Gonadal Function Flashcards by Iseoluwa Ojo

Reproductive endocrinology is made up of the hormones of the ______________ axis and the _________

These hormones are crucial for proper reproductive function.

hypothalamo-pituitary –gonadal

adrenal glands.

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Hormones

_________________
——————-
____________
___________________

Gonadotropin-releasing hormone (GnRH)
Leutinizing hormone (LH)
Follicle stimulating hormone (FSH)
Sex steroids (oestrogens, progesterone, and androgens)

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Male Reproductive Physiology

The function of the testes is to synthesize ________________

Sertoli cells in the ________ of the ________ play a cruicial role in ________________ and secrete ________ which inhibits _________________

both spermatozoa and androgens

seminiferous tubules

testes ;sperm maturation

inhibin ; pituitary secretion of FSH.

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Male Reproductive Physiology

Surrounding the seminiferous tubules are the _______ of ________ which produce testicluar ______ and necessary for sperm maturation, and secondary sex characteristics.

interstitial cells of Leydig

androgens

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Male Reproductive Physiology

GnRH is a ____peptide synthesized in the ________ and transported to the ________ where it stimulates release of ____________

deca; hypothalamus

anterior pituitary

both FSH and LH.

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Male Reproductive Physiology

LH acts on ________ to synthesize ______.

FSH acts on ________ to stimulate _______ and the synthesis and release of ______.

Leydig cells ; testosterone.

Sertoli cells ; gametogenesis

inhibin.

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Male Reproductive Physiology

Sex steroids and inhibin provide the negative feed back control of _______________ secretion respectively.

LH and FSH

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Androgens

Androgens cause ________ of the genital tract and maintenance of the male secondary sex characteristics

Muscle bulk, deepening of voice
Bone mass
Libido and sexual performance in men

masculinization

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__________ is the main androgen secreted by the ____ cells in men

Women produce _____% as much as men

Testosterone

leydig

5-10

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Other androgens secreted by the adrenal glands

List 4

Dehydroepiandrosterone (DHEA)
Dehydroepiandrosterone sulphate (DHEA – S)
Androstenedione
Androstenediol

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Other androgens secreted by the gonads

List 2

Dehydroepiandrosterone (DHEA)
Androstenedione

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Biochemistry and Physiology

The synthesis of androgens begins with formation of __________ from _______

pregnenolone from cholesterol

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Biochemistry and Physiology

Testosterone circulates free or bound to plasma proteins like ____________________ and ____________.

sex hormone binding globulin and albumin

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SHBG binds ________________________. In either sex

increased SHBG ______eases oestrogen dependent effects and decreased SHBG ases androgen dependent effects.

both testosterone in males and oestradiol in females

incr

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Metabolism of testosterone
Testosterone : precursor for formation of ______(___________) and _______.

Both are active metabolites and are converted by _______ and _______ respectively.

DHT (dihydrotestosterone)

oestradiol

5α reductase; aromatase

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Metabolism of testosterone

Aromatisation occurs in _______ tissue of both sexes because of the high concentration of _ _______ in adipose tissue.

adipose

aromatase

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DHT is formed in _____ target tissues eg _______ and _____

androgen

skin and prostate.

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Metabolism of testosterone

Excretory products of these androgens constitute a group of androgens known as __________ – ketosteroids , 90% of which is excreted in ____.

‘17 - ketosteroids

urine.

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Male reproductive development

Fetus: has both _________ (female) and _________ (male) reproductive tracts.
The _________ duct differentiates into the fallopian tubes, uterus, upper vagina and female reproductive tract.
The ________ differentiates into vas deferens, epididymis, seminal vesicles and male reproductive tract.

Mullerian duct (female)

Wolffian duct (male)

Mullerian duct

Wolffian duct

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Male reproductive tract

In males, _______ maintains the _______ duct and ________ of the urogenital sinus and external genitalia.

________________ is responsible for repression of the Mullerian duct.

testosterone

Wolffian; virilisation

Mullerian Inhibiting Substance (MIS)

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Post natal development: Male reproductive system

After birth, concentration of testosterone increases and remains elevated for _______ then falls to baseline by ______ (< 1nmol/L). I

t remains low although (lower or higher?) in boys than girls till _______.

3 months

1 year

Higher ; puberty

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At birth concentration of testosterone is only SLIGHTLY higher in boys than girls.

T/F

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Puberty: Male Reproductive System

Hypothalamopituitary system becomes (more or less?) sensitive to feedback inhibition by circulating androgens, resulting in (lower or higher?) androgen secretion.

Less

Higher

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Puberty: Male Reproductive System

By 6/7 yrs of age, ______,_______, and ________ begin to increase. Puberty is associated with (diurnal or nocturnal?) surges of ____ and to a lesser extent ____.

androstenedione, DHEA and DHEA-S

nocturnal

LH; FSH

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Andropause The ______ process leads to physiological lowering of androgens in men ____ yrs and above. Symptoms include: - ____eased well being - ____eased energy levels - ____eased sexual function

aging; 50 decr; decr; decr

Andropause Unlike menopause, andropause does not result in _________________. The process is (more or less?) gradual, progressing over several decades.

absolute loss of gonadal function More

Disorders of male sex hormones Deficiency in sperm production and decreased testosterone secretion is known as __________. (Low sperm count)

hypogonadism

Disorders of male sex hormones They can be PRIMARY DISORDERS affecting the ____ or ____gonadotrophic ____gonadism.((high or low?) FSH/LH). Or due to a defect in the ______ or SECONDARY DISORDERS or ____gonadotrophic ____gonadism.

testes; hyper; hypo .(High FSH/LH). hypothalamus; hypo; hypo

Disorders of male sex hormones In hypogonadotrophic hypogonadism _____________ may be absent, or ______ may be absent.

both FSH and LH only LH

Disorders of male sex hormones Other male reproductive abnormalities include defects in androgen action, __________ ____________

impotence gynaecomastia.

Causes of primary hypogonadism Congenital defects – _______ syndrome or testicular _______ Acquired defects like testicular infections eg ______, trauma, _______ or _______ drugs

Klinefelter’s syndrome or testicular agenesis mumps, trauma, irradiation or cytotoxic drugs

Causes of secondary hypogonadism _________________ Hypothalamic disorders such as _______ syndrome

Pituitary tumours Kallman’s

Causes of secondary hypogonadism Kallman’s syndrome – decreased ______ during _____________ _ It is characterized by ________ and ______ in male or female patients, ____x more common in men. It is a congenital defect with several genetic causes.

GnRH embryonic development hypogonadism and anosmia 5x

Female reproductive physiology Consists of vagina, uterus, fallopian tubes and ovaries. Ovaries are located on either side of ______ near ___________. They produce _____ and secrete sex hormones ______ and _______

uterus ; fallopian tubes. ova ;progesterone and oestrogen.

Female reproductive physiology Every healthy female neonate has _____ primordial follicles, each containing and immature ovum of which ________ follicles will reach maturity.

400,000 300 to 400

Female reproductive physiology A ___________ is produced during each normal menstrual cycle at day ____. During ovulation the mature follicle _____ releasing the ______ into the _____ near the ___________.

single mature follicle; 14 ruptures; oocyte; space ; fallopian tube. After ovulation, granulosa and theca cells of the follicle become the corpus luteum. These luteal cells produce oestrogen and progesterone. If fertilization and pregnancy occur, the corpus luteum persists and continues to produce oestrogen and progesterone.

Female reproductive physiology After ovulation, ________ and _______ cells of the follicle become the _________. These _____ cells produce oestrogen and progesterone. If fertilization and pregnancy occur, the ______ persists and continues to produce oestrogen and progesterone.

granulosa and theca corpus luteum luteal

Female physiology If pregnancy does not occur, corpus luteum ______ and is replaced by _______

regresses; scar tissue.

Female physiology Fallopian tubes arise from the _____, extend towards the ______. They convey the _____ __ward from the ________ and provide site for _______ of oocyte. Fertilized egg is transported _____ along the ________ to the _______

Uterus ; ovaries sperm; up uterine cavity ; fertilization Back; fallopian tubes uterine cavity.

Uterine cavity is lined by _______ which undergoes___ changes in preparation for implantation and pregnancy. During the _____ phase, endometrial lining increases in thickness and vascularity.

endometrium; cyclical luteal

Role of the hypothalamopituitary axis In adult women, a tightly coordinated feedback system exists between ________,________, and ______ to cause menstruation.

hypothalamus, anterior pituitary and ovaries

Role of the hypothalamopituitary axis FSH stimulates ___________ LH stimulates ________ and ______ secretion from developing corpus luteum.

follicular growth ovulation; progesterone

Oestrogens Oestrogens are sex hormones responsible for development and maintenance of female sex organs and female secondary sex characteristics. T/F

Oestrogens Oestrogen and progesterone regulate the _____ cycle, _____ and ______ growth and _______ pregnancy.

menstrual breast and uterine maintain

Oestrogens Oestrogens affect _______ homeostasis, bone ___, _____eases linear bone growth and results in _______

calcium mass; incr epiphyseal closure.

Oestrogens Oestrogen depletion is associated with loss of _______ content, _____ease in stress fractures, post menopausal ________.

bone mineral incr osteoporosis

Oestrogen Secreted in adult women by ________ and _______ and during pregnancy by the ______. The ______ gland and ______ also secrete minute quantities of oestrogens.

ovarian follicles and corpus luteum placenta ; adrenal gland testes

____________ is the most important oestrogen.

Oestradiol

Progesterone like oestrogens is a female sex hormone. It is secreted from _______ through ________ just like in the ________.

cholesterol pregnonolone adrenal cortex.

Disorders of female gonadal function __________ __________ ________ ,_______, and ————

Hirsutism Virilism Subfertility, amenorrhoea and oligomenorrhoea

Hirsuitism _____eased body hair with ____ pattern distribution. Genetic in origin and (benign or malignant ?) in majority of cases. (present in some Nigerian tribes)

Incr male

Hirsuitism The commonest pathological cause is _____________ syndrome. It is important to exclude this diagnosis when investigating hirsute women.

polycystic ovarian

Virilism Although (common or uncommon?), is a sign of serious disease. Testosterone concentrations are markedly ________ in the virilised patient.

uncommon elevated

Virilism Symptoms include ______ pattern hair distribution, ______ of the voice and breast _______. Tumours of the _____ or the ________ are the likely cause.

male deepening atrophy ovary; adrenal gland

Subfertility, amenorrhea and oligomenorrhea Subfertility is defined as _______ of a couple to ______________________. A full clinical history will give information about previous pregnancies, contraception, serious illnesses, radiotherapy, cytotoxic drugs, smoking, drug usage, sex transmitted diseases, frequency of intercourse.

failure conceive after one year of regular, unprotected intercourse

Subfertility, amenorrhea and oligomenorrhea Physical examination, hypothalamopituitary disorders, thyroid disorders, Cushing’s syndrome, galactorrhoea, hirsutism. In ________ analysis should detail volume, sperm density, motility and presence of abnormal spermatozoa.

male semen

Subfertility, amenorrhea and oligomenorrhea Endocrine investigations of the infertile woman. Serum progesterone in the middle of the ______ phase or day ____ progesterone should be analysed. If > ____nmol/L, then patient is ovulating. If <____nmol/L, then patient is not ovulating.

luteal; 21 30; 10

Subfertility, amenorrhea and oligomenorrhea For women with irregular menses, measurement of _______ and ________(19- 100 IU/L) may detect ________ failure or __________ disease. Measurement of ______ and _______ are also important.

oestrodiol and FSH/LH primary ovarian polycystic ovarian prolactin and androgens

Causes of infertility in women ______________ failure Hyper _________ _________________ disease _________ syndrome _____gonadotrophic _____gonadism

Primary ovarian failure Hyperprolactinemia Polycystic ovarian disease Cushing’s syndrome Hypogonadotrophic hypogonadism

Endocrine investigations in the subfertile man In a man with ________ analysis no endocrine investigations are needed. In the hypogonadal male, _____ and _________ should be measured first.

normal sperm testosterone and gonadotrophins (FSH/LH)

Causes of subfertility in the male Primary testicular failure ___________ ———- disease (_______ syndrome) ____________ is a rare cause of infertility in the male.

Primary testicular failure Hypothalamic pituitary disease (Kallman’s syndrome) Hyperprolactinemia is a rare cause of infertility in the male.

Causes of subfertility in the male In both men and women a serum FSH concentration greater than ____ U/L indicates ________ ———- ———

23 primary gonadal failure.

Tests in Pregnancy Specific ______ changes Secondary _______ changes _________ monitoring ______ monitoring Metabolic effects of ________

hormonal metabolic Maternal Fetal; oral contraceptives