2. The Male Reproductive System
The male reproductive
system consists of:
īŧTestes
īŧGenital ducts
īŧAccessory sex glands
īŧPenis
ī§ The two primary
functions of the testis
are spermatogenesis,
and steroidogenesis
2
4. TESTES
ī§ The adult testes are paired ovoid organs that lie within the
scrotum, located outside the body cavity.
ī§ Each testis (or testicle) is surrounded by a dense connective
tissue capsule, the tunica albuginea , which thickens on the
posterior side to form the mediastinum testis .
ī§ From this fibrous region, septa penetrate the organ and divide it
into about 250 pyramidal compartments or testicular lobules.
ī§ Each lobule contains sparse connective tissue with endocrine
interstitial cells (or Leydig cells ) secreting testosterone, and
ī§ one to four highly convoluted seminiferous tubules in which
sperm production occurs.
4
5. Cont..
ī§ The testes develop retroperitoneally in the dorsal wall of the
embryonic abdominal cavity and are moved during fetal
development.
ī§ During migration from the abdominal cavity, each testis carries
with it a serous sac, the tunica vaginalis , derived from the
peritoneum.
ī§ A permissive temperature of about 34°C is maintained in the
scrotal sac by various mechanisms.
5
6. Cont..
ī§ Each testicular artery is surrounded by a rich pampiniform
venous plexus containing cooler blood from the testis, which
draws heat from the arterial blood by a countercurrent heat-
exchange system.
ī§ Evaporation of sweat from the scrotum
ī§ Relaxation or contraction of the thin dartos muscle of the
scrotum and the cremaster muscles of the spermatic cords
6
8. Cont..
Interstitial Tissue
ī§ The interstitial tissue of the testis between the seminiferous
tubules consists of sparse connective tissue containing
ī§ fibroblasts, lymphatics, and blood vessels including fenestrated
capillaries.
ī§ During puberty interstitial cells, or Leydig cells, develop as large
round or polygonal cells with central nuclei and eosinophilic
cytoplasm rich in small lipid droplets.
ī§ These cells produce the steroid hormone testosterone.
8
9. Cont..
ī§ Testosterone is synthesized by enzymes present in the smooth
ER and mitochondria
ī§ Testosterone secretion by interstitial cells is triggered by the
pituitary gonadotropin, luteinizing hormone (LH), which is also
called interstitial cell stimulating hormone (ICSH).
9
10. Cont..
Seminiferous Tubules
ī§ Sperm are produced in the seminiferous tubules at a rate of
about 2 Ã 108 per day in the young adult.
ī§ Each testis has from 250 to 1000 such tubules in its lobules, and
each tubule measures 150 to 250 Îŧm in diameter and 30 to 70
cm in length.
ī§ The combined length of the tubules of one testis totals about
250 m.
ī§ Each tubule is actually a loop linked by a very short, narrower
segment, the straight tubule, to the rete testis,
ī§ About 10-20 efferent ductules connect the rete testis to the
head of the epididymis.
10
14. Cont..
ī§ Each seminiferous tubule is lined with a complex, specialized
stratified epithelium called germinal or spermatogenic
epithelium.
ī§ The basement membrane of this epithelium is covered by
fibrous connective tissue, with an innermost layer containing
flattened, smooth muscle-like myoid cells.
ī§ The germinal epithelium consists of two types of cells
īŧLarge nondividing Sertoli cells: physically and metabolically
support developing sperm cell precursors.
īŧ Dividing cells of the spermatogenic lineage
âĸ Comprise four to eight concentric cell layers and produce the
cells that become sperm. 14
16. SPERMATOGENESIS
âĸ Spermatogenesis is the process by which spermatogonia develop
into sperm.
âĸ Spermatogenesis, the process by which sperm are produced
involves a complex and unique series of events.
âĸ It begins shortly before puberty, under the influence of rising levels of
pituitary gonadotropins, and continues throughout life.
âĸ Duration of spermatogenesis in humans is approximately 74 days.
âĸ Spermatogenesis is the first part of sperm production, including stem
cell mitosis and meiosis, and
âĸ Spermiogenesis is the final differentiation process occurring in the
haploid male germ cells
16
18. Cont..
Spermatocytogenesis
ī§ Spermatogonia is small round cells about
12 Îŧm in diameter.
ī§ These cells occupy a basal niche in the
epithelial wall of the tubules, next to the
basement membrane and closely
associated with Sertoli cell surfaces
18
19. Cont..
īSpermatogonia with dark, ovoid nuclei act as stem cells,
dividing infrequently.
ī Type A spermatogonia each undergo several unique clonal
divisions that leave most of the cells interconnected as a
syncytium.
īThese become type B spermatogonia, which have more
spherical and pale nuclei.
īEach type B spermatogonium then undergoes a final mitotic
division to produce two cells that grow in size and become
primary spermatocytes.
īThey are spherical cells with euchromatic nuclei
19
20. Cont..
īThe primary spermatocyte has 46 (44 + XY) chromosomes, the
diploid number.
īSoon after their formation, these cells enter the first meiotic
prophase that lasts about 3 weeks.
īThe primary spermatocytes are the largest cells of the
spermatogenic lineage.
īHomologous chromosomes separate in the first meiotic
division, which produces smaller cells called secondary
spermatocytes with only 23 chromosomes.
20
21. Cont..
īSecondary spermatocytes are rare in testis sections because
they are very short-lived cell.
īDivision of each secondary spermatocyte separates the
chromatids of each chromosome and produces two haploid
cells called spermatids each of which contains 23
chromosomes.
21
25. Cont..
Spermiogenesis
ī§ Spermiogenesis, the final phase of sperm production, is the
temperature-sensitive process by which spermatids differentiate into
spermatozoa.
ī§ Spermiogenesis is commonly divided into four phases:
ī§ In the Golgi phase the cytoplasm contains a prominent Golgi
apparatus near the nucleus, mitochondria, paired centrioles, and free
ribosomes.
ī§ In the cap phase the acrosomal cap spreads over about half of the
condensing nucleus.
ī§ In the acrosome phase the head of the developing sperm, containing
the acrosome and the condensing nucleus, remains embedded in the
Sertoli cell
ī§ In the maturation phase of spermiogenesis, unneeded cytoplasm is
shed as a residual body.
īŧSpermatids are released into the lumen of the seminiferous tubules
during the process called spermiation. 25
26. Cont..
Sertoli Cells
ī They are tall columnar or pyramidal epithelial cells that form
the basal lamina of the seminiferous tubules.
ī All cells of the spermatogenic lineage are closely associated
with the extended surfaces of Sertoli cells and depend on them
for metabolic and physical support.
ī Sertoli cells adhere to the basal lamina and their apical ends
extend to the lumen.
ī Each Sertoli cell supports 30 to 50 developing germ cells.
26
27. Cont..
īUltrastructurally Sertoli cells are seen to contain abundant SER,
some rough ER, well-developed Golgi complexes, numerous
mitochondria, and lysosomes
īImportant in Sertoli cell function are to form a blood-testis
barrier within the seminiferous epithelium.
ī The tightest blood-tissue barrier in mammals, this physical
barrier is one part of a system that prevents autoimmune
attacks against the unique spermatogenic cells.
27
28. Cont..
īļRelated to their role in establishing the blood-testis barrier,
Sertoli cells have three general functions:
īŧ Support, protection, and nutrition of the developing
spermatogenic cells:
īŧ Exocrine and endocrine secretion: Production of nutrients and
androgen-binding protein (ABP), glycoprotein inhibin, mÃŧllerian-
inhibiting substance (MIS)
īŧ Phagocytosis: excess cytoplasm shed as residual bodies is
phagocytosed and digested by Sertoli cell lysosomes.
28
29. INTRATESTICULAR DUCTS
īThe intratesticular ducts are
īŧ The straight tubules (or tubuli recti),
īŧ The rete testis, and
īŧ The efferent ductules.
ī All of which carry spermatozoa and liquid from the
seminiferous tubules to the duct of the epididymis.
ī The loops of seminiferous tubules join the rete testis by the
short straight tubules, which are lined initially only by Sertoli
cells.
īThese empty into the rete testis, an interconnected network of
channels lined with cuboidal epithelium and supported by
connective tissue of the mediastinum.
29
30. Cont..
īThe rete testis drains into about 20 efferent ductules.
īIt is lined by an unusual epithelium in which groups of non-
ciliated cuboidal cells alternate with groups of taller ciliated cells
and give the tissue a characteristic scalloped appearance.
īThe nonciliated cells absorb most of the fluid secreted by the
Sertoli cells of seminiferous tubules.
īThis absorption and the ciliary activity create a fluid flow that
carries sperm out of the testis toward the epididymis.
īA thin layer of circularly oriented smooth muscle cells in the
walls of efferent ductules aids sperm movement into the duct of
the epididymis.
30
33. EXCRETORY GENITAL DUCTS
īThe excretory genital ducts includes
īŧ The epididymis,
īŧ The ductus (or vas) deferens, and
īŧ The urethra.
īThey transport sperm from the scrotum to the penis during
ejaculation.
33
34. Cont..
Epididymis
īThe long, coiled duct of the epididymis, surrounded by
connective tissue,
ī It lies in the scrotum along the superior and posterior
sides of each testis.
īIt is 4 to 5 m in length.
īIt includes a head region where the efferent ductules
enter, a body, and a tail opening into the ductus
deferens.
34
35. Cont..
īWhile passing through this duct, sperm become motile and
their surfaces and acrosomes undergo final maturation steps.
īFluid within the epididymis contains glycolipid decapacitation
factors
ī Bind sperm cell membranes and block acrosomal reactions and
fertilizing ability.
īThe epididymal duct is lined with pseudostratified columnar
epithelium.
ī It consists of columnar principal cells, with characteristic long
stereocilia, and small round stem cells
35
36. Cont..
īThe principal cells secrete glycolipids and glycoproteins, but
also absorb water and remove residual bodies or other debris
not removed earlier by Sertoli cells.
īThe duct epithelium is surrounded by smooth muscle cells,
arranged as inner and outer longitudinal layers as well as a
circular in the tail of the epididymis.
īPeristaltic contractions move the sperm along the duct and
empty the body and tail regions at ejaculation.
36
38. Cont..
Ductus or Vas Deferens
īA long straight tube with a thick, muscular wall and a relatively
small
lumen, continues toward the prostatic urethra.
īIts mucosa is slightly folded longitudinally, the lamina propria
contains many elastic fibers, and the epithelial lining is
pseudostratified with some cells having sparse stereocilia.
īThe very thick muscularis consists of longitudinal inner and
outer layers and a middle circular layer.
īThe muscles produce strong peristaltic contractions during
ejaculation, which rapidly move sperm along this duct from the
epididymis. 38
39. Cont..
īThe ductus (vas) deferens forms part of the spermatic cord,
which also includes the testicular artery, the pampiniform
plexus, and nerves.
ī Each ductus passes over the urinary bladder where it enlarges
as an ampulla (L. a small bottle).
ī Within the prostate gland, the ends of the two ampullae merge
with the ducts of the two seminal vesicles, joining these ducts to
form the ejaculatory ducts which open into the prostatic urethra.
39
42. MEDICAL APPLICATION
īThe accessibility of the ductus (vas) deferens in the spermatic
cords allows for the most common surgical method of male
contraception: vasectomy.
īIn this procedure a very small incision is made through the
scrotal skin near the two ducts and each vas is exposed, cut,
and the two ends (or only the end leading to the abdomen) are
cauterized and tied.
īAfter vasectomy sperm are still produced, but they degenerate
and are removed by macrophages in the epididymis.
42
43. ACCESSORY GLANDS
īProduce secretions that are mixed with sperm during
ejaculation to produce semen and that are essential for
reproduction.
īThe accessory genital glands are
īŧ The seminal vesicles (or glands),
īŧ The prostate gland, and
īŧ The bulbourethral glands
43
45. Cont..
Seminal Vesicles
īThe two seminal vesicles consist of highly tortuous tubes, each
about 15 cm long, enclosed by a connective tissue capsule.
īThe unusual mucosa of the tube displays a great number of
thin, complex folds that fill much of the lumen.
īThe folds are lined with simple or pseudostratified columnar
epithelial cells rich in secretory granules.
īThe lamina propria contains elastic fibers and is surrounded by
smooth muscle with inner circular and outer longitudinal layers
that empty the gland during ejaculation.
45
46. Cont..
īThe seminal vesicles are exocrine glands in which production
of their viscid, yellowish secretion depends on testosterone.
īFluid from seminal vesicles typically makes up about 70% of
the ejaculate and its components include the following:
īŧFructose, a major energy source for sperm
īŧProstaglandins, stimulate activity in the female reproductive
tract; and
īŧFibrinogen, allows semen to coagulate after ejaculation.
46
48. Cont..
Prostate Gland
ī The prostate gland is a dense organ that surrounds the urethra
below the bladder.
ī It is approximately 2 cm à 3 cm à 4 cm in size and weighs
about 20g.
ī The prostate is a collection of 30 to 50 tubuloacinar glands
embedded in a dense fibromuscular stroma.
ī Ducts from individual glands may converge but all empty
directly into the prostatic urethra.
48
49. Cont..
The glands are arranged in three major zones around the
urethra:
īThe transition zone occupies only about 5% of the prostate
volume, surrounds the superior portion of the urethra, and
contains the periurethral mucosal glands.
īThe central zone comprises 25% of the glandâs tissue and
contains the periurethral submucosal glands with longer ducts.
īThe peripheral zone, with about 70% of the organâs tissue,
contains the prostateâs main glands.
49
51. Cont..
īThe tubuloacinar glands of the prostate are all lined by a simple
or pseudostratified columnar epithelium and
īThey produce fluid that contains various glycoproteins,
enzymes, and small molecules such as prostaglandins and is
stored until ejaculation.
īA clinically important product of the prostate is prostate-specific
antigen (PSA), a 34-kDa serine protease that helps liquefy
coagulated semen for the slow release of sperm after
ejaculation.
īElevated levels of circulating PSA indicate abnormal glandular
mucosa typically due to prostatic carcinoma or inflammation. 51
52. Cont..
īSmall spherical concretions, 0.2 to 2 mm in diameter and often
partially calcified, are normally present in the lumens of many
prostatic tubuloacinar glands.
īThese concretions, called corpora amylacea, containing
primarily deposited glycoproteins and keratan sulfate.
īHave no physiologic or clinical significance.
52
54. MEDICAL APPLICATION
īThe prostate gland is prone to three common problems:
(1) chronic prostatitis, usually involving bacteria or other
infectious agents;
(2) nodular hyperplasia or benign prostatic hypertrophy, occurring
mainly in the periurethral mucosal glands where it often leads to
compression of the urethra and problems with urination; and
(3) prostate cancer (adenocarcinoma), the most common cancer
in nonsmoking men, occurring mainly in glands of the peripheral
zone.
54
55. Cont..
Bulbourethral Glands
īThe paired round bulbourethral glands (or Cowper glands), 3-5
mm in diameter, are located in the urogenital diaphragm and
empty into the proximal part of the penile urethra.
īEach gland has several lobules with tubuloacinar secretory
units surrounded by smooth muscle cells.
īDuring erection the bulbourethral glands release a clear mucus-
like secretion that coats and lubricates the urethra in
preparation for the imminent passage of sperm.
55
56. Cont..
PENIS
īThe penis consists of three cylindrical masses of erectile tissue,
plus the penile urethra, surrounded by skin.
ī Two of the erectile massesâthe corpora cavernosaâare dorsal;
the ventral corpus spongiosum surrounds the urethra.
ī At its end the corpus spongiosum expands, forming the glans.
ī Most of the penile urethra is lined with pseudostratified
columnar epithelium.
ī In the glans, it becomes stratified squamous epithelium
continuous with that of the thin epidermis covering the glans
surface.
56
58. Cont..
īSmall mucus-secreting urethral glands are found along the
length of the penile urethra.
īIn uncircumcised men the glans is covered by the prepuce or
foreskin, a retractable fold of thin skin with sebaceous glands on
the internal surface.
ī The corpora cavernosa are each surrounded by a dense
fibroelastic layer, the tunica albuginea.
ī All three erectile tissues consist of many venous cavernous
spaces lined with endothelium.
ī Central arteries in the corpora cavernosa branch to form
nutritive arterioles and small coiling helicine arteries.
58
59. Cont..
īPenile erection involves blood filling the cavernous spaces in
the three masses of erectile tissue.
īTriggered by external stimuli to the CNS, erection is controlled
by autonomic nerves in these vascular walls.
īParasympathetic stimulation relaxes the trabecular smooth
muscle and dilates the helicine arteries.
īBeginning at ejaculation, sympathetic stimulation constricts the
helicine arteries and trabecular muscle
59
62. Female Reproductive System
īThe female reproductive system consists of internal sex organs
and external genital structures.
īThe internal female reproductive organs are located in the
pelvis
ī The external genital structures (external genitalia) are situated
in the anterior part of the perineum known as the vulva.
īThe internal female reproductive organs are the ovaries,
uterine tubes, uterus, and vagina.
īThe external genitalia include the mons pubis, labia majora and
minora, clitoris, vestibule and opening of the vagina, hymen,
and external urethral orifice.
62
65. OVARIES
īOvaries are almond-shaped bodies approximately 3 cm long, 1.5 cm wide,
and 1 cm thick.
īThere are three cell types in the normal ovary:
ī§ the multipotent surface (coelomic) epithelium,
ī§ the totipotent germ cells, and
ī§ the sex cordâstromal cells
īEach ovary is covered by a simple cuboidal epithelium, the surface (or
germinal) epithelium.
īOverlying a layer of dense connective tissue capsule, the tunica albuginea.
īProduction of gametes and steroid hormones are the two major functions
of the ovary.
65
66. Cont..
īThe ovaries have two interrelated functions: gametogenesis
(the production of gametes) and steroidogenesis (the
production of steroids).
īIn women, the production of gametes is called oogenesis.
īDeveloping gametes are called oocytes; mature gametes are
called ova
66
67. Cont..
The ovary is composed of a cortex and a
medulla.
īA section through the ovary reveals two
distinct regions:
ī§ The medulla or medullary region
ī§ is located in the central portion of the ovary and
contains loose connective tissue
ī§ A mass of relatively large contorted (twisted) blood
vessels, lymphatic vessels, and nerves.
ī§ The cortex or cortical region
ī§ is found in the peripheral portion of the ovary
surrounding the medulla.
âĸ contains the ovarian follicles embedded in a
richly cellular connective tissue.
67
68. âĸ The adult ovary can be subdivided
into three regions:
âĸ the cortex,
âĸ the medulla, and
âĸ the hilus regions.
âĸ The cortex consists of
âĸ the surface epithelium
âĸ tunica albuginea
âĸ ovarian follicles (primordial, primary
secondary
âĸ small, medium, large Graafian follicle and
âĸ corpora lutea
âĸ The medulla consists of
âĸ large blood vessels and nerves.
âĸ The hilus contains
âĸ large spiral arteries
âĸ the hilus or ovary Leydig cells
NB: There is no distinct border between the ovarian cortex
and medulla
69. Cont..
Early Development of the Ovary
ī§ In the first month of embryonic life, primordial germ cells
migrates from the yolk sac to the gonadal primordia.
ī§ A 2-month embryo 600,000 oogonia
ī§ More than 7 million by the fifth month.
ī§ Beginning in the third month, oogonia begin to enter the
prophase of the first meiotic division.
ī§ These cells arrested in meiosis are called primary oocytes
69
70. Cont..
ī§ By the seventh month of development, most oogonia have
transformed into primary oocytes within follicles
ī§ At puberty the ovaries contain about 300,000 oocytes.
īOnly about 450 oocytes are liberated from ovaries by ovulation.
70
71. Cont..
Ovarian Follicles
īAn ovarian follicle consists of an oocyte surrounded by one or
more layers of epithelial cells within a basal lamina.
īThe follicles that are formed during fetal life primordial follicles
consists of a primary oocyte.
īThe oocyte in the primordial follicle is spherical and about 25
Îŧm in diameter, with a large nucleus containing chromosomes
in the first meiotic prophase.
īThe organelles tend to be concentrated near the nucleus and
include numerous mitochondria, several Golgi complexes, and
extensive RER
71
74. Cont..
īBeginning in puberty with the release of FSH from the pituitary,
a small group of primordial follicles each month begins a
process of follicular growth.
This involves
īŧGrowth of the oocyte,
īŧProliferation and changes in the follicular cells,
īŧProliferation and differentiation of the stromal fibroblasts around
each follicle.
74
75. Cont..
Oocyte differentiation includes the following:
īŧ Growth of the cell and nuclear enlargement;
īŧ Mitochondria becoming more numerous and uniformly
distributed;
īŧ RER becoming much more extensive and Golgi complexes
enlarging and moving peripherally; and
īŧ Formation of specialized secretory granules called cortical
granules containing various proteases.
75
76. Cont..
īFollicular cells undergo mitosis and form a simple cuboidal
epithelium around the growing oocyte.
īThe follicle is now called a unilaminar primary follicle
īThe follicular cells continue to proliferate, forming a stratified
follicular epithelium, the granulosa
īFollicular cells are now termed granulosa cells and the follicle is
a multilaminar primary follicle.
īBetween the oocyte and the first layer of granulosa cells the
zona pellucida, 5 to 10 Îŧm thick and containing four
glycoproteins secreted by the oocyte.
76
77. Cont..
īStromal cells immediately outside each growing primary follicle
differentiate to form the follicular theca.
īŧA well-vascularized endocrine tissue, the theca interna
âĸ Characteristic of steroid-producing cells
âĸ Possess a large number of luteinizing hormone (LH) receptors.
īŧA more fibrous theca externa with fibroblasts and smooth
muscle
77
80. Cont..
īWhen the stratum granulosum reaches a thickness of 6 to 12
cell layers, īŦuid-īŦlled cavities appear among the granulosa
cells.
īAs the hyaluronan-rich fluid called liquor folliculi continues to
accumulate among the granulosa cells, the cavities begin to
coalesce, eventually forming a single, crescent shaped cavity
called the antrum.
īThe follicle is now identified as a secondary follicle or antral
follicle .
80
82. Cont..
īAs the secondary follicle increases in size, the antrum, lined by
several layers of granulosa cells, also enlarges.
ī The granulosa cells form a thickened mound, the cumulus
oophorus, which projects into the antrum.
ī The cells of the cumulus oophorus that immediately surround the
oocyte and remain with it at ovulation are referred to as the corona
radiata.
ī The mature or Graafian follicle contains the mature secondary
oocyte.
ī The mature follicle, also known as a GraaīŦan follicle, has a
diameter of 10 mm or more. 82
88. Ovulation & Its Hormonal Regulation
īOvulation is the hormone-stimulated process by which the
oocyte is released from the ovary.
īOvulation normally occurs midway through the menstrual cycle,
that is, around the 14th day of a typical 28-day cycle.
īIn the hours before ovulation, the mature dominant follicle
bulging against the tunica albuginea develops a whitish or
translucent ischemic area, the stigma, in which tissue
compaction has blocked blood flow.
īBefore ovulation the oocyte completes the first meiotic division
īThe cell is now the secondary oocyte and the other becomes
the first polar body.
88
89. Cont..
īA combination of hormonal changes and enzymatic effects is
responsible for the actual release of the secondary oocyte
These factors include:
īŧ Increase in the volume and pressure of the follicular fluid
īŧ Enzymatic proteolysis of the follicular wall by activated
plasminogen
īŧ Hormonally directed deposition of glycosaminoglycans
between the oocyteâcumulus complex and the stratum
granulosum
īŧ Contraction of the smooth muscle fibers in the theca externa
layer, triggered by prostaglandins.
89
90. Cont..
The increased level of GnRH causes a surge of LH release
triggers a sequence of major events in and around the dominant
follicle:
īŧMeiosis I is completed by the primary oocyte
īŧGranulosa cells are stimulated to produce much greater
amounts of both prostaglandin and extracellular hyaluronan
īŧBallooning at the stigma, the ovarian wall weakens
īŧSmooth muscle contractions begin in the theca externa
ī§ The increasing pressure with the follicle and weakening of the
wall lead to rupture of the ovarian surface at the stigma.
90
91. Cont..
Corpus Luteum
ī The collapsed follicle undergoes reorganization into the corpus
luteum after ovulation.
īAfter ovulation, the granulosa cells and theca interna of the
ovulated follicle reorganize to form a larger temporary
endocrine gland, the corpus luteum.
ī A lipid-soluble pigment, lipochrome, in the cytoplasm of the
cells gives them a yellow appearance in fresh preparations.
91
92. Cont..
īThe short-term fate of the corpus luteum depends on whether a
pregnancy occurs.
īThe ovulatory LH surge causes the corpus luteum to secrete
progesterone for 10 to 12 days.
īWithout further LH stimulation and in the absence of
pregnancy, both major cell types of the corpus luteum cease
steroid production and undergo apoptosis.
92
94. Cont..
īA consequence of the decreased secretion of progesterone is
menstruation, the shedding of part of the uterine mucosa.
īThe corpus luteum that persists for part of only one menstrual
cycle is called a corpus luteum of menstruation.
īRemnants from its regression are phagocytosed by
macrophages, produce a scar of dense connective tissue called
a corpus albicans
ī If fertilization and implantation occur, the corpus luteum
increases in size to form the corpus luteum of pregnancy.
īCorpus luteum of pregnancy is maintained by HCG for 4 to 5
months.
94
97. Hormonal regulation of ovulation
âĸ Growth of follicles during the first half of the menstrual cycle is
stimulated by FSH from pituitary gland.
97
98. Hormonal regulation of ovulation
âĸ Growing follicles produce estrogen, whose increased output exerts a
negative feedback on the FSH production causing an LH surge
98
99. Hormonal regulation of ovulation
âĸ The increased secretion of LH causes:
1. Final follicle maturation and ovulation
99
100. Hormonal regulation of ovulation
2. Formation of the corpus luteim which produces estrogen,
progesterone & inhibin that inhibit LH production, causing
degeneration of the corpus luteim after 14 days, unless fertilization
occurs.
100
101. Hormonal regulation of ovulation
âĸ If pregnancy takes place, human chorionic gonadotropin produced by
the developing placenta maintains the corpus luteim in the absence of
LH.
101
103. Clinical correlation
âĸ It also is the fifth leading
contributor to cancer
mortality in women,
âĸ Tumors of the ovary are
amazingly varied.
âĸ This diversity is attributable
to the presence of three cell
types in the normal ovary:
âĸ the multipotent surface
(coelomic) epithelium,
âĸ the totipotent germ cells,
and
âĸ the sex cordâstromal cells
103
104. ī Is about 12 cm long, and has four pats: infundibulum with fimbriae,
ampulla, isthmus and intramural or interstitial part.
Histology of the uterine tube
104
105. ī The wall of the oviduct consists of 3 layers
īŧ Folded mucosa
īŧ Thick, well-defined muscularis; Circular (or spiral) and longitudinal
layers of smooth muscle
īŧ Thin serosa covered by visceral peritoneum with mesothelium.
Histology of the oviduct
105
107. Histology of the oviduct
ī The mucosal lining is simple columnar epithelium composed of
two kinds of cellsâciliated and nonciliated.
ī Ciliated cells are most numerous in the infundibulum and ampulla.
ī The wave of the cilia is directed toward the uterus.
ī Nonciliated, peg cells are secretory cells that produce the fluid
that provides nutritive material for the ovum.
107
109. âĸ Lamina propria
â Made by loose connective tissue that can act like the uterus in an abnormal
implantation.
Histology of the oviduct
109
110. âĸ Muscular layer
â Made by: inner circular or spiral and outer longitudinal layers.
âĸ Serosa making the most outer layer.
Histology of the oviduct
110
112. ī Pear-shaped organ with thick, muscular walls
ī Has body (corpus), fundus and cervix parts.
ī The lumen of the cervix, the cervical canal, has constricted
openings at each end:
īŧ The internal os (L. os, mouth) opens to the main uterine lumen
and
īŧ The external os to the vagina
Histology of the uterus
112
113. ī The uterine wall is composed of three
layers
ī From the lumen to outward they are as
follows
īŧ The endometrium is the mucosa of the
uterus.
īŧ The myometrium is the thick muscular
layer. It is continuous with the muscle
layer of the uterine tube and vagina.
īŧ The perimetrium, the outer serous layer
or visceral peritoneal covering of the
uterus
Histology of the body and funds of uterus
113
114. Cont..
ī Both myometrium and endometrium
undergo cyclic changes each month to
prepare the uterus for implantation of an
embryo.
ī These changes constitute the menstrual
cycle.
ī The myometrium forms a structural and
functional syncytium.
ī The myometrium is the thickest layer of
the uterine wall.
ī The middle muscle layer contains
numerous large blood vessels (venous 114
116. âĸ Lamina propria
â Contain large amount of fibroblasts, ground substance, reticular
connective tissue and simple tubular glands (branched in deeper
portion).
Endometrium
116
117. âĸ During reproductive life, the endometrium consists of two layers or
zones that differ in structure and function
īŧ The stratum functionale or functional layer is the thick part of the
endometrium, which is sloughed off at menstruation.
īŧ The stratum basale or basal layer is retained during menstruation
and serves as the source for the regeneration of the stratum
functionale.
âĸ The stratum functionale is the layer that proliferates and
degenerates during the menstrual cycle.
Endometrium
117
118. â Undergoes cyclic changes in response to the ovarian
hormones
â Receives the coiled (spiral) arteries
â Subdivided based on the density of the lamina propria
Stratum functionale (pars functionalis) of endometrium
118
119. a. Stratum compactum
â Superficial and with large number of stromal cells that
appear epithelial cells.
b. Stratum spongiosum
â Deeper portion.
Stratum functionale (pars functionalis) of endometrium
119
120. âĸ Deeper and thinner portion.
âĸ Receives the straight arteries.
âĸ Retained during menstruation.
âĸ Contain the deeper parts of the uterine glands whose
lining cells replace covering epithelium after
mensuration.
Stratum basale (pars basalis) of endometrium
120
121. âĸ The thickest tunic of the uterus
âĸ Shows bundles of smooth muscle fibers separated by connective tissue
containing venous plexuses and lymphatics
âĸ The smooth muscle forms interwoven layers
âĸ Show 4 poorly defined layers.
â 1st and 4th layers are mainly longitudinal.
â The middle layers are highly vascular with arcuate arteries which give
the straight and coiled arteries.
Myometrium
121
122. ī At pregnancy show hyperplasia and hypertrophy, and synthesis collagen.
ī After pregnancy is reduced by reduction in the muscle size and destruction
and degradation of collagen.
Myometrium
122
123. âĸ Made by serosa or adventitia
âĸ Make the outer layer.
Perimetrium
123
126. Mucosa
âĸ Two types of epithelial lining
1. Simple columnar epithelium
that secret mucus
2. Stratified squamous
epithelium covers the
external vaginal surface.
Histology of the uterine cervix
126
128. âĸ Mucosa
â Do not shed during menstruation, but cyclic changes occur in the
amount and viscosity of its secretion.
Histology of the uterine cervix
128
129. âĸ Contain cervical glands which are:
â Mucous secreting
â Extensively branched.
â At ovulation secrete watery mucous
â At pregnancy secrete more viscous mucous
Histology of the uterine cervix
129
130. ī A few smooth
muscle fibers.
ī Dense
connective
tissue that make
about 85% , and
undergo
collagenolysis
during cervical
dilatation.
Histology of the uterine cervix
130
131. Menstrual cycle
âĸ Cyclic changes of the endometrium during the menstrual cycle are
represented by the proliferative, secretory, and menstrual phases.
âĸ The menstrual cycle is a continuum of developmental stages in
the functional layer of the endometrium.
âĸ It is ultimately controlled by gonadotropins secreted by the pars
distalis of the pituitary gland that regulate the steroid secretions of
the ovary.
âĸ The cycle normally repeats every 28 days, during which the
endometrium passes through a sequence of morphologic and
functional changes.
131
132. Proliferative (follicular) phase
âĸ During the 5th to 14th day of the menstrual cycle.
âĸ Development of ovarian follicles and production of estrogen.
132
133. Proliferative (follicular) phase
âĸ At the end of this phase:
â Thick endometrium with a diameter of 3 mm.
â Glands are straight tubules with narrow lumen
133
135. Secretory (Luteal) phase
âĸ Thick endometrium, 5mm in diameter by increased
accumulation of glandular secretion, edema and
increased stromal cells.
135
136. Secretory (Luteal) phase
âĸ Elongated and convoluted arteries reaching to the
superficial portions of the endometrium.
âĸ Reduced contraction of the myocytes causing no
interference with implantation.
136
139. Menstrual phase
âĸ Corpus luteim stops to function after serving for 14
days.
â Decreased estrogen and progesterone in the blood
causing: contraction of the coiled arteries leading to
necrosis and rupture of blood vessels.
â Detachment of stratum functionalis and gets sloughed
off.
139
143. ī Uterine glands secrete glycoproteins.
ī Vessels dilate.
Endometrium at pregnancy and implantation
143
144. âĸ Lamina propria swells and with decidual cells:
â Serve as embryothrophs.
â Protect uncontrolled invasion by the syncytiotrophoblast.
Endometrium at pregnancy and implantation
144
145. âĸ As decidua basalis make maternal part of the placenta
âĸ Fetal part is made by chroion frondosum
Endometrium at pregnancy and implantation
145
147. Histology of the Vagina
ī The vagina is a fibromuscular tube that joins internal reproductive
organs to the external environment.
The vaginal wall consists of the following
īŧ An inner mucosal layer has numerous transverse folds or rugae
and is lined with stratified squamous epithelium.
īŧ An intermediate muscular layer is organized into two sometimes
indistinct, intermingling smooth muscle layers, an outer
longitudinal layer, and an inner circular layer.
147
148. Histology of the Vagina
ī An outer adventitial layer is organized into an inner dense
connective tissue layer adjacent to the muscularis and an outer
loose connective tissue layer that blends with the adventitia of the
surrounding structures.
ī The lumen of the vagina is lined by stratiīŦed squamous, non-
keratinized epithelium.
ī Its surface is lubricated mainly by mucus produced by the cervical
glands.
ī The greater and lesser vestibular glands located in the wall of the
vaginal vestibule produce additional mucus that lubricates the
vagina.
ī Gland are not present in the wall of the vagina. 148
149. Histology of the Vagina
âĸ Lamina propria
â Increased amount of elastic fibers, lymphocytes and
neutrophils
â High amount vascularization giving fluid exudates
during sexual arousal.
â No sensory innervations, although a few pain fibers
may be found.
â No glands.
149
152. Histology of the External Genitalia (vulva)
âĸ Clitoris
â Made by two erectile bodies ending in glans clitoris
and prepuce.
â Lined by stratified squamous non-keratinized
epithelium.
152
153. Histology of the External Genitalia (vulva)
âĸ Labia minora
â Spongy connective tissue covered with skin.
â Lined by stratified squamous epithelium with a thin
layer of keratinized cells on the surface.
â Contains sebaceous and sweat glands on both
surface.
153
155. Histology of the External Genitalia (vulva)
âĸ Labia majora
â Made by adipose tissue within layer of smooth
muscles covered with skin.
â Inner surface is similar with labia minora.
â Outer surface has coarse curly hairs.
â Has increased amount of sebaceous and sweat
glands on both surface.
155
156. âĸ Greater vestibular glands (glandulae vestiularis
major, glands of Bartholins)
â One on each side
â Similar to bulbourethral glands
â Produce mucus
Histology of the External Genitalia (vulva)
156