PSY 215 - Exam 2

Measures of Pregnancy

Trimesters & Weeks

Conceptual age

Gestational age

Conceptual age

actual time since fertilization

Gestational age

first day of last menstrual period

Fertilization and Germinal period

10-14 days

Traveling through Fallopian tube 

• Ovulation 

• Fertilization (fusion of egg & sperm = zygote)

• Cell Division begins (cleavage every 12hrs = blastocyst)

• Implantation 

Blastocyst 

a fertilized egg that has 2 different layers:

• inner cell mass that become embryo is embedded into uterus lining

• Trophoblast which is a thin layer of cells that helps a developing embryo attach to the wall of the uterus, protects the embryo, and forms a part of the placenta 

Human chorionic gonadotropin hormone (hCG)

Fertilization & Germinal Stage (Hormones)

• produced by blastocytes 

• raises progesterone and estrogen 

• thickens uterine lining, suppresses mother’s immune system to prevent rejection of zygote

Embryonic period 

2-8 weeks

major organs and systems of the body develop (Endoderm, Mesoderm, Ectoderm) 

start of primitive heart beat

Endoderm

Lines the digestive and respiratory systems (stomach, intestines, lungs), as well as the liver, pancreas, and thyroid gland. 

Mesoderm

Forms the muscles, bones, cartilage, blood vessels, kidneys, heart, and reproductive organs.

Ectoderm

Develops into the skin, nervous system (brain, spinal cord, nerves), and sensory organs (eyes, ears, nose).

Organogenesis

formation of germ layer

Neural Tube

cylindrical structure that forms during early embryonic development and forms CNS

Anencephaly

failure of neural tube complete closure (front)

A baby born with an underdeveloped brain and an incomplete skull

prevented by folic acid

Spina Bifida

failure of neural tube complete closure (back)

A birth defect where the spinal cord does not close completely during pregnancy

prevented by folic acid 

Fetal Period (First trimester)

8-12 weeks

• Bone tissue formation (now called fetus)

• Genitalia formation

• Some sensory system formation

Fetal Period (Second trimester)

13-25 weeks

• Body growth

• Quickening starts 

• Senses develop 

• Viability determined (if born now, major medial intervention is needed) 

Fetal Period (Third trimester)

26-38 weeks

• Brain growth

• Fat deposits 

• Viability determined (if born now, more likely to survive) 

Quickening 

first time mother feels baby moving (second trimester) 

Proliferation

Phase 1 of brain development

• brain cells don’t change (long longevity) 

• cerebral cortex get build like a tree (oldest = inner, youngest = outer)

• central core/old brain gets built (oldest = outer, youngest = inner)

Migration

Phase 2 of brain development

• glial cells and chemical gradients move neurons to where they need to be 

Differentiation

Phase 3 of brain development

• Myelination

• Synaptogenesis

• Pruning

Myelination

glial cells produce myelin cells

Synaptogenesis

process of new synapse being formed

Pruning

process of deleting & weakening synapse

Development of Myelination

Frontal cortex is the last part to get this 

Synapse Density 

peak at 1yo 

early years = higher synapse connections bc not specialized yet 

later years = less synapse connections bc faster info processing time

Brain plasticity

brain can still change in connections among neurons

Experience expectant connections

process where brain forms fundamental neural pathways in response to universal environmental experiences that occur during critical periods of development EX: exposure to light OR language acquisition

Critical period

period of time we MUST experience certain experiences else we loose important developmental capabilities 

Experience dependent connections

brain’s neural structure is formed, strengthened/weakened depending on unique, individual experiences (ex: learning instrument) 

Prenatal environment

• Placenta 

• Umbilical cord 

• Amniotic fluid 

Placenta

provide nutrient and oxygen to fetus and remove waste

Umbilical cord

connects fetus to placenta providing oxygen (has 2 arteries and 1 vein)

Amniotic fluid

cushioning for fetus

Teratogens

substances and agents that causes structural/functional abnormalities in a developing fetus/embryo 

Principles of Teratology

Susceptibility: how the research applies to teratogenic in regards to the types of species and individuals involved

Questions of Teratology

• When? (impact on critical period)

• How? (regarding access to teratogen) 

• How much? (regarding dose-response relationship) 

• Which one? (teratogenic response: does it interfere w certain mechanisms/function of cells?) 

Categories of teratogens

• Diet 

• Drugs

• Disease 

• Environmental toxins 

• Maternal (and Paternal) health

Diet teratogens

• increase diet by healthy 300 calories 

• increase folic acid, iron, and calcium intake 

• limit caffeine (220mg) to avoid withdraws 

Drugs teratogens

• opioids: nows/nas

• avoid marijuana/CBD/vaping/Herbal supplements 

Diseases teratogens

• pregnancy induced HTN

• Pre-eclampsia

• Toxemia

• RH incompatibility

• Gestational diabetes

RH incompatibility

diff Rh proteins between baby and mother = mother’s WBC destroy baby’s RBC —> anemia

Gestational diabetes 

uncontrolled levels of high blood sugar = baby store sugar as fat

Environmental toxin

lead exposure

toxoplasmosis

Tonic Reflex

disappears at 7 months 

Rooting reflex

turn their head and open their mouth when the side of their cheek or mouth is touched (disappears at 4 months)

Sucking reflex

automatically sucks when something touches the roof of its mouth (disappears at 2 months) 

Moro/Startle reflex

reflex for an infant when he or she is startled or feels like they are falling (disappears at 3 months)

Babinski reflex

stroking the sole of the foot, causing the big toe to move upward and the other toes to fan out (disappears at 4 months)

Crawling reflex

perform crawling-like movements when placed on their stomach and pressure is applied to their feet (disappears at 2 months) 

Stepping reflex

feet make stepping motions like walking when held upright with their soles touching a flat surface (disappears at 3 months)

Placing reflex

the ability to place a limb (usually a hand or foot) onto a surface when its upper side is brought into contact with that surface (disappears at 3 months) 

Palmer/Grasping reflex

grasp objects or fingers placed in their palms (disappears at 6 months)

Prematurity

• Pre-term: 35/37 weeks

• Very pre-term: 30/32 weeks

• Extremely pre-term: 26/28 weeks

Results of prematurity

• Respiratory Distress Syndrome (caused by lack of surfactant) 

• Bronchopulmonary dysplasia 

• Retinopathy

• Trouble with temperature regulation, physiological regulation, and feeding

Preventing Sudden Infant Death Syndrome

• Place baby on their back to sleep

• Use a firm, flat sleep surface

• Avoid bed sharing

• Keep the room temperature cool

• Avoid blankets in crib

• No smoking around baby