Ductus deferens Seminiferous tubules The cells of Leydig in testes secrete testosterone T T secreted at puberty produces 2 o sex characteristics spermatogenesis amp maintain tracts ID: 594165
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Slide1
Epididymis
Ductus
deferens
Seminiferoustubules
The cells of Leydig in testes secrete testosterone (T) T secreted at puberty produces 2o sex characteristics, spermatogenesis, & maintain tracts
Sperm productionSlide2
Spermatogenesis
: spermatogonia (2N) spermatozoa (N)
Epididymis
Ductusdeferens
Seminiferous
tubules
Sperm productionSlide3
Lumen of
seminifeous
tubuleSertoli cellSpermatidsSecondary
spermatocytePrimaryspermatocyteSpermatogonium
Mitosis
Meiosis
Sertoli
cellSlide4
Controlling sperm productionUnlike females, males produce sperm from puberty onward
Spermatogenesis controlled by LH and FSHSlide5
LH & FSH in males
LH acts on Leydig cells for T prod’n
FSH acts on Sertoli cells for sperm prod’n (inhibin provides negative feedback)Slide6Slide7
Sperm production, viability influenced by:
Smoking, marijuana useAlcohol abuseAnabolic steroids, overly intense exercise, stressTight underwear, pantsEnvironmental pollutants (pesticides, lead, paint, radiation, heavy metals)Causes of infertility?Slide8
Spermatids become motile and are stored in epididymis and ductus deferens
Sperm storageSlide9
Seminal vesicles supply fructose, prostaglandins for muscle contraction, & fibrinogenProstate gland secretes alkaline fluid and clotting enzymesBulbourethral glands
add mucus for lubricationMaking something to swim inProstate gland
TestisDuctus deferens
BulbourethralglandUrinary bladderSeminal vesicleSlide10
Signals for erection and ejaculationArousalPudenal
nerves carry signals from penis to lower spinal cord & brain Spinal reflex and brain send PNS signals to penile arteriolesArousal causes muscle contractions that incr. physical stimulation – positive feedbackEjaculationDramatic shift to SNS – contractions move semen to urethra and outSlide11Slide12
Viagra blocks PDE5, a enzyme that breaks down a local signal that causes dilation in response to NO There are many PDE’s – PDE5 is mainly in the penis
How does Viagra work?Slide13
Female reproductive anatomyOvaries produce
estrogen, progesterone, and are site of oogenesisEstrogen: maintenance of the female tracts, 2o sex characteristics, ova maturation and releaseSlide14
Oogonia divide mitotically Meiosis I produces a primary oocyte
(diploid), surrounded by follicle cells These oocytes develop into secondary oocytes on a cyclical basis Oogenesis overviewSlide15
Follicular phase - first half of cycle when follicles mature and are ovulatedLuteal phase - second half of cycle when uterus is prepared for implantation
Ovarian cycleFollicular LutealSlide16
Primary follicle
oocyte
Follicle cells
Looking within the ovary…follicular phase
FSH and LH levels are increasingSlide17
Follicle cells secrete estrogen
Dividing
follicular cells
Thecal cells
Primary
oocyte
Looking within the ovary…follicular phaseSlide18
antrum
Antrum collects fluid with estrogen
Estrogen inhibits FSH and LH, so FSH
Looking within the ovary…follicular phaseSlide19
Low to moderate levels of estrogenSlide20
Follicle (thecal) cells
Follicle (granulosa) cells
Antrum
primary oocyte
Late follicular phase
High estrogen levels promote LH secretion w/ positive feedback loopSlide21
High levels of estrogenSlide22
Late follicular phase
Mature
follicle
Antrum
Oocyte finishes meiosis Iit now is a 2o oocyteSlide23
Follicle
remains
secondary oocyte
Egg is flushed out
Pop! Ovulation!Slide24
How do fraternal vs. identical twins occur?Why are male and female gametes produced in different ways?Student questionsSlide25
corpus
luteum
Luteal phase
Corpus luteum secretes progesterone and estrogenSlide26
Estrogen and progesteroneEstrogen initiates preparation of
endo- and myometrium, ‘prime’ uterus for progesterone (follicular phase)Progesterone endometrium vascularization, glycogen, decrease contractions (luteal phase)Progesterone inhibits LH and FSH (this is how birth control pills work)Slide27
If the corpus luteum degenerates, progesterone drops and menstruation occursChanges in endometrium
Degenerating
corpus luteumSlide28
Why cramping during periods?What is the physiology of menstruation?Why do birth control pills effect periods?Often estrogen levels are lower w BCPStudent questionsSlide29Slide30
Fertilization normally occurs within a day of ovulation
Contractions of the myometrium help some sperm reach the oviductBut if there are sperm around…
acrosomein actionSlide31
Embryo
Trophoblast
Implants the embryo
Blastocyst
Cleavage
Fertilization
Ovulation
Implantation
Embryo forms before reaching the uterusSlide32
Blastocyst secretes chorionic gonadotropin
Endometrium has glycogen, and becomes more vascularized from progesterone40% of blastocysts never implantSettling into the uterus…Slide33
Trophoblast
enzymes digest proteins of the endometrium. This carves a hole for implantation.Settling into the uterus…
Endometrium
Trophoblast
Embryo
Embryo
EndometriumSlide34
Embryo
Eventually forms
chorionSlide35
Placenta = chorion from embryo and uterine lining from mother. These tissues interlock like ‘fingers’
Projections of chorion have capillaries to form placental villi. They extend into the mother’s blood. Placenta developmentSlide36
Gasses, wastes, nutrients diffuse
bw capillaries of mother and fetusDrugs, pollutants, chemicals also diffusePlacenta development
mother’s blood
Placental villus
Amniotic sac
ChorionSlide37
What does alcohol do to cause fetal alcohol syndrome? How does drug use during pregnancy affect a fetus?Question:Slide38
Human chorionic gonadotropin (hCG)
Estrogen
Progesterone
Fertilization
DeliverySlide39
Relaxin from placenta softens the cervix and pelvisUterus has mild contractions. Baby’s head is down in pelvis
High levels of estrogen make the uterus more sensitive to oxytocin. Progesterone levels dropGetting ready for birth....Slide40
Stretching the cervix causes more oxytocin to be releasedOxytocin induces stronger contractions
Positive feedback with oxytocinSlide41
Lactation