Histo 3:
The Female Reproductive System:
Uterus and Vagina
Per Brodal
Institutt for medisinske basalfag
Universitetet i Oslo
9th Semester 2008
The Uterus
Corpus uteri
Isthmus
Internal os
Canalis cervicis
Cervix uteri
Vagina
External os
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Corpus uteri (cross section)
Perimetrium (serosa
and subserosa)
Myometrium
Endometrium
Vessels in the
parametrium
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Menstrual Cycle
Progesterone
Estrogen
1
5
Menstruation
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Proliferative phase
28 Days
Secretory phase
4
Layers of the Endometrium
Spiral artery
Functional layer
(functionalis)
Straight artery
(basal artery)
Basal layer
Muscular layer
(myometrium)
PROLIFERATIVE PHASE
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SECRETORY PHASE
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The endometrium The mucosa of the uterus
 Epithelium: Simple columnar epithelium
(surface and glands)
 Stroma: Mesenchyme-like loose connective
tissue
 Specialized to enable the blastocyst to
implant and grow
 Forms the maternal portion of the placenta
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Early Proliferative Phase
Endometrium
Myometrium
Basal layer
Gland
Bundles of smooth
muscle cells
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Late Proliferative
Phase
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Late
Proliferative
Phase
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Secretory Phase
Functional layer
Basal
layer
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Secretory
Phase
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Secretory Phase
Hypertrophy of
glandular cells
and Edema
Spiral artery
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Menstruation
 Spasmodic contractions of the spiral arteries due to
discontinuation of progesterone
 Ischemia – loss of contractility
 Bleeding – 30-50 ml
 Rests of the functional layer and blood – not
coagulating
 Takes place at various sites in a sequence
 Epithelization takes place continuously after
shedding
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The Cervix
Mucus producing
epithelium
Fibromuscular
stroma
Transition between
cylindrical and stratified
squamous epithelium
Nabothian cysts
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Cervix
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Cervical Mucosa
Mucus plug in the cervix –
viscous except at the time of
ovulation
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The cervical mucosa may extend to the
vaginal surface of the portio
Most cervical carcinomas arise from
the squamous epithelium
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”Erosion”
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The Myometrium
Coiled arteries
Bundles of
smooth
muscle fibers
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Organization of the myometrium
DURING PREGNANCY:
 The muscle fibers
increase in length 710 fold
 The fibers unwind
 Abundant
connective tissue
allows movement of
the smooth muscle
bundles
 The growth of the
muscle fibers occurs
first at the site of
implantation
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Uterus in Pregnancy and after Delivery
First mainly growth
of muscle fibers,
thereafter mainly
stretching
Involution
9
10
6
2
5
9
Benninghoff/Goerttler
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Months of
pregnancy
Days after
delivery
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The vagina
 Stratified squamous epithelium (non-keratinized),
20-30 layers
 Lamina propria with venous plexuses
 No glands
 Two layers smooth muscle, mixed with many
elastic fibers
 Very distensible
 Rich sensory innervation of the lamina propria
and muscular layer
•
but few pain fibers from the upper part
 pH 4-5 due to lactobazillus acidophilus
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Pelvic floor (female monkey)
Urethra
Vagina
Rectum
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Cyclic Changes of the Vaginal
Epithelium
 Follicular phase: The thickness of the epithelium
increases
• The superficial cells accumulate glycogen and
•
become strongly eosinophilic with pyknotic nuclei
Exfoliation of cells increases and reaches a maximum
at ovulation
 Luteal phase: The thickness decreases
•
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The cells are more basophilic and are exfoliated in
clusters
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Vaginal Smears
Section
Smear
Follicular phase
Superficial
Intermediate
Parabasal cells
Presence of estrogen is necessary for
surface epithelial cells to become
eosinophilic
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Luteal phase
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Cervical Smear
Cylindrical cells
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