The Menstrual Cycle and Fetal Development Flashcards

Vocabulary terms covering the female reproductive system, the menstrual cycle, fertilization, fetal development, and fetal circulation based on the lecture notes.

Menarche

The first menstruation.

Menstruation (menses)

Periodic uterine bleeding and vaginal discharge of bloody fluid from the nonpregnant uterus that begins 14 days following ovulation.

Puberty

The transitional stage between childhood and sexual maturity where reproductive organs mature and one becomes capable of reproduction.

GnRH (Gonadotropin-releasing hormone)

A hormone secreted by the hypothalamus that stimulates the anterior pituitary to secrete FSH.

FSH (Follicle-stimulating hormone)

Hormone that stimulates the development of ovarian graafian follicles and the production of estrogen in the ovaries.

LH (Luteinizing hormone)

A hormone whose marked surge at day 13-14 of a 28-day cycle precedes the release of the ovum from the graafian follicle.

Menstrual phase

The first phase of the endometrial cycle (days 1-5) characterized by the shedding of the endometrium.

Proliferative phase

The phase of the endometrial cycle where the endometrium is built up under the influence of estrogen, 'the builder'.

Secretory phase

The phase of the endometrial cycle characterized by marked swelling and growth due to progesterone, 'the maintainer'.

Ischemic phase

The phase of the endometrial cycle where blood supply to the endometrium is blocked and necrosis occurs.

Mittelschmerz

Midcycle or ovulation pain that occurs on day 14 of the ovarian cycle.

Luteal phase

The ovarian cycle phase spanning days 15-28 that ends with the onset of menses.

Corpus luteum

A small yellow body developed within a ruptured ovarian follicle that produces progesterone during the second half of the menstrual cycle.

Conception

The union of a single egg and single sperm, resulting in 46 chromosomes or 23 pairs.

Mitosis

The process where body cells replace and repair themselves while supporting the diploid number of 46 chromosomes.

Meiosis

The process by which germ cells divide and decrease their chromosomal number from the diploid ($46$) to the haploid ($23$) number.

Oogenesis

The process of egg or ovum formation that begins during fetal life.

Spermatogenesis

The process of maturation in males in which spermatocytes become spermatozoa.

Scrotum

A fibromuscular pouch divided by a median septum forming two compartments containing the testis, epididymis, and part of the spermatic cord.

Epididymis

A C-shaped structure lying along the posterior border of each testis responsible for transporting sperm to the vas deferens.

Morula

A 12-16 cell solid sphere formed 3 days after fertilization.

Blastocyst

A structure developed 5 days after fertilization that consists of an embryoblast and a trophoblast.

Embryoblast

The inner cell mass of a blastocyst that gives rise to the embryo.

Trophoblast

The outer layer of cells of a blastocyst that gives rise to the placenta.

Implantation (nidation)

The embedding of the fertilized ovum in the upper, posterior wall of the uterine mucosa, occurring day 6-10 post fertilization.

Ectoderm

The upper germ layer that gives rise to the epidermis, glands, nails, and hair.

Mesoderm

The middle germ layer that gives rise to bones, teeth, and muscles.

Endoderm

The lower germ layer that gives rise to the epithelium lining of the respiratory and digestive tracts.

Chorion

The outer fetal membrane derived from the trophoblast.

Amnion

The inner fetal membrane developed from the interior cells of the blastocyst.

Oligohydramnios

A condition of having less than $300\,ml$ of amniotic fluid, often associated with renal abnormalities.

Polyhydramnios

A condition of having more than $2\,L$ of amniotic fluid, associated with gastrointestinal malformations.

Yolk Sac

A cavity that transfers maternal nutrients and $O_2$ to the embryo and forms primitive RBCs during the first 6 weeks.

Wharton’s jelly

Connective tissue within the umbilical cord that prevents compression of blood vessels.

AVA

The acronym for the vessels in the umbilical cord: 2 Arteries and 1 Vein.

Viability

The capability of the fetus to survive outside the uterus; in Texas, this age is 20 weeks or a birth weight of $350\,g$.

Ductus Venosus

A fetal circulation shunt connecting the umbilical vein to the Inferior Vena Cava.

Foramen Ovale

A fetal circulation shunt between the right atrium and left atrium.

Ductus Arteriosus

A fetal circulation shunt from the pulmonary artery to the aorta.

Dizygotic twins

Fraternal twins resulting from 2 ova and 2 sperm, possessing different genotypes.

Monozygotic twins

Identical twins resulting from 1 ovum and 1 sperm, possessing the same genotype.