Female Reproduction II Flashcards
Oviduct subdivisions
- infundibulum- funnel shaped end where the oviduct lumen opens to the peritoneal cavity. Finger-like fimbriae surround the opening
- ampulla- longest portion, widest after the infundibulum
- isthmus- straight portion connecting the ampulla and uterus
- intramural part- passes through uterine wall
General Histology of Oviducts
- three layers: inner mucosa, middle muscularis, outer serosa
- no submucosa
Oviduct mucosa
-mucosal folds- fill much of the oviduct lumen. Most elaborate in ampulla simplest in the intramural part
-mucosal epithelium- simple, columnar epithelium, lines the oviduct lumen and surfaces of fimbrae two cell types:
+ciliated cells: pale eosinophilic cytoplasm, large euchromatic basal nucleus, prominent apical cilia and darkly staining basal bodies at the cilia bases. Function to sweep the oocyte complex or fertilized embryoes toward the uterus
+secretory cells: dark staining due to secretory products. Apical surfaces protrude above the epithelial surface, resembling pegs, hence also called peg cells. Function: their secretions nourish and protect gametes/embryos, and capacitate sperm activation
- lamina propria: highly cellular, well-vascularized CT. In the fimbriae, also contains smooth muscle to support fimbriae movements
- hormone sensitivity: estrogen stimulates cilia elongation, increased secretion by secretory cells, and hypertrophy of both epithelial cell types
Oviduct muscularis
- smooth muscle and some CT. Thick, inner, circularly-oriented layer and thin, outer, longitudinally-oriented layer. Thickens and becomes better defined from the infundibulum toward the uterus
- bends the infundibulum close to the ovary
- sweeps the fimbriae over the ovary surface
- peristaltic contractions propel fertilized embryos toward the uterus
Oviduct serosa
- well vascularized loose connective tissue
- simple squamous to cuboidal mesothelium covering
Ectopic pregnancy
- a fertilized embryo unable to reach the uterus may implant in the oviduct mucosa
- in absence of intervention or spontaneous termination: developing placenta erodes large blood vessels, growing embryo ultimately ruptures the oviduct, lethal hemorrhaging results
Anatomical overview of uterus
- upper uterine body, referred to hereafter simply as the uterus
- lower uterine cervix
- three histological layers: inner endometrium, middle myometrium, and outer perimetrium (or epimetrium)
Endometrium
- stroma- CT of amorphous group substance, some type II collagen, many fibroblasts
- surface epithelium: simple columnar epithelium that is only sometimes present
- uterine glands: simple, tubular glands lined by simple, columnar secretory cells. Continuous with the surface epithelium
- circulation:
- spiral arteries supply the upper endometrium (portion closest to the lumen), called the functional layer (functionalis)
- straight arteries supply the lower endometrium, called the basal layer (basalis)
- changes in ovarian hormones through the menstrual cycle cause loss and regrowth of the functional layer
- three recognized uterine phases: menstrual, proliferative, and secretory
Menstrual phase endometrium
- hormonal control:progesterone loss after luteolysis causes constriction of spiral arteries, hypoxia of functional layer. Straight arteries, and therefore the basal layer are not affected
- menstrual flow or menses: sloughing of the functional layer in response to tissue hypoxia
- thin endometrium, lacks a surface epithelium, very short glands
Proliferative phase endometrium
- hormonal control: estrogen produced by growing ovarian follicles acts as mitogen, promoting proliferation of stromal and gland cells
- surface epithelium regenerates from proliferating uterine gland secretory cells
- stroma thickens through replication of basal layer fibroblasts and production of extracellular material
- uterine glands lengthen
- spiral arteries grow into the reformed functional layer and sprout arterioles
- thick (2-3 mm) endometrium, numerous mitotic figures, particularly among the secretory cells, long,straight, narrow glands
Secretory phase endometrium
- hormonal control: progesterone from the corpus luteum stimulates secretory cell hypertrophy and secretory activity, and promotes vascular changes
- secretory cells hypertrophy: results in coiling of the uterine glands
- secretory cells secretory actvity: secrete glycogen-rich product through apocrine mechanism, glycoprotein-rich product through merocrine mechanism
- secretions: primary nutrition source for the embryo prior to and during implantation. Cause dilation of uterine glands
- thin-walled vascular lacunae develop and fill with blood. Provide abundant blood flow to the placenta in the event of implantation and pregnancy
- very thick (5-6 mm) endometrium, dilated coiled uterine glands, secretory product accumulated in secretory cells and gland lumens, prominent spiral arteries
Endometriosis
-presence of endometrial stromal and parenchymal cells outside the uterus
-endometrium sloughed during menses passes retrograde through the oviducts, into the peritoneal cavity
-potential sites: ovaries, outer surfaces of the oviduct or uterus, broad ligaments, colon, rectouterine pouch, and rectal sheath
Consequences
-endometrial tissue remains hormone sensitive, undergoing cycles of growth followed by bleeding through the menstrual cycle
-results in pain, inflammation, and the formation of adhesions between the organs and wall of the peritoneal cavity
-chocolate cyst- specific case of endometrial tissue invading the ovary tunica albuginea
Myometrium
- thickest layer of uterine wall
- bundles of smooth muscle are separated by connective tissue
- organized into three partially interwoven layers
Changes in myometrium during pregnancy
- hyperplasia (increase in cell number) of smooth muscle cells
- hypertrophy (increase in cell size) of smooth muscle cells
- increase collagen production by smooth muscle cells
- these changes thicken and strengthen the myometrium during pregnancy
- changes revert after pregnancy through smooth muscle cell apoptosis and/or atrophy and removal of excess collagen
Uterine leiomyomas
- fibroids
- benign smooth muscle tumors in the myometrium
- occur in one out of every four women
Perimetrium (Epimetrium)
- serosal where exposed to the peritoneal cavity: loose connective tissue, prominent blood vessels, covering the mesothelium. Continuous with the broad ligament (the uterine mesentery)
- adventitial where not exposed: loose connective tissue that blends into surrounding tissues
Cervical mucosa
- mucosal epithelium: simple, columnar epithelium of mucous secretoy cells
- cervical glands: long, non-coiled, branching tubular glands with wide lumens
- secretory product: mucus. Consistency is hormone dependent
- Nobothian cysts- result from occlusion of cervical gland ducts, secretory product accumulates in the plugged ducts, not neoplastic and generally resolve without intervention
Cervical wall
- dense connective tissue with smaller amounts of smooth muscle
- during pregnancy collagen and elastin rearrange to facilitate parturition
External os
- protrusion of the cervix into the superior portion of the vagina
- transformation zone:
- on the external os
- junctional between cervical simple, columnar mucosal epithelium of the cervix and stratified, squamous mucosal epithelium of the vagina
- most frequent origin of cervical carcinomas
- Papanicolaou test (Pap smear)- cytological examination of transformation zone scrapings. For early detection of pre-cancerous changes. Pap smears have dramatically reduced the incidence of and mortality from cervical cancer
Vagina mucosa
- mucosal epithelium- stratified, squamous, non-keratinized, epithelial cells accumulate glycogen. After desquamation, released glycogen is fermented to lactic acid by resident Lactobacilli bacteria, creating an acidic environment that inhibits infectious agents
- frequently infilitrated by lymphocytes and neutrophils
-lamina propria: well vascularized, rich in elastic fibers that continue into the muscular layer, abundant lymphocytes and neutrophils, no glands
Muscular layer of vagina
-smooth muscle fibers in two indistinct layers: an inner circular and an outer longitudinal layer
Vagina adventitia
- elastic connective tissue
- resilient shealth around the muscular layer
Nipple and areola
- highly pigmented skin
- long dermal papillae
- pigmentation and prominence increase at puberty
- radial and circumferential smooth muscle fibers in underlying dense, irregular connective tissue allows nipples to become erect
- sebaceous glands, sweat glands, and glands of Montgomery (modified mammary glands) underlie the areola
Parenchyma of breast
- the mammary glands (ducts and secretory elements)
- modified apocrine sweat glands
- compound tubuloalveolar glands
Stroma
-connective tissue surrounding the parenchyma
Breast lobe
- largest unit of duct system
- each lobe drains into a lactiferous duct and lactiferous sinus at the nipple
- 15-25 lobes per breast
- fibrous connective tissue and white adipose tissue separates lobes
- lactiferous ducts subdivide within lobes to form interlobular ducts (extralobular ducts) which eventually terminate at the breast lobules
Breast lobule
- basic structural unit of the duct system
- intralobular ducts, secretory elements in loose connective tissue stroma
- separated by dense irregular connective tissue stroma, some adipocytes
- terminal duct lobular unit: a breast lobule plus its associated interlobular duct
- the breast changes greatly in response to hormones
Breast overvirew
- the breast is subdivided into lobes, separated by connective and adipose tissue septa and overlying an adventitia
- the breast lobe is composed of one lactic sinus and all its associated ducts
- lactic ducts from the lactic sinus subdivide to form interlobular ducts which ultimately terminate at breast lobules
- the interlobular duct transitions into an intralobular duct as it enters the lobule, wherein it continues to subdivide, eventually terminating at tubuloalveolar secretory structure
Breast development during puberty
- histology before puberty for both genders: lactiferous sinuses near the nipple, small, branching ducts
- changes during puberty for girls: estrogen stimulates breast enlargement, duct system elongates, adipose and connective tissue accumulate, differences in breast size defined by adipose and connective tissue content
Inactive adult breast
-Parenchyma:
duct elements: simple, cuboidal epithelium
little to no secretory component
myoepithelial cells: abundant between the duct epithelium and basement membrane, stellate shaped with arms that wrap around the duct epithelium, in histological sections: triangular nuclei, eosinophilic cytoplasm
Stroma:
- loose connective tissue within lobules
- dense irregular connective tissue with some adipocytes between lobules
Menstrual cycle changes:
- early in the cycle:duct lumens reduced
- at ovulation: secretory cells increase in height, produce some secretions
Breast during pregnancy
- parenchyma grows as a result of estrogen, progesterone, prolactin, and placental lactogen; stroma decreases
- plasma cells, lymphocytes, eosinophils infiltrate the intralobular stroma
Breast first half of pregnancy
- intralobular duct cells proliferate (strongly estrogen-dependent); mitotic profiles apparent
- end buds (stratified, cuboidal epithelium) form at duct ends
- duct cell cytoplasm becomes basophilic, in preparation for protein production
Breast second half of pregnancy
- end buds hollow out to form alveoli as a basophilic secretion in the lumen
- alveoli: simple, cuboidal epithelium, numerous myoepithelial cells
- fat and protein droplets accumulate in alveolar epithelial cells
- lipid droplet sometimes appears as a pale area of the apical cytoplasm
- apocrine snouts appear on the alveolar epithelial cell apical surfaces
Lactating breast
- milk accumulates in alveoli as a basophilic secretion in the lumen
- alveolar epithelial cells: prominent basophilic cytoplasm, frequently a large pale apical cytoplasmic lipid droplet. Produce colostrum/milk
- myoepithelial cells: contraction assists in milk expulsion. Stimulated by oxytocin
- alveoli that are actively producing milk and those that are resting co-exist in the same breast
Colostrum
- first secretion released after childbirth. Transitions to milk after a few days
- higher protein, vitamin A, and antibody content than milk; lower lipid, carbohydrate
- colostrum antibodies: IgAs produced by plasma cells in the intralobular stroma. Provide newborn with passive immunity
Milk
- protein component released by merocrine secretion
- lipid component released by apocrine secretion
- milk production stimulated by prolactin
Menopause and Breast
- atrophy of breast parenchyma
- alveoli disappear; ducts persist
- reduction of stroma
- loss of fibroblasts, collagen, elastic fibers
Breast cancer
- most frequently diagnosed cancer in women
- lifetime risk in the US is 1 in 7
- most frequently arises from the terminal duct lobular unit
Identifying different uterine mucosae
- the late menstrual phase endometrium has a thin layer of stroma with short glands, but no surface epithelium
- the proliferative phase endometrium has a thick layer of stroma with an intact surface epithelium and long, straight glands with narrow lumens
- the secretory phase endometrium has a thick layer of stroma with an intact surface epithelium and long, coiled glands with wide lumens
- the cervical mucosa has a thick stroma with an intact surface epithelium and long, branched, non-coiled glands with wide lumens
