Review of Reproductive Physiology and Anatomy Flashcards
What is oogenesis
The total number of oocytes is present and birth and decreases during life
When is maturation of oocytes stimulated
At puberty
When is oogenesis arrested
In diplotene phase of meiotic prophase
What is the hilum
Where blood vessels enter/ exit
What is the medulla
Vascularised loose connective tissue
What is the cortex composed of
Ovarian follicles and dense irregular connective tissue
What are germ cells
Ovarian follicles
What is the stroma
Dense irregular connective tissue
Where do ovarian follicles start to develop
In the stroma
What is the dense irregular connective tissue in the cortex made up of
Collagen
What is the tunica albugenia
A layer of connective tissue underlying the germinal epithelium, it is a white fibrous outer layer
Where is the germinal epithelium
On the outside
What is the germinal epithelium
Modified visceral peritoneum
What does collagen provide
Structural support
What are the 3 different types of ovarian cancer
Epithelial, germ cell and stromal
What is the most common ovarian cancer
Epithelial
What is the uterine tube
A smooth muscle tube
How does the uterine tube contract
Via peristalsis
What is the site of fertilisation
The uterine tube
Where are the fimbriae located
At the end of the infundibulum
What are fimbriae and what is their function
They are finger like structures which pick up the oocyte
Describe the ampulla
It is wide, convoluted and has a thin wall
Where precisely does fertilization ususally take place
In the ampulla
Descrive the isthmus
It is narrow, straight and has a thick wall
How does the isthmus contract
Via peristalsis
What is the function of the isthmus
It contracts via peristalsis projecting the spermatozoa towards the oocyte and the oocyte/ zygote towards the uterus
What is the last part of the uterine tube
The intramural
Describe the epithelium of the uterine tube
Highly convoluted with many mucosal folds to increase the surface area of epithelium
Why does the uterine tube need epithelium need to have a large surface area
To increase the surface area in contact with the oocyte/zygote and to control the movement of the oocyte/zygote
Compare the wall of the ampulla to the wall of ths isthmus
The ampulla has a thinner wall compared to the thick wall of the isthmus
What kind of epithelium do the uterine tubes have
Simple cuboidal epithelium
What 2 types of cells make up the epithelium of the uterine tubes
Secretory (peg) and ciliated
Describe the function of the secretory cells
Watery secretion for gamete nourishment
Describe the ciliated cells
Alter in height during menstruation
What effect do microorganisms such as chlamydia trachomatis have on the cilia and structure of the epithelium
The cilia are unable to move oocytes down the uterine tube and therefore result in an increased risk of ectopic pregnancy/ sterility
What is the uterus comprised of
The body, fundus and cervix (neck)
Where is para/perimetrium located
At the top of the uterus
What is para/perimetrium
Visceral peritoneum
Where is myometrium located
In the body of the uterus
What is myometrium
A network of interwoven smooth muscle and connection tissue
Describe the key features of the myometrium
The myometrium is able to respond to hormones which results in hypertrophy/ hyperplasia (increase in size and no. of cells to accommodate the increase in the size of the foetus and project the foeuts during childbirth) during childbirth
In the lead up/ during childbirth what hormones control the myometrium
Prevented (inhibited) by relaxin and stimulated by oxytocin
What and where is the endometrium
It is the outer most layer in the body of the uterus
Describe the key features of the endometrium
It is shed and rebuilt during the menstrual cycle and is the location where the zygote imbeds itself and the placenta develops from
Where are submucosal uterine fibroids located
Between the endometrium and myometrium
Where are intramural uterine fibroids located
Within the myometrium
Where are subserosal uterine fibroids located
Between the myometrium and parametrium
Where are pudunculated uterine fibroids located
Often in the fundus or within the cavity, sometimes in the vagina
What can all uterine fibroids cause issues with if too big
Urination and defecation
What are the two types of stratum in the epithelium of the uterus
Stratum basalis and stratum functionalis
Describe stratum basalis
It remains at all times
Describe stratum functionalis
It is shed during menstruation
Which stratum is shed during menstruation
Stratum functionalis
What is located in the stratum basalis
The endometrial glands, vascular connective tissue and spiral arteries
What is a key feature of the stratum basalis
It is highly vascular
What do the endometrial glands produce
Glycogen
What is the small hole in the center of the cervix called
External os
What is the function of the external os
It is how the cervical cavity communicated with the vagina
What are the two types of endometrium the cerix contains
Endocervix and ectocervix
Describe the endocervix
It lines the inside of the cervix and is composed of simple columnar cells and crypts which are mucus secreting cells
What does oestrogen do to the mucus in the cervix
Decreases the viscosity of the mucus
Describe the ectocervix
It is stratified squamous non-keratinised and is continuous with the vagina
Why does the vagina require stratified squamous non-keratinised epithelium
To protect it from abrasion that occurs during sexual intercourse
What is the junction between the two types of epithlial cells in the cervix called
The squamocolumnar junction
Describe the squamocolumnar junction
It is a transformational zone as dysplasia (cellular change) occurs here. It can move to outside the cervix during different stages of development
Describe primordial follicles
Enclosed by a single layer of flattened pre-granulosa cells and basal lamina
When is development of the primordial follicles stimulated
At puberty and then every fertile month
What do the primordial follicles develop into
Primary follicles
Describe a unilayered primary follicle
Oocyte enlarges and granulosa cells increase in size and become cuboidal
What does the oocyte begin to produce
Zona pellucida
What are the functions of zona pelludica
Produces glycoproteins and proteoglycans. It is important in binding of the spermatozoa
Describe a multilayerd primary follicle
Granulosa cells increase in number and in thickness-stratified. The zona pellucida is assembled (fully developed) and stromal cells begin to form the theca
How is the theca formed
Stromal cells begin to form concentric layers around the follicle
How do zona pelludica communicate with eachother
Via gap junctions
What does GnRH stand for
Gonadotrophin releasing hormone
Where is GnRH produced
The hypothalamus
How does GnRH reach the pituitary gland
Travels via the portal vein
What does GnRH stimulate
Rlease of LH and FSH in the pituitary gland
What does FSH stimulate
Follicle development
Describe a secondary follicle
Spaces develop containing follicular fluid which coalesce to form a cavity, there are 2 layers of ovarian stroma, theca cells, granulosa cells
What are the two layers of the ovarian stroma
Theca interna and theca externa
Describe the theca interna
Large steroid hormone producing cell (used in the production of oestrogen)
Describe the theca externa
Small compact cells continuous with the stroma
What do thecal cells produce and what then happens to this product
Produce steroids which are converted via granulosa cells into oestrogen
What do granulosa cells express
FSH and oestrogen receptors
What does oestrogen stimulate
Further granulosa development and therefore its own production (+ve feedback on itself)
What stimulates the production of oestrogen
FSH, oestrogen is released by granulsa cells and stimulated its own production via +ve feedback
What does moderate levels of oestrogen in the blood do
Inhibits FSH secretion and GnRH), yet the tonic secretion of LH is unaffected
What happens to the uterus during the proliferative phase
Oestrogen produced by the developing follicles increases the thickness of the endometrium, proliferation of the stratum basalis to form the stratum functionalis, straight endometrial glands elongate and spiral arteries elongate in the highly vascular stroma
Which days encompass the proliferative phase
Day 6-14
Describe the Graafian (tertiary) follicle
Contains an antrum which is a large, fluid filled cavity and an oocyte which a thick zona pellucida and the oocyte is surrounded by crona radiata
What is the function of the corona radiata
Provides nutrients
What is another name for the tertiary follicle
Graafian follicle
At which stage is the follicle ready for ovulation
Once it has become a Graafian (tertiary) follicle
What do high oestrogen levels cause
A surge in LH
What stimulates ovulation
A surge in LH
What does a surge in LH stimulate
Ovulation and formation of the corpus luteum
On which day does ovulation usually occur
Day 14
What causes a stigma
The mature follicle protruding onto the surface of the ovary
What does LH stimulate specifically in the follicle
Proteolytic activity in the theca externa and tunica albuginea causing the ovum to be expelled into the entrance of the uterine tube
What does LH break down
The surface layer of the uterine tube resulting in the oocyre being expelled from the ovary
How does the corpus luteum form
LH stimulates the transformation of follicular cells into the corpus luteum. LH stimulates the transformation of granulosa cells into corpus luteum (lutinisation)-LH receptors
Why is the corpus luteum yellow
There is lipid in the cells
What are the two endocrine glands in the corpus luteum
Granulosa cells and theca externa cells
What do granulosa cells in the corpus luteum secrete
Progesterone
What do theca externa cells in the corpus luteum secrete
Oestrogen
What stimulates progesterone secretion from the corpus luteum
LH
When does the secretory/ progesteronal phase occur
Day 14-25
What happens during the secretory/ progesteronal phase
The stroma is at it’s most vascular, glands become tortuous (saw toothed)
What is the role of progesterone secreted from the corpus luteum
It thickens the endometrium for
What features occur in the stroma when it is at its most vascular
Coiled (spiral) arteries which pass all the way throughout the length of the endometrium
When do gland become saw toothed
In the secretory phase
What do glands produce in the secretory phase and why
Produce thick glycogen-rich product which is released for nourishment of the developing blastocyte
What do high levels of progesterone do
Inhibit LH and FSH release
When does the corpus albicans form
Day 25
How does the corpus albicans form
Loss of LH leads to the involution (leutrolysis) of the corpus luteum and decreased progesterone secretion. Cells are replaced by collagen. A fibrous ovoid structure remains which is a corpus albicans ‘white body’
Why is the corpus albicans white
Due to the collagen
What happens during menstruation
Absence of progesterone secretion from corpus luteum results in contraction of spiral arteries in ischaemia, degeneration of the stratum funcionalis, shed as menses
Why does contraction of the spiral arteries in ischaemia occur
Not enough blood supply to functionalis layer therefore it it shed
