Chapter 16: Reproduction Flashcards
organs of the male reproductive system
testes and epididymis
male gonads that produce reproductive cells and sperm
testes
process of sperm formation, occurs in walls of seminiferous tubules
spermatogenesis
2 testes located in the ________ outside the abdominal cavity
scrotum
testes are outside the abdominal cavity because spermatogenesis requires a ________ temperature than body cavity
cooler
site of sperm maturation and storage, also outside of the body cavity
epididymis
testes contain tiny, tightly packed ___________ tubules where sperm is formed
seminiferous
seminiferous tubules empty into the _________
epididymis
sperm maturation continues here
head of epididymis
sperm storage occurs here, empties into the vas deferens
tail of epididymis
thick tubule lined with smooth muscle, sperm is stored here
vas deferens
after leaving the scrotum, the two vas deferens wrap around the bladder and each one is joined by a _________ gland and __________ vesicle to form two ejaculatory ducts
secretory; seminal
spermatozoa, male reproductive cells (gametes)
sperm
pea-sized glands inferior to the prostate that joins the urethra
bulbourethral glands
three secretory glands in the male reproductive system
seminal vesicles, prostate gland, and bulbourethral glands
gonadatropin-releasing hormone (GnRH) is released by the __________ and travels to the anterior pituitary gland where it stimulates the release of _________ and _______
hypothalamus; follicle-stimulating hormone (FSH); luteinizing hormone (LH)
gonadotropins stimulate the gonads (tests and ovaries) to _________ and ________
stimulate gamete maturation;
stimulate production of sex hormones (estrogen and testosterone)
there is negative feedback by sex hormones on ______ and _________
GnRH; gonadotropin secretion
FSH acts on Sertoli cells to stimulate production of ________ and _______
sperm; inhibin
LH acts on leydig cells to stimulate production of ________
testosterone
inhibin and testosterone provide negative feedback to inhibit production of _______, _______, and ______
GnRH; FSH; LH
release of GnRH is triggered by action potentials in the __________
hypothalamus
pulsatile release of GnRH is important because continuous stimulation causes the GnRH-responsive cells in the pituitary to become ___________
desensitized
anabolic steroid hormones that have musicalizing actions
most potent in testes is testosterone
androgens (masculinizing hormones
can be converted into peripheral tissues to even more potent dihydrotestosterone (DHT), done by the 5-a-reductase enzyme
testosterone
testosterone is converted to the female hormone estradiol (estrogen) through the enzyme ________
aromatase
engorgement with blood of the 3 cylindrical vascular compartments in the penis
occurs when various inputs trigger neurons into the penis that release nitric oxide
erection
impotence
the consistent inability to achieve or maintain an erection
erectile dysfunction
causes of erectile dysfunction
nerve damage, endocrine disorders, disease, depression
treatment for erectile dysfunction
drugs (viagra, levitra), leads to relaxation of the small arteries in the penis and engorgement of the penis with blood
undescended testis
when one or both testes do not descend into the scrotum
can cause reduced fertility because undescended tests is too warm for normal spermatogenesis
cryptorchidism
loss of normal levels of testosterone release from the testes
hypogonadism
loss of testosterone before puberty can result in a lack of secondary _______ characteristics
sex
results from enlargement of the prostate, starts in middle age
benign prostatic hyperplasia (BPH)
causes of BPH
testosterone from testis (leydig cells) converted to DHT in prostate (by 5-a-reductase)
DHT causes prostate to enlarge, causing pressure in urethra
symptoms of BPH
increased urination frequency and urgency
difficulty urinating
treatment for BPH
drugs that inhibit conversion of T to DHT can shrink the prostate
organs of the female reproductive system
uterus and vagina
where fetal development occurs, behind and above the bladder
uterus
canal between the uterus to the outside
vagina (birth canal)
lower portion or the uterus that leads to the vagina
cervix
external genitalia
vulva
attached to uterus by two stalks, female gonads, produce female gametes (ova/eggs) and female sex hormones (estrogen and progesterone)
ovaries
attached to uterus
uterine tubes or oviducts
open into abdominal cavity
openings are surrounded by long, fingerlike projections (fimbriae)
fallopian tubes
release of an ovum from the ovary
ovum enters fallopian tube and travels towards uterus
matures in uterus - is spermatozoa is present, the ovum may be fertilized
ovulation
fertilization occurs in the __________
fallopian tubes
most primitive female germ
divide during fetal life
differentiate into primary oocytes BEFORE BIRTH
oogenesis
order of differentiation in oogenesis
oogonia -> primary oocyte -> first polar body and secondary oocyte -> second polar body and ovum
primary oocytes complete meiosis I to become secondary oocytes just prior to ___________
ovulation
secondary oocytes complete meiosis 2 to become ovum in the ___________ only after it is fertilized by a spermatozoa
fallopian tube
where eggs exist
in ovarian follicles that permit ovulation
portion of follicle left behind after ovulation
corpus luteum
types of ovarian follicles
primordial, primary, secondary, mature
primordial follicles are composed of __________
granulosa cells
how primordial follicles differentiate into primary follicles
the oocyte increases in size, proliferation of the granulosa cells, and a thick coat surrounds the oocyte (zona pellucida)
thick outer covering of human egg cell, penetrated by sperm acrosome
zona pellucida
outer layer of cells around the preantral follicles
theca
how preantral cells differentiate into mature follicles
the antrum, a fluid filled space, is formed and expands
the egg sits on a mound of granulosa cells called the cumulus oophorous
mound of granulosa cells that holds the egg in a mature follicle
culumulus oophorous
fates of the follicles
ovulation or atresia
apoptosis of the follicle
atresia
stage of follicles are most present in __________
primordial follicles
during each menstrual cycle, only one follicle makes it to maturity
dominant follicle
when more than one egg is fertilized
fraternal twins
if no pregnancy occurs, the mature follicle ruptures into __________, and granulosa cells enlarge and form gland-like structure that _________
corpus luteum; degenerate
when one dominant follicle matures (days 1-14)
follicular phase of the menstrual cycle
ovulation occurs on day ____
14
when the corpus luteum is formed then degenerates (day 14-28)
luteal phase of the menstrual cycle
hormones released dung the follicular phase
estrogen and inhibin by the granulosa cells
hormones released during the luteal phase
estrogen and progesterone by the corpus luteum
where conversion of androgens to estrogen occur
granulosa cells
positive feedback occurs during the menstrual cycle when
high levels of estrogen are secreted by the mature follicle during the follicular stage triggers a spike in LH called the LH surge
stimulates ovulation and development of the corpus luteum
LH surge
the drop in FSH and LH hormones in the female menstural cycle indicates
the end of the luteal phase and that the corpus luteum disappears and no longer produces sex hormones
different types of hormonal birth control
progestin
progestin + estrogen
drugs that stimulate ovulation
GnRH stimulates LH and FSH
inhibits effects of estrogen
cells that synthesize androgens in the female reproductive system
theca cells
muscles that make up the uterus
myometrium (thick) and endometrium (epithelial linining)
order of the uterine phases
menstrual -> proliferative -> secretory
uterine phases that occur during the follicular phase
menstrual and proliferative
when the endometrium sloughs off if pregnancy has not occurred
menstrual phase of the uterine cycle
when the endometrium starts to regrow
proliferative phase of the uterine cycle
under control of progestins and estrogens from ovary
endometrium secretes factors prepares for embryo to implant and support pregnancy
secretory phase of the uterine cycle
name for symptoms of the menstrual phase
dysmenorrhea
cause of dysmenorrhea
prostaglandins stimulate contractions in the uterus and other smooth muscle
pre-menstrual disorders
PMS and PMDD
growth of endometrial tissue outside of uterus
endometriosis
ability to support pregnancy and utilizing energy to switch from growing to reproducing
puberty in females
first menstural period
menarche
lack of normal menstrual flow
amenorrhea
failure to start normal periods at puberty
primary amenorrhea
loss of normal menstrual periods due to pregnancy, menopause, or stress
secondary amenorrhea
when follicles and eggs have disappeared through apoptosis
atresia
hormone levels in menopause
follicles are no longer present, so there is no estrogen/progesterone/inhibin secretion by corpus luteum, therefore no feedback inhibition to LH and FSH
LH and FSH are high
stage immediately before menopause where physical changes begin to occur (12 months without period)
perimenopause
difference between obese and not obese women who go through menopause
obese women experience less loss of estrogen symptoms due to their fat cells being able to convert androgens into estrogens
egg lifespan
1-2 days
time sperm is viable in the female reproductive tract
4-6 days
required for sperm to be activated to fertilize an egg
capacitation
breakdown of the sperm cell’s acrosome which allows for the release of enzymes during fertilization
female secretions make sperm more motile and allow it fuse with an egg
capacitation
when the follicle ruptures from the ovary, the egg is surrounded by
the zona pellucida and some granulosa cells (called corona radiata)
thick outer covering of human egg cell with multiple receptors for proteins on the sperm head to allow penetration by sperm acrosome
zona pellucida
how sperm binds to egg
sperm approach the zona pellucida and undergo acrosome reaction that causes the release of digestive enzymes to break down zona pellucida
the first sperm to pass through the zona pellucida fuses with the plasma membrane of the egg
when the sperm binds to the egg,
cortical granules fuse with the egg plasma membrane and release contents into the extracellular space between the egg and zona pellucida to inactivate sperm receptors and harden the zona pellucida
to release contents between the zona pellucida and the egg to inactive sperm receptors and prevent sperm from fusing with the egg
purpose of cortical granules
fertilized egg not implanted into the uterus
zygote
a zygote that is implanted into the uterus during the first 2 months of development
embryo
after two months of developmental gestation
fetus
fertilization occurs in the _________ fallopian tube
distal, not ventral
cell growth process that occurs in the fallopian tubes
cleavage, when no cell growth occurs and the zygotic cells get smaller and smaller
zygote after 3 days
morula (12-15 cell ball)
cell that is undifferentiated and has capability to form into any cell
totipotent
zygote when it begins to differentiate
blastocyst (when it loses its totipotency)
when implantation occurs after ovulation
7 days (6 after fertilization)
outer layer of blastocyst
trophoblast
phase that implantation occurs
during luteal secretory phases and progresterone causes thickening of endometrium
part of the blastocyte that becomes the embryo
inner cell mass
part of the blastocyte that becomes the placenta
trophoblast (outer layer)
when the zygote implants in the fallopian tube or abdomen
ectopic pregnancy
the placenta is composed of _________ and _________ tissues
maternal; fetal
purpose of the placenta
deliver oxygen and nutrients and remove waste
produce estrogen and progesterone that maintains pregnancy
embryonic structures of the placenta
chorion, chorionic villi, umbilical vein and 2 arteries (umbilical cord)
derived from the trophoblast
chorion
fingerlike structures of chorion in the maternal blood pools
chorionic villi
placenta is fully formed ___________ after implantation
5 weeks
how oxygen and nutrients from the mother get to the fetus
in the maternal blood, it passes through the chorionic villi and delivered to the fetus via umbilical vein
the umbilical vein acts in a different manner than expected because it takes nutrients from the maternal blood and __________ to the fetus
carries it
the umbilical arteries act in a different manner than expected because it takes fetal waste _________ the fetus and delivers it to the ________ to enter the maternal blood
away from; placenta
maternal and fetal blood supplies _________ mix
DO NOT
barrier between maternal and fetal blood supplies
chorionic villi
agents that cause birth defects
teratogens
forms between the embryo and chorion
amnion, an epithelial membrane
amnion layer will eventually hold amniotic fluid and fuses with the _______
chorion
trophoblasts secrete ______
hCG
prevents the degeneration of the corpus luteum, which maintains the secretion of estrogen and progesterone and prevents the mentsrual cycle from occurring
hCG
sex hormones that are produced during pregnancy and by what cells
estrogen and progesterone
in 1-2 months: the corpus luteum
for the remainder of pregnancy: the placenta
it is important for estrogen and progesterone to increase continuously throughout pregnancy to provide negative feedback to inhibit _______ and ________
FSH; LH
pregnancy induced hypertension, protein in urine, maternal vasoconstriction
pre-eclampsia
onset of seizures in a woman with pre-eclampsia
eclampsia
childbirth
parturition
hormones secreted during childbirth
oxytocin and prostaglandins to increase contractions (positive feedback loop)
sites of milk production
alveoli
cells that surround the alveoli and adjacent ducts
myoepithelial cells (contractile cells to eject milk)
stimulates synthesis of milk
prolactin
inhibits milk production during pregnancy
estrogen and progesterone, even though prolactin levels are high
causes increased prolactin secretion
suckling
hormone that prolactin inhibits
GnRH and then LH/FSH which is why lactation is sometimes used as birth control
watery milk produced in the first few days after birth containing proteins, immune cells, antibodies, but few nutrients (later milk will contain nutrients, growth factors, hormones, and antibodies)
colostrum
woloffian system becomes
male reproductive tract
mullerian system becomes
female reproductive tract
gonadal ridge forms testes
+ SRY
gonadal ridges form ovaries
- minus SRY
function of the MIS hormone secreted by the testes
degenerates the mullerian ducts to form the male reproductive tract
androgen receptors can’t bind to testosterone (occurs in XY individuals, no internal reproductive system and female external genitalia)
androgen insensitivity syndrome
too much androgen in XX individuals that causes masculinization
congenital adrenal hyperlasia