Reproductive System Flashcards
Unit 6
List the functions of the reproductive system.
produce, store, nourish, and transport gametes
Describe the hormonal control of testicular and ovarian function (HPG)
Regulates ovarian or testicular functions. Produces gametes, sex hormones.
Describe the functions of LH in males
stimulates insterstitial endocrine (Leydig) cells to produce testosterone
Describe the functions of FSH in males
stimulates sustenocytes to keep high levels of testosterone
Describe the function of testosterone in males
stimulates spermatogenesis
Describe the function of inhibin in males
produced by sustenocytes, “inhibits” anterior pituitary (FSH only)
Describe the functions of LH in females
stimulates thecal cells in ovary to produce androgens
Describe the functions of FSH in females
stimulates granulosa cells of follicle in ovary to produce estrogen
Describe the function of estrogen in females
stimulates oogenesis and follicle development in ovary
1st: rising estrogen acts back on hypothalamus and pituitary (negative feedback)
2nd: brief positive feedback causes ovulation
Describe the function of progesterone in females
produced from corpus to maintain uterine wall. acts back on hypothalamus and pituitary (negative feedback)
Describe the function of inhibin in females
produced by granulosa cells, also acts on anterior pituitqary to “inhibit” FSH only
What is puberty?
the period where adolescents reach sexual maturity and become capable of reproduction
What changes happen during puberty that allow secondary sexual characteristics to occur in males?
bone and muscle growth, epiphyseal plate closure, change in CNS behaviors, thickened thyroid cartilage, deepened voice, increased BMR
Describe the effects of aging on the reproductive system
young female: leptin levels must be adequate for puberty to occur.
seasoned female: menopause (ages 46-54): occurs after 1 year of no menstruation. decline in estrogen-> loss of bone mass
seasoned male: decline in testosterone, but can father children through 80 years of age
Define menopause and menarche
menopause: occurs after 1 year of no menstruation
menarche: 1st menstrual period due to hormones stabilizing
What is the first step in spermatogenesis?
spermatogonia near seminiferous tubule wall divide by mitosis. type A daughter cells always remain at wall, type B cells develop into primary spermatocyte, they migrate to the lumen
What is the 1st step of oogenesis?
Oogonia (stem cell) develop while the female is a fetus. Many mitotic divisions result in primordial follicles. Oocyte halts at prophase of meiosis I.
Describe the structure of a sperm
Head (contains genetic material and the acrosome, contains enzymes for egg entry)
Midpiece (contains lots of mitochondria for cellular metabolism)
Tail (flagellum for movement)
Describe the structure of an ovulated oocyte
it is protected by a thick glycoprotein layer called the zona pellucida and a crown of granulosa cells called the corona radiata
List the structures sperm pass through in order to leave the body
testes->epididymis-> ductus deferens-> ejaculatory duct-> urethra
Describe the structure and function of the testis
the gamete producing organs of the male, surrounded by the scrotum.
Describe the structure and function of the epididymis
sperm finish their maturation here. there are three segments; head, body, and tail
Describe the structure and function of the scrotum
composed of skin, connective tissue, and a layer of smooth muscle called the dartos muscle. protects the testes.
Describe the structure and the function of the ductus deferens
a duct that transports the sperm.
Describe the structure and the function of the ejaculatory duct
passes through the prosthetic gland to deliver them to the urethra.
Describe the structure and the function of the penis
used for urination and sexual intercourse
What is the role of the sustenocytes in the blood-testis barrier?
prevents the immune system from attacking sperm
What is semen? What is it composition and what do each constituent do?
fluid that contains chemicals to nourish and activate sperm.
Differentiate among the seminal vesicles, prostate gland, and bulbourethral glands.
The seminal vesicles and prostate gland work together to form 90% of semen. The bulbourethral glands are located at the root of the penis which lubricates the spongy urethra.
Describe the structure and function of the ovaries
female gonads that produce oocytes.
Describe the structure and function of the uterine tubes and fimbriae
the fimbriae “catch” the oocyte and bring it into the tube. the uterine tubes bring the eggs to the uterus.
Describe the structure and the function of the uterus and the cervix
the uterus is where a fertilized oocyte implants and a baby develops. the cervix allows fluids to pass from the uterus to the vagina.
Describe the structure and function of the vagina
it is an 8-10 inch long passageway. a baby is born through the vagina.
Describe the structure and the function of the labia
fatty folds that inclose the vestibule.
Describe the structure and the function of the clitoris
composed of erectile tissue
Describe the structure and function of the mammary glands
modified sweat glands, that produce milk for babies
what is the follicular phase?
days 1-13, follicle selection and development. increased estrogen, follicle secreted. Estrogen increase causes LH surge. primary oocyte completes meiosis I and becomes secondary oocyte.
What are signs of ovulation?
twinge of abdominal pain, inflammatory response, weakening of ovary wall
What steps occur leading up to fertilization?
- sperm undergo capacitation
- sperm olfactory receptors sniff out chemical signals from oocyte
- sperm wiggles through corona radiata
- sperm binds to zona pellucida (increases sperm calcium-> sperm acrosomal reaction)
- sperm binds to oocyte membrane receptors and cell membranes fuse
- sperm nucleus enters oocyte (increase oocyte calcium-> oocyte cortical reaction, zona pellucida hardens stopping polyspermy.)
- oocyte finally finishes meiosis II
- sperm and oocyte nuclei swell and move towards each other
- fertilization!
What is fertilization?
nuclei membranes rupture, mixing maternal and paternal DNA forming zygote
What is a zygote?
undergoes mitosis through cleavage, making many clones.
What is a morula?
cluster of 16 cells
What is a blastocyst?
ring of trophoblast cells and inner cell mass.
What is implantation?
blastocyst erodes endometrium to bury into uterine wall, endometrium covers blastocyst.
What is the source of hCG and what does it do?
human chorionic gonadotropin. produced from trophoblast cells. maintains corpus luteum and causes fetal development.
What determines genetic sex?
the sperm cell carries either an X or Y chromosome, which determines the genetic sex
How do male and female structures develop in vitro?
xy develops testes. xx develops ovaries. begins during week 5 with gonadal ridge that develop male and female ducts. germ cells signal development of testes or ovaries and the opposite ducts degenerate.
What secretes GnRh
hypothalamus
What stimulates the anterior pituitary to release gonadotropins
HPG axis
Gonadotropins stiumlate…
production of sex hormones in gonads
What kind of feedback loop does testosterone have with the hypothalamus and pituitary
negative feedback loop
What causes corpus luteum development?
LH surge at ovulation
What changes happen during puberty that allow secondary sexual characteristics to occur in females?
bone and muscle growth (pelvis widens), epiphyseal plate closure, change in CNS behaviors, increased fat deposit in mammary glands and breast development, enlargement of reproductive organs and first menarche.
what is the main characteristic of puberty in males?
testosterone causes sperm production
what is the main characteristic of puberty in females?
estrogen causes gamete production
What is the 2nd step in spermatogenesis?
Primary daughter cells undergo meiosis I. Secondary spermatocyte undergo meiosis II and become a spermatid
What is the 3rd step in spermatogenesis?
Spermiogenesis! Spermatids must become motile. DNA compacts, cell elongates and sheds cytoplasm, spermatids form a tail
What is the 2nd step in oogenesis?
Over 1 year, primordial follicle grows into the primary follicle, then into secondary follicle
what is the 3rd step in oogenesis?
secondary follicle has multiple cell layers, gains theca folliculi
what is the 4th step in oogenesis?
secondary follicle becomes vesicular follicle as antrum develops.
What is the 6th step of oogenesis?
Ovulation releases secondary oocyte from follicle (and ovary)
what is the 5th step in oogenesis?
at the end of follicle development, oocyte finishes meiosis I resulting in secondary oocyte (functional gamete halted at metaphase of meiosis II). This is a polar body, there’s no cytoplasm or organelles, the cell dies.
when is oocyte development halted?
prophase of meiosis I
when is secondary oocyte development halted?
metaphase of meiosis II
when does an oocyte get to completely finish meiosis II?
when it is fertilized
what is ovulation?
day 14. LH causes oocyte release from follicle and ovary.
what is the luteal phase?
LH forms corpus luteum from follicle. Corpus luteum produces estrogen and progesterone for 10 days, then degenerates. PHASE IS ALWAYS 14 DAYS LONG
What are the three phases of the menstual cycle?
Menstrual phase (days 1-5), Proliferative phase (days 6-14), secretory phase (days 15-28)
what are the three phases of the ovarian cycle?
Follicular phase (days 1-13), Ovulation (day 14), Luteal phase (last 14 days!)
what is the difference between the ovarian and uterine cycle.
they are correlated, but the uterine cycle is driven by the pituitary hormones (FSH,LH) while the ovarian cycle is driven by ovarian hormones (estrogen, progesterone)
what is the menstrual phase?
days 1-5, drop in estrogen and progesterone. sheds blood and stratum functionalis of endometrium. (in the ovary the maturation of the next oocyte begins)
what is the proliferative phase?
days 6-14. estrogen levels increase. new stratum functionalis of endometrium forms. (in ovary the oocyte matures and is ovulated.
what is the secretory phase?
days 15-28. progesterone from corpus luteum signals further development of endometrium. if fertilization occurs, hormones increase until placenta takes over. if fertilization does not occur, hormones decrease causing the deterioration of the endometrium.
which phases correlate to each other in the ovarian and uterine cycles?
menstrual and proliferative= follicular
secretory= luteal
