lecture 15 bio142

analogous structures

perform similar functions but evolved indepedentally, not from a recent common ancestor. The vas deferns are analogus to the fallopian tubes

functions of the female reproductive system

1. produce androgens, sex horomones, such as estrogens amd progesterone

2. reproduction through ovum (oogensis)

3. sexual activity

4. support growth and survival of an embryo from conception till birth

5. nourshing new born infant through breast feeding

introduction to the female (ovarian) reproductive system

the female or ovarian reproductive system functions to produce gametes and reproductive hormones, just like the male reproductive system; however it also has the additional task of supporting the developing fetus and delivering it to the outside world. Unlike its male counterpart, the female reproductive system is located primarily inside the pelvic cavity.

internal female genitilia

the major organs of the female reproductive system are located inside the pelvic cavity

ovaries

produce oocytes and sex hormones

fallopian (uterine) tubes

transport secondary oocytes in the direction of uterus, fertilization happens here

uterus

muscular organ and site of implantation, placenta formation, and fetal development

cervix

acts as a barrier to protect the uterus, allows passage of menstrual fluids to exit the body, produces cervical mucus that nourishes sperm and promotes fertility. During child birth the cervix must dilate to pass the baby from the uterus to the vagina

cesarean section (c-section)

the surgical delivery of a baby through a cut (incision) made in the mothers abdomen and uterus

it is often performed because vaginal delivery would put the mother and baby at risk, common reasons for c section include

obstructed labor, breech birth, twins, advanced maternal age (over 35), maternal health issues such as: obesity, high BP, large uterine fibrosis

20% of the worlds births is done thru c section

and 32% of us births are done through c section

mons pubis

rounded fatty eminence that cushions the pubic symphysis; covered with coarse pubic hair after puberty

labia majora

two elongated hair-covered skin folds that extend from the mon pubis. They contain sebcaucous glands, aprocrine glands, and adipose tissue. They are homologus to the scrotum

labia minora

two smaller folds located medial to the labia majora. They dont have hair or adipose tissue but they do have many sebcacous glands

vestibule

region located between the labia minora. From anterior to posterior, it contains the clitoris, the external urethral orifice, and the vaginal orifice

clitoris

small mass of erectile tissue located where the labia minora meet anteriorly. It is homologus to the penis

prepuce of clitoris

skin folds formed by the union of the labia minora; they serve as the hood of the clitoris

external urethral orifice

serves as the outlet for the urinary system. It has no reproductive function in the female system

the ovarian cycle takes place in the ovary whereas

the menstrual (uterine) cycle occurs in the uterus

the ovarian cycle prepares

the egg for fertilization

the menstrual cycle prepares

the uterine wall to receive a fertilized egg

ovulation

is the phase of the female menstrual cycle that involves the release of an egg (ovum) from one of the ovaries. It generally occurs about two weeks before the start of the menstrual period

fertilization is the fusion of

the male and female gamete. This process causes changes of the membrane of the now fertilized egg, such as blocking further fertilization of the sperm (polysperma)

development continues along the length of the fallopian tubes until a

multilayered blastocyst implants into the uterus

research over many years has confirmed that cervical cancer is most commonly caused by a

sexually transmitted infection with human papillomavirus (HPV). There are over 100 related viruses in the HPV family, and the characteristics of each strain determine the outcome of the infection

HPV is common across al demographics with the highest prevalence of HPV infections being

females aged 18-24 (30-40% depending on study)

HPV strains are classified as high or low risk according to their potential to cause cancer. Though most HPV infections do not cause disease,

the disruption of normal cellular functions in the low risk forms of HPV can cause the human host to develop genital warts

often, the body is able to clear an HPV infection by normal immune responses within 2 years.

However the more serious, high risk infection by certain HPV can result in cancer of the cervix. HPV strain 16 and 18 account for more than 70% of cervical cancer diagnoses.

high risk variants of HPV block hosts cell’s ability to

prevent mutated cells from dividing

development of cervical cancer protein p53

plays a vital role in detecting mutations and preventing mutant cells from growing. high risk variants of HPV inhibit p53 this permits the growth of mutant and potentially cancerous cells

preventing cervical cancer caused by HPV

vaccines, protections, and screenings via a pap smear all play significant roles in reducing the development of cervical cancer.

PAP smears sample cells of the cervix allowing

the detection of abnormal cells

HPV infections targeted by vaccine have decreased since vaccination was introduced

88% down among teen girls, 81% down among young women, should recommend HPV vaccine to all children aged 11 and 12

2018T - HPV

vaccine is approved for males

hpv males recommenced 9-26 to prevent hpv related cancers (anal, mouth, throat) and genital warts.

It is most effective when given ages 11-12 though it is approved up until age 45, with adults 27-45 advised to discuss benefits with their doctor

HPV vaccine, the most recent vaccine prevents against

90% of hpv strains that cause cancer, 90% of hpv strains that cause anal cancer, 90% of hpv strains that cause genital warts, most strains that cause mouth and throat cancers

lactation feedback loop

1. stimulus baby suckles breast

2. receptor sensory receptors in the skin of the breast detect suckling and send nerve impulses to hypothalamus

3. control center hypothalamus signals posterior pituitary to release oxytocin

4. effect breast is stimulated to eject milk
   breast milk released baby cotinues suckling postive feedback loops

tubal ligation & vasectomy

very effective but considered permeant

hormonal implants and intrauterine device (IUD)

what they have in common, release progestin (synthetic progesterone), suppressing ovulation, reversible

nexplanon (implant)

location: in arm subdermal implant

most common side effect irregular bleeding

paragard copper IUD

very long lasting (10+ years), no hormonal side effects, reversible, may increase bleeding and cramping, copper creates a toxic and inflammatory environment that kills sperm, works immediately after insertion

all of the hormonal methods from the okay category contain

progestin + estrogen that prevent ovulation

the pill

taken daily, most user dependent easiest to miss doses

the patch

replaced weekly, less frequent dosing → slightly more consistent

the ring

inserted monthly

the shot (depo-provera)

given every 3 months, no daily/weekly action most consistent group, progestin only, return to fertility is often delayed 2-3 months,

what do many users develop from the shot depo-provera

amenorrhea (absence of menstruation) after one year

diaphragm (barrier method)

placed over the cervix before intercourse, used with spermicide (chemical that kills sperm), prevents sperm from entering uterus, must remain in place for at least 6 hours after intercourse

fertility awareness (timing method)

avoids intercourse during the fertile window, based on predicting when ovulation occurs by tracking menstrual cycle, and basal body temperature 0.3-0.5c

condoms

have strong STI prevention 80-90% reduction in transmitting HIV, chlamydia, gonorrhea, and hepatitis b, they do not provide protection against STIs that cause genital ulcers or lesions such as HPV (warts) and HSV (herpes), and syphilis