03 Biological Beginnings, Prenatal Development, and Childbirth

Practice flashcards covering biological beginnings, mechanisms of heredity, prenatal development, and the childbirth process based on lecture notes.

Fertilization

The beginning of development where the sperm and ovum combine to create a zygote in the fallopian tube.

Ovulation

The rupture of a mature follicle which occurs every $28$ days until menopause.

Dizygotic Twins

Fraternal twins that result from the fertilization of $2$ separate eggs by $2$ sperms; they tend to run in families.

Monozygotic Twins

Identical twins that result from the cleaving of $1$ fertilized egg.

Mitosis

The process by which a somatic cell’s nucleus duplicates itself to form two new cells, preserving the genetic identity of the parent cell.

Meiosis

A specialized form of cell division involved in the production of gametes for sexual reproduction, resulting in four non-identical haploid daughter cells.

Methylation

Process where tiny atoms attach themselves to the outside of a gene, resulting in certain genes becoming turned on or off.

Susceptibility Genes

Genes that make an individual more vulnerable to specific diseases or accelerated aging.

Autosomes

Chromosomes that are not related to sexual expression.

X-linked Inheritance

A pattern occurring when a mutated gene is carried on the X chromosome; it is more commonly expressed in males due to the lack of a second X chromosome.

Allele

Two or more alternative forms of a gene that occupy the same position on paired chromosomes and affect the same trait.

Homozygous

Possessing two identical alleles for a specific trait.

Polygenic Inheritance

Inheritance of traits that are controlled by multiple genes, each with a small additive effect.

Multifactorial Transmission

A phenomenon by which environmental experience modifies the expression of the genotype for most traits.

Epigenesis

Mechanism that turns genes on or off and determines the functions of body cells; cells are particularly susceptible during puberty and pregnancy.

Genetic Imprinting

Occurs when the expression of a gene has different effects depending on whether the mother or the father passed on the gene.

Down Syndrome (Trisomy 21)

Abnormality involving an extra copy of chromosome $21$, associated with intellectual disabilities and distinctive facial features.

Cri-du-chat Syndrome

Abnormality involving a deletion on the short arm of chromosome $5$, where the infant may have a cry resembling a cat.

Phenylketonuria (PKU)

Caused by the inability to metabolize the amino acid phenylalanine, leading to intellectual disability if untreated.

Sickle-cell Anemia

Condition where a recessive gene causes red blood cells to become hook-shaped, limiting the body's oxygen supply.

Turner Syndrome (XO)

Condition in females with a single X chromosome ($45$, X), characterized by short stature, webbed neck, and infertility.

Klinefelter Syndrome (XXY)

Condition in males with an extra X chromosome ($XXY$), resulting in reduced fertility and gynecomastia.

Heritability

A statistical estimate of the contribution of heredity to individual differences in a specific trait within a given population.

Canalization

Process where heredity restricts the range of development for some traits, meaning it would take an extreme change in environment to alter their course.

Niche-picking

Also known as active genotype-environment correlation, it occurs when individuals seek out environments compatible with their interests.

Cephalocaudal Principle

Dictates that development proceeds from the head to the lower part of the trunk.

Proximodistal Principle

Dictates that parts of the body near the center develop before the extremities.

Gestational Age

The age of an unborn baby dated from the first day of an expectant mother’s last menstrual cycle.

Blastocyst

A fluid-filled sphere of cells ($64$ to $128$ cells) that floats freely in the uterus before implantation.

Organogenesis

The stage where organs and major body systems like the respiratory, digestive, and nervous systems develop rapidly.

Amniocentesis

A procedure between the $15^{th}$ and $18^{th}$ weeks of pregnancy where amniotic fluid is withdrawn to detect chromosomal or metabolic disorders.

Teratogen

An environmental agent, such as alcohol or radiation, that can interfere with normal prenatal development.

Parturition

The act or process of giving birth, typically beginning about $2$ weeks before delivery.

Apgar Scale

A system that evaluates an infant’s heart rate, respiratory effort, muscle tone, body color, and reflex irritability.

Postpartum Depression

A major depressive episode occurring about four weeks after delivery involving strong feelings of sadness, anxiety, or despair.

Kangaroo Care

Skin-to-skin contact where the infant is carried by the parent, intended for low-birth-weight and preterm infants.