M2-Lecture1 Flashcards
ePreconception period is:
Period preceeding, including and immediately following human conception.
Prenatal period
Fertilization has occured and zygote is formed
Period between conception & birth
Perinatal period
Period immediately before and after birth.
Which trimester includes important developmental milestones and give examples:
First
Fertilization, pre-embryonic & embryonic period.
In first trimester basic structure of organs and tissues forms, what is this called?
Organogenesis
First trimester name of the developing baby:
Second trimester and third trimester: Fetal
Embryonic
What are finger-like projections that help guide the egg from the ovary into the fallopian tube after ovulation facilitating the meeting of egg & sperm for fertilization:
Fimbria
On what day after fertilization does the morula become blastocyst (dividing cells with central cavity filled with fluid - blastocoel:
Fifth day
What is a solid ball of cells that forms after the fertilization of an egg and the first few rounds of cell division, and is surrounded by ZP (16 cells)?
Morula
What does the blastocyst form into:
- Trophectoderm (outer layer): Placenta (trophoblast cells) & fetal membranes.
- Inner mass at one pole that will form the embryo
Fluid filled cavity (overall structure and deve. of embryo)
What is the outerlayer of the blastocyst?
Trophectoderm
What do uterine secretions provide to the blastocyst following the multiplying of the inner & outer cell masses:
Oxygen & metabolic substrates
Because the uterine secretions are inadequate, that’s why within 24 hours of hatching or day 6 after fertilization, the blastocyst implants in uterine lining, which has access to glycogen filled stromal cells (which supply nutrients). T/F
True
Gylcogen filled stromal cells are necessary for continued growth. T/F
True
Sperm can remain in the uterus for several days?
Yes
Sperm penetration causes zona pellucida to become impermeable by other sperm. what is this called?
Cortical reaction
How does sperm penetrate the ZP:
Acrosome of sperm binds to ZP, specifically ZP3 protein. Enzymes hyaluronidase and acrosin are released.
These enzymes help the sperm penetrate the ZP.
What fast block of the ploysperms?
Depolarization of egg’s membrane
The slow block involves:
Cortical reaction, where cortical granules release substances that modify ZP
Zygote fusion of two gametes, 46 chromosomes, divides by:
Mitosis
When does implantation occur:
By the end of first week. Blastocyst implants in uterine lining.
When the inner mass cell forms two-layered disc of embryonic cells, what is the fluid filled component btw. it & the trophoblast?
Amniotic cavity
Briefly explain what occurs during embryonic week 2 (GA week 4) development - early stages of embryonic deve.:
- Inner cell mass forms two-layered disc of embryonic cells (Bilaminar embryonic disc)
Upper Layer: Epiblast
- Develops into amnion, which fill with amniotic fluid
- Also forms the embryo.
Lower Layer: hypoblast
- Forms the yolk sac
What does the amniotic fluid contain?
Initially maternal plasma & later fetal urine.
Function of the amniotic fluid:
Protects embryo and allows movement.
During week 3, the yolk sac - allantois, contributing to the umbilical cord structure & the Chorion, outermost membrane surrounds all and plays key role in placenta development. T/F
True
The function of the yolk sac:
Provides early nutrition & blood circulation until placenta takes over in week 4.
Source of blood & germ cells.
Name the two layers that form when the trophoblast divides:
syncytiotrophoblast and cytotrophoblast
What consists of individual mononucleated cells that arise from the trophoblast after implantation.
Cytotrophoblast
What is formed by the fusion of cytotrophoblast cells, creating a multinucleated layer that invades the uterine wall. and nutrient and gas exchange btw. mother & embryo, produces hormones like hCG.
Syncytiotrophoblast
How can pregnancy be clinically detected:
hCG - corpus luteum (helps sustain the corpus luteum (produces progesterone and estrogen) from degradation.
When does embryonic disc (epiblast) differentiate into germ layers:
During embryonic week 3 (GA Week 5)
Name the three germ layers (kown as trilaminar embryonic disc):
Ectoderm
Mesoderm
Endoderm
When does the fetal begin to assume human shape:
56 days (8 weeks)
During the 56 days/8 weeks, a lot of rogans are formed but not fully differentiated. T/F
True
The first 8 weeks of embryonic period are very critical because of risk of deformities, miscarriage, and neural tube defects. T/F and what’s needed.
True
Folic acid
Embryological events during first 8 weeks:
Organs form from the three germ tissues. basic body plan.
Where is folic acid most abundant:
In Dark leafy green vegetables and spinach
Btw. which weeks does a women first learn of pregnancy?
Weeks 3-8
Thalidomide is given to cancer patients and why?
It prevents formation of blood vessel, so that tumors do not use the nutrients to spread.
External genital develop late? T/F
True
Each germ layer gives rise to specific tissue types & organs. T/F
True
What is the formation of organs from germ layers following gastrulation:
Organogenesis
Organogenesis occurs mainly during embryonic week 4-8 (GA 6-10).
During embryonic weeks 4-8, the embryo is most sensitive to harmful factors, such as (ex. alcohol, radiation, infectious agents, drugs, nutritional supplements, etc.) T/F
True
Totipotent (egg) gives rise to germ layers (pluripotent) then different organs (multipotent). T/F
True
What do endoderm (inner layer) give rise to:
lung cells
Thyroid
digestive cells
What do mesoderm (middle layer) give rise to:
Cardiac muscle
Skeletal muscle
Tubule cells
RBC
Smooth muscle
Endoderm, ectoderm and mesoderm give rise to specialized cells by epigenetics? T/F
True
Ectoderm (outer layer) give rise to:
Skin cells
Neurons (nerve cells)
Pigment cells
Describe the steps of placenta formation (placentation):
Implantation days 5-6:
blastocyst implants into uterine wall
Trophoblast differentiation: ○ Cytotrophoblast:
Syncytiotrophoblast:
Formation of chorion (week 2-3): trophoblast & mesoderm combine to form it.
Vascularization: blood vessels begin to form within the chorion
Mature placenta (weeks 4 and beyond).
Around week 12, the placenta becomes fully functional. T/F
True
Placenta is the vital organ of pregnancy. T/F
True
Placenta is responsible for all maternal-fetal exchange? T/F
True
What organs have later development:
Neural
Genital
Respiratory
Bones
What is the placenta involved in:
Metabolism
Barrier
Endocrine
Immune
What occurs in the second & third trimesters:
Includes fetal period
Growth & differentiation of formed organs
Growth in fetal size and length (2nd trimester)
Growth in fetal weight (3rd trimester)
What happens during growth in fetal weight:
Deposition of subcutaneous fat
Characteristic of buckle fracture:
bulging or “buckle” of of the bone rather than complete break
What is the most common fracture seen in children (but less common in fetuses due to flexibility of developing bones):
Buckle fracture
What is the process of giving birth to an offspring called:
Parturition
Describe the steps of parturition:
- Sequential, changes in myometrium, decidua & cervix
- Days to weeks
- Release from the inhibitory effects of pregnancy on the myometrium (lower progestrone)
Indicators of labor based on clinical diagnosis:
Uterine contraction increasing in frequency & intensity
Cervical effacement & dilation
Parturition is initiated by the fetus: T/F
True
Phases 1 of parturition:
Phase 1: quiescent phase (by progestrone & PGI2, relaxin, PtHrP, calcitonin gene-related peptide, vasoactive intestinal peptide and nitric oxide (NO).
What’s the role of the components of phase 1:
To inhibit release of intracellular calcium for myometrial contractility.
Phase 2 of parturition:
Activation of uterine function
Rise in estrogen & CRH
The impact of rise in estrogen & CRH:
May lead to up-regulation of genes required for contraction during mechanical stretch.These CAPs include connexin 43, prostaglandin and oxytocin receptors (OTRs).
Phase 3 of parturition:
Stimulation of uterus by uterotonics including prostaglandins, oxytocin, & CRH, cytokines.
During parturition there is increased synthesis of cytokines resembling inflammation: T/F
True
Phase 4 of parturition:
Involution phase - after the delivery of the fetus & placenta.
Effects of oxytocin
Parturiton mechanisms:
Progesterone withdrawal
Estrogen bioavailability
Responsiveness of myometrium to prostaglandins & oxytocin
CRH & HPA axin activation
Uterine stretch
During parturition, progesterone may still be high, but receptors are removed. T/F
True
What is the primary hormone of pregnancy:
Progesterone
Progesterone is made by both placenta (takes over) & corpus luteum during pregnancy. T/F
True
Progesterone sustains uterine quiescence throughout pregnancy. T/F
True
During pregnancy there is hyperesterogenic state. T/F
True
The placenta is the primary source of estrogen once stimulated by maternal & fetal adrenal glands: T/F
True
Concentrations of estrogen increase with gestational age:
True
Estrogen promote myometrial changes or uterine contraction. T/F
True
Mechanisms of myometrial changes:
Increase of prostaglandin receptors
high Oxytocin receptors
high myometrial gap junctions
up-regulate enzymes responsible for muscle contractions
Estrogen promotes cervical rippening?
Yes
During parturition, on what receptors does CRH act upon?
Hormonal, vascular, & inflammatory
What is the most common neuropeptides involved in parturition?
CRH
Placenta is capable of synthesizing & releasing many neurohormones, & neuropeptides. T/F
True
What share sequences homologies with CRH & have similar biological effects:
Urocortins (Ucn, Ucn2, Ucn3)
Role/function of neurohormones and neuropeptides:
Act locally in modulating pituitary-like hormones, & resemble the HP target gland axes
Women who plan to get pregnant receive blood test. Why?
To make sure that they don’t have hypothyroidism.
Thalidomide was only teratogenic in humans. T/F
True
Fetal blood does not touch maternal blood (tree-like structure). T/F
True
The syncytiotrophoblast is the layer that forms the villi. the syncytiotrophoblast extends out into the uterine tissue, creating the finger-like projections known as chorionic villi. These villi are essential for increasing the surface area for maternal-fetal exchange of nutrients, gases, and waste products. The underlying cytotrophoblast contributes to the formation of the villi but is primarily responsible for providing cells that support the syncytiotrophoblast. T/F
True
Cytotrophoblast would penetrate the syncytiotrophoblast layer and form outer cytotrophoblast layer. It has primary villi, secondary villi, and teritiary villi. The villous cytotrophoblast cell is a type of cell found within the chorionic villi (created by syncytiotrophoblast) of the placenta. FYI: the blood vessels are also located in the chorionic villi. T/F
True
Bones are not fully mineralized until about 2 years old. T/F
True
Decrease in progesterone needs to happen for parturition. T/F
True
Oxytocin relies on positive feedback loop. T/F
True
In mother, cortisol inhibits hypothalamic CRH & pituitary ACTH release, creating negative feedback loop. T/F
True
CRH is stimulated by cortisol from the decidua, trophoblast, fetal membranes, creating positive feedback loop for both the mother & fetus. T/F
True
Maternal CRH increases even as fetal CRH decreases due to cortisol feedback. T/F
True
Role of elevated cortisol from stimulating CRH in pregnancy:
Changes in estrogen & progesterone ratios that prepare the body for labor.
Myometrial contractility, relaxation or contractility depending on receptor.
Inflammation in myometrium
Fetal adrenal function, lung maturation, & surfactant production
Oxytocin is a polypeptide hormone? T/F
True
What produce oxytocin:
Maternal hypothalamus (posterior pituitary)
Uterine contraction
Placenta & decidua to produce prostaglandins
Prostaglandins are cyclic fatty acids, PGF2a & PGE2, and stimulate uterine contraction? T/F
True
What produces prostaglandins?
Placenta & uterine tissue
Estrogen from ovaries induces oxytocin receptors on uterus: T/F
True
CRH are neuropeptide produced by the hypothalamus, maternal & fetal brain, placenta? T/F
True
Important component of HPA axis:
Can be activated by stress
Action of produced glucocorticoids:
High estrogen production
High prostaglandin synthesis
Placental estrogen induce synthesis of prostaglandins, and its production in chorion and amnion cells. T/F
True
the potential for fetal cortisol negative feedback action on fetal ACTH production is reduced by increased production of corticosteroid-binding globulin (CBG) at the end of pregnancy. T/F
True
Placental estrogens enhance placental CRH production, second positive feedback loop? T/F
True
Placental CRH synthesis is stimulated by fetal cortisol (positive feedbackloop): T/F
True
Rotate the baby to prevent head or skull deformation: T/F
True
Fetal Health Metrics or good prenatal care assessments:
Maternal weight gain
M cardiovascular adaptation
Insulin requirements
Fetal growth profiles
Genetic screening (no injection of needless to prevent risk of infection) ultrasound scanner
Placental health
Uterine, placental. and umbilical blood flow
Pregnancy hormones & their effects:
Estrogen, cortisol, human placental lactogen can have blocking effect on insulin.
Our insulin needs start to increase from when you are 20 weeks pregnant. Eventually, you may need 2 or 3 times the amount of insulin that you had before you were pregnant.
T/F
True
How to counteract the blocking effect of these pregnancy hormones:
Need more insulin for food to pass into your own body cells (and feed the fetus)
Neonatal health metrics at birth:
Gestational age at delivery
Mode of delivery
Birthweight centile
Neonatal biometrics
Neonatal organ function
Feeding behaviors
NICU Admission
Complications and pregnancy outcomes
Infertility and miscarriages
Ectopic pregnancies
Pre-term Birth
Placenta-Mediated Disease
Placenta previa
Placenta accreta
Molar pregnancies
Fetal growth restriction (FGR/IUGR)
Preeclampsia
Gestational Diabetes *
Stillbirth*
*significant
What is one of the causing of pre-term birth.
The woman not knowing that she is pregnant and leads to poor prenatal care.
Birth <37 weeks gestation is pre-term birth and early pre-term birth is <32-34 weeks.
Yes
More than 90% of pre-term birth survive. T/F
True
Causes of pre-term births:
Stress, systemic material genital tract infections, placental ischemia, or vascular lesions, & uterine contraction.
This lungs are not well-developed.
What makes pre-term birth have increased morbidity & adult chronic disease:
Hypertension
Cardiac dysfunction
Lung disease
glucose intolerence
Developmental programming are missed
What is impaired intrauterine fetal growth:
Fetal growth restriction (10th, 5th, 1th percentiles)
Characteristics of FGR:
IUGR/FGR - did not reach full growth (abnormal uterine and/or umbilical artery blood flow) due to issues with the placenta.
SGS - small compared to normal distribution. may not be pathological.
10% of births in Canada
Ethology of IUGR:
Maternal factors, placental & cord abnormalities, fetal malformations
infection, malaria, chromosomal abnormalities, etc.
Pre-eclampsia is an hypertensive disorder (placental issue not mother’s health issue but affects the mother not the fetus) with placental origin: T/F
True
Leading cause of maternal and fetal mortality & morbidity.
1/2o pregnancies
Pre-eclampsia
Can lead to eclampsia (maternal seizures). T/F
True
S&S of pre-eclampsia:
Hypertension after 20 weeks gestaition
Systolic >140 mmHg or diastolic >80 mmHg
Proteinuria
Edema
Abnormal liver function
HELP syndrome
Pre-eclampsia has no cure.
Yes
but delivery of placenta
When the placenta cannot meet the fetal demands, the mother may develop hypertension as her body attempts to compensate for the inadequate placental function. This cycle can lead to further complications for both the mother and the fetus. T/F
True
Etiology of pre-eclampsia:
Placental hypoxia and damage
Excessive shedding of placental debris in maternal circulation
Maternal inflammation and endothelial dysfunction
Pre-term birth & FGR are common occurences: T/F
True
Pre-eclampsia associated with cardiovascular & metabolic diseases in later life of offspring. T/F
True
Two-hit combination of pre-eclampsia:
immunomodulatory and antiangiogenic signals (mid to late gestation)
later host susceptibility marked by unhealthy lifestyle
Pregnancy predicts long-term health risk for mothers:
yes
After preeclampsia, women have an increased risk of vascular disease. T/F
True
Diabetes mellitus associated with pregnancy. T/F
true
Majority of mother snot diabetic before pregnancy, but often goes away after pregnancy?
True
Inability to produce insulin secretion to compensate for pregnancy induced insulin resistance - hyperglycemia. Dangerous for mother and fetus.
GD
GD affects upto 26% of pregnancies:
Yes
Risk factors of GD:
Advanced maternal age
Smoking
Obesity
