This is a presentation of ovarian follicles made by mohamed alzayat - mansoura faculty of medicine. Hopefully it would help you.

1. Ovarian follicles

2. Introduction
 The Ovary :
The human ovary consists of an inner medulla and outer
cortex with indistinct boundaries.
The medulla contains the blood vessels and nerves, while the
cortex is occupied by developing follicles.
A cross-section of an ovary will reveal follicles in various stages
of development. The next sections will describe the histological
features of each stage of follicular development and the major
functional changes in the cells compose follicles.

4. Primordial Follicle
 These follicles consist of oocytes surrounded by a single layer
of squamous follicular cells which have a basal lamina and
joined by desmosomes.
Primary oocyte:
- sphirecal in shape , about 30 µm in diameter.
- it has large vesicular rounded and eccentric nucleus
with large nucleolus.
- it’s cytoplasm is pale acidophilic and the organelles
tend to gather close to the nucleus.

6. Primary follicle
They are similar to the primordial follicle but:
the primary oocyte are larger in size
follicular cells become cubical then columnar
A- primordial follicle
B- primary follicle
1-oocyte
2-follicular cells

8. Growing follicles
Primary oocyte:
- it doubles its size
- become surrounded by acidophilic membrane
called zona pellucida which is glycoprotein in nature
produced by both the oocyte and follicular cells.
- by EM its cell membrane produce microvilli into the
zona pellucida.

10.  Follicular cells:
- FSH → the follicular cells proliferate to form many layers
- LH → they begin to secrete follicular fluid which accumulate
in multiple spaces
- these spaces join to form a single cavity called antrum which
divides the follicular cells into :
a- cumulus oophorus: surround the oocyte, and connect it to
one side of the follicle.
b- granulosa cells: they line the cavity, polygonal in shape with
pale acidophilic cytoplasm and central rounded nuclei. They
secrete estrogene hormone.

11. Theca folliculi:
- a capsule result from condensation of stroma
around the follicles
- later the differentiate into theca interna and theca
externa
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2
3
4
5
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Oocyte
Pellucid zone
Stratum granulosum
Theca interna
Theca externa
Antral follicle
Cumulus oophorus
Basal lamina between theca and stratum
granulosum

13. Grafiaan follicle
 The Graafian follicle is the stage after the first meiotic division has
completed but before ovulation.
 The 2ry oocyte, having undergone the first meiotic division, is
located eccentrically, 120 µm, contain 23d-chromosomes.
 It is surrounded by the zona pellucida and a layer of several
columnar cells known as the corona radiata which send processes
into zona pellucida giving nutrition to the oocyte.
 The theca folliculi differentiated into:
- theca interna: cellular, vascular and secrete estrogene
- theca externa: fibrous and less vascular.

15. Ovulation
When the follicular fluid is markedly increased it ruptures
and realese the 2ry oocyte on the surface of the ovary.
the ovum will consist of three structures: oocyte, zona
pellucida and corona radiata.

16. Corpus luteum
After release of the ovum, the remaining cells of the
granulosa and theca interna form the corpus luteum. The
center contains the remains of the blood clot that formed
after ovulation.
Surrounding the clot are glanulosa lutein cells have an
appearance characteristic of steroid-producing cells, with
pale cytoplasm.
on the outside theca lutein cells which are smaller and more
deeply stained. These cells produce progesterone and to a
lesser extent cholesterol.

18. Corpus Albicans
If fertilization does not occur, the cells of the corpus
luteum remain active for roughly 14 days until the levels
of LH fall and the corpus luteum involutes to form the
corpus albicans.
 The secretory cells of the corpus luteum degenerate, are
phagocytosed by macrophages and replaced by fibrous
material.

20. Atretic Follicle
Each menstrual cycle, several primordial follicles are
stimulated to continue development but only one follicles
completes development to release an ovum.
The other follicles degenerate through a process called
atresia which can occur at any stage of development.
During atresia, granulosa cells undergo apoptosis and are
replaced by fibrous material.
The oocyte degenerates and the basement that separated
the oocyte from granulosa cells thickens to become the
glassy membrane.