Ch. 6 Key Terms

Allantonis

Sac-like vascular structure that lies below the chorion and develops from the hindgut

Atretic

Blockage or absence of a structure

Broad ligament

Fold of peritoneum that connects the uterus to the pelvic

Carnegie staging

A method used to classify the embryo and places the embryo into categories depending on age, size, and morphological characteristics

Cloaca

Cavity that is part of the development of the digestive and reproductive organs

Coelomic epithelium

An outer layer of fetal tissue

Diploid

Normal number of paired chromosomes

Embryogenesis

Formation of an embryo

External genitalia

The visible reproductive and urinary structures located outside the body, collectively known as the vulva in females (including the mons pubis, labia, clitoris, and openings for the urethra and vagina) and the penis and scrotum in males, serving roles in reproduction, urination, and sexual sensation

Gonadal ridges

Structure that appears at approximately 5 weeks gestation and becomes either ovaries or testes

Hydrometrocolpos

Accumulation of secreted fluid resulting in distention of the uterus and vagina because of obstruction

Hydronephrosis

Urine collection in the kidneys because of distal obstruction

Hydroureter

Large, sometimes, tortuous, ureter because of distal blockage

Hymen

After normal development, the center core of cells hollows out to form a lumen in the vagina. The vagina is now separated from the urogenital sinus only by a thin tissue plate, the hymen

Indifferent gonad stage

Primitive sex cords form anastomoses with a portion of the mesonephric duct, thus establishing the first urogenital connections in the embryo. After the degeneration of the second stage kidney, the mesonephros - the male embryo - appropriates its mesonephric duct and converts it into genital canals. These stages are similar between the two sexes, and it is impossible to determine gender through morphology 

Inducer germ cells

Primordial germ cells (PGCs)—the precursors to sperm and eggs—that are not inherited maternally, but rather induced by signaling factors within the embryo or in a lab setting

Mesonephric ducts (Wolffian ducts)

Connection between the mesonephros and cloaca

Mesonephros

Second stage of kidney development (also termed wolffian body)

Mesovarium

Section of the uterine broad ligament that covers the ovary

Müllerian ducts (paramesonephric ducts)

Paired ducts that becomes the oviducts, uterus, cervix, and upper vagina

Oocytes

Female germ cells

Pre-embryonic phase

The chromosomal gender or sex is determined in the first Carnegie stage at fertilization with the fusion of the sperm and egg; lasts into the third week

Primitive sex cords

As the primordial cells are invading the ridges, coelomic epithelium grows into the underlying mesenchymal tissue. Active tissue growth here forms the primitive sex cords

Primordial follicle

The primary locate with its surrounding granulosa cells

Primordial germ cells

Precursors of germ cells, become oocytes or spermatozoa in the adult

Pronephros

Primary or first kidney, which develops in the embryo

Proper ligament

A band of connective tissue that lies between the two layers of the broad ligament and connects the lower pole of the ovary within the lateral uterine wall

Suspensory ligament

A triangular fold of peritoneum that actually forms the upper lateral corner of the broad ligament. This ligament suspends both the ovary and the fallopian tube by its confluence with the parietal peritoneum at the pelvic brim

Urogenital

Pertaining to the urinary and genital system

Vaginal plate

The distal end of the uterovaginal canal makes contact with the posterior wall of the urogenital sinus. These structures fuse and form the vaginal plate (a solid group of cells)

Vascular stroma

A supporting tissue