterfly
what does the thyroid gland do?
controls many things in the body including development, homeostasis, and metamorphosis
what converts T4 into T3? why is it converted?
deiodinases (removal of an iodine)
- T3 is what binds to receptors (T4 does not)
describe the Atlantic Halibut research
looked at muscle and skin tissues of the fish to see if metamorphic changes occurred as a result of T4 to T3 conversion
- looked at the deiodinases
- found that D2 and D3 expression drives metamorphosis
what happened in amphibians when T3 was blocked?
no. metamorphosis occurred
- instead of turning into a frog, it turned into a giant tadpole
what are the four clinical features of fetal alcohol syndrome?
facial dysmorphology
neurobehavioral disabilities
growth retardation
CNS dysfunction
describe what happens when glial cells are exposed to alcohol prematurely
reduces differentiation
- impairs astroglial proliferation, survival, and function
- decreased white matter
describe the Shh experiment with ethanol
half injected with ethanol, other half injected with antibody to remove Shh
- showed physical similarities b/w both groups
- PCR was ran to show a decrease in Shh and TF’s when introduced to ethanol
- Shh that uses PATCHED receptor was decreased
what is Marfan Syndrome?
dominant genetic disorder that affects connective tissue
what gene in Marfan Syndrome does it mutate? describe what it normally does
fibrillin-1 gene (FBN1)
- makes elastic fibers & microfibrils
what is the diagnostic tool used to classify Marfan Syndrome? describe how it works
Ghent nosology
- created a chart of symptoms to reference when making a diagnosis
- long limbs, issues with cardiovascular & muscular systems
- aortic valve issues (aneurysms -> weak & widened wall)
describe the experiment to find the mutations that lead to Marfan’s Syndrome
isolated and sequenced FBN1
- missing EGF-like domains led to the most severe cases
- result of inframe exon skipping
what is mosaic pleiotropy?
gene is independently expressed in many tissues of the body
what two cell types interact to form teeth?
mesenchymal & epithelial
what are the 5 stages of tooth development?
- initiation (6-7 week)
- bud (8 week)
- cap (9 week)
- bell (10-14 week)
- maturation
what is occurring during the initiation stage of tooth development? (include genes)
forms primary epithelial bands & dental placodes
- Fgf8 activates Pax9 = tooth development
- BMPs block Pax9 in the areas we don’t want teeth
what is occurring during the bud stage of tooth development? (include genes)
dental placodes invaginate
- Fgf9 activates MSX1 = epithelial cells move into mesenchymal cells
what is occurring during the cap stage of tooth development? (include genes)
unequal rate of division (creates a concave shape)
- Fgf20 produced by enamel knot (epithelial)
- Fgf3 produced by mesenchymal cells
what is occurring during the bell stage of tooth development? (include genes)
produce dentin and enamel (mineralization)
- triggered by the decrease in Fgf’s
what produces dentin and enamel?
odontoblasts = dentin
ameloblasts = enamel
what is important to know about the enamel knot in relation to rate of cell division?
enamel knot does NOT have Fgf receptors
- leads to less growth in this area which creates that concave shape
what is LADD syndrome?
missing teeth, underdeveloped salivary glands, etc.
- due to a missense mutation in Fgf receptors
- codes for a different amino acid
what are the three phases of normal wound healing?
- inflammation
- proliferation
- scar remodeling
what is different about scar formation in the early embryo?
no scar formation
- scar formation correlates with hair follicle development
- does not need amniotic fluid to do healing
what are the two Wnt pathways? which one is used for early embryo wound healing?
Canonical = scar formation, can’t make new skin cells
Non-canonical = NO SCAR, plasticity for re-epithelialization
describe the experiment with grafting human fetal skin onto mice
cutaneous (in skin) = scar tissue
subcutaneous (under skin) = no scar
- proved that subcutaneous is less physiologically active
what Wnt is responsible for blocking the canonical pathway to allow for the non-canonical pathway to be active? describe what promotes this
Wnt5a
- Wnt 5a promotes EMT (epithelial mesodermal transition) to activate mesenchymal cells to divide and close the wound through contraction of the skin
what week of development is the most susceptible to ethanol? what stage of development does this correlate with?
3rd week of development
- gastrulation
- embryonic stage
what three main types of cells are impacted by ethanol exposure in the neuro, cardio, and ocular regions?
Neuro = cranial neural crest cells
Cardio = heart progenitor cells
Ocular = retina
what structure in the brain has the most damaging effects when exposed to ethanol? when does this structure form?
Corpus Callosum
- 6-7th week
what is the difference between Symmetric and Asymmetric effects for FAS?
Symmetric = 1st & 2nd trimester, defects of whole fetus
Asymmetric = 3rd trimester, normal head, underdeveloped abdomen
what chemical mechanism does alcohol effect?
one-carbon metabolism
- methylation of DNA & histones
describe the miRNA experiment for FAS
miRNA’s are needed for stem cell renewal & blocking transcription of a gene (regulates proteins produced)
- when a fetus is exposed to alc, these miRNAs were overexpressed
- decreased osteogenic differentiation (production of bone stem cells)
what was the one miRNA that was decreased in the FAS experiment?
miR-206-3p
what is a orofacial cleft?
lip & roof of mouth doesn’t join and creates a facial abnormality
what are the three types of orofacial clefts? describe the difference b/w them
unilateral = one side of lip, MOST COMMON
bilateral = both sides of lip
isolated = cleft palate w/o lip deformity
what is the difference between nonsyndromic and syndromic? what is an example of a syndromic disease that involved a cleft lip
nonsyndromic = isolated defect
syndromic = defect seen with other abnormalities
- Patau Syndrome (hernia, cardio defects, renal issues)
what weeks of development does the cleft lip form?
4th-12th week
- fusion occurs anterior to posterior
describe the experiment looking at the effect of specific genes on cleft lips (list the three genes they studied). Which gene was the main gene found to have an effect?
epithelium and connective tissue was collected from a nonsyndromic patient
- looked at expression of Pax7, Pax9, and RYK in a normal vs effect patient
- Pax7 was found to be the MAIN gene involved with cleft lip
what does Pax7 do for cleft development?
craniofacial development
- neural crest cells
- MAIN GENE!!!!!
what does Pax9 do for cleft development?
RNA polymerase that regulates protein expression
- dependent on cleft type
what does RYK do for cleft development?
ectoderm development
- formation of craniofacial regions
what does the amygdala do? where in the brain is it found?
limbic system, temporal lobe
- involved in senses, behavior, learning, memory
- processing emotion, interpreting social cues
describe the experiment focusing on how maltreatment can effect the brain (mention the gene they looked at but don’t describe it)
go/no-go task
- humans were placed in an MRI scanner and shown threatening images
- mice were well taken care of, and then placed into a cage with bright lighs, no odor, and boring (threatening)
- they then measured the c-Fos expression in the amygdala
what does the c-Fos gene do? what function did it have on the amygdala?
cell proliferation and cell differentiation
- correlated with anxiety
- turns a short-term stimuli into a long-term response
what is fragile X syndrome?
X-linked recessive disorder that causes intellectual disability
- creates large ears, hyper-extensible joints
- due to the mutation of the promoter of FMR1 gene
what is situs solitus?
normal symmetry of organs
what is situs inversus?
inverted symmetry of organs
- asymptomatic
what is situs ambiguous?
inverted symmetry of organs
- severe medical issues
when in development, does the L/R axis form in chicks (stage & developmental stage)? what structure is the most important for determining this
stage 5 -> gastrulation
- Hensen’s Node!
what main molecule is responsible for activating Pitx2 on the left side?
Nodal
what organ does Pitx2 form? which side is this on?
right side of lung
what are the two TF’s that are activated by Pitx2? (list them, don’t describe)
Foxh1
Nkx2
describe how Pitx2 TFs are regulated
ASE enhancer regulates the binding of Pitx2 to Foxh1 & Nkx2
what are the functions of Foxh1 and Nkx2?
Foxh1 = target of nodal signaling, initiates asymmetry
Nkx2 = late-stage expression of Pitx2
what is the Nodal Flow Hypothesis
cilia tilt toward the LEFT side to move nodal & extracellular fluid
- breaks up symmetry in early embryo
