Unit 15: Female Reproductive System

ovaries

primary sex organs or gonads

• Paired glands weighing about 3 g each

• Resemble large almonds

• Attached to ligaments in pelvic cavity on each side of uterus

ova

sex cells

graafian follicles

About 350 to 500 mature follicles

oocyte

immature sex cell

antrum

hollow chamber of secondary follicles

Oogenesis

This meiotic cell division produces daughter cells with equal chromosome numbers (23) but unequal cytoplasm; ovum is large; polar bodies are small and degenerate

Granulosa cells

surrounding the oocyte in the mature and growing follicles produce estrogen

Corpus luteum

produces progesterone

Estrogen

causes development and maintenance of secondary sex characteristics

Progesterone

stimulates secretory activity of uterine epithelium and assists estrogen in initiating menses

Fallopian Ducts

uterine tubes

• Extend about 10 cm from uterus into abdominal cavity

• Expanded distal end surrounded by fimbriae

• Mucosal lining of tube is directly continuous with lining of abdominal cavity

Uterus

• Composed of body, fundus, and cervix

• Lies in pelvic cavity just behind urinary bladder

• Myometrium is muscle layer

• Endometrium lost in menstruation

Menopause

End of repetitive menstrual cycles (about 45 to 50 years of age)

Vagina

• Distensible tube about 10 cm long

• Located between urinary bladder and rectum in the pelvis

• Receives penis during sexual intercourse and is birth canal for normal delivery of baby at end of term of pregnancy

Vestibular glands

Bartholin’s and Skene glands

• Secrete mucus lubricating fluid

• Ducts open between labia minora

Vulva

Several structures, which includes mons pubis, clitoris, external urinary meatus, labia minora, hymen, openings of vestibular gland ducts, orifice (opening) of vagina, and labia majora

Perineum

Area between vaginal opening and anus

episiotomy

Surgical cut during childbirth

Breasts

• Located over pectoral muscles of thorax

• Size determined by fat quantity more than amount of glandular (milk-secreting) tissue

• Lymphatic drainage important in spread of cancer cells to other body areas

Lactiferous ducts

drain at nipple, which is surrounded by pigmented areola

Menses

Small patches of dead cells of uterine lining slough off leaving torn blood vessels; menstrual bleeding comes from these torn vessels

Proliferative phase

• Days between the end of menses and secretory phase

• Varies in length; the shorter the cycle, the shorter the proliferative phase; the longer the cycle, the longer the proliferative phase

Epitheliel cells reproduce, repairing the uterine lining

Ovulation

Typically occurs 14 days before the next menses begins

• Timing of ovulation has great practical importance because of the possibility of fertilization

• Most sperm retain their fertilizing power for only 24 to 72 hours after being deposited into female reproductive tract

• A woman's fertile period lasts only a few days each month

Ovum is release from ovary and moves into uterine tube for possible fertilization

Secretory phase

• Days between ovulation and beginning of next menses

• Secretory about 14 days before next menses

• Characterized by further thickening of endometrium and secretion by its glands in preparation for implantation of fertilized ovum

• Combined actions of the anterior pituitary hormones FSH and LH cause ovulation

• Sudden sharp decrease in estrogens and progesterone bring on menstruation if pregnancy does not occur

Uterine lining prepares fro pregnancy (impantation of fertilized ovum) by growing thivker, secreting, and developing greater blood supply; on last day, blood supply decreases greatly, causing some lining cells to die

Menstrual cycle

 Control of the menstrual cycle

➢ Secretion of gonadotropin releasing hormone (GnRH) stimulates the secretion of FSH and LH from the anterior pituitary gland

➢ Ovulation occurs because of the combined actions of the two anterior pituitary hormones

➢ Birth control pills that contain estrogen substances suppress FSH secretion

Follicular Phase

Pituitary Hormone Effect: LH and FSH stimulate several follicles to grow

Ovarian Hormone Effect: Dominant Follicle produces estradiol which:

• Inhibits GnRH, FSH, and LH Production

• Causes Endometrium to Thicken

Hypothalamus secretes GnRH to Anterior Pituitary which secretes (+) FSH and LH to Follicles of Ovaries which secrete Estradiol to the (-) Endometrium of the Uterus, Anterior Pituitary, and Hypothalamus

Ovulation Phase

Pituitary Hormone Effect: LH and FSH stimulate maturation of one of the growing follicles

Ovarian Hormone Effect: Growing Follicle continues to produce estradiol which:

• Stimulates GnRH, FSH, and LH Production

• LH surge triggers ovulation

Hypothalamus secretes GnRH to Anterior Pituitary which secretes (+) FSH and LH to Follicles of Ovaries which secrete Estradiol to the (+) Endometrium of the Uterus, Anterior Pituitary, and Hypothalamus

Luteal Phase

Pituitary Hormone Effect: LH stimulates formation of a corpus luteum from follicular tissue left behind after ovulation

Ovarian Hormone Effect: The corpus luteum secretes progesterone which:

• Inhibits GnRH, FSH, and LH Production

• Maintains the Endometrium; as the corpus luteum degrades, progesterone declines, initiating sloughing of stratum functionalis

Hypothalamus secretes GnRH to Anterior Pituitary which secretes (+) FSH and LH to Follicles of Ovaries which secrete Progesterone to the (-) Endometrium of the Uterus, Anterior Pituitary, and Hypothalamus