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134 Cards in this Set

  • Front
  • Back
Name the 4 types of sex.
Genetic: sex chromosomes
Gonadal: gonadal histology
Genital: external characteristics
Gender ID
Define Hermaphroditism.
The presence of both gonadal sexes.
Define Male Hermaphroditism.
The presence of testes and some or all of the female tract and external genitalia.
Define Female Hermaphroditism.
The presence of ovaries and some or all of the male tract and external genitalia.
At birth, at what stage of development are the gametes of males and females?
Males: within the testes as a primordial germ cell. Has undergone mitosis to duplicate in number, but no meiosis.
Female: all of the oogonium have undergone mitosis to duplicate in number and the first steps of meiosis I. They arrest in prophase of meiosis I.
What regions of the Y chromosome and hormones are necessary for the development of the male?
SRY of the Y chromosome
Anti-Mullerian Hormone (from sertoli cells)
Testosterone (from leydig cells)
What is Turner's syndrome?
XO female
the loss of one chromosome results in ovarian dysgenesis, but no loss of the female ducts or genitalia.
Results in unique characteristics such as a webbed neck and shield chest.
Describe the development of the testes.
Primordial germ cells migrate along the gonadal ridge and form a primordial gonad which is bipotent for testis or ovary.
The specific development of testes is NOT hormone dependent.
With the presence of XY the MEDULLA of the gonad develops to form the seminiferous tubules, spermatogonia, sertoli cells, and leydig cells.
Describe the development of the ovaries.
Primordial germ cells migrate along the gonadal ridge and form a primordial gonad which is bipotent for testis or ovary.
The specific development of ovaries is NOT hormone dependent.
With the presence of XX the CORTEX of the gonad develops to form the secondary sex cords, oogonia, theca cells, and granulosa cells.
What is the "default" pathway of genital or phenotypic sex?
Formation of the female (mullerian) tract.
What determines the sexual dimorphisms between males and females?
Differences in the amounts of hormones and the patterns of their secretion.
NOT due to differences in the hormones themselves.
What do the Wolffian ducts form?
The epididymis, vas deferens, seminal vesicles, and ejaculatory duct.
What to the Mullerian ducts form?
The fallopian tube, cervix, upper vagina.
What hormone determines the male external genital structure development?
Dihydrotestosterone (DHT)
Formed from Testosterone by 5α-Reductase.
What hormones determine the female extermal genitalia?
None. The absence of testosterone and DHT.
Growth of the structures to normal size, however, requires estrogen.
What does the genital tubercle form?
Male: glans penis
Female: clitoris
What do the urogenital folds form?
Male: ventral penis
Female: labia minora
What do the labioscrotal folds form?
Male: scrotum
Female: labia majora
Describe the arrangement of the germ cells in the seminal vesicles.
The mitotically dividing stem cells, spermatogonia, lie along the basement membrane outside the blood/testes barrier. Spermatagonia which undergo meiosis (spermatocytes) mature into spermatatids. These undergo spermatogenesis and mature into spermatozoa on the adluminal side of the seminal vesicles to be stored in the epididymis.
What are the 3 main functions of the sertoli cells?
1. provide nutrients to the differentiating sperm
2. form tight junctions to form the blood-testes barrier
3. secrete aqueous fluid into the lumen of the seminiferous tubules to help transport sperm through the tubules into the epididymis
What occurs in spermatogenesis?
Spermatid → spermatozoa
Nucleus condenses
Cytoplasm shrinks
Formation of the acrosome
Development of a tail
What is spermeation?
the process of extruding flagellated spermatozoa in the seminiferous tubule lumen
What are the functions of the epididymis?
sperm maturation: gain motility, lose cytoplasm
reservoir for sperm
stabilize acrosome
What are the functions of the prostate?
formation of alkaline secretions to neutralize vaginal secretions
function in NO production and the formation of an erection
What are the functions of the seminal vesicles?
formation of secretions of prostaglandins to cause contractoins of the uterus and fallopian tubes to aid in sperm movement
What inhibits the release of GnRH?
Dopamine, Endorphins, Norepinephrine, CRH (stress)
What is an important characteristic of GnRH release?
It is pulsatile.
Continuous exposure to GnRH is inhibitory to FSH and LH release.
What are the two major male gonodotropin hormone pairs?
Testosterone/LH (leydig cells)
Inhibin/FSH (sertoli cells)
What stimulates Leydig cells to produce their product?
LH stimulates Leydig cells to produce testosterone.
What hormones, other than LH, act on Leydig cells?
Prolactin increases the # of LH receptors.
GH activates the cells
Estradiol and activin from Sertoli cells inhibits leydig cells.
Inhibin from sertoli cells activates leydig cells.
What stimilates sertoli cell function?
FSH to facilitate sperm development
Androgens ("T") from leydig cells to coordinate sperm development
What are some of the functions FSH has on sertoli cells?
increases androgen binding protein/receptors to increase "T" responses and conc near developing sperm
increases p-450 aromatase to convert "T" to estradiol
increases inhibin production to reduce FSH secretion and elevate leydig cell "T" formation
increases growth factors
What positive feedback exists between Leydig and Sertoli cells?
Testosterone produced from the leydig cells causes increased inhibin formation in the sertoli cells which increases testosterone production in the leydig cells
What are the 19 Carbon products of steroid hormone formation?
Androgens: DHEA, androstenediol, androsterone, testosterone, di-hydrotestosterone
How is testosterone carried in the plasma?
45% bound to SHBG (sex hormone binding globulin)
55% bound to albumin
2% free and active
Is DHT more or less potent then Testosterone?
DHT is 30-50x more potent than Testosterone
What converts Testosterone to DHT?
5α-reductase
How is testosterone excreted?
<2% as free testosterone
converted to 17-ketosteroids and DHT and conjugated to water soluble forms and excreted
How can benign prostate hypertrophy be treated?
5α-reductase inhibitor (finasteride) because DHT causes prostate growth.
What autonomic nervous system branch controls male erection versus ejaculation?
parasympathetic - erection
sympathetic - ejaculation
How do the parasympathetics lead to penile erection?
Ach released by the parasympathetic neurons act on muscarinic receptors to activate NO release and lead to vasodilation and relaxation of smooth muscle.
Increased blood flow in the cavernous tissue leads to engorgement and compression of the outflow pathway.
What controls the emission and ejaculatory phases?
emission: movement of ejaculate into proximal urethra by sympathetic control of alpha adrenergic receptors on smooth muscle.
Ejaculation: spinal cord (S2-S4) reflex triggered by semen entry into bulbous urethra
What causes primary gonadal abnormalities which lead to hypergonadotropic hypogonadism?
high LH and FSH
low Testosterone and DHT
Examples:
Klinefelters (XXY)
True hermaphrotism
defective androgen synthesis
What are causes of Tertiary (hypothalamic) and secondary (pituitary) Hypogonadotropic Hypogonadism?
Low LH and FSH
Low Testosterone and DHT
Examples:
Kallmann's syndrome (isolated LH or FSH deficiency)
hyperprolactinemia
malnutrition/anorexia
congenital defects
What are the causes of Pseudohermaphroditism?
Defects in androgen action:
complete androgen insensitivity (testitcular feminization)
incomplete androgen sensitivity (testosterone receptor defect, 5a reductase defect
What is the difference between infertility and impotence?
Infertility: inadequate production of functional sperm
Impotence: inability to form a functional erection
Describe the stimulators and inhibitors of GnRH release from the hypothalamus.
Stimulates: Norepinephrine
Inhibits: Dopamine, endorphins, CRH
What are the effects of the posterior pituitary hormone, oxytocin?
increases uterine contractions (partuition)
causes milk ejection from the mammary gland
What are the general effects of FSH in a woman?
stimulates follicular development and estradiol secretion
What are the general effects of LH in a woman?
promote ovulation and luteinization of the ruptured follicle (the developing corpus luteum)
What are the two main gonadotropin hormone pairs in women?
Estrogen/LH (theca)
Follistatin (and inhibin)/FSH (granulosa) while activin activates FSH release
What is are the major sources of progesterone?
Corpus luteum
placenta
What are the three hormones which are considered collectively as estrogen?
Estradiol (E2) dominant hormone
Estrone (E1)
Estriol (E3)
What hormone is present in ovaries which is necessary for the conversion of testosterone to estradiol?
aromatase
How are estrogens and progesterones metabolized?
The hormones are sent to the liver and converted to water soluble intermediates and excreted.
How are the sex hormones transported in women?
Estrogen: mainly albumin and SHBG (sex hormone binding globulin) ~2% free
Progesterone: mainly CBG (cortisol binding globulin) and albumin ~2% free
Testosterone: mainly SHBG and albumin ~1% free
What is the fundamental reproductive unit of the ovary?
one oocyte surrounded by a cluster of granulosa cells
Do the number of oocytes continuously decline from birth?
Yes, unlike males.
Women born with ~2 million oocytes while men can make up to 200-300 million a day.
Describe the development of a primordial follicle in an ovary.
Formed prior to birth. Consists of an oocyte separated by a basement membrane from squamous follicular cells from stroma. Arrest in prophase and begin to undergo atresia.
90-95% of follicles are in this state.
Describe the development of a primary follicle in an ovary.
The follicular cells surrounding the oocyte differentiate into a single layer of granulosa cells to support the oocyte.
Occurs between ages 13-50.
Describe the development of a secondary follicle in an ovary.
During one cycle (due to FSH>LH) a few oocytes undergo this transformation and causes the granulosa cells to multiply, the stromal cells to differentiate into theca cells, an antrum forms, the oocyte grows, gap and tight junctions form between granulosa and theca cells, and the zona pellucida forms immediately around the oocyte.
Describe the development of the Graafian follicle within the ovary.
Among the secondary follicles one is selected to be dominant and form the graafian. Exponential growth (1000x) of the follicle occurs with the antral fluid.
What occurs during ovulation?
The graafian follicle ruptures to release the oocyte into the peritoneal cavity which is swept up by the fimbriae of the fallopian tubes. The first meiotic division occurs. The granulosa and theca cells remain and form the corpus luteum.
What is luteolysis?
The regression of the corpus luteum if no fertilization of the released oocyte occurs.
What is the Corpus Albicans?
The fibrous scar left from a corpus luteum.
What are the three phases of the menstrual cycle?
Follicular - ~14 days (variable) time for follicular growth
Ovulatory - ~1-3 days, time of final oocyte maturation and release
Luteal - 14 days (not variable), time of corpus luteum formation and secretion of hormones
Describe the control and consequences of the LH surge
The rise in estrogen levels normally inhibits LH secretion. However, with sustained exposure to high levels of estradiol there is a switch which results in the estradiol stimulating LH release.
Causes: increase in GnRH receptors on gonadotrophs, increase in GnRH release, causes a decrease in estogen levels.
What hormone dominates the follicular phase?
Estradiol
What hormone dominates the luteal phase?
Progesterone (from corpus luteum)
What are the LH and FSH relative concentrations at differnt periods of development?
Childhood: FSH>LH
Reproductive age: LH>FSH
Senescence: FSH>LH
What is required for the development of primordial follicles to primary follicles?
Gonadotropins
Which cells of the ovaries lack aromatase?
Theca cells
Describe the two compartment theory for follicular estradiol production.
Cholesterol is taken up by the vascularized theca cells and converted to Testosterone which is transported to the granulosa cells and formed into estradiol. The granulosa cells can also uptake cholesterol in a limited way and form progesterone but only do so in the luteal phase. They are unable to convert the progesterone into testosterone.
What cell type to theca and granulosa cells turn into in the corpus luteum?
Lutein cells
What do the lutein cells of the corpus luteum form?
Progesterone
Initially lose aromatase activity so limited estrogen production, but later recovers
What is the proliferative phase of the menstrual cycle?
The thickening of the stromal and endothelial layers of the uterus.
Coincides with the mid-to-late follicular phase.
Dominated by estradiol
What is the secretory phase of the menstrual cycle?
The increased vascularization and glycogen content of the endometrium. Stroma becomes edematous.
Spans from the day of ovulation to the late luteal phase.
Dominated by progesterone.
What is the menstrual phase of the menstrual cycle?
Caused by declining progesterone/estrogen and results in restriction of the spiral arteries, proteolytic digestion of the endometrium, and infiltration of monocytes and leukocytes
Prior to ovulation how does the cervical mucus change?
There is an increase in quantity and alkalinity and decrease in viscosity. Ferning pattern on slide is characteristic.
Changes promote the survival of sperm.
What are five main actions of estradiol?
Inhibit the growth of cohort follicles.
Prime GnRH action on LH release and stimulate ovulatory LH surge.
Prepare uterine endometrium for progesterone to evoke secretory response.
Affect fallopian tube to favor transport of ovum and zygote.
Alter cervical mucus to enhance sperm transport.
What happens in menopause?
Ovulation cessation (~age 51)
Follicle sensitivity to FSH and LH declines.
Follicles disappear.
Loss of negative feedback from estradiol and inhibin causes increase in FSH and LH, FSH>LH.
What are some of the consequences of menopause?
osteoporosis
CV disease
thinning of vaginal epithelium
decreased breast mass
vascular flushing
What is the definition and causes of Primary Amenorrhea?
the absence of menses in a phenotypic female by age 17
Causes: Turner's, testicular feminization, hormonal disorders
What is the definition and causes of Secondary Amenorrhea?
cessation of menses for longer than 6 months
Causes: pregnancy, lactation, menopause, hyper-prolactinemia
What is the definition and causes of Oligomenorrhea?
Infrequent periods (cycle length >35 days)
Causes: changes in CNS control of GnRH secretion ie. stress and illness. Intense exercise, extreme weight loss, anorexia nervosa
What is the definition and causes of Dysmenorrhea?
painful menses related to uterine contractions may involve pelvic pain, nausea, vomiting, diarrhea
Causes: prostaglandin synthesis from E2 and progesterone leading to uterine contraction and ischemia
Treatment: prostaglandin synthesis inhibitors and oral contraceptives
What is the definition and causes of Hirsutism?
inappropriately heavy hair growth in androgen sensitive areas
Causes: intake of exogenous androgens, adrenal hyperplasia, Cushing's
What is the definition and causes of Virilization?
Hirsutism (hair growth) and further androgen stimulation ie clitoral hypertrophy, deepening voice, temporal balding, etc.
Causes: excessive androgen production, androgenital syndrome
What is the definition and causes of Premenstrual Syndrome?
physical and behavioral symptoms which interfere with normal life in luteal phase.
Symptoms: abdominal bloating, fatigue, breast tenderness, irritability
How many carbons are in estrogens?
18 (aromatized androgen and removes one C)
What cells (male and female) does FSH stimulate?
Sertoli
Granulosa
What cells (male and female) does LH stimulate?
Leydig
Theca
What is thelarche?
breast budding, delayed if doesn't occur by age 13
What is adrenarche?
first appearance of pubic hair growth
What is the average age of menarche?
12.5, no menarche 2.5 years after thelarche (breast budding) is abnormal.
What is the first sign of puberty in males and females?
testicle enlargement
breast budding
What is considered precocious puberty?
Females: breast bud development < 6 yo
Males: testicle enlargement < 9 yo
Describe the development of the testes and what it causes to form around them.
Testes form retroperitoneally causing the peritoneal layers to be pulled down with the testes and form the tunica vaginalis.
What is the tunica vaginalis?
It is derived from the peritoneum and includes the outer parietal and inner visceral layers.
What is the tunica albuginea?
It is thick collagenous connective tissue around the testes which thickens at the mediastinum and the lobuli testis (septa between the lobules).
How many lobules are in each testes?
~250
What is the tunica propria?
Are several layers of fibroblasts surrounding each seminiferous tubule.
What occurs in the seminiferous tubules?
The development of sperm. The spermatogenic lineage is 4-8 layers thick.
What are tubuli recti?
Straight tubes which connect the seminiferous tubules to the rete testis. They are gradually reducing number of spermatogenic cells and sertoli cells.
Has cuboidal epithelium with dense connective tissue.
What is the rete testis?
The continuation of the tubuli recti to the ductus efferentes.
Has highly branched, irregular shaped lumen channels that are lined with cuboidal epithelium.
What are the ductus efferentes?
The continuation of the rete testis which have variable height cuboidal epithelium and an scalloped shaped lumen.
Unique feature: Cilia are motile to move the immotile sperm towards the epididymis.
Have a thin layer of smooth muscle cells
What is the ductus epididymis?
The storage area for mature sperm and gain motility. Is a single, highly convoluted tubule. Contains pseudostratified epithelium with stereocilia which is not motile, but used for absorbtion of H20. Contains some smooth muscle to facilitate sperm movement.
What is the ductus deferens?
The vas deferens. Which is the continuation of the epididymis towards the prostatic urethra. Is a single straight tube with pseudostratified columnar epithelium and non-motile stereocilia. There is a lumen of longitudinal folds and lots of elastic fibers.
There are three smooth muscle layers inner longitudinal, middle circular, and outer longitudinal.
What is the ampulla of the ductus deferens?
The region of the vas deferens near ppening to the prostatic urethra.
What are the ejaculatory ducts?
The region of the ductus deferens within the prostate gland which subsequently joins to the urethra.
What occurs in spermatogenesis?
Spermatogonia --> spermatocyte
What is the difference between type A and type B spermatogonia?
Type A are commited to mitosis and are attached to the fibroblasts (niche cells) which form the basement membrane of the seminiferous tubules by adhesion molecules.
Type B have lost contact with the adhesion molecules and are signaled to enter meiosis.
What is the difference between primary and secondary spermatocytes?
Primary spermatocytes (4n)
Secondary spermatocytes (2n)
During meiosis which chromosomes separate when?
During the 1st division: The 2 maternal chromatids separate from the 2 patenal because they are bound by unprotected Rec8 cohesion protein.
In the 2nd division: the sister chromatids separate from each other because the Sgo1 protection of the Rec8 is degraded and allows Rec8 cohesion to degrade.
What occurs in spermiogenesis and what are its three phases?
spermatids -->spermatozoa
Golgi phase: acrosomal granules, vesicles, axoneme, and flagellum form
Acrosomal phase: acrosomal cap formed from acrosomal vesicle
Maturation phase: shedding of residual cytoplasm and release of spermatozoa
What are the contents of the acrosome cap?
hydrolytic enzymes:
hyaluronidase, neuramidase, acid phosphatase, and protease
What hormones are made by sertoli cells?
androgen binding protein, inhibin, anti-mullerian hormone, testicular transferin (iron transport), glial cell line derived neurotrophic factor, aromatase
Where do sertoli cells form tight junctions?
on the adlumenal side of the spermatogonia
What are some of the functions of sertoli cells?
provide physical support, form the blood-testis barrier, provide nutrients, phagocytosis of the residula cytoplasm, forms hormones
Describe the appearance of sertoli cells.
Triangular shape nucleus with very prominent nucleoli.
spans the width of the seminiferous tubule wall although the nucleus lies on the basement membrane.
Describe the Leydig cells.
Are interstitial cells which lie outside of the seminiferous tubule basement membrane. They contain a central nucleus, eosinophilic cytoplasm, large SER and mitochondria with tubular cristae. They are seen near blood vessels bewteen the tububles.
What is kisspeptin?
A protein which binds to the receptor on the basophils of the anterior pituitary and induces LH/FSH formation.
What are the seminal vesicles?
two highly tortuous tubes which contribute 75-85% of seminal fluid. Contain pseudostratified columnar epithelium with many secretory granules and a thin smooth muscle layer.
What is the prostate gland?
Tubuloalveolar glands which are encapusulated by a fibroelastic capsule rich in smooth muscle. Synthesizes and stores prostatic fluid and concretions or glycoproteins. Consists of three layers: outer main glands (peripheral), middle submucosa (transitional), inner mucosal (central)
What are the bulbourethral (Cowper's) glands?
Tubular glands which secrete mucus lubricant.
What makes up erectile tissue?
venous spaces which are lined with unfenestrated endothelial cells separated by trabeculae.
Consists of connective tissue and smooth muscle.
What are the two branches of the central artery of the penis?
Nutrient arteries
Helicine arteries which open directly into the erectile tissue.
What are the glands of Littre?
mucous secreting glands
What two types of epithelium make up the penile urethra?
Shaft: pseudostratified columnar
Glans: stratified squamous
What is in the cortical and medullary regions of the ovary?
Cortical: stromal cells, follicles at various stages of development, avascularized.
Medulla: loose connective tissue, amorphous ground substance, vascularized, few cells
What is the cellular composition of the ovarian follicles?
oocytes and granulosa cells
What is a primary oocyte?
A 4n oocyte arrested in prophase of meiosis I.
When does a primary oocyte become a secondary oocyte?
10 hours before ovulation.
The oocyte finishes meiosis I and forms one polar body and becomes 2n.
What is the zona pellucida?
glycoproteins