ENDOCRINOLOGY PART 4 Flashcards
main source of sex hormones
GONADS
produce sperm
○ sexual development (muscle enlargement,
growth of body hair, voice changes, male
sexual drive)
Testes: androgens ( testosterone)
produce eggs
○ secrete estrogen and progesterone and relaxin
○ for sexual development (breast enlargement, distribution of fats),
menstruation, pregnancy
Ovaries: located in the pelvis
pair of small, almond-shaped organs located in the female
reproductive system, situated on either side of the uterus. They serve as the
primary reproductive organs in females, responsible for producing eggs (ova)
through oogenesis and synthesizing estrogen and
progesterone, which regulate the menstrual cycle and support
pregnancy.
OVARIES
are a pair of oval-shaped organs
located within the scrotum. They are responsible for producing
sperm cells and synthesizing testosterone which is crucial for
the development of male reproductive and secondary sexual
characteristics.
testes or male gonads
C19 steroid hormone principally synthesized by the
Leydig Cells the testis
Controlled primarily by FSH and LH
testosterone- C19
Best time for sample collection
8:00 to 10:00 am
(low testosterone, high
FSH and LH)
primary hypogonadism
low testosterone,
low/normal FSH and LH)
secondary hypogonadism
C18 steroid hormone with a phenol A ring
Arises through structural alteration of the testosterone
molecule
Not produced by the ovaries after menopause
estrogen- c18
Functions: breast development, maturation of the
external genitalia, deposition of body fat, and
termination of linear growth (secondary sexual
characteristic in the female)
estrogen
3 forms of estrogen
estrone
estradiol
estriol
precursor of estrone and estriol
estradiol
major estrogen secreted by the placenta
during pregnancy; down syndrome marker
estriol
active form of estrogen
estradiol
C21 steroid hormone produced mainly by the
granulose (lutein) cells of the corpus luteum in the female
Dominant hormone responsible for the luteal phase cycle among females
Prime secretory product of the ovary, together with estrogen
Used primarily for the evaluation of fertility in female
progesterone - c21
are determined during the
early second trimester by screening of maternal serum for levels of AFP, HCG,
unconjugated estriol (uE3), and inhibin A
neural tube defects
down syndrome
Genetically female but whose phenotypic
characteristics are, to varying degrees, male
Exposure to androgens before the 12th week of
gestation
FEMALE PSEUDOHERMAPHRODITISM
Genetically female but whose phenotypic
characteristics are, to varying degrees, male
Exposure to androgens before the 12th week of
gestation
FEMALE PSEUDOHERMAPHRODITISM
Most common form of hypogonadotropic
hypogonadism due to deficiency of GnRH
Both seen in males and females
kallmann syndrome
Development of secondary sexual characteristics
in girls < 8 yrs old and boys < 9 yrs old
Premature hair and breast development
precocious puberty
Androgen insensitivity syndrome
Defect in androgen action
Males w/ female habitus and develop breast tissue
Blind vagina with rudimentary testes
testicular feminization syndrome
This is a surgical procedure to remove one or both
testicles. It is commonly performed as a treatment
for testicular cancer, to reduce testosterone levels in
individuals with advanced prostate cancer, or as part
of gender confirmation surgery for transgender
individuals
orchidectomy
This condition occurs on one-third of post-pubertal
males with mumps orthorubulavirus infection
(mumps) and is the most frequent extra-salivary
manifestation of this highly contagious infection.
Most cases of orchitis occur 4 to 6 days of parotitis
mumps orchitis
This is a condition in which one or booth testers fail
to descend into the scrotum during fetal
development
cryptoorchidism
characterized by a lack
of germ cells. Men present with small testes, high
FSH levels, azoospermia, and normal testosterone
levels.
sertori cells only syndrome
sertoli cell only syndrome may arise from
Yq11 microdeletions
genetic condition in
males where they are born with and extra X
chromosome (XXY), leading to infertility, reduced
testosterone levels, and potential developmental
and physical difference
klinefelter syndrome XXY
occurrence of low
testosterone levels together with low or
inappropriately normal GnRH, FSH, or LH levels.
hypogonadotropic hypogonadism
characterized by ovarian failure resulting in
elevation of FSH concentrations, with or
without LH elevations, with low levels of
estrogen
hypergonadotropic hypogonadism
○Ovarian failure
○Menopause
○Turner’s syndrome (45, X)
○Polycystic ovarian syndrome (PCOS)
○Hirsutism
hypergonadotropic hypogonadism
resulting in decreased
sex steroid production, is a common cause of
secondary amenorrhea, and FSH and LH levels
are usually <10 IU/L
hypogonadotropic hypogonadism ovarian
Examples:
○Anorexia nervosa
○Runner’s amenorrhea
○Hypothyroidism
○Pituitary tumors
○ Prolactinomas
hypogonadotropic hypogonadism
Lies in the upper part of the thoracic cavity important
in the immune system, especially early in life
Secretes thymosin
○ Helps in the development of WBCs (T cells
thymus gland
small pinecone shaped located in the middle of the brain
Secretes melatonin
pineal gland /body
decreases the secretion of LH and FSH by
decreasing the release of hypothalamic
releasing hormone (inhibits functions of
reproductive system
MELATONIN
plays an important role in the onset of puberty
regulates sleep and wake cycle
FUNCTION: Receive information about the state of the light-dark cycle from the environment and convey this information to produce and secrete the hormone
melatonin
pineal gland
Synthesized within the _____ (cells in the
pineal gland) from tryptophan, mostly occurring
during the dark phase of the day
melatonin - n-acetyl-5-methoxytryptamine
pinealocytes
Only secreted during the dark period of the day
Natural neurotransmitter-like compound
Regulate the sleep cycle by controlling the circadian
rhythm; regulates the immune system
Health benefits: Anti-oxidant and anti-aging properties
melatonin
Causes of variations of melatonin
posture at night
alcohol
inhibit secretions
light stimuli
Plasma melatonin in adults:
60-70 mg/dl
