Child Psych Implantation and Embryonic Stage

pregnancy

highly variable even within the same couple, due dates are rarely birthdates, 3 trimesters

first trimester for mother

1. pregnancy test - measure HCG in urine/blood

2. morning sickness - can happen any time of day, good for baby

prenatal development for child

1. zygote (germinal)

2. embryo

3. fetus

implantation

1. endometrium is receptive to implantation for 4-5 days

2. blastocyst attaches to the endometrium via villi

3. blastocyst is now an embryo

4. trophoblast - umbilical cord, amnion, chrion, placenta, cells that contribute to birth

5. embryoblast > baby

zygotic phase

1. 23-48 hours after fertilization

2. fertilized egg begins to divide

3. splitting of cells = cleavage

morula phase

1. zygote becomes morula (mass with many divided cells or blastomeres)

2. cells divide into groups (what will become baby and what will become placenta)

blastocyst phase

1. air bubbles appear in morula and grow to become amniotic sac

2. blsatocyst attaches itself to fallopian tube

3. “hatches” egg in uterus and attach to walls

3 stages of implantaion

1. apposition - adhesion of blastocyst to wall of uterus

2. stable adhesion - continuation of first stage to make it more secure

3. invasion - blastocyst buries itself in outer walls of uterus, baby begins interaction with mother’s cells

problems with implantation

1. genetic causes - missing genetic material, chromosomal problems

2. timing issues - ideal implantation time 8-9 days after ovulation

3. maternal causes - uterine and fallopian issues, lead to miscarriages but don’t know exact cause

4. endometriosis - condition where tissue from uterus moves to other parts of body, can cause clots and cysts and infertility

5. uterine fibroids - tumors in uterus (fibroids)

6. previous abortions

7. previous STIs

8. ectopic pregnancy - implantation in wrong part of body

types of fertility drugs

1. clomiphene - increase hormone production, triggers ovulation

2. gonadotropins - produce multiple ova at ovulation

other methods for pregnancy

1. artificial insemination - implant sample of sperm during ovulation

2. assisted reproduction technologies (ART) - donors

3. IVF - ova on petri dish with doses of sperm

4. gamete intrafallopian transfer (GIFT) - sperm injected into fallopian tubes

5. ICSI - sperm injected into ovum, places in uterus

6. assisted hatching - increase chances blastocyst will attach to endometrial wall

multiple births

1. nonidentical multiples (fraternal) - separate ova and sperm

2. identical multiples - single ova and sperm (monozygotic)

3. diamnotic and monochrionic - type of identical twins with seperate amniotic sacs but shared placenta

4. monoamniotic and monochorionic - rare type of identical twins, same amniotic sac and placenta

5. conjoined twins

placenta

allows baby and mother’s cells to not kill each other, mediator

placenta functions

1. lung function - absorb oxygen from mother to baby

2. kidney function - regulates toxins and byproducts for baby

3. digestive system - gives basic needs to baby

4. endocrine system - alters hormones from mother’s body

potential issues with placenta

1. placenta previa - placenta in cervix, placenta can bleed and come apart in labor

2. placenta abruption - premature separation from wall of utero, 1/80

umbilical cord

connects baby to placenta

parts of umbilical cord

1. yolk sac - outside embryo and filled with fluid that helps baby grow

2. allantois - collects waste

3. wharton’s jelly - flexible tissue that allows baby to move out of body

amniotic sac

sac filled with fluid to protect baby while giving birth, cushioning pressure, lubricant

amniotic sac problems

1. premature rupture - water breaking early, requires c section, induced birth

2. oligohydramnios - too little amniotic fluid, late pregnancies, birth defects

3. polyhydramnios - fluid builds up and is premature rupture that can lead to defects

gastrula

3 layers of endoderm, trimester functions

patterns of development

1. organogenesis

   • embryonic cells arrange into shield

   • nervulation - 1st stage, flat neural plate that forms groove, forms brain and spinal cord

   • nervous system development - forms parts of brain

   • heart development - cells clump together and form heart, heart beats faster everyday

4th week

embryo changes shape, arms begin to appear, arches for face/neck/eyebuds/earbuds

5th week

head grows to accommodate brain growth spurt, looks more human

6th week

intestines, umbilical cord, genetials, skeleton, muscles

7th week

fingers, knees, toes, ankle, organs working

8th week

brain waves begin, eyes finish developing, tail disappears

trophoblast

cells that support the baby: placenta, umbilical cord, amnion, chorion

embryoblast

cells that become baby (blastocyst becomes baby)

miscarriages

1. rate = 15% - 30%

2. percentage of miscarriages associated with chromosomal abnormality or developmental defect = 60%

ectopic pregnancies

1. when baby gets stuck in fallopian tube instead of uterus

2. the baby will not survive but an abortion (laparoscopic surgery) needs to happen to save mother

zygotic development

1. during the germinal period (0-14 days), the following occurs:

   • mitosis (cleavage)

   • no growth in size (blastocyst)

   • 2 layers (1 is baby and 1 is stuff to help baby)

embryo development

1. During weeks 3-8, the following occurs:

   • differentiation in the earnest (cells specialize) into 3 layers

     • endoderm (inner) - internal organs

     • mesoderm (middle) - muscles, skeleton, blood vessels

     • ectoderm (outer) - nervous system, skin, teeth AND creates neural tube (brain and spinal cord)

neural tube problems

1. anencephaly (missing cortex) - missing part of the brain, death after birth

2. spina bifida (exposed spinal nerves) - spinal cord doesn’t develop

how does embryo growth occur?

1. cephalocaudal (head down) - develop head first then everything else

2. proximal distal (center outward) - inside out, inner layer first