Female Reproductive II

Mammary Tissue During Pregnancy

-Breasts enlarge under the influence of multiple hormones, such as estrogen, progestrone, prolactin, and human placental lactogen. The ducts proliferate and grow alveoli at their ends. The terminal epithelium of the intralobular ducts proliferates and differentiates into secretory cells and secretory alveoli.

Mammary Glands

Accessory skin glands that become specialized in the production of milk. About 15-25 lobes of compound tubloalveolar glands in each breast are separated by adipose tissue and bands of dense connective tissue. Each lobe empties into a lactiferous duct with terminal expansion (lactiferous sinus) before opening independently onto the the densely innervated papilla (nipple).

Menopause and Mammary Tissue

After menopause, the secretory components, ducts, and adipose in the interlobular connective tissues in the mammary glands atrophy, in a process known as senile involution.

Menstrual Cycle: General

Can be divided into several phases. The ideal cycle is 28 days long. The endometrium goes through cyclic changes as the levels of estrogen and progesterone change under the influence of pituitary FSH/LH during the menstrual cycle. Thee phases of the cycle: 1. Menstrual Phase 2. Proliferative (Follicular; estrogenic) Phase 3. Secretory (luteal; progestational) Phase

Clitoris

Consists of two erectile corpora cavernosa that end in a glans clitoridis. Surrounded by a prepuce and covered by a stratified squamous epithelium. The erectile tissue contains fibromuscular trabeculae and cavernous sinuses lined by epithelium.

Menstrual Phase

Days 0 - 5 Coiled arteries undergo intermittent constriction, leading to ischemia of the tissue. The tissue of the stratum functionale degenerates and sheds. Debris, blood, and uterine fluid are discharge through the vagina as menses.

Secretory Phase

Days 15 - 28 The final phase of the menstrual cycle. Progesterone from the corpus luteum continues the increase in thickness of the endometrium. The endometrial glands grow and become highly coiled and have a sacculated appearance in longitudinal sections. Coiled arteries elongate and grow toward the luminal surface, reaching maximum length by day 2p. The glands secrete glycoprotein-rich mucus that creates a favorable environment for the implantation of a zygote.

Proliferative Phase

Days 5 - 14 (LEFT PHOTO) Also called the follicular or estrogenic phase. Estrogen from the developing follicle causes cells to migrate from the uterine gland epithelium in the stratum basale and regenerate the endometrium. The stratum functionale thickens, the glands lengthen, and remain straight. Spiral arteries accompany the regenerating glands.

Mammary Gland Lobules, Intralobular Ducts, and Myoepithelial Cells

Each lobe is divided into lobules. Most consist of several blind-ended intralobular ducts lined by cuboidal epithelium on a basal lamina and surrounded by myoepithelial cells. These cells have abundant actin filaments in the cytoplasm and will contract under the influence of oxytocin.

Portio Vaginalis

External surface of the cervix protrudes into the vaginal canal. This portion is called the portio vaginalis. Surface is covered by glycogenated stratified squamous epithelium that is continuous with and histologically identical to the mucosa of the VAGINAL FORNICES. The area around the external os (transformation zone) is a common site of cervical cancer)

Secretory Cells

Have appearance of protein-secreting cells. Are in the terminal epithelium of the intralobular ducts.

Mucosa Layout and Cells

Highly folded. Includes the lamina propria and lining epithelium. Two main types of cells: 1. Ciliated Cells -Sweep fluid toward the uterus 2. Peg Cells -Secrete a protective glycoprotein mucus. During ovulation, both hypertrophy to help propel the oocyte. These cells atrophy after the follicular growth phase; they lose their cilia.

Lactation and Suckling

Lactation is maintained by the suckling of the infant, which INHIBITS dopamine release from the hypothalamus Without the inhibitory effects of dopamine, PROLACTIN secretion from the pituitary increases, which in turn stimulates milk production The alveoli will otherwise degenerate when prolactin levels fall with weaning.

Cervical Canal

Lined by simple columnar epithelium, unlike the portio vaginalis. Has branched cervical glands, which secrete cervical mucous. Internal Os: End of the canal that opens into the uterine cavity. External Os: The end of the canal that opens into the vagina.

Serosa

Most of the uterus (fundus and corpus) is covered by serosa, which is called the perimetrium in the uterus. An adventitia also occurs where the uterus is attached.

Vagina

Muscular tube extending from the cervix to the external genitalia. Serves as a copulatory organ as well as the birth canal. Glands are not present in the vagina and lubrication involves the secretions from the cervical and Bartholin Glands.

Uterine Tubes (Oviducts)

Muscular tube that connects the ovary to the uterus. It is suspended by ligaments and mesentery. It is a typical hollow organ and consists of three layers: 1. Mucosa 2. Muscularis 3. Serosa There is NO distinctive submucosa. The oviducts are both open at the INFUNDIBULUM, with the FIMBRIAE, which make contact with the ovary and receive the egg after ovulation.

Muscularis and Serosa

Muscularis surrounds the mucosa of the oviduct. It consists of: 1. Inner circular 2. Outer longitudinal These also help propel the oocyte using peristalsis. The outermost layer of the oviduct is the serosa, which is part of the visceral peritoneum.

No Fertilization vs. With Fertilization

No Fertilization: The corpus luteum declines, the endometrium degenerates, the cycle repeats. With Fertilization: The corpus luteum is maintained adn the endometrium participates in the formation of the placenta. There is no shedding of the uterine lining, which results in the "first missed period."

Uterus

Par shaped muscular organ situated in the pelvic . The corpus (body), is the large round middle region. The fundus is the part of the body superior to the entry of the uterine tubes. The cervix of the uterus is the narrow neck, the downward extension of the uterus into the vagina. There are three layers of the uterus: 1. Endometrium 2. Myometrium 3. Perimetrium (serosa/adentitia)

Mammary Glands: Third Trimester of Pregnancy

Plasma cells can be seen in the interlobular connective tissue. They add IgA and IgG into the mammary secretions. Secretion does not appear in the lumens of the glands until late in pregnancy, when they contain colostrum.

Breast Tissue Development

Pre-Puberty: The mammary glands are nonfunctional and contain lactiferous ducts and sinuses. The small nipple is surrounded by a lightly pigmented areola. Puberty: Glands increase in size from increased adipose and connective tissue. The nipples enlarge and become prominent. There is proliferation of the lactiferous ducts, which increase in length and diameter and undergo significant branching.

Colostrum

Protein-rich "first milk." Found in the lumens of the glands in late pregnancy. During lactation, the lumens contain lipid-rich milk.

Ampulla and Isthmus

Region of the oviduct where fertilization occurs. This region is the longest and most expansive due to the presence of many mucosal folds. The folds are most prominent in the ampulla, and become smaller closer to the uterus, in the region known as the isthmus.

Vestibule

The area surrounding the vaginal and urethral openings. Covered by stratified squamous epithelium. Greater vestibule glands (Bartholin Glands) are mucous glands located on opposite sides of the vestibule. Lesser vestibular glands are smaller and are scattered around the vestibule.

Endometrial Blood Supply

The endometrium receives a dual blood supply and is made of two layers: 1. Stratum functionale 2. Stratum basale -constitutes the reserve cells layer -responsible for the regeneration of the endometrium

Duct System

The intralobular ducts drain into interlobular ducts. These lead to larger lactiferous ducts, that in turn empty into lactiferous sinuses. 1. Intralobular 2. Interlobular 3. Lactiferous Ducts 4. Lactiferous Sinuses These are all surrounded by myoepithelial cells. The rise of estrogen at ovulation induces proliferation of the ducts, which can cause premenstrual breast enlargement, transient edema, and tenderness.

Squamocolumnar Junction

The junction between the endocervical glandular mucosa and the squamous epithelium of the exocervix.

Physiologic Changes of the Uterine Cervix

The mucosa of the cervical canal is not shed during menstruation. The biochemical and physical properties of the cervical mucus change during the menstruation cycle: -At ovulation, thin, watery secretion allow entry by sperm. -In the luteal phase (and pregnancy), the secretions are abundant and thick, preventing entry of bacteria. High collagenase activity in the cervical wall preceding parturition leading to cervical dilation.

Endometrium

The mucosal lining of the uterus is made up of simple columnar epithelium over a lamina propria. Has three kinds of cells: 1. Secretory Cells 2. Ciliated Cells 3. Basal reserve cells Simple tubular glands dip down from the luminal surface into the lamina propria with the openings appearing as little pits on the surface.

Myoepithelial Cells and Milk Ejection

The myoepithelial cells int he alveoli contact. This is triggered during suckling which causes oxytocin release from the neurohypophysis. This hormone stimulates myoepithelial contraction, ejecting milk from the alveoli and into the lactiferous ducts.

Myometrium

The thick muscular wall of the uterus and is made up of several poorly defined muscle layers. The arcuate arteries, which give rise to the straight and coiled arteries of the endometrium, are found in the middle layer. The smooth muscle cells undergo extensive hypertrophy AND hyperplasia during pregnancy. A surge of oxytocin from the pituitary promotes the forceful contraction what expel the fetus.

Vulva and Labia

There are several folds of skin that comprise the vulva. The labia minora are skin folds with acore of spongy erectile tissue, which contain sweat and sebaceous glands on both sides, but do not have hairs. Covering the labia minora are labia majora, skin folds with cores of subcutaneous fat and a thin layer of muscle. The outer surface contains coarse hair and sebaceous and sweat glands.

Wall of the Vagina

Three layers: 1. Mucosa 2. Muscularis 3. Adventitia Proliferation and maturation of the mucosal epithelium is under the influence of ovarian hormones. The epithelium thus undergoes changes during the menstrual cycle an also changes as the female advances in age. Extensive capillary plexuses in the mucosa lamina propria provide transudate that seeps into the lumen during sexual excitement. The mucosa contains few sensory nerve endings.