lecture 15 Female reproductive system

Female reproductive system primary functions

Produce hormones (estrogen, progesterone)

produce oocytes (oogenesis)

support embryo/fetus

enable sexual activity

nourish infant via lactation

Location of female reproductive system

Primarily within pelvic cavity

Ovaries function

Produce oocytes and secrete sex hormones

Fallopian (uterine) tubes function

Transport oocyte toward uterus; site of fertilization

Uterus function

Site of implantation, placenta formation, fetal development

Cervix function

Barrier to uterus

passage for menstrual flow

produces cervical mucus

dilates during childbirth

Vulva definition

External female genitalia

Cesarean section (C-section) definition

Surgical delivery through incision in abdomen and uterus

Common reasons for C-section

Obstructed labor, breech birth, twins, maternal age >35, obesity, hypertension, fibroids

Ovarian cycle vs menstrual cycle

Ovarian cycle prepares egg; menstrual cycle prepares uterine lining

Ovulation definition

Release of egg from ovary ~2 weeks before menstruation

Fertilization definition

Fusion of sperm and oocyte

Polyspermy prevention

Changes in egg membrane block additional sperm after fertilization

Blastocyst definition

Multilayered structure that implants in uterus

Path of oocyte

Ovary → fallopian tube (fertilization) → uterus (implantation)

Oogenesis definition

Formation of female gametes (ova)

SRY gene function

Encodes transcription factor that turns genes on/off for male development

With SRY gene

Male reproductive structures develop

Without SRY gene

Female reproductive structures develop

Homologous structures definition

Structures derived from common ancestor (e.g., glans penis and clitoris)

Analogous structures definition

Structures with similar function but different evolutionary origin

Female reproductive hormones

Estrogen and progesterone

Male vs female testosterone levels

Females have ~1/8 testosterone compared to males

Wolffian ducts (male)

Develop into epididymis and vas deferens

Wolffian ducts (female)

Degrade

Müllerian ducts (female)

Form uterus and fallopian tubes

Müllerian ducts (male)

Degrade

Ovarian cycle purpose

Prepare egg for fertilization

Menstrual cycle purpose

Prepare uterine lining for implantation

HPV (human papillomavirus) definition

Common STI linked to cervical cancer

HPV prevalence

Highest in females ages 18–24 (30–40%)

HPV strains classification

Low-risk (warts) vs high-risk (cancer)

High-risk HPV strains

16 and 18 (cause >70% of cervical cancer cases)

How HPV causes cancer

Inhibits p53 tumor suppressor → mutated cells divide uncontrollably

p53 function

Detects DNA damage and prevents mutated cell growth

Cervical cancer prevention

HPV vaccine, safe sex, Pap smears

Pap smear purpose

Detect abnormal cervical cells

HPV vaccine recommendation

Ages 9–26 (ideal 11–12), approved up to 45

Breasts function

Accessory organs that produce milk

Lactation feedback loop

Suckling → oxytocin & prolactin release → milk production & ejection → continued stimulation maintains loop

Birth control permanent methods

Tubal ligation, vasectomy

Hormonal implant (Nexplanon)

Subdermal arm implant, releases progestin, suppresses ovulation, can cause irregular bleeding

Hormonal IUD

Releases progestin, suppresses ovulation, reversible

Copper IUD (Paragard)

Non-hormonal, creates toxic environment for sperm, long-lasting (>10 years), may increase bleeding

Pill characteristics

Daily, user-dependent, easy to miss doses

Patch characteristics

Weekly replacement, more consistent than pill

Ring characteristics

Inserted monthly

Shot (Depo-Provera)

Every 3 months, progestin-only, may cause amenorrhea, delayed fertility return

Barrier method (diaphragm)

Covers cervix, used with spermicide, must remain 6 hours post-intercourse

Fertility awareness method

Avoid sex during fertile window using cycle and temperature tracking (0.3–0.5°C change)

Condom effectiveness

80–90% reduction in HIV, chlamydia, gonorrhea, hepatitis B

Condom limitation

Does not fully protect against HPV, HSV, syphilis