Histology: Female Reproductive Flashcards
Ovary

Produces oocytes and hormones (endocrine)
Cortex
- Ovarian follicles at various stages of development
Medulla
- Loose CT
- Blood Vessels
Germinal Epithelium
- Simple Cuboidal Epithelium
- Continuous with mesovarium
Tunica Albuginea
- Dense CT layer deep to germinal layer

Ovarian Follicles
- Oocytes develop as follicles surrounded by follicular (supporting) cells
-
At birth, 600,000-800,000 oocytes present at birth
- Arrested in prophase of meiosis I
-
At birth, 600,000-800,000 oocytes present at birth
Primodial Follicles
- Present at birth
Primary Follicles
- Unilaminar or Multilaminar
Secondary Follicle
- Development of antrum
Graafian Follicle
Ovarion Cycle
- Regulated by gonadotropins
- Follicle Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
Follicular Phase
- FSH stimulates development of primordial follicles
- LH surge triggers ovulation
Luteal Phase
- Corpus luteum secrete progesterone

Primordial Follicle
-
Primary oocyte
- Surrounded by single layer of squamous follicular cells
- Large eccentric nucleus; finely dispersed
- Large nucleolus
- Present at birth
- Located just beneath tunica albuginea

Early Primary Follicle
- Unilaminar
- Follicular cells become cuboidal
- Oocyte enlarges
-
Zona Pellucida
- __Between oocyte and follicular cells
- Made of proteins
- Contains sperm receptors

Late Primary Follicle
-
Multilaminar primary follicle
- Layer of cells called stratum granulosum
- Stratified epithelium
- Gap Junctions between granulosa cells
- No blood-follicle barrier
- Layer of cells called stratum granulosum
-
Thick Zona Pellucida
- Cortical granules; contain proteases that are exocytosed during fertilization
- Theca folliculi

Secondary Follicle

- Fluid-filled antrum appears among granulosa cells
- Follicle grows from 0.2 mm to 10 mm
- Oocyte is 125 um in diameter
- Theca cells differentiate into 2 layers:
-
Theca Interna
- Highly vascular
- Cuboidal Cells secreting androgens (estrogen precursors)
- Lipid-appearance
-
Theca Externa
- Outter CT
-
Theca Interna

Mature/Graafian Follicle
- Follicle and antrum enlarge –> 1-2 cm diameter
- Uniform stratum granulosum, except:
-
Cumulus Oophorus
- Attaches oocyte to wall of follicle
-
Corona Radiata
- Surrounds oocyte
- Goes with oocyte during ovulation
-
Cumulus Oophorus

Follicular Stigma
- Mature follicle bulging out of surface of ovary

Ovulation
- Secondary oocyte released from mature follicle
- Occurs on day 14
- LH surge around day 13, stimulate 1st meiotic division just prior to ovulation
- Granulosa cells stop producing estrogen
- Egg degenerates within 24 hours if not fertilized

Atresia
- Several follicles being to develop during each cycle, only one reaches maturity
- Others undergo atresia:
- Apoptosis and detachment of granulosa cells
- Autolysis of oocyte
- Macrophages phagocytose debris
- Others undergo atresia:

Corpus Luteum
- Results following ovulation
- Follicular wall collapses forming deep folds
- Secretes progesterone for 10-12 days
-
Luteinization
-
Granulosa and theca cells differentiate into luteal cells:
-
Granulosa Lutein Cells:
- Large/centrally located around cavity
- Secrete progesterone and inhibin (prevents secretion of FSH/LH)
- Convert androgens to estrogen
-
Theca Lutein Cells
- Smaller, located peripherally in folds
- Secrete progesterone and androgens
-
Granulosa Lutein Cells:
- Cells increase in size and accumulate lipid droplets
-
Granulosa and theca cells differentiate into luteal cells:

Corpus Luteum of Menstruation
- If fertilization does not occur, degenerates into corpus albicans
- Scar of dense CT formed by fibroblasts
- Decreased progesterone stimulates menstruation

Corpus Luteum of Pregnancy
- If fertilization occurs, corpus luteum increases in size
- Secrete progesterone for 4-5 months
- Human chorionic gondaotropin secreted from embryo, maintains corpus luteum
- Secrete progesterone for 4-5 months

Hormonal Regulation
- Pituitary gland regulated by hypothalamus
-
Anterior Pituitary secretes FSH and small LH in follicular phase
- Stimulate ovarian follicles
- Estrogens (low levels) feed back onto anterior pituitary and inhibit FSH and LH
- Day 13 –> threshold level of estrogen is stimulatory on anterior pituitary –> LH surge and ovulation
- LH stimulate corpus luteum formation, which secrete progesterone
- Inhibits FSH/LH
- LH stimulate corpus luteum formation, which secrete progesterone
-
Anterior Pituitary secretes FSH and small LH in follicular phase
Fertilization
- Occurs in ampulla of uterine tube
- Sperm must be in reproductive tract and capacitated
- Must penetrate coronoa radiata and zona pellucida
- binding of ZP leads to acrosome reaction
- Sperm and oocyte plasma membranes fuse
- Oocyte complete second meiotic division
- Male and female pronuclei fuse to form zygote with 2n (46) chromosomes
Uterine Tubes

Mucosa:
- Simple columnar epithelium
- 2 Functional States of same cell:
- Ciliated Cells: motile to direct egg to uterus
- Secretory/Peg Cells: produce secretions to nourish oocyte
- Regulated by hormones (estrogen increases ciliated cells; progesterone increases peg cells)
- 2 Functional States of same cell:
- Longitudinal folds project into lumen
Muscularis:
- Interwoven circular and longitudinal layers
Serosa:
- Mesosalpinx
- Peritoneum

Uterus
- Wall has three layers:
-
Endometrium:
- Mucosa
- Undergoes changes during menstrual cycle
-
Myometrium
- Thick, muscular layer
-
Perimetrium
- Serosa
-
Endometrium:

Myometrium
- 3 poorly defined muscle layers
- Inner and outer muscular layers parallel to long axis of uterus
-
Stratum Vasculare
- Middle circular layer
- Contains large blood vessels
- During pregnancy, muscles undergo hypertrophy and hyperplasia

Endometrium
- Simple columnar epithelium; secretory and ciliated cells (like uterine tube)
- Uterine Glands
- Functional Layer:
- Proliferates and degenerates with each menstrual cycle
- Sloughed off during menstruation
- Basal Layer:
- Retained during menstruation to regenerate functional layer
Uterine Vasculature
-
Arcuate Arteries
- Form anastomosing network within myometrium
-
Radial Arteries
- Enter basal layer of endometrium
- Straight arteries supply basal layer
-
Spiral Arteries
-
Extend into functional layer
- Distal portions grow/degenerate in response to estrogen/progesterone
- Regulated by hormones
-
Extend into functional layer

Uterine Cycle
Proliferative Phase
- Day 5/6 through Day 14
- Concurrent with follicular development in ovary
Secretory Phase
- Conincides with functional corpus luteum and progesterone secretion
Menstrual Phase
- Conincides with degeneration of corpus luteum and decline in hormones

Proliferative Phase

- Rapid proliferation of cells in functional layer
- Continues until 1 day after ovulation
- Endometrium 3 mm thick
Uterine glands in image without large lumen

Secretory Phase

- Endometrium becomes edematous
- Becomes 5-6 mm thick
- Glands enlarge and become corkscrew shaped
- Spiral arteries lengthen and become more coiled

Menstrual Phase

- Rapid decline in hormone levels as corpus luteum degenerates
-
Prostaglandins released in endometrium
- Contraction of spiral arteries causes functional layer to become ischemic and sloughs off (menstruation)
- Uterine glands stop secreting

Cervix
- Endocervical mucosa (in cervical canal)
- Simple columnar epithelium
- Branched cervical mucous glands
- During luteal phase, secrete thick, viscous mucus
- Little change during menstrual cycle (not shed)
- Exocervical Mucosa (outside of cervix)
- Stratified squamous non-keratinzed epithelium
- No glands
- Tranformation Zone
- Abrupt transition between mucosas

Vagina
- Mucosa
-
Stratified squamous non-keratinized epithelium
- Lots of glycogen in cytoplasm (nourishes microflora of vagina)
- Lactobacilli metabolize glycogen and produce lactic acid –> vagina has acidic pH
-
Stratified squamous non-keratinized epithelium
- Muscular Layer
-
2 layers of smooth muscle; poorly defined
- Inner circular, outer longitudinal
-
2 layers of smooth muscle; poorly defined
- Adventitia
- Inner layer dense CT
- Outer layer loose CT (continuous with endopelvic fascia)

Mammary Glands
-
Branched tubuloalveolar glands
- Modified apocrine sweat glands
- Each beast contains 15-20 lobes
- Each has lactiferous duct
- Lactiferous sinus
Prior to puberty, both sexes have lactiferous sinuses with few ducts
- Estrogen prolongs the duct system

Terminal Duct Lobular Unit
- Terminal ductules in inactive glands
- Surrounded by intralobular stroma connect with intralobular collecting duct

Inactive Mammary Gland
- TDLU consist of terminal ductules with a single layer of columnar glandular epithelial cells
- Myoepithelial cells surround ductules
- Epithelial cells more columnar

Active Mammary Gland
- Estrogen stimulates elongation and branching of terminal ductules
- Progesterone stimulates proliferation of alveoli from ends of terminal ductules
- Epithelial cells become cuboidal with basal nuclei

Lactating Mammary Gland
- Lipids appear black
- Prolactin stimulates lactation after parturition
2 Mechanisms of Secretion
- Apocrine: lipids
- Secretory products in apical cell and pinched off
- Merocrine: proteins
- Produced in rER, packaged into vesicles via golgi and exocytosed
Colostrum
- First milk after birth
- Thick, viscous, yellowish
- High in immunoglobulins for newborn
Milk-Ejection Reflex
- Nipple stimulated by suckling, causing oxytocin released from posterior pituitary, stimulates contraction of myoepithelial cells

Nipple
- Stratified squamous keratinized epithelium
-
Lactiferous ducts open independently at nipple surface
- Lactiferous sinus lined with stratified cuboidal epithelium
- Ducts lined with simple cuboidal
