Microscopic structures of Male & female reproductive

organs

LG 1

Female Reproductive system• It consists of the organs that are responsible for reproduction,

secretion of female sex hormones needed for growth of the genital organs and expression of secondary sexual characteristics.

• It also consists of the genital organs that provide room for implantation and growth of pregnancy to term. These organs include the fallopian tubes, uterus, vagina and vulva.

LG 2

LG 3

The Ovary• The ovaries have two functions - "production" and ovulation of

oocytes and the production and secretion of hormones. • The ovary is attached to the broad ligament by a short fold

of peritoneum, called the mesovarium, through which vessels and nerves pass to the ovary and enter it at the hilus of the ovary.

• Like so many other organs the ovary is divided into an outer cortex and an inner medulla. The cortex consists of a very cellular connective tissue stroma in which the ovarian follicles are embedded. The medulla is composed of loose connective tissue, which contains blood vessels and nerves

LG 4

Microscopic features of the Ovary• The surface of the ovary is covered by a single layer of cuboidal

epithelium, also called germinal epithelium. It is continuous with the peritoneal mesothelium. Fibrous connective tissue forms a thin capsule, the tunica albuginea, immediately beneath the epithelium.

LG 5

LG 6

LG 7

The oviduct• The oviduct functions as a conduit for the oocyte, from the

ovaries to the uterus. Histologically, the oviduct consists of a mucosa, a muscularis and a Serosal coat

LG 8

Oviduct ….cont• The mucosa• is formed by a ciliated simple columnar and secretory epithelium

resting on a very cellular lamina propria. The number of ciliated cells and secretory cells varies along the oviduct. Secretory activity varies during the menstrual cycle, and resting secretory cells are also referred to as peg-cells. Some of the secreted substances are thought to nourish the oocyte and the very early embryo.

LG 10

Oviduct ….cont• The muscularis• It consists of an inner circular muscle layer and an outer

longitudinal layer. An inner longitudinal layer is present in the isthmus and the intramural part of the oviduct.

LG 11

Oviduct ….cont• Serosa coat: • It consists of single layer of mesothelial cells of visceral

peritoneum forms the serous coat.

LG 12

The Uterus

LG 13

• The walls of the uterus are composed of a mucosal layer, the endometrium, and a fibromuscular layer, the myometrium. The peritoneal surface of the uterus is covered by a serosa.

LG 14

Histological aspect

• Endometrium• The endometrium consists of a simple columnar epithelium

(ciliated cells and secretory cells) and an underlying thick connective tissue stroma. The mucosa is invaginated to form many simple tubular uterine glands. The glands extend through the entire thickness of the stroma.

LG 15

Histological aspect…

• Myometrium• The myometrium (Gr. mys, muscle, + metra, uterus), the

thickest tunic of the uterus, is composed of bundles of smooth muscle fibers separated by connective tissue. The bundles of smooth muscle form four poorly defined layers.

LG 17

Histological aspect…

Uterine Cervix• The cervix is the lower, cylindrical part of the uterus, and it differs in

histological structure from the rest of the uterus. The lining consists of a mucus-secreting simple columnar epithelium. The cervix has few smooth muscle fibers and consists mainly (85%) of dense connective tissue. The external aspect of the cervix that bulges into the lumen of the vagina is covered with stratified squamous epithelium.

LG 18

LG 19

MEDICAL APPLICATION

After menopause the mucosa wall shrinks, the columnar cells become flat and secretory features decrease causing dryness of the vagina, which may cause painful sexual intercourse also called dyspareunia.

THE VAGINA

LG 20

The Vagina • Is a fibromuscular canal which extend from the cervix and opens

at the vulva. On cross section it consists of three layers; a mucous layer, a muscular layer, and outer fibrous layer.

LG 21

• Mucosa: the stratified squamous epithelium

…vagina• Muscularis• Inner circular and outer longitudinal layers of smooth muscle

are present. Inferiorly, the striated, voluntary bulbospongiosus muscle forms a sphincter around the vagina.

LG 22

…vagina• The fibrous coat:• This consists of dense collagenous inner layer and outer loose

connective tissue that merges with the adventitia of the urinary bladder and the rectum.

• The outer layer is rich in blood & lymphatic vessels, and nerves. The inner layer is rich in elastic fibers believed to contribute to the elasticity and strength of the vaginal wall.

LG 23

FEMALE EXTERNAL GENITALIA

LG 24

External genitalia• The female external genitalia are collectively known as

vulva. These includes the clitoris, labia minora, labia majora, and vestibular glands.

LG 25

External genitalia…

• Clitoris:• This develop from common origin as the dorsal part of the penis

and is homologous to the corpora cavernosa of the penis. It has two small erectile tissue erectile tissue the corpora cavernosa, which ends in a poorly developed glans clitoris.

• The clitoris is highly supplied by sensory nerve endings.

LG 26

External genitalia…

• The labia minora:• These are two flaps made up of core of connective tissue rich in

elastic fibers and many blood vessels.• It is lined by stratified squamous epithelium. The epithelium is

rich in pigment cells and sebaceous glands are present in both surfaces.

LG 27

External genitalia…

• The labia majora:• These are two folds of skin located external to labia minora. The

core of labia majora is made up of subcutaneous tissue rich in adipose tissue and thin layer of smooth muscle fibers underneath.

• The outer surface is lined by keratinized stratified squamous epithelium, similar to skin in every aspect. The inner does not contain hair but has sweat and sebacous glands.

LG 28

External genitalia…• The vestibule:• Is the space surrounded by labia. Both vagina and urethra open in

the vestibule. It is lined by stratified squamous epithelium and contain mucous secreting glands; these are minor & major vestibule glands.

• The minor vestibule glands• Are located around the urethral opening and clitoris. They

secrete mucus that lubricates the vulva. These glands resemble the glands of Littre in the male urethra.

LG 29

External genitalia…

• The major vestibule glands• Are commonly known as Bartholin glands; they are located in

the wall of the vestibule and open in the inner surface of the labia majora. These glands are tubuloalveolar type and secrete lubricating mucus. They are equivalent to male bulbourethral glands.

LG 30

Microscopic structures of Male reproductive

organs

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The internal male genitalia• The internal male genitalia consist of the testes with the

adjoining epididymis, the vas deferens and the accessory sex glands, namely the seminal vesicles, the prostrate and the bulbourethral glands

LG 32

The testes• The testes have, like the ovaries, two functions: they produce

the male gametes or spermatozoa, and they produce male sexual hormone, testosterone, which stimulates the accessory male sexual organs and causes the development of the masculine extra genital sex characteristics

LG 33

LG 34

LG 35

The testes…

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Clinical applicationhydrocoele

Testes…– The testis is surrounded by a thick capsule, the tunica

albuginea, from which a conical mass of connective tissue, the mediastinum testis, projects into the testis.

– Deeper to the tunica albugenia the testes is covered by a vascular tunic known as the tunica vasculosa

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Lobuli testis• Each lobule is occupied by one to four seminiferous tubules

enmeshed in a web of loose connective tissue that is rich in blood and lymphatic vessels, nerves, and interstitial cells, also known as Leydig cells. Seminiferous tubules produce male reproductive cells, the spermatozoa, whereas interstitial cells secrete testicular androgens.

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Histological aspect…

• On cross section the tubules have an outer lining membrane and inner epithelium

• Limiting membrane (tunica propria) that lies external to the basement membrane containing collagen fibers and smooth muscle cells (myoid cells)

• Epithelium of the seminiferous tubules is made up of stratified epithelium containing cells known as spermatogenic cells at different stages of maturity to spermatozoa. Another type of cell is sertoli cells (sustenticular or suporting cells)

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Ducts of the Testis• Spermatozoa pass via the tubuli recti (low columnar epithelium)

and the rete testis (flattened or cuboidal epithelium) into numerous ductuli efferentes, which are lined by a columnar epithelium, which consists of both absorptive and ciliated cells. The height of the two cells types which form the epithelium of the ductuli efferentes is variable which gives the lumen a characteristic wavy outline

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Epididymidis • They are lined with alternating clumps of tall and short

pseudostratified columnar cells thus giving rise to the saw-toothed appearance of the luminal surface. Most cells of the epithelium, also called principal cells, have long stereocilia. Stereocilia are non-motile structures, which in the EM resemble large microvilli.

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Vas deferens (ductus deferens)

• Connects epididymis to the prostatic urethra.

• It has inner mucous membrane, middle muscularis layer, Outer adventitia layer.

• The mucous membrane: It is lined by a pseudostratified columnar epithelium. Similar to the epididymis, cells have long stereocilia.

• The lamina propria is unusually rich in elastic fibres.

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VAS DEFERENS H&EVAS DEFERENS H&E

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• The middle muscularis is well developed (up to 1.5 mm thick) and consists of three layers; intermediate thick circular layer of smooth muscle between thinner inner and outer thick longitudinal layers.

• The muscularis is the structure which makes the vas deferens palpable in the spermatic cord.

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Vas deferens…