Histology of Female Reproductive Tract

Question 1

identify the following structures within the female reproductive tract:

a) uterine tube
b) overy
c) uterus
d) cervix
e) vagina
f) external geniltalia

Answer 1

Question 2

what are the two functions of the ovary?

Answer 2

produce gametes (termed oogenesis in females)

produce steroids such as oestrogens and progesterogens (mainly progesterone)

Question 3

what are the two different parts to the structure of the ovary?

Answer 3

medulla = forms the core of the organ and contains loose connective tissue, contorted arteries, veins and lymphastics and is continuous with the hilum of the organ

cortex = has scattered ovarian follicles in a highly cellular connective tissue stroma. The outer shell of the cortex is a dense connective tissue layer called the tunica albuginea, which is covered by a single layer of cuboidal cells called germinal epithelium

Question 4

identify the stages of follicle development from the primordial follicle to the corpus albicans?

Answer 4

Question 5

identify the cortex and medulla of the ovary on histological slide?

Question 6

how are mature oocytes (ova) formed during embryonic development?

Answer 6

early in embryonic development (around week 6), germ cells from the yolk sac invade the ovaries and proliferate by mitosis to form oogonia

these cells will undergo development and division via meiosis to form mature oocytes

Question 7

differentiate between the terms oogenesis and folliculogenesis?

Answer 7

oogenesis = development of oocytes, the female germ cells, from oogonia

folliculogenesis = the growth of follicle, which consists of the oocyte and any associated support cells

Question 8

as a female progresses from embryo to menopause, how does the form of gamete change?

Answer 8

*before birth, meiosis begins in the oocytes but halts at prophase I

*if the oocyte undergoes further development, meiosis will restart but many will remain in this state for several decades

*in a 20yo, something like 15 follicles restart developing per day, dropping to perhaps 1 per day in a 40 yo

Question 9

what is “atresia”?

Answer 9

an apoptosis based process which causes the loss of oogonia and oocytes

the cell is resorbed following cell death

Question 10

within a foetal ovary, what type of cells do primary oocytes have to associate with to avoid death?

Answer 10

pregranulosa cells - these are squamous but if the follicle enters the growth phase, they will become cuboidal

Question 11

once the oocyte is enlarged, what begins to gorm between the oocyte and the granulosa cells?

Answer 11

zona pellucida

Question 12

once the oocyte is enlarged and the zona pellucida begins to form, what is the next stage of development?

Answer 12

the granulosa cell layer proliferates

inner layers of the adjacent stromal cells (theca folliculi) transform to form theca interna which will go on to secrete oestrogen precursors which will be converted to oestrogen by the granulosa cells (GC)

the outer layers remain fibroblast-like and form the theca externa

Question 13

how is a secondary follicle then formed after the proliferation of the granulosa cell?

Answer 13

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 continue to proliferate

Question 14

what are the largest antral follicles called?

Answer 14

Graafian follicles - can reach about 20mm diameter

Question 15

what events occur within the follicles one day before ovulation?

Answer 15

the oocyte in the largest graafian follicle will complete meiosis I but instead of producing 2 equal cells, it will produce one cell called a secondary oocyte (similar in size to primary) and one tiny polar body that carries second nucleus away to degenerate

this secondary oocyte will then begin the second phase of meiosis but will stop at metaphase II - it will only complete meiosis to become fully mature after it has been released (ovulation) and fertilised by sperm (producing second polar body)

Question 16

what is the follicular stigma?

Answer 16

area of ovary which indicates imminent rupture of the follicle

this will then release the oocyte and the granulosa cells that surround it (which are then referred to as the corona radiata)

Question 17

after ovulation, what does the follicle transform into and what is the role of this?

Answer 17

transforms into a corpus luteum with the theca and granulosa cells secreting oestrogens and progesterone, which helps prepare the uterus for implantation

Question 18

what occurs to the corpus luteum if:

a) no implantation occurs?
b) implantation occurs?

Answer 18

a) no implantation = it will become a white coloured connective tissue called the corpus albicans
b) implantation = 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

Question 19

what is the role of the uterine tubes in the transportation of the ovum?

Answer 19

the funnel shaped infundibulum moves so that its opening is adjacent to the site where the follicle ruptures

the ovum moves down the tube propelled by gentle peristalsis and currents created by the ciliated epithelium (secretory cells in the epithelium secrete nutrients)

Question 20

where does fertilisation usually occur?

Answer 20

ampulla

the fertilised ovum is then transported to the uterus for implantation

Question 21

describe the mucosa of the ampulla of the uterine tube?

Answer 21

the mucosa is highly folded and lined by simple columnar epithelium with ciliated cells and secretory cells

this is surrounded by smooth muscle (SM)

Question 22

describe the difference in epithelium and smooth muscle of the ampulla and the rest of the tube lining?

Answer 22

tube lining has simpler architecture and the epithelium is mostly secretory with few ciliated cells

there are said to be 2 layers of smooth muscle (SM) in the ampulla and 3 here in the isthmus of uterine tube

Question 23

what 3 layers is the uterine wall made of?

Answer 23

endometrium = shed during menstruation, made of tubular secretory glands embedded in connective tissue stroma

myometrium = 3 layers of smooth muscle combined with collagen and elastic tissue

perimetrium = outer visceral covering of loose connective tissue covered by mesothelium

Question 24

what two layers is the endometrium divided into?

Answer 24

stratum functionalis = undergoes monthly growth, degeneration and loss

stratum basalis = reserve tissue that regenerates the functionalis

Question 25

what happens to the uterus during the proliferative phase?

Answer 25

the stratum basalis proliferates and glands, stroma and vasculature grow

this increases the thickness of the endometrium by reconstituting the stratum functionalis

Question 26

what happens to the glands of the uterus during the secretory phase?

Answer 26

the glands become coiled with a corkscrew appearance and secrete glycogen

Question 27

what happens to the uterus during the menstural phase?

Answer 27

arterioles in the stratum functionalis undergo constriction, depriving the tissue of blood and causing ischaemia with resultant tissue breakdown, leakage of blood and tissue sloughing

Question 28

what does the cervix look like histologically?

Answer 28

short cylinder with a small lumen that projects into upper vagina

it is mostly fibrous connective tissue covered by stratified squaous epithelium on its vaginal surface, but transitioning into mucous secreting simple columnar epithelium

Question 29

what part of the cervix is a common site of dysplasia and neoplastic changes?

Answer 29

the transition zone

this leads to cervical cancer, most frequently benign in this transition zone

Question 30

the mucous secreting epithelium of the cervical canal is deeply furrowed, forming glands - what are these glands called and what are their function?

Answer 30

endocervical glands

secretion of these glands varies from thin and watery in proliferative phase (allowing passage of sperm) to thick and viscous following ovulation (preventing the passage of sperm or microorganisms)

Question 31

endocervical glands in the cervical canal can become blocked, what does this cause?

Answer 31

causes the glands to expand with secretions forming a Nabothian cyst

Question 32

what are the four layers of the vagina?

Answer 32

non-keratinised stratified squamous epithelium - during repro years, this layer is thicker and cells are enlarged due to glycogen accumulation

lamina propria - connective tissue rich in elastic fibres and thin-walled blood vessels

fibromuscular layer - inner circular and outer longitudinal smooth muscle

adventitia

Question 33

there are glands within the wall of the vagina - true or false?

Answer 33

false - there are no glands, but it is lubricated by mucous from the cervical glands and fluid from the thin walled blood vessels of the lamina propria

Question 34

how is the growth of pathogenic bacteria in the vagina inhibited?

Answer 34

commensal bacteria metabolise the glycogen to lactic acid which inhibits growth of pathogenic bacteria

Question 35

what is the mons pubis?

Answer 35

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

Question 36

what are the labia majora?

Answer 36

extensions of the mons pubis, similar in structure and rich in apocrine sweat glands and sebacious glands and with small bundles of smooth muscle

hair follicles on the outer surface, but not inner

Question 37

what are the labia minoria?

Answer 37

thin skin folds that lack subcutaneous fat and hair follicles but are rich in vasculature and sebaceous glands that secrete directly onto the surface of the skin

keratinized epithelium extends into the opening of the vagina to the level of the hymen, where there is a transition to non-keratinised stratified squamous epithelium

Question 38

what does the clitoris contain?

Answer 38

two tubes of erectile vascular tissue (corpora cavernosa) covered by a fibrocollagenous sheath covered by skin with rich innervation and a thin epidermis