PRENATAL (conception to birth)

Fertilization

The process where sperm and ovum (sex cells) combine to form a single zygote, which duplicates via cell division.

Example: A single sperm fertilizes an egg in the fallopian tube to create a zygote.

Ovulation

The monthly rupture of a mature follicle in an ovary, releasing an ovum, continuing until menopause.

Example: An egg released mid-cycle into the fallopian tube ready for conception.

Dizygotic Twins (Fraternal Twins)

Twins resulting from two separate eggs fertilized by two different sperm; can be the same or different sex.

Example: A brother and sister born at the same time who share typical sibling levels of genetic material.

Monozygotic Twins (Identical Twins)

Twins resulting from the cleaving of a single fertilized egg; generally genetically identical. Example: Two identical brothers formed when one embryo splits into two.

Heredity

The genetic transmission of heritable characteristics from parents to offspring.

Example: Passing down eye color or height traits from parents to children.

Deoxyribonucleic Acid (DNA)

A long, spiraling ladder-like molecule with steps made of chemical base pairs (Adenine, Thymine, Cytosine, Guanine).

Chromosomes

Coils of DNA made of smaller segments called genes.

Mitosis

The process of cell division in non-sex cells.

Example: Skin cells dividing to heal a surface scratch.

Meiosis

The process of cell division in sex cells (sperm and egg).

Mutation

A mistake during the copying of genetic code, creating a permanent alteration in genetic material.

Autosomes

Chromosomes that are not affiliated with sexual expression.

Sex Chromosomes

The 23rd pair of chromosomes that indicates biological sex (XX for female, XY for male).

Alleles

Alternative forms of a gene that produce different expressions of a characteristic.

Example: Having an allele for blue eyes from one parent and brown eyes from another.

Homozygous

Possessing two identical alleles for a specific trait.

Example: Inheriting two identical blue-eye alleles.

Heterozygous

Possessing two different alleles for a specific trait.

Example: Inheriting one brown-eye allele and one blue-eye allele.

Dominant

An allele that is always expressed as a trait when present.

Recessive

An allele whose trait usually does not show unless paired with another recessive allele.

Polygenic Inheritance

The interaction of several genes to influence a single characteristic. Example: Complex traits like height or skin tone controlled by multiple genes acting together.

Phenotype

The observable physical or behavioral characteristics of an individual.

Example: Actual hair color, height, or eye color seen on a person.

Genotype

The underlying genetic composition or code of an individual.

Epigenesis

The process where environmental influences alter chemical molecules on genes to turn gene expression on or off without altering the DNA sequence.

Example: Susceptibility to epigenetic changes during critical periods like puberty or pregnancy.

Carriers

Individuals who carry one bad copy of a recessive gene and one good copy, not expressing the condition themselves.

Genotype-Environment Interaction

The differing effects of similar environmental conditions on genetically distinct individuals.

Genotype-Environment Correlation

The tendency of the environment to reinforce genetic differences

Passive Correlations

Parents provide an environment that naturally encourages inherited traits (e.g., musical parents filling a home with instruments)

Reactive (Evocative) Correlations

Children evoke different responses from others based on their genetic makeup (e.g., a naturally smiley baby receiving extra attention).

Active Correlations (Niche-Picking)

Individuals actively seek out or create environments compatible with their genotype (e.g., an athletic child signing up for sports teams)

Down Syndrome

Caused by an extra copy of chromosome 21.

Treatment: Surgery, special education (SPED).

Klinefelter Syndrome

Klinefelter syndrome occurs in males who have an extra X chromosome, resulting in XXY. (e.g men with high pitched voice)

Treatment: Hormone therapy.

Fragile X Syndrome

Abnormality in the X chromosome, that can cause intellectual and developmental difficulties.

Turner Syndrome

Turner syndrome occurs in females who are missing all or part of one X chromosome.

Treatment: Hormone therapy.

Cystic Fibrosis

Overproduction of mucus in lungs and digestive tract. Severe respiratory infection.

Treatment: Physical therapy.

Diabetes

Body does not produce enough insulin.

Treatment: Insulin

Hemophilia

Delayed blood clotting. (e.g scrap on knee and it bled too much)

Treatment: Blood transfusions.

Huntington's Disease

Central nervous system deteriorates, causing muscle problems and mental decline. (e.g. involuntary muscle movements)

Phenylketonuria

Build-up of phenylalanine in the body. Inability to breakdown protein.

Treatment: Special diet.

Sickle-Cell Anemia

Red blood cells deform, limiting body oxygen supply. Painful joint episodes.

Treatment: Penicillin, antibiotics, pain relievers.

Spina Bifida

Incompletely closed spinal canal. Too much spinal fluid.

Treatment: Surgery.

Tay-Sachs Disease

Accumulation of lipids in the nervous system. Severe neurodegeneration.

Treatment: Medication, special diet.

Anencephaly

Absence of brain and skull tissue.

Polycystic Kidney Disease

Enlarged with cluster fluid-filled kidneys.

Treatment: Kidney transplant

Alpha Antitrypsin Deficiency

Enzyme deficiency causing cirrhosis of the liver in early infancy. Damage with long tissue and abnormal build up of protein.

Alpha Thalassemia

Severe anemia through lack of carrying oxygen; nearly all affected die soon after birth.

Treatment: Frequent blood transfusions.

Beta Thalassemia

Lower level of blood. Severe anemia; often fatal in adolescence or young adulthood.

Treatment: Blood transfusions.

Duchenne Muscular Dystrophy

Muscle weakness in males, minor intellectual impairment.

In Vitro Fertilization (IVF)

Assisted reproduction where eggs and sperm are combined outside the body in a laboratory dish.

Ultrasound Sonography

Non-invasive technique using high-frequency sound waves aimed at the abdomen to detect abnormalities, fetal count, and biological sex with no risk.

Fetal MRI

Diagnostic imaging using powerful magnetic fields and radio waves for detailed views of organs and structures.

Chorionic Villus Sampling (CVS)

Removal of a small placenta sample for genetic testing (carries a small risk of limb deformity).

Amniocentesis

Withdrawal and testing of amniotic fluid to screen for chromosomal and metabolic disorders.

Maternal Blood Screening

Blood test to identify elevated risk factors for specific birth defects.

Prenatal Cell-Free DNA Scans

Extraction and analysis of fetal DNA from maternal blood for early genetic evaluation.

Gestation

The duration between conception and birth (typically 37 to 41 weeks).

Gestational Age

The age of the fetus measured starting from the first day of the mother's last menstrual period.

Cephalocaudal Principle

Developmental sequence proceeding from head to lower extremities (e.g., the head develops earlier than the legs).

Proximodistal Principle

Developmental sequence proceeding from the body's center outward

Example: an infant who can move their shoulders and swipe at a toy with their whole arm before they can pick up a small object with their fingers.

Germinal Stage (Fertilization to 2 weeks)

Implantation & beginning of development.

Blastocyst

fluid-filled ball of cells that travels to the uterus and implants around day 6.

Trophoblast

outer layer of cells that provides nutrition and support to the developing embryo.

Differentiation

cells become specialized for specific functions.

Three germ layers

Ectoderm = OUTSIDE → skin, hair, nails, teeth, sensory organs, nervous system

Mesoderm = MIDDLE → muscles, bones/skeleton, circulatory and excretory systems

Endoderm = INSIDE → digestive system and other internal organs

Amniotic sac

protects and cushions the embryo/fetus.

Placenta

exchanges oxygen and nutrients from the mother and removes wastes.

Umbilical cord

connects the developing baby to the placenta

Embryonic Stage (2 to 8 weeks)

Organs are forming. MOST VULNERABLE STAGE!

Organogenesis

rapid formation of the major body organs and systems.

Stillbirth

fetal death/loss occurring after 20 weeks of gestation.

Fetal Stage (8 weeks to birth)

Growth, maturation, and functioning (reflexes). Hearing develops, allowing the fetus to respond to sounds, including the mother’s voice.

Functions of each stage

The germinal stage is mainly implantation and early cell development.

the embryonic stage is when the major organs and body structures form.

the fetal stage is characterized mainly by growth, refinement, and functional maturation.

Teratogen

An external environmental agent that can interfere with prenatal development and cause birth defects or developmental problems.

Nutrition

Folic acid → important for proper neural tube development

DHA & Omega-3 → support brain and nervous system development

Thalidomide

A drug historically associated with severe birth defects (esp limbs).

Neonatal Abstinence Syndrome (NAS)

Withdrawal symptoms experienced by a newborn after birth following prenatal exposure to certain substances.

Fetal Alcohol Syndrome (FAS)

Results from prenatal alcohol exposure. Affect physical growth, facial development, and the central nervous system.

Nicotine & Tobacco

Can interfere with oxygen and normal fetal growth.

Toxoplasmosis (brain and eyes)

A parasitic infection that can be acquired through contaminated food, particularly undercooked/raw meat, and exposure to contaminated cat feces/litter.

Rubella (hearing and heart)

A viral infection during pregnancy that can cause congenital abnormalities, including hearing and heart defects)

Parturition

biological preparation and process leading to childbirth.

It involves changes in the:

• Uterus

• Cervix

• Other reproductive tissues

Labor

the physical process of giving birth, involving regular uterine contractions and cervical dilation.

Braxton-Hicks Contractions

Irregular “practice” contractions that can occur before true labor.

First stage of delivery

Longest stage. Regular contractions become stronger and more frequent. The cervix dilates to about 10 cm. Ends when the cervix is fully dilated.

Second stage of delivery

Begins when the cervix is fully dilated. Baby descends through the birth canal. Ends with the birth of the baby.

Third stage of delivery

After the baby is born, the placenta separates from the uterine wall. Placenta and fetal membranes are expelled.

Electronic Fetal Monitoring

Continuous tracking of fetal heart rate to evaluate stress during contractions.

Pharmacological Support

Analgesics (pain relief)

Epidural Block (for regional lower-body nerve block)

Pudendal Block (for vaginal area)

Oxytocin/Pitocin (synthetic hormone to stimulate contractions)

Childbirth

Methods like Lamaze (patterned breathing) or Bradley Method (partner-coached relaxation) aimed at minimizing fear and pain.

Cesarean Delivery

Surgical removal of the baby via abdominal/uterine incisions, utilized during complications, maternal bleeding, or Breech Position (buttocks or feet emerging first).

APGAR Scale

Immediate evaluation (at 1 and 5 minutes post-birth) covering Appearance, Pulse, Grimace, Activity, and Respiration.

Scores below 3 indicate a medical emergency.

Brazelton Neonatal Behavioral Assessment Scale (NBAS)

Neurological and reflex test given 24–36 hours after birth.

Neonatal Intensive Care Unit Network Neurobehavioral Scale

Assessment measuring stress responses, self-regulation, and newborn behavior.

Fontanels

Soft spots on the skull where cranial bones have not fused.

Lanugo

Fine, downy prenatal hair.

Vernix Caseosa

Protective, waxy skin coating that guards against infection.

Meconium

Greenish-black waste material excreted by the newborn's digestive tract.

Postpartum Blues vs. Postpartum Depression

Postpartum Blues: Mild, temporary sadness, anxiety, or emotional instability lasting a few days post-delivery.

Postpartum Depression: Major depressive episode occurring weeks after delivery that interferes with daily functioning and infant care.