histo female repro I Flashcards
What does the female reproductive system cosists of?
Ovaries
Uterine tubes
Uterus
Vagina
Mammary Glands
Female reproductive organs undergo cyclic changes from puberty to menopause.
What are the functions of the ovaries?
Production of gametes and steroid hormones are the two major functions of the ovary.
In the female the production of gametes is called oogenesis. Developing gametes are called oocytes and mature gametes are called ova
Which are the major gorups of steroid hormones in the ovaries?
- Estrogens
Promote maturation and growth of internal and external sex organs, at puberty promote breast development. - Progestogens
Prepare the internal sex organs (mainly uterus) for pregnancy. Also prepare the mammary gland for lactation.
Both hormones play an important role in the menstrual cycle
describe the histological feature of th eovaries?
Cortex
Site of ovarian follicles embedded in a richly cellular Connective tissue (CT)
Medulla
Highly vascular, loose CT, site at which the major vessels enter and leave the ovary
identify
Ovary monkey
Describe the epithelium of the cortex of the ovary
Germinal epithelium (instead of mesothelium) covers the ovary .It is a single layer of cuboidal cells.
Tunica albuginea (Dense CT, fibrous layer)lies between the germinal epithelium and the cortex.
Ovarian follicles provide the microenvironment for the developing oocytes.
Stroma:
Highly cellular, containing spindle shaped fibroblast-like cells. Scattered smooth muscle fibers
70% of ovarian cancers arise from the epithelial surface
When does the ovarian cycle begin?
Beginning at puberty, the cortex of the ovary undergoes a month cycle of changes in morphology
what are the phases of the ovarian cycle?
This can be divided in 2 phases:
Follicular Phase (Days 1-14)
Growth of follicle into a mature follicle and ovulation at day 14 (aprox.). Characterized by follicular stimulation by FSH and synthesis of estrogen.
Luteal Phase (Days 15-28)
The remains (remnants) of the mature ovarian follicle develop a corpus luteum. Characterized by formation of corpus luteum in response to burst of Luteinizing Hormone (LH) and by synthesis of progesterone
describe follicle development
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During puberty small groups of follicles undergo cyclic growth and maturation.
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Cyclic of maturation and ovulation is established and continues in parallel with the menstrual cycle.
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Primordial follicles undergo follicular growth and single mature follicle is produced each month.
wht are the different stages of follicular growth
1.Primordial follicle
2.Unilaminar(early) primaryfollicle
3.Multilaminar (late) primaryfollicle
4.Secondary or antral follicles
5.Mature (Graafian) follicle
explain the early stages of oogenesis
The primordial germ cells (PGCs) migrate from the yolk sac to the genital ridge which eventually forms the ovary.
In the fetal ovary, massive mitosis increases the number of oogoniato up to several million by the end of the 5thfetal month
By the end of the 7thmonth, the oogonia have all transformed into primary oocytes. OOGONIA ARE ONLY FOUND IN THE FETAL OVARY
The oocytespresent at birth remain arrested in development at the 1st meiotic division. The cells at this stage are the primary oocytes. They become surrounded by a single layer of flattened (squamous) follicular cells to form a primordial follicle.
eaht are primordialfollicles>
Primary oocyte surrounded by single layer of “flat” follicular cells.
WHat is the earliest stage of follicular development?
primordial follicles
describe th eprimordial follicles?
Are the smallest of the ovarian follicles.
Typically are found in the stroma of the cortex beneath the tunica albuginea
Consists of the primary oocyte surrounded by a single layer of squamous follicular cells
identify
primordial follicles
identify
follicular cells, oocyte primary, primordial follicle woth primary oocyte
Describe the early unilaminar primary folicles
Characterized by having a single layer of cuboidal follicular cells around the primary oocyte
Primary oocyte and follicle are both larger than primordial follicle
Zonapellucida: acidophilic refractivelayer between the oocyte and the follicular cells. Made of glycosaminoglycansand glycoproteins
identify
early unilaminar primary follicle
identify
primordial follicle
identify
primary follicles
describe th emultilaminar late primary follicles
Follicle cells undergo mitotic proliferation to form the stratified granulosa layer. Follicle cells are now called granulosa cells, and have gap junctions between them.
Connective tissue surrounding the follicle develops into the theca folliculi.
Maturation of the oocyte occurs.
Multiple disperse Golgi appears from Balbianibody.
Increase in mitochondria, RER, small vesicles. Cortical granules.
identify
late primary follicle, gap jucnctions in between granulose cells and oocyte
explain the gap junction coupling in the ovarian follicle
The oocyte is surrounded by a thick layer of extracellular matrix called the zonapellucida.
The surrounding granulosacellsare coupled to each other by gap junctions
In addition, the granulosacells extend processes through the zonapellucidaand make gap junctions with the oocyte.
identify
- granulosa cells
- zona pellucida
- oocyto primario
late primary follicle
identify
Secondary or Antral follicle
what is the secondary follicle characterized by?
characterized by having one or more fluid containing spacesdevelop in the granulosa cell layer (antrum)
what is the fluid in the antrum called?
The fluid is called liquor folliculiand is rich in hyaluronic acid
what factors are required for oocyte and follicular growth?
Follicle stimulating hormone (FSH)
Growth factors: Epidermal growth factor and insulin-like growth factor I (IGF-I).
Calcium ions (Ca 2+)
what do the granulosa cells secrete and the concentration?
secrete oocyte maturation inhibitor. The concentration is highest in small follicles and lowest in mature follicles. The secondary follicle largest, continues to grow and reaches 10 mm or more in diameter.
what sithe theca interna?
is highly vascularized. Ultrastructural characteristics of steroid-producing cells. Posses Luteinizing hormone (LH) receptors. In response to LH stimulation they synthesize and secrete androgens (androstenedione) precursors for estrogen
what is the theca externa?
is the outer connective tissue. It contains collagen fibers and also smooth muscle
identify
theca inetrna and theca externa
what dies theca interna produce?
The theca internacells produced the androgens(androstenedione)
In response to FSH the granulosa cells uptake these androgens and the enzyme aromataseconverts them to estrogens.
Estrogens stimulate granulosa cells to proliferate and increase follicle’s size.
This synthesis and secretion of estrogen is under FSH control
explain the synthesis of estrogen in the ovary and th ecollaborative of theca interna and granulosa cells
Synthesis of estrogens in the ovarian follicle. Synthesis of estrogens in the ovary requires collaboration between theca interna and granulosa cells. Theca interna cells express both luteinizing hormone (LH) and low-density lipoprotein (LDL) receptors on their surface. LH stimulation of theca interna cells facilitate conversion of cholesterol (liberated from lactate dehydrogenase [LDH]) to pregnenolone (P5) and then via further intermediates into androgens (androstenedione and testosterone). These androgens diffuse into neighboring granulosa cells where they are converted to estrogens by the enzyme P450 aromatase. Granulosa cells express follicle-stimulating hormone (FSH) receptors and their activation by FSH is a primary stimulator of P450 aromatase activity. FSH also promotes the conversion of estrone to 17β-estradiol. ATP, adenosine triphosphate; cAMP, cyclic adenosine monophosphate
exaplain the components of the mature follicle
In the late antral follicle the region of the granulosa cells associated with the oocyte forms a thickened hill-like region known as the cumulus oophorus
The granulosa cells immediately around the oocyte are the corona radiata, and will remain with the oocyte when it is ovulated
The stroma cells around the follicle become organized into the theca interna and theca externa
identify
mature follicle
identify
The Graafian follicle contains the mature secondary oocyte
what are th ecomponents of the graffian follicle (mature follicle)
The GraafianFollicle contains the mature secondary oocyte
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The other developing follicles degenerate (Atresia)
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The Graafianfollicle enlarges to a diameter of 10mm or more
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The granulosalayer becomes thinner relative to the diameter of the follicle
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Normally will not recognize a Graafianfollicle histologically
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Not every large antralfollicle is a Graafianfollicle.
identify
grafian follicle mature follicle
what is responsible for the release of thre secondary oocyte at ovulation?
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Increase in pressure and volume of follicular fluid
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Enzymatic proteolysis of the follicular wall by activated plasminogen
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Hormonally directed deposition of glycosaminoclycansbetween oocyte-cumulus complex and the stratum granulosum
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Contraction of smooth muscle fibers of the theca externa layer: triggered by prostaglandins
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If fertilization does not occur the secondary oocyte degenerates
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Normally only one follicle completes maturation
exaplain ovulation process
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Occurs around the 14thday of the cycle in response to a surgein luteinizing hormone (LH) levels from the pituitary.
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This increase in LH is stimulated by the high levels of estrogenproduced by the developing follicles.
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Just prior to ovulation (12-24 hours after the LH surge), the first meiotic division of the primary oocyte resumes, resulting in the formation of the secondary oocyte and the first polar body.
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The Graafian follicle ruptures through the thinned ovarian wall and the secondary oocyte is released from the Graafian follicle. The oocyte is them transported into the uterine tube
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The secondary oocyte is arrested at metaphase of the second meiotic division and is completed only if the oocyte is penetrated by spermatozoon.
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If fertilization occurs the second meiotic division is completed and forms a mature ovum.
What happens with the follicles that are not ovulated?
Since only one follicle is ovulated per cycle, the fate of most follicles is to degenerate by a process called atresia.
99.9% of the follicles undergo atresia. This can occur at any stage of follicular development
explain atresia
Involves the degeneration of both the oocyte and the granulosa, as a result of repeated apoptosis cycles and phagocytosis of debris by invading macrophages.
The zona pellucida, resistant to autolytic changes becomes folded, usually persists for a longer period of time.
identify
Atretic follicle
exaplain the lutheal phase of ovary anf formation of corpus luteum
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If ovulation occurs, the follicular wall composed of granulosa cells and the theca internacells differentiate into the specialized steroid secreting cells of the corpus luteum
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The granulose cells (80% of corpus luteum) become the granulosa lutein cells and synthesized progesterone, estrogens and inhibin
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The theca interna cells (20%) become the theca lutein cells which are thought to make androgens and progesterone as well
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If implantation occurs, human chorionic gonadotropin(HCG) from the trophoblastwill maintain the corpus luteumof pregnancy. Its function begins to decline after 8 weeks of pregnancy
identify
lutheal phase of ovary formation of corpus luteum
CORPUS LUTEUM
CORPUS LUTEUM
Identify
Granulosa lutein cells and theca lutein cells
what is the corpus albucans and when does ir occur?
If fertilization and implantation DO NOT occur the corpus luteum remains active only 14 days.
The corpus luteum begins to degenerate, cells undergo autolysis and are replaced with a fibrous connective tissue scar called the corpus albicans
The corpus albicans will slowly disappear over a period of several months
identify
corpus albicans
identify
PCOS , no hay ovulation, primordial follicles no progresan, tunica albuginea muy desarrollada
what innervated ovaries?
autonomic ovarian plexus
- Sympathetic and parasympathetic fibers (not well understood the distribution)
Sensory nerve endings are scattered in the stroma
About half of women experience midcyclepain (“mittelschemrtz”)
what is capacitation?
Capacitationand Fertilization occurs in the Female reproductive tract
During this activation process, structural and functional changes take place in the spermatozoon to penetrate the corona radiate and increased affinity to bind to zona pellucida
what is hyperactivation of spermatozoa?
Hyperactivationof the spermatozoa, which manifests as a vigorous, whiplash-like beating pattern of their flagella. Activation of transmembrane Ca2+channel proteins called CatSpers. This is important for male fertility
exaplain the pituitary control of ovarian function
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The interaction between the pituitary and ovarian function is complex
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At the beginning of the cycle, the pituitary releases FSH which causes the follicular growth of some of the follicles
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The antral follicles produce increasing amounts of estrogen
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In response to the rising levels of estrogen, the pituitary secretes a burst of luteinizing hormone (LH)which stimulates ovulation, and supports the formation of the corpus luteum
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The corpus luteum produces progesteronewhich blocks the release of FSH and production of estrogen
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As the corpus luteum degenerates, the falling progesterone levels allow FSH to be released again, initiating the beginning of the menstrual cycle again
hat is the function of the fallopian tube?
To transport the ovum from the ovary to the uterus. Site of fertilization
what are the segments of the uterine tubes?
Four segments:
1. Infundibulum is funnel shaped segment adjacent to ovary
- Ampulla is the longest and best developed segment. Highly complex folding of the mucosa.
Site of fertilization - Isthmusis a narrow segment adjacent to the uterus
- Uterine or Intramural part, lies within the uterine wall and opens into the cavity of the uterus
describe the ampulla of oviduct
The wall of the uterine tubes is made of:
The serosa: mesothelium and thin layer of CT
The muscularis: inner relatively thick circular layer of smooth muscle and an outer thinner longitudinal layer of smooth muscle.
The mucosa : simple columnar epithelium. Folded mucosa that projects into the lumen. The folds are more numerous and folded in the ampulla and become smaller in the isthmus.
identify
Ampulla of the Oviduct
identify
Ampulla of the Oviduct
describe the mucosa of the oviduct
(Simple columnar ciliated epithelium)
Ciliated cells: more numerous in ampulla and infundibulum. Cilia oriented towards the uterus
Peg cells (nonciliated): secretory cells produce nutritive fluid for ovum
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Epithelial cells undergo hypertrophy during follicular phase of ovary and atrophy during luteal phase.
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Estrogen stimulates ciliogenesis and progesterone increases number of secretory cells
identify
Mucosa of Oviduct
identify
Mucosa of Oviduct, peg cells
