2. Male Reproductive System
This system has four major divisions:
the testis, the genital ducts, the
auxillary glands, and the penis.
3. The Testis
• These paired glands (plural = testes) are mixed
exocrine and endocrine glands.
4. Scrotum
• The testes are suspended within the scrotum, which is, in
part, an extension of the abdominal body wall lined by
serosa internally and covered externally by integument. No
slide is available.
Integument
• This has a stratified squamous epithelium with large
sebaceous and sweat glands.
Dartos muscle (smooth muscle)
Tunica vaginalis (parietal layer of serosa)
• The parietal layer of this serosa adheres to the inner aspect
of the scrotal wall; it is reflected onto the external surface
of the testis as the visceral layer (see below).
5. Structure of the Testis
Seminiferous tubules (schematic). These are the sites of
spermatogenesis. The stratified epithelium contains
two cell types, Sertoli cells and spermatogenic cells
(schematic). External to the seminiferous tubule
epithelium is a basement membrane and lamina
propria. Smooth muscle-like cells (myoid cells,
peritubular cells) also surround the tubule.
1. Sertoli cells (sustentacular cells). These are
supporting, non-spermatogenic cells.
• Identify Sertoli cells (50X, 100X, 100X, 100X). The
cytoplasmic outline of these large cells is often
difficult to discern, but their nuclei are
characteristically large and oval, with a prominent
round nucleolus (best seen in slide E-27).
7. Structure of the Testis
2. Spermatogenic cells (schematic, schematic). As they
develop, these cells move from the basal layer of the
seminiferous tubule toward the lumen, thereby giving the
epithelium its stratified appearance. You should identify
the following cells/stages in spermatogenesis:
1. Spermatogonia (100X, 100X). These cells are primitive germ
cells localized at the basement membrane of the epithelium.
There are two basic types, but you do not need to distinguish
between them. [Type A spermatogonia, which are the true
germ cells, and Type B spermatogonia, which differ from the
type A cells in that they represent the first step in
spermatogenesis].
2. Primary Spermatocytes (100X, 100X, 100X). The first stages
of meiosis have begun. These cells are formed from the Type
B cell. The nuclei of primary spermatocytes are large in size,
and contain clumped checkerboard-like chromatin.
8. Structure of the Testis
Spermatogenesis (cont):
3. Secondary Spermatocytes. These cells are
formed when the primary spermatocytes
complete the first meiotic division. These
secondary spermatocytes complete the second
meiotic division so quickly that few, if any, of
these cells will be present on your slides.
4. Spermatids (100X, 100X). These haploid cells are
formed from the secondary spermatocytes. These
cells will undergo spermiogenesis (the formation
of mature spermatozoa). These cells can be
identified by their significantly smaller, dark
nuclei and by their position closer to the lumen
of the tubule. Note that late spermatids look very
much like spermatozoa; they can be distinguished
because late spermatids are still embedded
within Sertoli cells. (schematic, 40X, 40X).
5. Spermatozoa (100X). These cells are closest to
the lumen of the tubule. Their nuclei are very
small, dark, and oblong. Look for their flagella
(100X) protruding into the lumen of the tubule.
Spermatozoa may also be free in the lumen of the
seminiferous tubule.
9. Interstitium of Testis
• Look in the spaces between the seminiferous
tubules, and identify connective tissue
elements, blood vessels, and nerves (50X).
• Identify Interstitial Cells of Leydig (40X, 50X,
100X). These large endocrine cells synthesize
and secrete testosterone.
11. Male Genital Ducts
The genital duct system is composed of seven
histologically distinct zones: straight tubules,
rete testis, ductuli efferentes, ductus
epididymis, ductus deferens, ampulla of the
ductus deferens, and ejaculatory duct. The
first three are found within the testis.
12. Straight Tubules (Tubuli Recti)
• At the apex of each
testicular lobule,
convoluted seminiferous
tubules are replaced by
short, straight seminiferous
tubules (10X, 40X, 100X).
Only Sertoli cells are
present in the tubule
epithelium, which is now
simple columnar. The
straight tubules are very
short, and therefore
difficult to find.
13. Rete Testis
• Look in the testicular
mediastinum, and
identify the straight
tubules opening into a
network of
interconnected ducts of
variable caliber, the rete
testis (2X, 10X, 40X).
The irregularity of the
rete testis lumen is an
identifying
characteristic.
14. Ductuli Efferentes (Efferent Ductules)
• Arising from the rete testis and emerging from the
mediastinum of the testis are 10-15 efferent ductules (2X,
20X). Note the alternating groups of tall and short
columnar cells, which give the epithelium a very irregular,
undulating or scalloped appearance (20X, 100X).
• Note that many of the tall columnar cells are ciliated
(100X); these cells transport spermatozoa along the duct.
These are the only true motile cilia in the entire genital
duct system.
• Identify a thin layer of circularly arranged smooth muscle
fibers (20X) just external to the basement membrane of the
epithelium. What is the function of this smooth muscle?
15. Ductus Epididymis
• Formed by several coalescing efferent ductules, the
ductus epididymis (2X, a single duct) forms the body
and tail to the epididymis. Note the
characteristic, regular outline of the lumen (20X), and
the even height of the epithelial cells that bear
numerous stereocilia (extra-long non-motile
microvilli). Compare this lumen to that of adjacent
efferent ductules.
• Note that this epithelium (10X, 50X) is pseudostratified
columnar, with basal and tall columnar cells.
• Identify the circularly-arranged smooth muscle layer
(10X) external to the epithelium.
17. Ductus Deferens (Vas Deferens)
• This is a thick-walled, non-coiled,
muscular tube that transports the
spermatozoa from the epididymis
to the urethra (2X, 4X).
Mucosa
• Identify pseudostratified
epithelium (20X, 50X). Why is this
type of epithelium called pseudo-
stratified?
• Identify apical stereocilia (50X) on
the tall epithelial cells (except in
the ampullar region).
• Note that the entire mucosa is
thrown into longitudinal folds
(20X), giving the lumen a
characteristic stellate (star-shaped) Note: 3 muscle layers
appearance. Inner= longitudinal
Middle= circular
Outer= longitudinal
18. Ductus Deferens (Vas Deferens)
Muscularis
• Identify the three layers of smooth
muscle (10X) that comprise the
thick muscularis: inner longitudinal
layer (40X), thick middle circular
layer (40X, 40X), and thick outer
longitudinal layer (40X).
Adventitia. This region is located
external to the muscularis, and
within the spermatic cord.
• Identify skeletal muscle (2X, 4X,
cremasteric muscle), arteries (10X,
20X), nerves (10X, 40X),
lymphatics, and pampiniform
plexus (2X, 10X, anastomosing
veins).
• Note that the veins of the
pampiniform plexus have unusually
thick walls (20X), and, at first
glance, look like arteries.
19. Ampulla of Ductus Deferens
• This represents the enlargement of the
terminal portion of the ductus deferens
(schematic). The mucosa (10X) is extensively
folded to form deep diverticula and pocket-
like recesses. The muscularis is irregularly
arranged, but a distinct outer longitudinal
smooth muscle layer (10X, 40X) remains. A
specific slide of this structure is not present
in your slide collection.
20. Ejaculatory Ducts
• Each ejaculatory duct (one on each
side) is formed by the union of the
ampulla of the ductus deferens
with the excretory duct of the
seminal vesicle (see below).
• The ducts course through the
prostate gland to enter the urethra
(0.3X; 0.3X; 0.6X).
• Note that the ejaculatory ducts
have a simple columnar epithelial
lining (5X; 40X).
• Identify smooth muscle in the wall
of the ejaculatory duct (5X; 20X).
What is the function of this smooth
muscle?
Prostate gland
21. Male Urethra
• The male urethra is part of the urinary system
as well as the male reproductive system.
There are three structural portions: the
prostatic urethra, membranous urethra, and
penile urethra. Anywhere along the urethral
mucosa, small depressions or pits of mucosal
acini can be found; these are known as glands
of Littré.
22. Prostatic Urethra
• So called because the prostate surrounds
the urethra as it extends from the bladder.
The epithelium is the transitional type, as in
the bladder. The muscularis has an inner
longitudinal and outer circular layer of
smooth muscle arranged as scattered
bundles.
23. Membranous Urethra
• This segment of the urethra, about 1cm in
length, exits the prostate and perforates the
perineal membrane to enter the penis.
• Note that the mucosal epithelium (40X) is
pseudostratified or stratified columnar.
• Identify smooth muscle fibers in the wall of this
portion of the urethra (0.3X).
• The membranous urethra is also encircled by a
sphincter of skeletal muscle fibers (0.3X) from
the deep transverse perineal muscle.
24. Penile Urethra
• This portion of the urethra passes through
the corpus spongiosum (see below) of the
penis.
• Note that the mucosal epithelium (40X) is
psuedostratified or stratified columnar, with
terminal portions becoming stratified
squamous. It is surrounded by the
spongiosum of the penis.
• Identify glands of Littré (20X).
25. Auxillary Glands
• Associated with the genital ducts are three
auxiliary glands: seminal vesicles, prostate,
and bulbourethral glands. These glands add
secretions to the spermatozoa to form the
semen.
26. The Seminal Vesicle
• These paired glands are actually
outpocketings of the ductus deferens and are
located in the vicinity of the ampulla of the
ductus deferens (2X), which is not present in
this slide. The seminal vesicles secrete a
yellowish, viscid fluid that is rich in fructose,
and that comprises about 20% of semen
volume.
The Mucosa
• Identify the large highly convoluted lumen
(2X), which contains extensive mucosal
foldings that give a honeycomb appearance.
• Note that the epithelium consists of
secretory cells (10X, 40X, 100X) in a
pseudostratified columnar, or sometimes
simple columnar, arrangement.
Muscularis
• Identify inner circular and outer longitudinal
smooth muscle layers (4X, 40X) of the
sheath.
27. The Prostate
• A single gland that surrounds the ejaculatory ducts, the prostate is a
composite of 30-50 tubulo-alveolo-saccular glands that secrete a thin,
alkaline, milky fluid that is high in acid phosphatase, fibrinolysin, and
citric acid. This secretion accounts for 75% of semen volume.
Capsule
• Under low magnification, identify the capsule (2X) of fibroelastic
connective tissue (containing smooth muscle cells, 20X) that surrounds
the entire gland, and is continous with the connective tissue septa and
stroma (50X).
Secretory Units
• Identify secretory alveoli and tubules (4X, 20X). Note that these are quite
irregular and have large lumens.
• Identify prostatic concretions (4X, granules). These granules appear as
multi-layered acidophilic material and they are a distinguishing feature of
the prostate gland.
• Note that the epithelium of the prostate gland (20X, 50X) is composed of
simple columar to pseudostratified columnar epithelium.
28. Bulbourethral Glands
(Cowper’s Glands)
• These small, paired mucous-type glands (1X, 2X) are embedded in
the connective tissue that surrounds the membranous urethra.
They produce a specialized mucus that is secreted into the posterior
portion of the cavernous segment of the urethra.
• Identify skeletal muscle fibers (4X, 20X) outside the capsule.
• Identify smooth muscle and skeletal muscle within the connective
tissue septa of the gland. Smooth muscle and elastin fibers can be
found in the intralobular connective tissue.
• Examine the secretory units (4X, 40X); note that these tubulo-
alveolar glands are lined with cuboidal or columnar epithelium.
29. Major Structural Components
(Erectile Tissue)
• The penis contains a core of erectile tissue
within a fibrous tunica albuginea (1X). These
structures are surrounded by a layer of loose
connective tissue that contains blood vessels,
nerves, and the occasional Pacinian corpuscle
(1X; 10X). The looseness of this C.T. layer (1X)
prevents damage to the overlying skin as it
moves longitudinally during intercourse.
What is the function of the mechanoreceptors
in this location?
Corpus Cavernosa Urethra (Corpus Spongiosum).
The urethra passes through this structure (1X,
4X).
• Identify large cavernous sinuses (4X, 20X), and
fibroelastic connective tissue trabeculae with
smooth muscle fibers (20X), throughout this
erectile tissue.
Corpus Cavernosum Penis. These paired erectile
bodies (1X, 4X) are located dorsally.
• Note that their structure (4X) is very similar to
that of the corpus spongiosum.
• Identify sinuses and smooth muscle (20X).
30. Blood Supply to Penile Erectile Tissue
Deep arteries (4X, 10X).
• Note that only one is present in each erectile body.
Helicine arteries.
• Identify these spiralled arteries (1X, 2X) in the flaccid
penis.
Cavernous spaces (sinuses) located within the erectile
tissues.
• Identify these spaces (20X), and note that they are
filled by blood from the helicine arteries, and lined
with endothelial cells.
31. Female Reproductive System
The female reproductive system has four main
components: ovaries, the genital tract (uterine tubes,
uterus, and vagina), external genitalia and mammary
glands. Throughout the reproductive period, these
components undergo cyclic changes in structure and
function, under the control of hormonal and nervous
mechanisms. In addition to the studying the four main
components, we will briefly discuss oogenesis and
examine the stages of follicular development.
32. Ovaries:
General Structure
• Surface epithelium: Note that
this is a simple cuboidal
epithelium (40X), sometimes
incorrectly called "germinal
epithelium". Most of this
epithelium is not present on
your slides due to tissue
processing, but some remnants
should be present.
• Tunica albuginea: Identify this
thin, fibrous connective tissue
layer (20X, 50X) directly
underneath the surface
epithelium. Ova must cross this
layer to be released at
ovulation.
33. Ovaries:
General Structure
• Cortex: The cortex (1X, 4X)
comprises the major portion of
the ovary.
– Note the presence of many
ovarian follicles (4X) of various
sizes within the connective tissue
stroma of the cortex.
– Note that the connective tissue
(50X) contains closely-packed,
fine collagenous and reticular
fibers.
• Medulla: Identify the stroma (50X,
50X), a loose, highly-vascularized
fibroelastic connective tissue with
scattered smooth muscle cells.
Note that the medulla is
continuous with the hilum of the
ovary (1X). The hilum of the ovary
may not be apparent in some
slides due to the plane of section.
34. Ovaries:
Ovarian Follicles
• There are 5 main types of follicles, classified
according to their stage of development. The
follicles present in the cortex represent ova
and their associated follicular cells at various
stages of development.
35. Ovaries:
Primordial Follicles
• These are the most primitive, and most abundant, type
of follicle. Each follicle contains a primary oocyte (a
female germ cell which has been sustained in the
prophase stage of meiosis I since fetal life). Identify the
single layer of squamous follicular cells (100X, 100X)
surrounding the primary oocyte.
• Study the oocyte (100X, 100X) at higher power. Note
the relatively sparse cytoplasm (compared to the more
mature oocytes), and a very prominent nucleolus
(100X) within a large nucleus.
36. Ovaries:
Primary Follicles
• Upon appropriate hormonal
stimulation, primordial follicles are
induced to develop into primary
follicles.
Early primary follicle.
• Note that the single layers of follicular
cells (100X, 100X) become cuboidal to
low columnar in shape.
Late primary follicle.
• Identify an extracellular, glycoprotein-
containing layer, the zona pellucida
(50X, 50X), between the oocyte and
follicular cells.
• Note that the follicular cells have
proliferated to form a stratified layer
of cells, the stratum granulosum; the
cells are now called granulosa cells
(50X, 50X).
• Identify the connective tissue capsule,
the theca folliculi (50X, 50X), that has
formed external to the granulosa cells.
38. Ovaries:
Secondary (Antral) Follicles
• At this stage of development, fluid-filled spaces
within the stratum granulosum have developed,
forming the follicular antrum (50X). Note that
the zona pellicuda (the basement membrane-like
extracellular matrix between the oocyte and
granulosa cells) has become prominent (20X,
50X).
• Identify the prominent basement membrane
(100X) now surrounding the follicle, known as the
glassy membrane.
40. Ovaries:
Graafian Follicles
• The Graafian follicle is the mature follicle, and is quite large. The increase in its size
is primarily due to the increase in the size of the follicular antrum. Normally, in
humans, only one of these follicles will actually be ovulated during each menstral
cycle. Find a Graafian follicle (20X), and note that the stratum granulosum has
thinned as the antrum has increased in size.
• Identify the cumulus oophorus (40X). During formation of the antrum, the oocyte
and a portion of the follicular cells become eccentrically located within the follicle;
this eccentric mound of granulosa cells is the cumulus oophorus.
• Identify the corona radiata (20X, 40X). This structure is formed from those
granulosa cells that are directly associated with the oocyte. These cells will
accompany the oocyte after ovulation.
• Note that, at this stage, the theca folliculi has differentiated into two layers (100X),
the theca interna and the theca externa.
• Identify the theca interna, and note that it is the more vascularized of the two
layers (100X). It is responsible for estrogen production.
• Identify the theca externa (100X, 100X), and note that it is composed of a simple
connective tissue layer.
41. Graafian Follicle at Ovulation
• The oocyte and the corona radiata separate from the
cumulus oophorus.
• The primary oocyte completes meiosis I and becomes a
secondary oocyte. It then undergoes its second maturation
division, which will only proceed to metaphase II. It will
only complete cell division if fertilization occurs.
• The follicle ruptures by accumulation of fluid in the antrum.
This is a rare occurrence; you will not see it in your slides!
• The ovum, with the corona radiata, is released into the
peritoneal cavity and taken up into the uterine tube.
• The remaining portions of the follicle develop into a corpus
luteum.
42. Corpus Luteum
(Non-Pregnant)
• This is the follicle remnant after ovulation; it will develop into a temporary endocrine structure. The
corpus luteum forms by the proliferation of the granulosa cells, and the differentiation of those
cells into progesterone-producing cells. Non-pregnant state. The corpus luteum contains the
differentiated granulosa cells, now referred to as granulosa lutein cells (10X, 50X).
• Try to find a yellowish pigment that can sometimes be observed in granulosa lutein cells.
• Identify theca lutein (10X, 50X) or paralutein cells, which are cells of the theca interna that
continue to produce estrogen during the post-ovulation period.
• Look for a central blood clot or empty cavity (10X) that may be observed in the antrum of this
newly formed corpus luteum (dependent on plane of section).
• O-37 (Ovary, 7 months pregnancy; H&E)
E-37 (Ovary, 7 months pregnancy; trichrome)
• Corpus luteum of pregnancy (2X). Note the size of this structure relative to the entire ovary. It is
very large and in many of the slides it appears to occupy most of the ovary.
• E-56 (Ovary; PAS)
• Corpus albicans. This is the involuted form of the corpus luteum, the remnant form of a corpus
luteum that develops if pregnancy does not occur, or postpartum. Note that the corpus albicans
(4X) is rather acellular and avascular, and resembles scar-like connective tissue.
43. Corpus Luteum
Granulosa lutein
Central
blood clot or
empty cavity
44. Corpus Luteum
(Pregnant)
• Note the size of this structure relative to the
entire ovary. It is very large and in many of the
slides it appears to occupy most of the ovary.
45. Corpus Albicans
• This is the involuted form of the corpus
luteum, the remnant form of a corpus luteum
that develops if pregnancy does not occur, or
postpartum.
• Note that the corpus albicans (4X) is rather
acellular and avascular, and resembles scar-
like connective tissue.
46. Atretic Follicles
• These are follicles that failed to reach
maturity, and are now degenerating. This
event can occur at any stage of development,
and the resulting follicles vary greatly in
appearance.
• Try to find an atretic follicles (40X), which
often contain remnants of the zona pellucida
or the glassy membrane, and dead granulosa
cells in the antrum.
48. The Genital Tract
• This portion of the female reproductive
system consists of oviducts, uterus, and
vagina. Each of these is a hollow structure
with a wall of smooth muscle, a mucosal
lining, and a covering of serosa or adventitia.
49. The Oviducts
• After ovulation, the ovum is drawn into the infundibulum
of the oviduct. Thereafter, it passes through the ampulla,
isthmus, and intramural regions of the oviduct before
entering the uterus.
• 3 layers:
– Mucosa: Note that the epithelium (100X) is simple columnar,
and that some cells are ciliated. Non-ciliated cells are thought to
secrete nutritive material for the ovum.
– Muscularis: Identify an inner circular (40X) and an outer
longitudinal (10X, 20X) smooth muscle layer.
– Serosa: This is actually a reflected peritoneum. Identify the
mesothelium (20X) on the outermost portion of these organs.
50. Portions of the Oviduct
• Infundibulum (2X). This is a funnel-shaped portion of the oviduct
that opens into the peritoneal cavity. Note that it has numerous
fringed extensions of the epithelium, called fimbriae (10X),
extending into the peritoneal cavity toward the ovary.
• Ampulla (2X, 2X, 10X). This segment constitutes two thirds of the
length of the oviduct. Note that this region is thin-walled, and has a
large luminal area (10X) with a mucosa that is thrown into
exaggerated, branching folds.
• Isthmus (2X, 10X). Note that the lumen (10X) is much less folded
here than in the ampulla, and it is more stellate (star-shaped).
• Note that the outer muscular layers (40X) are thick and compact.
• Intramural region (within the uterus) (2X). Note that folds of the
mucosa (4X) are reduced to small bulges in this segment.
• Note that the muscle layers blend into the myometrium (4X) of the
uterus, while the mucosa blends into the uterine endometrium.
51. The Uterus
• The uterine mucosa undergoes marked cyclic changes, and
the muscularis is considerably more substantial than in the
oviduct. The two major anatomical divisions of the uterus
are the body and the cervix. The uterine wall has three
layers: endometrium, myometrium, and perimetrium.
• Perimetrium: Identify the simple squamous epithelium
(mesothelium, 40X) of the serosal layer.
• Myometrium: Identify three layers of smooth muscle:
innermost longitudinal (4X, 20X), middle circular and
oblique (4X, 20X), and outermost longitudinal (4X, 20X).
These can be difficult to distinguish in some slides.
52. The Uterus
• Endometrium:
– Both the cervix and the body of the uterus are induced by ovarian
activity to undergo cyclic changes, although those of the body of the
uterus are considerably more pronounced and complex.
– Epithelium
• Simple columnar epithelium. Note that the epithelium invaginates into uterine
(endometrial) glands (2X, 10X, 40X) that extend through the entire thickness
of the endometrium. Uterine glands are simple, tubular glands with some
basal branching.
– Lamina propria (10X)
• This is composed of irregular, stellate cells and reticular fibers and is unusually
thick (2X).
– Stratum basalis (basal layer)
• Note deep straight arteries (4X, (10X) in the endometrial layer next to the
myometrium.
• Identify coiled arteries (4X, 20X) lying slightly more superficially.
53. The Uterus
• Endometrium (cont.):
– Stratum functionalis (functional layer). This layer is
lost at menstruation. It is made up of two sublayers,
the stratum spongiosum and stratum compactum.
• Stratum spongiosum (spongy layer). This middle zone
exhibits a spongy stroma due to edema.
– Identify the characteristic corkscrew-shaped uterine glands (2X,
4X, 10X) in the progestational phase.
– Identify the characteristic spiralled arteries (20X).
• Stratum compactum (compact layer). This superficial layer
has a relatively compact appearance.
– Identify the straight neck portion of the uterine glands (20X) near
the endometrial surface.
54. Corkscrew Uterine Glands of the
Stratum Spongiosum
Straight neck
portion of
glands in the
stratum
compactum
55. Endometrial Cyclic Changes
• Cyclic changes occur in the endometrium,
whereby the endometrium passes through four
phases (i.e. proliferation, secretion, ischemic, and
menstruation phases). You should note the
histological characteristics of endometrium
during each of these phases:
– Proliferative (Follicular) Phase
– Progestational (Secretory or Luteal) Phase
– Ischemic (Premenstrual) Phase
– Menstrual Phase
56. Proliferative (Follicular) Phase
• During this phase, mitosis is occurring in both
lamina propria stroma and epithelial glands.
• Note that, early in this phase, the stratum
functionalis is relatively thin, and that the
epithelium is low columnar.
• Note that, by the late proliferative phase (2X),
the glands are considerably longer with larger
lumens, and the functionalis becomes packed
with glands.
57. Progestational (Secretory/Luteal)
Phase
• The three strata are most readily identified at this stage.
Early in this phase, profuse glandular secretion begins.
• Examine the epithelium (40X) on higher power, and note
that cells are now tall columnar (why?).
• Note that, by late secretory phase, glands take on a "saw-
tooth" or "corkscrew" appearance (2X, 4X, 10X).
• Identify spiral arteries (10X) extending nearly to the
endometrial surface.
• The stratum basalis remains firmly attached to the
myometrium. Note that the ends of the tubular
endometrial glands (10X) extend into this deepest layer.
59. Menstrual Phase
• At this time, the ischemia
caused by the constriction
of the spiral arteries results
in necrosis of the stratum
functionalis. This is
followed by the shedding of
this layer.
• Identify ruptured blood
vessels (20X) and torn
glands (20X) in this stage.
• Note that the basal layer
(10X), with remnants of
the endometrial
glands, remains intact.
60. Endometrium of Cervix
• Identify the mucus-secreting, simple columnar
epithelium on the luminal surface. Note that
this epithelium is continuous with the moist,
stratified squamous epitelium that covers the
external (vaginal) surface of the cervix (20X).
• Identify the mucosa and the underlying
myometrium (10X).
61. Placenta
• Identify the fetal surface (4X), which is covered by
the simple cuboidal or squamous epithelium of
the amnion (100X).
• Identify the chorionic plate (1X ,4X), which is
made up of dense connective tissue and which lies
immediately under the amnion. The umbilical
vessels of the fetal circulation branch through this
plate.
• Identify large chorionic stem (anchoring) villi (2X),
which form connective tissue columns that span
the width of the placenta from the fetal to the
maternal side.
• Identify small chorionic villi (4X), which branch
from these stem villi; the small villi lie in the
maternal blood that fills the intervillous spaces
(10X). The villi (40X, 40X) themselves also contain
blood vessels, which are branches of the fetal
umbilical vessels. These vessels are surrounded by
connective tissue (mesenchyme), and each villus is
covered by trophoblastic cells.
62. Placenta
• Examine the trophoblastic cells,
and note that the innermost layer
of cells, the cytotrophoblast
(100X), forms a cubodial
epithelium. The outer layer, which
is more irregular and amorphous, is
the syncytiotrophoblast (100X).
• Identify the maternal side of the
placenta, the decidua basalis (4X),
to which the stem villi attach. This
is modified endometrial tissue and
can be identified by the presence
of large decidua cells (10X, 40X).
• Note that the endometrium
merges with the myometrium of
the uterus.
63. Umbilical Cord
• Identify the two umbilical arteries (4X, 40X);
these are unusual because the tunica media
contains both an inner longitudinal and outer
circular smooth muscle.
• Identify the single umbilical vein (4X, 40X). The
vein is unusual because its wall consists primarily
of tunica media, rather than tunica adventitia as
in other veins. This vein carries oxygenated blood
from the placenta to the fetus.
64. The Vagina
• The fibromuscular vaginal wall consists of mucosa, muscularis, and
adventitia.
Mucosa
• Note that the vaginal mucosal epithelium (1X, 4X, 20X) is thick, non-
keratinized stratified squamous.
• Note that the portion of cervix protruding into the vagina is covered
by the same type of epithelium (20X).
• Identify mucosal rugae (mucosal foldings, 4X).
• Note that the (10X, 20X). lamina propria contains abundant
leukocytes (20X) and an extensive vascular plexus
Muscularis
• Identify two layers of smooth muscle (4X), an inner circular and an
outer longitudinal layer (they may be somewhat indistinct).
Adventitia
65. Female External Genitalia
• In the female, the clitoris, labia minora, labia
majora, and vestibular glands comprise the
external genitalia, or vulva.
66. Mammary Glands
• These are actually specialized cutaneous sweat glands
located in the subcutaneous region. Merocrine and
apocrine secretion both occur during lactation; lipid
globules are released by an apocrine process, while milk
protein is secreted by a merocrine process (schematic).
• Examine both active (4X) and inactive (4X) mammary gland
sections, and compare secretory lobules in these two
conditions (schematic). Note the abundant C.T. (connective
tissue) in resting mammary gland.
• Identify myoepithelial cells (50X). What do they do here?
• Identify mammary gland ducts (4X, 40X).
