The paired gubernacula (from Ancient Greek κυβερνάω = pilot, steer), also called the caudal genital ligament, are embryonic structures which begin as undifferentiated

mesenchyme Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood, or bone. The interactions between mesenchyme and epithelium help to form nearly ever ...

attaching to the caudal end of the

gonad A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gon ...

s (

testicle A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is Homology (biology), homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of Androgen, androgens, p ...

s in males and

ovaries The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...

in females).

Structure

The gubernaculum is present only during the

development of the reproductive system The development of the reproductive system is the part of embryonic growth that results in the sex organs and contributes to sexual differentiation. Due to its large overlap with development of the urinary system, the two systems are typicall ...

. It is later replaced by distinct vestiges in males and females. The gubernaculum arises in the upper abdomen from the lower end of the gonadal ridge and helps guide the testis in its descent to the inguinal region.

Males

* The upper part of the gubernaculum degenerates. * The lower part persists as the gubernaculum testis (" scrotal ligament"). This ligament secures the testis to the most inferior portion of the scrotum, tethering it in place and limiting the degree to which the testis can move within the scrotum. * Cryptorchidism (undescended testes) are observed in ''INSL3''-null male mice. This implicates INSL3 as a key hormone in the growth and differentiation of the gubernaculum to allow transabdominal migration. Higher testicular temperatures associated with cryptorchidism is associated with reduced fertility.

Females

* The gubernaculum has two vestigial remnants in females, the

ovarian ligament The ovarian ligament (also called the utero-ovarian ligament or proper ovarian ligament) is a fibrous ligament that connects the ovary to the lateral surface of the uterus. Structure The ovarian ligament is composed of muscular and fibrous tissue ...

and the round ligament of the uterus (''ligamentum teres uteri'') which respectively serve to support the ovaries and uterus in the pelvis. * Development of the gubernaculum in female mice overexpressing ''INSL3'' causes descended ovaries and reduced fertility. This ovarian descent is more pronounced by the additional administration of dihydrotestosterone, which suppresses development of the cranial suspensory ligament. Therefore, maintenance of the cranial suspensory ligament prevents abdominal translocation of the ovaries.Adham et al., Mol Endocrinol 2002, 16, 244-252

Development

As the

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

and

labia majora In primates, and specifically in humans, the labia majora (: labium majus), also known as the outer lips or outer labia, are two prominent Anatomical terms of location, longitudinal skin folds that extend downward and backward from the mons pubis ...

form in males and females respectively, the gubernaculum aids in the descent of the gonads (both testes and ovaries). The testes descend to a greater degree than the

and ultimately pass through the

inguinal canal The inguinal canal is a passage in the anterior abdominal wall on each side of the body (one on each side of the midline), which in males, convey the spermatic cords and in females, the round ligament of the uterus. The inguinal canals are lar ...

into the

. The mechanism of this movement is still debated.

History

The gubernaculum was first described by John Hunter in 1762. The term comes from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

meaning to steer, pilot or the

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...

or helm.

References

External links

* - "Inguinal Region, Scrotum and Testes: The Scrotal Ligament" {{Development of urinary and reproductive systems Abdomen Embryology of urogenital system