Embryogenesis and Development of the Reproductive System

Mammalian Fertilization

Combines egg and sperm chromosomes for sex determination.

Sex Chromosomes

Inherited chromosomes determining biological sex (XX or XY).

Female Chromosomes

Two X chromosomes (XX) define female sex.

Male Chromosomes

One X and one Y chromosome (XY) define male sex.

Diploid

Cell with two sets of chromosomes (XX or XY).

Haploid

Cell with one set of chromosomes (X or Y).

X Chromosome

Larger chromosome, carries many genes, always inherited from mother.

Y Chromosome

Smaller chromosome, contains SRY gene for male development.

SRY Gene

Sex-determining region of Y chromosome, directs male phenotype.

Genotypic Sex Determination

Sex determined by genetic makeup, common in many species.

Temperature-Dependent Sex Determination

Sex determined by environmental temperature, seen in some reptiles.

Behavioral Sex Determination

Sex changes driven by visual cues in certain fish species.

Embryogenesis

Process of development from fertilized egg to embryo.

Blastocyst

Stage following fertilization, consists of inner cell mass and trophoblast.

Inner Cell Mass (ICM)

Forms the embryo during early embryogenesis.

Trophoblast

Outer layer of blastocyst, develops into placenta.

Germ Layers

Three layers formed during differentiation: ectoderm, mesoderm, endoderm.

Ectoderm

Outer germ layer, forms skin and nervous system.

Mesoderm

Middle germ layer, develops into muscles and reproductive system.

Endoderm

Inner germ layer, forms internal organs and lining.

Pituitary Gland

Hormone center controlling reproductive functions.

Hypophysis

Greek term for pituitary, means 'lying underneath.'

Posterior Pituitary

Derived from neural tissue, stores hormones like oxytocin.

Anterior Pituitary

Synthesizes hormones like LH and FSH, derived from ectoderm.

Rathke's Pouch

Diverticulum forming anterior pituitary from oral cavity.

Infundibulum

Diverticulum forming posterior pituitary from brain tissue.

Sella Turcica

Saddle-shaped depression in sphenoid bone protecting pituitary.

Primordial Germ Cells (PGC)

Cells initiating formation of gonads in embryos.

Gonadal Ridge

Area where PGC migrate to form gonads.

PGC

Primordial germ cells that migrate during development.

Bipotential Gonads

Indeterminate gonads that can develop into ovaries or testes.

Chemoattraction

Chemical signals guiding PGC migration in embryos.

Primitive Sex Cords

Structures formed from genital ridge growth by PGC.

Mesonephros

Primitive kidney involved in reproductive duct development.

Wolffian Ducts

Mesonephric ducts forming the male reproductive tract.

Mullerian Duct

Paramesonephric duct forming the female reproductive tract.

AMH

Anti-Mullerian Hormone produced by Sertoli cells.

Leydig Cells

Cells that produce testosterone in males.

Testicular Descent

Process of testes moving into the scrotum.

Gubernaculum

Ligamentous cord aiding testicular descent.

INSL-3

Hormone promoting gubernacular growth and testicular descent.

Cryptorchidism

Condition of undescended testes in males.

Inguinal Hernia

Condition where intestine slips through inguinal canal.

Mullerian Duct Regression

Process that occurs in the absence of SRY.

Primordial Follicles

Ovarian structures developing throughout female life.

Freemartin

Intersex condition in cattle due to shared blood flow.

Urogenital Sinus

Structure contributing to female reproductive tract formation.

Cervix Formation

Result of fusion of Mullerian ducts in females.

Vaginal Canal

Developed from fused Mullerian ducts in females.

Testes Location

Develop near kidneys before descending into scrotum.

Sertoli Cells

Support cells in testes producing AMH.

Androgen Insensitivity

Condition where XY individuals do not respond to testosterone.

XX Development

Ovaries develop in the absence of SRY.

XY Development

Testes develop in the presence of SRY.

Gubernacular Regression

Process completing testicular descent into the scrotum.

Hormonal Signaling

Essential for proper reproductive system development.

Pituitary Role

Central in regulating reproductive development.