NCM 107: Pregnancy Diagnosis and Fertilization

Practice flashcards covering definitions, physiological changes, obstetric formulas, and diagnostic signs of pregnancy based on the lecture transcript.

Corona radiata

The outer layer of protective covering of the human ovum.

Zona pellucida

The inner layer of protective covering of the human ovum.

Insemination

The deposition of sperm cells in the female internal organs, which occurs during sexual intercourse.

Capacitation

Structural changes the sperm head undergoes when it reaches the uterus to prepare for fertilization.

Hyaluronidase

An enzyme secreted by the sperm to dissolve the corona radiata of the ovum.

Acrosin

An enzyme secreted by the sperm to dissolve a portion of the zona pellucida.

Polyspermy

The state where multiple sperm enter an ovum, which is prevented by structural changes in the plasma membrane after the first sperm enters.

Zygote

The first cell formed from the fertilization of sperm and ovum, containing $46$ chromosomes.

Morula

The stage of the zygote when it consists of $16$ or more blastomeres.

Blastocyst

A ball-like structure composed of an inner cell mass (embryonic disc or blastocoele) and an outer layer (trophoblast).

Trophoblast

The outer layer of the blastocyst that gives rise to the placenta, fetal membranes, umbilical cord, and amniotic fluid.

Ectoderm, Mesoderm, and Entoderm

The three primary germ layers that arise from the blastocoele or embryonic disc.

Implantation

The process where the blastocyst attaches to the endometrium, occurring $6-7$ days after fertilization.

Langhan's layer

Also known as the cytotrophoblast, the inner layer of trophoblasts that protects the fetus against $Treponema\text{ }pallidum$.

Syncytiotrophoblast

The outer layer of trophoblasts that produces hormones; also known as the syncytium.

Decidua

The term for the endometrium after implantation has occurred.

Decidua basalis

The layer of the decidua situated directly under the site of implantation.

Amniotic fluid

A clear, colorless to straw-colored liquid with a volume of $500$ to $1000\text{ }ml$ and a pH of $7.0$ to $7.25$.

Wharton's jelly

A gelatinous substance found inside the umbilical cord.

Duncan mechanism

The maternal side of the placenta.

Schultze mechanism

The fetal side of the placenta.

Gravidity

The total number of times a woman has been pregnant, regardless of the duration.

Parity

The total number of pregnancies reaching the age of viability ($\text{parity } \times 20$ weeks) regardless of the outcome.

Naegele rule

A formula to calculate EDD: $\text{EDD} = \text{1st day of LMP} - 3 \text{ months} + 7 \text{ days} + 1 \text{ year}$.

McDonald's Rule

An obstetric method used to estimate gestational age in weeks by measuring fundal height: $\text{GA} = \text{FH(cm)} \times \frac{8}{7}$.

Johnson's Rule

A formula used to estimate fetal weight: $\text{EFW} = (\text{SFH} - 11 \text{ or } 12) \times 155\text{ gms}$.

Haase Rule

An obstetric formula used to estimate the age of the fetus from its crown-to-heel length ($\text{length} = \text{age}^2$ for the first $5$ months).

Bartholomew's Rule

A guideline to estimate gestational age based on fundal height milestones, such as reaching the umbilicus at $20$ weeks.

Presumptive (Subjective) signs

Symptoms of pregnancy that the woman experiences and reports, like amenorrhea, nausea, and fatigue.

Probable (Objective) signs

Signs perceived by an examiner, such as Goodell's sign, Chadwick's sign, and positive pregnancy tests.

Positive (Diagnostic) signs

Signs that offer conclusive proof of pregnancy: fetal heartbeat, palpable fetal movement by an examiner, and visualization via ultrasound.

Goodell's sign

A softening of the cervix.

Chadwick's sign

A bluish or purple discoloration of the mucous membranes of the cervix, vagina, and vulva.

Hegar's sign

A softening of the isthmus of the uterus (the area between the cervix and the body of the uterus).

Quickening

The mother's perception of fetal movement, often described as a fluttering sensation.

Uterine souffle

A soft, blowing sound at the same rate as the maternal pulse caused by increased blood flow through the placenta.

Ambivalence

The common reaction in the 1st trimester of feeling both pleased and not pleased about the pregnancy.

$$\beta \text{-hCG}$$

The major analyte produced by the developing embryo used to establish pregnancy in laboratory tests.