User:Atcovi/Spring2024/Child Psychology/Ch. 3

Pregnancy is considered from the last menstrual period before conception to birth (280 days/.78 years), or from the 'assumed date of fertilization' (2 weeks after the start of the woman's last menstrual cycle). The latter would be 266 days or .74 years. Pregnancy is divided into 3 stages:


 * Germinal stage (first 2 weeks)
 * Embryonic stage (3-8 weeks)
 * Fetal stage (3rd month/12 weeks to birth)

We can also describe this as prenatal development in terms of 3 trimesters, consisting of 3 months each.

Quizlet: https://quizlet.com/874119455/child-psych-ch-3-flash-cards/?new

3.1 - Describe the events of the germinal stage of prenatal development, focusing on source of nourishment and implantation.
The germinal stage is the period of development that takes place between conception (a zygote is formed) and the implantation of the embryo.

The wandering mass of cells are nourished by its ownself: the yolk of the ovum (eg cell), hence why the blastocyst only gains mass when nourishment is given. This begins once it implants itself on the walls of the uterus.
 * 36 hours after conception: Zygote divides. Divides multiple times as it makes its way to implantation.
 * The zygote divides so many times that it becomes a blastocyst, a stage in the germinal period of prenatal development where the zygote turns into a bunch of different cells encapsulating a circle of fluid.
 * Inside the blastocyst, a platelike inner part will become the ectoderm, mesoderm, and the endoderm of the embryo - known as the embryonic disk. These parts will become the fetus later on.
 * The outer part, on the other hand, is the trophoblast. It first is made up of a single layer of cells, but will soon become 4 protective membranes. This is where the amniotic sac, placenta, chorion and umbilical cord develop.
 * The umbilical cord is a tube that connects the fetus to the placenta, which is an organ that serves as a train station between the uterine wall and the fetus in order for the latter to develop and get rid of wastes.

1/5 pregnancies result in a spontaneous abortion, occuring within the first 3 months.

Emotional support from healthcare professionals is needed for women who go through a spontaneous abortion, which seems to be lacking (2016 study).

3.2 - The Embryonic Stage
The embryonic stage lasts from 2 weeks to 8 weeks. Major organ systems develop here. They develop in the following trends:


 * Cephalocaudal - head to tail
 * Proximodistal - near to far

The embryonic disk's outer ectoderm develops into the nervous system, sensory organs, nails, hair, and teeth. 21 days in, two ridges appear in the embryo and fold to make up the neural tube. The inner endoderm forms the digestive and respiratory system. Later, the mesoderm develops into the excretory, reproductive, and circulatory system.

In the 5-6 week mark, both male and female have sexually undifferentiated goands and 2 sets of primitive duct structures, either the Mullerian (female) ducts and Wolffian (male) ducts. They look like female genitalia.
 * 3rd week after conception: head and blood vessels form.
 * Towards end of 1st month: arms and legs start to develop, facial features develop, brain has developed. Upper arms and legs develop BEFORE the forearms and lower legs. Hands and feet develop.
 * 6-8 weeks: webbed finger and toes.
 * End of second month: Limbs separated and elongated.

In the 7th week, the genetic code comes through.

The amniotic sac, filled with helpful amniotic fluid, is what allows the embryo/fetus to move throughout the mother's stomach with no problems.

The placenta and umbilical cord allows the embryo to exchange nutrients and wastes with the mother, whilst having its own circulatory system (developed by the mesoderm, remember!). There is a risk of germs, but it is NO WHERE near as bad as alcohol coming through to the embryo.

Hormones

 * Androgen - Male sex hormones make the difference. If little androgen, the Wolffian ducts go away and the female sex organs develop. Without androgen, we'd all look like women!
 * Testosterone - Male sex hormone produced by testes that make men, MEN!
 * Dihydrotestosterone (DHT) - Creates the male genital organs
 * Mullerian inhibiting substance - prevents Mullerian ducts into developing female duct system.

3.3 - Fetus Stage/Trimester Review
The fetal stage lasts from the 3rd month until birth. By the end of the first trimester (week 1 - week 12 [3 months]), the major organs have been developed, the eyes, toes, and fingers have been also developed. You can also see what gender the fetus is. This is the hardest for mothers, as morning sickness is habitual.

The second trimester (week 13 - week 26 [6.5 months]) is where the fetus has their organ system developed even further & they grow hella big! Hair even comes through! Mothers will usually feel fetal movements at this time.

The third trimester (week 27 - birth [9 months]) is where the hearts and lungs develop to be able to sustain life. Best period for birth is at the end of the 8th month. In the 7th month, the fetus turns upside down because they know they are about to come through!

Drugs/Hormones/Substances

 * Accutane is used for acne. Cause problems during 1st trimester.
 * Thalidomide babies
 * Antibiotics can be harmful, including bone issues/asthma development.
 * Tetracycline can cause bone abnormalities.
 * Hormones, like the man-turning progestin and DES, that are aimed to prevent miscarriages - THOUGH it seem to mess with sexual organs/cause cancer.
 * Too much of Vitamins (A & D) have caused trouble to the CNS.
 * Heroin, cocaine and methadone are no-brainers. Mixed studies for marijuana - but can cause startling/tremors.
 * Alcohol can penetrate the placenta, potentially causing fetal alcohol spectrum disorder. Symptoms of FASD include smaller bodies/brain, underdeveloped jaws, flattened noses, and numerous cognitive impairments. Facial deformities usually go away by teenagehood, but the intellectual impairments persist.
 * Caffeine increases chances of miscarriage/low-birth weight. Cigarettes are bad too, since it deprives the baby from oxygen.Photo of baby with FAS.jpg exposure to heavy metals (lead, mercury, zinc), paint fumes, and even X-rays can cause intellectual disfunction and deformation of the organs, though ultrasound is safe.