Gonadal Function Review Flashcards

These vocabulary flashcards cover the key terms, hormones, anatomical structures, and clinical disorders related to the male and female gonadal systems as presented in the lecture notes.

Gonads

The male and female reproductive organs, specifically the testes in males and the ovaries in females.

Testes

The male gonads responsible for producing sperm cells and sex hormones.

Ovaries

The female gonads responsible for producing eggs and sex hormones like Progesterone and Estrogen.

Primary Sexual Characteristics

The internal and external genitals present at birth.

Secondary Sexual Characteristics

Observable traits that develop during puberty, such as hair distribution, breast growth, and changes in body shape.

Gonadotropins

Hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH) that act on the gonads.

Primordial Germ Cells

The beginning sex cells that migrate to the gonadal ridges by the sixth week of development.

Bipotential

The stage during embryonic development where the gonad can follow either the male or female pathway.

Testis-Determined Factor (TDF)

A gene on the short arm of the Y chromosome that acts as a switch to divert development into the male pathway.

Leydig Cells

The primary source of testosterone or androgens in males, located between the seminiferous tubules.

Seminiferous Tubules

Highly coiled structures within the lobules of the testes where sperm production occurs.

Inguinal Canal

The passage through which the testes descend from the abdominal cavity into the scrotum during the last two months before birth.

Scrotum

An external pouch containing the testes that maintains a temperature about $2^{\circ}\text{C}$ below normal body temperature to ensure viable sperm production.

Tunica Albuginea

A tough, white fibrous connective tissue capsule that surrounds each testis and forms septa partitioning the organ into lobules.

Rete Testis

A network of tubules where seminiferous tubules converge before leading into efferent ducts.

Sertoli Cells

The cells within seminiferous tubules that produce sperm cells, primarily influenced by FSH.

Follicle-Stimulating Hormone (FSH)

A gonadotropin that acts primarily on Sertoli cells to induce spermatogenesis in males and stimulates estrogen production in females.

Luteinizing Hormone (LH)

A gonadotropin that acts primarily on Leydig cells to induce testosterone synthesis in males and triggers ovulation in females.

GnRH (Gonadotropin-Releasing Hormone)

A hormone generated by the hypothalamus in a pulsatile fashion that determines the production of FSH and LH.

HPG Axis

The Hypothalamic-Pituitary-Gonadal axis, the hormonal signaling system regulating reproductive function.

CYP11A1 (P450scc)

The enzyme responsible for the first step in testicular steroidogenesis, converting cholesterol to pregnenolone.

SHBG (Sex-Hormone Binding Globulin)

A circulating protein to which approximately 45% of testosterone is bound.

Inhibin

A hormone produced by Sertoli cells in males and ovaries in females that provides negative feedback to inhibit FSH production.

$$5\alpha\text{-reductase}$$

The enzyme that converts testosterone into the more potent dihydrotestosterone (DHT) in target tissues like the prostate.

Dihydrotestosterone (DHT)

The active form of testosterone essential for the development of the prostate and male external genitalia.

Wolffian Duct

The embryonic structure that differentiates into the male genital tract when exposed to testosterone.

Anti-Mullerian Hormone (AMH)

Also known as Müllerian Inhibiting Substance (MIS), it is produced by Sertoli cells to aid in the regression of the female primordial genital tract in males.

Tanner Staging

A system devised by Marshall and Tanner used to categorize the stages of genital, pubic hair, and breast development.

Hypergonadotropic Hypogonadism

A group of disorders characterized by low sex hormone levels (testosterone or estrogen) and elevated FSH or LH levels.

Klinefelter's Syndrome

A genetic disorder, most commonly with a karyotype of $47,XXY$, resulting in small testicles, gynecomastia, and azoospermia.

Azoospermia

The medical term for the absence of sperm in the semen.

Gynecomastia

The enlargement of breast tissue in males, often seen in conditions like Klinefelter's Syndrome.

Testicular Feminization

Also known as Androgen Insensitivity Syndrome, it is a condition where a mutation in the androgen receptor results in a female phenotype in a chromosomal male.

Myotonic Dystrophy

An autosomal dominant condition characterized by primary hypogonadism, muscle weakness, and a distinct "Hatchet Face" appearance.

Sertoli Cell-Only Syndrome (SCOS)

Also known as Del Castillo Syndrome, it is characterized by a lack of germ cells resulting in azoospermia while maintaining normal testosterone levels.

Hypogonadotropic Hypogonadism

A condition defined by low testosterone levels together with low or inappropriately normal FSH or LH levels.

Kallmann’s Syndrome

A form of hypogonadotropic hypogonadism characterized by delayed puberty and the absence of olfactory function.

Anosmia

The complete lack or loss of the sense of smell, a distinguishing feature of Kallmann's Syndrome.

Thelarche

The development of breast tissue, typically the earliest sign of sexual development in females.

Menarche

The initiation of menses (the first menstrual cycle).

Precocious Sexual Development

The exceptionally early occurrence of secondary sexual characteristics in young children due to premature sex steroid exposure.

Amenorrhea

The absence of menstruation during the reproductive years; classified as Primary (never started) or Secondary (ceased after starting).

Oligomenorrhea

Irregular and inconsistent menstrual bleeding with cycle lengths exceeding 35 to 40 days.

Menorrhagia

Dysfunctional uterine bleeding that lasts in excess of 7 days.

Follicular Phase

The phase of the menstrual cycle that begins with menses and ends with the LH surge.

Luteal Phase

The phase of the menstrual cycle following ovulation, characterized by progesterone production from the corpus luteum.

Turner’s Syndrome

A congenital chromosomal abnormality resulting in premature ovarian failure, often presenting with physical traits like a webbed neck.

Polycystic Ovary Syndrome (PCOS)

A disorder presenting with chronic anovulation, hirsutism, infertility, and multiple ovarian cysts visible via ultrasound.

Hirsutism

Abnormal, abundant terminal hair growth in women in areas where it is not normally found.

Ferriman-Gallwey Scale

A measurement technique used to quantify hirsutism by assessing hair thickness in nine specific body areas.