Reproduction and Development Flashcards
male primary sex organs
- testes
female primary sex organs
- ovaries
scrotum
- suspends testes outside body cavity
sperm need two things for maximum viability
- cooler temperature for sperm synthesis. cooler than body temperature.
- high testosterone levels
two jobs of the testes
- make sperm
- make testosterone
interstitiaL cells
- found in between tubules
- Leydig cells
- make testosterone
- stimulated by LH
spermatogonia
- undergoing replication and mitosis
sustentacular cells
- form walls of seminiferous tubules
- sertoli cells
- sustain sperm development
- secrete nutrients
- secrete androgen binding protein
spermatogenesis
- happens on a daily basis
- spermatogonium
- mitosis to produce two spermatogonium
- spermatogonium (2n2x) - 1
- activate
- primary spermatocyte (n2x) - 1
- meiosis I
- secondary spermatocytes (n2x) - 2
- meiosis II
- spermatid (n) - 4
primary sex organs
- make gametes (sperm and ova)
seminiferous tubule
- where sperm production takes place
androgen binding protein
- binds testosterone to help concentrate it in the seminiferous tubules
spermatogonia
- ultimately become sperm
- found between sustentacular cells
- still diploid
lumen of seminiferous tubule
- find sperm
FSH
- stimulate Susentacular cells
- stimulate Spermatogonia
vas deferens
- long muscular duct
- peristalsis for movement of the sperm
- enters body cavity
epididymis
- seminal vesicles come together to form
- provide nutrients and keep sperm in a suspended state
- gives swimming ability
- final maturation of sperm and storage until ejaculation
urethra
- carries both urine and semen
- not simultaneously
role of accessory glands
- produce semen
- nutritious (fructose)
- alkaline fluid
seminal vesicles
- 60% of total ejaculate volume
- fructose, HCO3-, activating enzymes
- prostaglandins (trigger cervical dilation and vaginal contractions)
prostate
- 35% of total ejaculate volume
- “clotting factor” - 10 mins
- keeping the sperm where they need to go
bulbourethral gland
- 4% of total ejaculate volume
- activated on arousal
- secrete mucus to clean the urethra (precum) and neutralize any acid from urine
sperm pathway
- seminiferous tubules
- epididymis
- vas deferens
- urethra
sperm is what percent of ejaculate
- only 1%
enlarged prostate
- impinges on the urethra and makes it difficult for urine to pass through
physiological function of the penis
- place sperm as close to cervix as possible
arousal under what control
- parasympathetic control
erection
- dilate the erectile arteries swelling the spongy tissue
- penis become erect
- labia and clitoris enlarge
lubrication
- activation of bulbourethral gland (males)
- activate the greater vestibular glands (females)
orgasm under what control
- parasympathetic control
emission
- mix sperm and semen in urethra
- contraction of vas deferens and accessory glands
ejaculation
- sperm are propelled through the vas deferens and ejaculated
- reflexive rhythmic contraction
- vagina contracts and cervix dilates
resolution under what control
- sympathetic control
- female resolution a lot longer than male
- arteries constrict and blood leaves the erectile tissue
male system
- wolffian system
female system
- mullerian system
- default
gender development in males
XY -> 7-8 weeks of development -> testes
- testosterone (develops Wolffians)
- Mullerian inhibiting factor (MIF)
- inhibits mullerian system
labia
- skin folds that enclose openings
- clitoris, urethral opening, vaginal opening
greater vestibular glands
- secrete alkaline mucus on arousal
- help make vagina less acidic
- near the back of the vestibule
mammary glands
- produce milk (prolactin)
- oxytocin allows for milk letdown
vagina
- stretchy and muscular
- “birth canal”
- acidic interior - keeps pathogens from growing. not good for sperm
cervix
- opening to the uterus
non-fertile cervix
- most days of the month
- closed, plugged by a thick, acidic mucus
fertile cervix
- only a few days of the month
- dilate slightly ( 1 cm)
- mucus becomes thin, stretchy, alkaline
uterus
- pregnancy develops here
endometrium
- built up and shed monthly
- fertilized egg implants here
myometrium
- smooth muscle layer (oxytocin)
- unique in that cell retain their ability to divide
uterine tubes
- connect uterus and ovary
- fallopian tubes
- fertilization occurs here
- tubal ligation occurs
- lined by cilia to move the egg to the uterus
vestibule
- urethral opening
- vaginal opening
two jobs of the ovary
- make the eggs (ova)
- make estrogen and progesterone
oogenesis prenatal stage
- oogonia
- mitosis
- oogonia (200K-400K)
- activation
- primary oocyte (halt in prophase I)
monthly from puberty (menarche 1st cycle) to menopause
- 5-6 primary oocytes
- complete meiosis I
- 1 secondary oocyte + first polar body
- halt at metaphase II
- ovulated and stops
if fertilized
- secondary oocyte
- complete meiosis II
- ovum + second polar body
endocrine regulation of menstrual cycle
- hypothalamus
- GnRH
- anterior pituitary
- FSH, LH
- ovary
- estrogen, progesterone (feedback to AP and hypothalamus to turn off release of stimulus)
- uterus
follicular phase of ovarian cycle
- days 1-13
- build follicle (oocyte + all supporting cells)
- triggered by FSH
- secretes estrogen
ovulation of ovarian cycle
- day 14
- release secondary oocyte and some supporting cells
- triggered by LH surge
luteal phase of ovarian cycle
- days 15-26
- corpus luteum forms from follicular remains
- triggered by LH to maintain
- secretes mostly progesterone and some estrogen
menstruation of uterine cycle
- days 1-5
- low estrogen and progesterone
- cause shedding of old endometrium
proliferative phase of uterine cycle
- day 6-14
- rising estrogen and progesterone levels
- causes rebuilding of endometrium
secretory phase of uterine cycle
- days 15-28
- stable estrogen and progesterone
- enhance endometrium in case implantation happens
- secretion of nutrients into endometrium
- glycogen, lipoproteins
fertility drugs
- work to increase the number of primary oocytes released
structure of oocyte
- oocyte
- zone pellucida
- granulosa cells
- thecal cells
estrogen positive feedback
- at very high levels it feeds back to anterior pituitary to release more LH
- at moderate levels it has negative feedback
combined effect of estrogen and progesterone
- strong negative feedback on anterior pituitary
big link to endometrium
- link to estrogen
in presence of hcg
- corpeus luteum does not degenerate
- estrogen and progesterone levels do not fall off
- never start shedding endometrium
birth control pills
- combination of estrogen and progesterone
- stable levels of E and P day 7-28
- inhibits FSH and LH
- follicle not going to be stimulated to develop
- no LH surge and no ovulation
- less endometrium to make less likely for implantation.
- periods are a lot shorter and lighter because there is a lot less endometrium to get rid of.
fast block to polyspermy
- egg membrane depolarizes to prevent other sperm from wanting to fertilize the egg
- triggers slow block
slow block to polyspermy
- Ca2+ levels increase causing cortical reaction
- zona pellucida hardens and separates from egg surface
acrosomal vesicles of sperm
- top of sperm head
- contain digestive enzymes to eat through corona radiata of egg
- takes a few sperm to do this
cleavage
- dikaryon (1 cell with 2 nuclei)
- oocyte meoisis II + kick out second polar body
- syngamy (unity sperm and egg DNA)
- zygote - single cell, diploid nucleus
- 2-cell stage
- replication and mitosis
- morula - solid ball of cells
- blastula - hollow ball of cells
- implants in wall of uterus
- traveling down uterine tubes to uterus.
implantation
- trophoblast
- inner cell mass
inner cell mass
- develop into fetus and umbilical cord
trophoblast
- becomes placenta
- secretes hCG which replaces LH
- corpus luteum maintained until the 3rd month when the placenta sustains itself
stem cells
- undifferentiated cells
- can reproduce to make more stem cells
where are stem cells found?
- brain
- skin
- bones
- gonads
- intestines
body tissue stem cells
- adult stem cells
blastocyst stem cells
- embryonic stem cells
determination
- cell becomes committed to a particular fate
- irreversible
- cytoplasmic and nuclear changes
differentiation
- physical changes to a specific cell type
pluripotent cells
- can become any cell type within the body
- cannot become the placenta (outside the embryo)
multipotent cells
- can become some but not all cell types
- bone marrow and blood stem cell
totipotent cells
- can become any cell type include placental cells
- zygote is the only cell that can do this
embryonic stage
- first 8 weeks of development after fertilization (2-10 weeks medically pregnant)
- gastrulation
- neurulation and organogenesis
gastrulation
- first half of embryonic stage
- form 3 primary germ layers
endoderm
- inner skin and glands (organs that secrete things)
- GI and respiratory tract
- pancreas
- liver
- adrenal gland
- bladder
mesoderm
- muscle, bones, CV system, urogenital
- blood
- non-gland organs
ectoderm
- outer skin and nervous system
- hair, nails
neurulation and organogenesis
- second half of embryonic stage
- form nervous system
- form all organs in the body
fetal stage
- week 12 - visible gender ID
- week 16 - baby muscle contractions can be felt by mom
- week 24 - eyelids unfuse, baby responds to external stimuli
- week 28 - testes descend if male
- week 33 - surfactant to prevent collapse of alveoli
- week 38 - full term birth
3 triggers for labor
- irritable uterus - wants to contract
- placenta deteriorates
- uterus is stretched
- baby’s head stretches cervix
- stimulates hypothalamus
- posterior pit releases oxytocin
- myometrium (uterus) contracts
= positive feedback
stage 1 of labor
- cervical dilation (10 cm)
stage 2 of labor
- fetus is moved into birth canal and is born
stage 3 of labor
- the placenta is expelled
baby changes
- ALL CIRCULATORY IN NATURE
- close lung bypasses
- close liver bypass
- close umbilical vessels
- arteries close first - carry blood away from baby’s heart toward placenta
- veins close second - carry blood toward baby heart away from placenta
- stop making fetal hemoglobin
changes in mom
- delivers placenta
- estrogen and progesterone drop
- release inhibin on prolactin
- prolactin levels rise
- make milk -> baby nurses -> more prolactin
- oxytocin
- milk ejection -> baby nurses -> more oxytocin
breached babies
- harder to get baby moving and typically result in C sections
lung bypass of baby
- vessel between the pulmonary artery and the aorta (ductus arteriosus)
- hole between the right and left atria
fetal hemoglobin
- has higher affinity for oxygen than does adult hemoglobin
- steal oxygen from mom’s hemoglobin so affinity must be higher
- mom delivers less to tissues
