Week 1 - B - Histology of the female reproductive system Flashcards
What is the lower part of the uterus known as where a narrowing occurs to form the cervix?
This is the internal os (internal orifice of the uterus)
The lower part of the uterus is known as the cervix The opening of the cervix is known as the internal os - where the uterus narrows and the opening of the cervix into the vagina is known as what?
The external os
What are the two main functions of the ovary?
They produce gametes - oogenesis - formation of eggs
Produce steroids - mainly oestrogens and progestogens (mainly progesterone)
Structure: the ovary has a medulla and a cortex: The medulla forms the core of the organ and contains loose connective tissue, contorted arteries, veins and lymphatics, and is continuous with the hilum of the organ. The cortex has scattered ovarian follicles in a highly cellular connective tissue stroma. What is the dense connective tissue layer which is the outer shell of the cortex?
This is the tunica albuginea
What colour is the tunica albuginea?
The tunica albuginea is white hence the name the white coat
What is the thin layer that covers the tunica albuginea (tunica albuginea - outer shell of dense connective tissue)? Give both names for this single layer
This is a single layer of cuboidal cells called the germinal epithelium - also known as ovarian surface epithelium
What is the difference in tissue types between the tunica albuginea and the germinal (ovarian surface) epithelium?
Tunica albuginea is the dense connective tissue outer coat of the ovary
Germinal epithelium is a single layer of cuboidal cells that cover the tunica albuginea
What is the earliest recognisable female germ cell? It can undergo mitosis
This is the primordial germ cell
At what week in embry development do the primordial germ cells invade the ovary and undergo mitosis to form oogonia? What are the oogonia a precursor to? Do they form this via mitosis or meisosis?
The primordal germ cells invade the ovary in week 6 of development to undergo mitosis to form the oogonia
The oogonia divides in the process of meisosis to form oocytes
What is the difference between oogenesis and folliulogenesis?
Oogenesis is the development of the oocytes, the female germ cells, from the oogonia (which develops from the primordial germ cell at 6 weeks)
Folliculogenesis is the development of the follice , which cosnsits of the oocyte and any supporting cells
When oogonia are formed in utero, there are millions and progressivley there becomes less and less until menopauase What is the loss of oogonia and oocytes by the apoptosis based process known as?
This is known as follicular atresia
Before birth meiosis begins in the occytes but what stage is this halted and until when?
The primary occytes are suspended in prophase 1 until puberty where one oocyte (usually) is chosen per month to undergo ovulation
How many follicles mature each month and how many are actually ovulated? When does the primary oocyte suspended in prophase 1 begin mieisosis again?
Around 20 follicles mature per month but only one is ovulated
The primary oocyte undergoes meisosis again during puberty when one egg is ovulated each month
What stage does the secondary oocyte arrest in and when does it complete meisosis? What signifies the fertilization of the egg?
Secondary oocyte arrests in metaphase II and a polar body is formed - the egg is then ovulated
When fertilisation occurs the secondary oocyte divides and a second polar body and fertiised egg is formed
The formation of two polar bodies signifies fertilisation
The pregranulosa cells here are squamous but once the follicle enters the growth phase, what are the hallmark cells of the primary follilce known as?
The hallmark cells of the primary follicle are the cuboidal follicular (granulosa) cells
What do the inner and outer stromal cells that surround the primary follicle divide to become?
The inner stromal cells divide to become the theca interna and the outer stromal cells divide to become the theca externa
The theca interna produces oestrogen precursors which are converted to oestrogen by which cells?
The theca interna produces the oestrogen precursors which are converted to oestrogen by the granulosa (follicular) cells
What hormone stimulates the follicle (granulosa) cells to produce oestrogen?
This would be the follicle stimulating hormone - remember the theca interna produces the oestrogen precursors to make oestrogen
In the follicular phase of the menstrual cycle, growth is regulated by secretion of ______ from the anterior pituitary, which stimulates production of _____________ by granulosa cells and functions to mature the competing follicles. Late in the follicular phase the dominant follicle begins producing its own estrogen independent of FSH and a large increase in estrogen induces a __________ feedback to the hypothalamus and pituitary that leads to a large release of ____ that will ultimately drive ovulation
- FSH
- Estrogen
- Positive
- LH
The oestrogen surge stimulates LH production due its positive feedback on LH whcih drives ovulation
As the follicle enlarges, a space, called the antrum (A), filled with follicular fluid begins to form and enlarge in the granulosa cell layer (GC), forming a secondary follicle. Overall the follicle enlarges as the antrum enlarges, and the granulosa and thecal layers (theca interna, TI, and theca externa, TE) continue to proliferate. What is the cell name of the very largest antral follicles?
These are the Graffian follicles - the ovum develops in the graafian follilces prior to ovulation
In the graafian follicle, what is the dense cloud of granulosa (follicle) cells surrounding the primary oocyte known as?
The dense cloud of granulosa cells in the graafian follicle (mature follicle) is known as the cumulus oophorus
CO - cumulus oophorus
A - antrum
TI - theca interna
If ovulation is to occur, the oocyte will poke towards the outside of the ovary and the oocyte will be released out of the side of the ovary with a little cloud of granulosa cells surrounding it known as what? They are the surrounding cells which are the innermost cells of the cumulus oophorus that surrounds the ovum
These are the corona radiata
One day before ovulation, the oocyte in the largest Graafian follicle will complete meiosis 1, but instead of producing two equal cells, it will produce one cell called a secondary oocyte, similar in size to the original primary oocyte, and one tiny polar body that carries the second nucleus away to degenerate. The secondary oocyte will then begin into meisosis and stop at what stage?
The secondary oocyte will be suspended in metaphase II
When will the secondary oocyte complete meisosis?
It will only complete mesisosi after it has become a mature oocyte after it has been released (ovulated) and fertilised by a sperm - producing a secondary polar body
What is the follicular stigma? What is the tunica albuginea?
Follicular stigma - this is where the oocyte is bulging against the ovary becoming ready to ovulate and enter the fallopian tube
The tunica albuginea is the dense connective tissue outer cortex covering of the ovary
After ovulation the left over follicle cells form the corpus luteum What is this process known as? How long will the corpus luteum grow for? What does the corpus luteum secrete to help prepare the uterus lining for implantation? Why will it degenerate and what will the degenration form? (what colour is this?
The process of the corpus luteum forming from the left over follicle cells is known as luteinisation
The corupus luteum grows for 8-9days secreting progesterone to help prapre the uterus lining for implanatation and if after 12 days there is no production of HCG (would be produced by the placenta), the corpus luteum degenerates to form the corpus albicans
Corpus albicans is white connective tissue
. If implantation occurs, the placenta secretes HCG which prevents degeneration of the corpus luteum for a time and so maintains progesterone levels, which in turn maintains the pregnancy. When does the surge in LH occur for ovulation to occur? When can progesterone levels be measured to see if ovulation has taken place? What day of the menstrual cycle does ovulation normal take place?
LH surge occurs 36.5 hours before ovulation due to the positive feedback by the oestrogen made by the theca interna and granulosa cells
Progesterone levels can be measured on day 21 of the mestrual cycle to see if ovulation has occured
Ovulation usually occurs on day 14 of the menstrual cycle
What are the other two names for the uterine tubes?
The uterine tubes are also known as the fallopian tubes or oviducts
What is the function of the fimbriae?
When the secondary oocyte is ovulated, the cilia of the fimbriae sweep the ovulated egg into the fallopian tubes
What part of the uterine tubes does fertilisation usually occur in?
Fertilisation usually occurs in the ampulla of the uterine tube and the fertilized ovum is then transported to the uterus for implantation
From fimbriae of the fallopian tube to uterus, what are the different sections of the fallopian tubes?
Fimbriae - infundibulum - ampulla - isthmus - uterus
The uterine wall has three layers What are they? What is the innermost layer? Which is the layer shed during menstruation? Which is the most highly vascularised layer?
Endometrium Myometrium Perimetrium
Endometrium is shed during menstruation
Myometrium is the most highly vascularised uterine wall layer
What are the two layers of the endometrium?
The two layers of the endomertium are the stratum functionalis and the stratum basalis
Which layer of the endometrium is shed and which stays to regenerate the shed layer?
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At the end to the menstrual cycle the upper portions of the spiral arteries are responsive to hormones and will go into spasm depriving the stratum functionalis of oxygen and nutrients causing the stratum functionalis of endometrium to slough away Why is it that the stratum basalis will not also slough away?
This is because the stratum basalis also gets its blood supply from the straight artery which will supply the necessary nutrients
What can be seen in the bottom picture?
Can see the blood loss from the spasming spiral arteries in the stratum functionalis which is leading to the O2 and nutrient deprivation of the stratum functonalis
The cervix is a short cylinder with a small lumen that projects into the upper vagina. It is mostly fibrous connective tissue covered by stratified squamous epithelium on its vaginal surface, but transitioning to mucous secreting simple columnar epithelium. What is the small lumen projecting into the vagina known as? Where does cervical cancer most commonly begin?
Small lumen projecting into the vagina is known as the external os (external ostium of the uterus)
Cervical cancer most commonly begins in the transition zone from aquamous to columnar epithelium
The vagina has four different layers Why is the non-keratinized stratified squamous epithelium layer thicker during reproductive years?
This layer is thickened during reproductive years due to glycogen accumulation
How does having the glycogen accumulation in the stratified squamous epithelium layer help the vagina? (vaginal pH is acidic)
The commesnal vaginal flora feed on the glycogen producing lactic acid which gives the vagina an acidic pH to fend off unwanted organisms from growing
Commensal bacteria metabolize the glycogen to lactic acid which inhibits the growth of pathogenic bacteria.
Mons pubis: Skin which contains highly oblique hair follicles (produce coarse, very curly hair characteristic of pubic hair), overlying a substantial subcutaneous fat pad, which itself overlies the pubic symphysis What are the extensions of the mons pubis on either side of the vagina known as? What re the sweat glands found in this extension? (they are also found in the armpits)
Mons pubis continues to form the labia majora
The sweat glands found in the labia majora are known as the apocrine sweat glands - these are the odorous sweat glands found in the axilla
Labia majora is also rich in sebaceous glands - these produce sebum (oily substance)
What are the other labia? LAck subcutenous fat and hair follicles
This is the labia minora
The clitoris contains two tubes of erectile tissue similar to the penis WHat are these tubes known as? What is the tube that the urethra goes through in the penis known as?
The corpus cavernosum
Known as the corpus spongiosum
What is the normal amount of blood lost during ovulation? What is a heavy period defined as? (Menorrhagia?)
Normal amount of blood lost is 30-40mls
Menorrhagia is 60mls or more in each cycle
