Histology Of The Female Reproductive System Flashcards
The FRS consists of
the internal and external genitalia
Internal genitalia of the FRS consists of:
- 2 ovaries
- 2 oviducts
- The uterus
- The vagina
Functions of the FRS
- Gamete production - oocyte
- Environment for fertilization
- Embryo nurturing
- Steroidal hormone
The shape of the ovaries
Almond
Size of the ovary
Measures ~ 3 cm long, 1.5 cm wide and 1 cm thick
The ovary is covered by what kind of epithelium?
…simple cuboidal epithelium called the germinal epithelium.
The germinal epithelium is continuous with the ___ and overlays a layer of ___
mesothelium, dense connective tissue capsule - the tunica albuginea
___ is responsible for the whitish color of the ovary
Tunica albuginea
The ovary is divided into:
2 parts:
• The cortex
• The medulla
The ovarian cortex is filled with…
a highly cellular connective tissue stroma and many ovarian follicles. It is most prominent.
The medulla contains…
… loose connective tissue and blood vessels
There is no sharp demarcation between the cortex and the medulla. True or false?
True
Types of ovarian follicles
- Primordial follicle
- Unilaminar primary follicle
- Multilaminar primary follicle
- Antral follicle
- Mature/graafian follicle
- Atretic follicle
- Corpus luteum
- Corpus albicans
An ovarian follicle consists of
an oocyte surrounded by one or more layers of epithelial cells surrounded by basal lamina
The ovarian follicles formed during fetal life are called ___ and they are present in ___
primordial follicles (PFs), in the superficial areas of the cortex
Primordial follicles consist of…
…a primary oocyte enveloped by a single layer of flattened follicular cells
The oocyte in the primordial follicle is…
spherical and measures about 25 µm in diameter
Properties of primordial follicle
- Large nucleus with chromosomes in the first meiotic prophase
- Organelles are concentrated near the nucleus and includes:
- Basal lamina surrounding the follicular cells marks a clear boundary between the follicle and the vascularized stroma, acting as a blood-follicle barrier
Organelles in the primordial follicle are
Numerous mitochondria
•Golgi complexes and
•Extensive rough endoplasmic reticulum
Follicular growth and development, as triggered by FSH, happens as follows…
- Growth of the oocyte
- Proliferation and changes in the follicular cells
- Proliferation and differentiation of the stromal fibroblasts around each follicle
Selection of the primordial follicles and the dominant follicle destined to ovulate both involve:
•Complex hormonal balances and •Subtle differences among follicles in: - FSH receptor numbers - Aromatase activity and - Estrogen synthesis and other variables
Under the influence of FSH, an oocyte will…
…grow most rapidly during the first part of follicular development to reach a diameter of about 120µm
•Oocyte differentiation involves the following:
- Growth of cell and nuclear enlargement
- More Mitochondria becomes
- More extensive RER and enlarged Golgi
- Formation of specialized secretory granules called cortical granules containing various proteases
Stages of follicular growth
Unilaminar primary follicle Granulosa epithelium Zona pellucida Theca cells Oocyte
The zona pellucida (ZP) measures ___ and consists of ___
5-10 µm thick, 4 glycoproteins
What differentiates to become the vascularized follicular theca?
The stromal cells immediately surrounding the primary follicle
The follicular theca will further differentiate into
2 distinct structures around the growing follicle:
- Theca interna
- Theca externa
The Theca interna is
A well vascularized endocrine tissue secreting androstenedione
The Theca externa is
A fibrous tissue consisting of fibroblasts and smooth muscle cells
With increasing growth in oocyte size and granulosa cell numbers, the follicle moves…
… deeper in the ovarian cortex
Secondary or antral follicles are formed from…
Follicular fluid accumulation in the spaces in the granulosa layer
Follicular fluid contains:
- Hyaluronate
- Growth factors
- Plasminogen
- Fibrinogen
- Anticoagulant heparan sulphate proteoglycan
- Steroids- estrogens, progesterone and androstenedione
- Binding proteins
A mature follicle has thick thecal layers. True or false?
True
A mature follicle normally takes about __ to develop from a primordial follicle
90 days
When do follicles become atretic?
at any stage
During atresia, follicular cells and oocytes undergo…
apoptosis
Features of atretic follicles include:
- Detachment of the apoptotic granulosa cells
- Autolysis of the oocyte
- Collapse of zona pellucida
How are atretic follicles formed?
A large number of ovarian follicles undergo degeneration and become atretic
The oviducts are muscular tubes with considerable mobility. True or false?
True
Length of the oviduct
10-12 cm
The oviduct opens into the…
peritoneal cavity near the ovary with a fringe of fingerlike extensions called fimbriae
Parts of the uterine tubes
The tube is divided into 4 parts:
- The infundibulum
- Ampulla
- Isthmus
- Uterine/intramural part
What part of the oviduct does fertilization take place?
The ampulla
Which part of the oviduct contains fimbriae?
- Infundibulum
- The ampulla
- The isthmus
- Uterine or intramural part
The longest and expanded region of the oviduct is the ___
The ampulla
The wall of the oviduct consists of:
- A folded mucosa
- A thick muscularis
- A thin serosa covered by visceral peritoneum with mesothelium
Serosa of the oviduct
It is thin and covered by visceral peritoneum with mesothelium
Describe the muscularis of the oviduct
It is thick with somewhat interwoven circular or spiral and longitudinal layers of smooth muscle
Epithelium of the mucosa of the oviduct
It is lined by a simple columnar epithelium on a lamina propria of loose connective tissue
Properties of the mucosa of the oviduct
It has numerous branching longitudinal folds most prominent in the ampulla
Where are the mucosal folds smaller or absent?
They are smaller in the region closer to the uterus and are absent in the intramural portion
The epithelium of the oviduct contains
Two interspersed functionally important cell types:
- Ciliated cells
- Secretory peg cells- nonciliated, apical ends bulge into the lumen
Cilia of epithelial cells of the oviduct during follicular and luteal phases
Triggered by estrogens, the cilia elongates and both cell types undergo hypertrophy during follicular phase and atrophy with loss of cilia during late luteal phase
What happens to the infundibulum during ovulation?
At the time of ovulation, the uterine tube shows active movement. The fringed infundibulum moves very close to the ovary and partially covers its surface
What propels the oocyte towards the ampulla where fertilization occurs during ovulation?
The sweeping muscular contractions of the fimbriae and the ciliary activity of the epithelium
Oocyte is viable for about ___ if not fertilized
24 hours
Parts of the uterus :
- The lumen, the cervical canal has constrictions at 2 ends
- Internal os which opens into the uterine lumen
- External os which opens into the vagina
- Body - largest part entered in by the tubes
- Fundus - curved superior part between the tubes
- Isthmus - narrow part
- Cervix - lower cylindrical end
The lumen, the cervical canal has constrictions at 2 ends, which are?
- Internal os which opens into the uterine lumen
* External os which opens into the vagina
The uterine wall has 3 major layers:
Perimetrium
Myometrium
Endometrium
Which layer of the uterine wall has an outer connective tissue layer and is adventitial in some areas but largely a serosa covered by mesothelium
Perimetrium
The endometrium is lined by…
…simple columnar epithelium
Myometrium during pregnancy
- It undergoes extensive growth involving both hyperplasia and hypertrophy
- Smooth muscle cells actively synthesize collagen strengthening the uterine wall
- After pregnancy, muscles shrink and many undergo apoptosis, excess collagen is removed
The lamina propria of the endometrium contains
primarily type III collagen fibers with abundant fibroblasts and ground substance
The endometrium is subdivided into
2 zones:
- Basal layer
- Functional layer
Which layer of the endometrium is affected by the menstrual cycle?
The functional layer undergoes profound changes but the basal layer remains relatively unchanged
Blood supply of endometrium
- Arcuate arteries in the middle layers of the myometrium send two sets of smaller arteries to the endometrium:
1. Straight arteries which supply only the basal layer
2. Spiral arteries- which are longer and sensitive to progesterone supplies functional layer
Which hormone(s) controls growth and differentiation of epithelial cells and associated connective tissue?
Estrogens and progesterone
What influences cyclic changes in levels of the ovarian hormones, causing the endometrium to undergo cyclic structural modifications?
Gonadotropins
Phases of the menstrual cycle
Menstrual
Proliferative
Secretory
The beginning of the proliferative phase is also called
the follicular or estrogenic phase
After ovulation, the secretory or luteal phase starts as a result of
the progesterone secreted by the corpus luteum
The endometrium reaches its maximum thickness of __ as a result of ___
5mm, accumulation of secretions and edema in the stroma
What inhibits strong contractions of the myometrium that might interfere with embryo implantation?
Progesterone
The mucosal lining of the endocervix is…
…a mucus secreting simple columnar epithelium on a thick lamina propria
The region of the cervix where the endocervical canal opens into the vagina is called
the external , which is covered by the endocervical mucosa which has stratified squamous epithelium
The endocervical mucosa contains…
many branched cervical glands which produce mucus and are often dilated
The endocervical mucosa is more affected than the endometrium during menstruation. True or false?
False. It is less affected.
Changes in cervical secretions
- During ovulation - mucosa secretions are maximal and watery
- In the luteal phase - high progesterone levels cause the mucosa secretions to become viscous
- During pregnancy - the cervical glands proliferate and secrete abundant, highly viscous mucus which forms a plug in the endocervical canal
The wall of the vagina lacks glands. True or false?
True
Layers of the vaginal wall
- A mucosa
- Muscular layer
- Adventitia
Mucus covering the lumen of the vagina is produced by
the glands of the uterine cervix
During intercourse, additional lubricating mucus is provided by…
…a pair of large and many small vestibular glands opening into the vestibule
The vestibule is covered by…
stratified squamous epithelium which merges with the epidermis of the surrounding skin
The vestibular mucosa is abundantly supplied with sensory nerves and the range of tactile receptors normally present in skin. True or false?
True
The epithelium of the vagina mucosa is…
…stratified squamous with a thickness of 150-200 µm in adults
During the premenstrual and menstrual phases of the cycle, leukocytes are particularly numerous throughout the mucosa and in the lumen. True or false?
True
The vaginal mucosa has a lot of sensory nerve endings. True or false?
False, they’re few
The muscular layer of the vagina is composed mainly of
two indistinct layers of smooth muscle comprising of
- circular bundles next to the mucosa
- longitudinal bundles near the adventitia layer
The epithelial cells of the vagina don or contain keratohyaline and undergo keratinization to form keratin plates as in the epidermis. True or false?
False. They contain a small amount of keratohyaline and don’t undergo keratinization
Stimulated by estrogens, the epithelial cells synthesize and accumulate glycogen. True or false?
True
Importance of glycogen in the vagina
When the cells desquamate, bacteria metabolize glycogen to lactic acid, causing a relatively low pH within the vagina which helps provide protection against pathogens