human development - fertility Flashcards
what is the oviduct?
it is the passage way from the ovaries, where eggs travel.
it is more commonly known as the fallopian tube or the uterine tube.
the eggs that travel along the oviduct will either fertilise into a zygote by a sperm, or degenerate in the body
what is the vulva?
the part of the female genitals outside the body
what is the main function of the uterus?
to nourish the developing fetus prior to birth
what is an oocyte?
an immature egg
oocytes can develop into maturity from within a follicle. These follicles are found on the outside layer of the ovaries
describe the two parts to the ovaries
- medulla: contains connective tissue and vascular system to provide the blood supply to the ovaries
- cortex: contains follicles in all stages of development. these follicles are responsible for the maturation of oocytes
what is an early primary follicle?
a follicle recruited for development, at the start of each menstrual cycle.
consists of a single oocyte surrounded by a single layer of follicular cells
how many eggs does a woman have before birth?
7 million
how many eggs does a woman have at birth?
2 million
how many eggs does a woman have when they hit puberty (first period)
0.5 million
how many eggs does a woman have when they hit their menopause?
none
what is the zona pellucida?
thin band of glycoproteins that separates the oocyte and the follicular cells. Specific proteins on the sperm will bind to complementary glycoproteins in the zona pellucida
what is the antral follicle count?
the number of follicles visible in the ovary at any given time. measured using an ultrasound scan
what is the difference between a primordial follicle cells and primary follicle cells?
- primordial: first class of follicles formed in the ovaries and consist of a single oocyte surrounded by a single layer of SQUAMOUS granulosa cells. they are in the dormant state until they receive signals otherwise
- primary: consists of a central oocyte surrounded by a layer of CUBOIDAL granulosa cells
what is the normal number of follicles in both ovaries?
10 - 20 follicles at any given time
if a woman has less than 10-20 follicles in both ovaries at any given time, what does this suggest?
that they have a lower reproductive potential
what hormone test can we use to test the ovarian reserve (egg count?)
anti-mullerian hormone test
what are the 3 phases of the ovarian cycle?
- follicular phase
- ovulatory phase
- luteal phase
what days does the follicular phase occur?
days 1-10
what days does the ovulatory phase occur?
days 11-14
describe what happens during the follicular phase
- pituitary glands secrete FSH, which signals the ovaries to grow 10-20 follicles
- only one follicle fully matures
- the other grown hormones contribute to the endocrine function of the ovary by producing oestrogen
why does FSH begin to drop?
oestrogen feedback to the pituitary glands
how many follicles can withstand the drop in FSH and why?
only one follicle can withstand the drop in FSH because they have a higher concentration of FSH receptors. The other follicles die out (atresia)
describe what happens during the ovulatory phase
- dominant follicle causes significant rise in oestrogen
- positive feedback mechanism of oestrogen causes a surge in LH
- oocyte undergoes cell division
- follicular wall thins and ruptures
- oocyte enters abdominal cavity near fimbriae of fallopian tube
- shortly before ovulation, fimbriae sweep over surface of ovaries
- oocyte enters tube and is propelled by cilia, fallopian tube contracts
what are fimbriae?
finger like projections in the fallopian tube
describe what happens during the luteal phase
- corpus hemorrhagicum structure is formed. This is a temporary structure that is formed immediately after ovulation from the ovarial follicle, as it collapses and fills with blood, which quickly clots
- this develops into the corpus luteum (yellow body)
- accumulation of lutein (yellow lipid pigment) and other lipids marks the transition to granulosa lutein cells
what happens to the corpus luteum if implantation doesn’t occur?
corpus luteum degrades to corpus albicans
what happens to the corpus luteum if fertilisation occurs?
corpus luteum persists and secretes progesterone
why is the corpus luteum important?
it is an important support for the embryo as it the source of oestrogen and progesterone
what is the function of progesterone?
maintains the uterus lining
what is the difference between an oocyte and an ovum?
- oocyte: developing egg
- ovum: mature egg
- oogenesis: differentiation of the ovum
what are the actions of oestrogen?
- stimulates oogenesis and follicular development
- stimulates growth of breasts during pregnancy
- stimulates GH secretion, which promotes bone growth in adolescence
- promotes proliferative-phase uterine conditions
- decrease output of kidneys, which promotes fluid retention
what are the actions of progesterone?
- promotes secretory-phase uterine conditions
- suppresses uterine contractile activity during pregnancy
- promotes growth of glandular tissue in breasts
- inhibits movement of the bowel
what is the normal position of the uterus?
- 80% anteflexion (flexed towards abdominal wall)
- 20% retroflexion (tilted back to the back wall)
what are the 4 sets of suspensory ligaments?
- broad ligament: side of uterus
- uterosacral ligament: behind uterus
- round ligament: front of uterus
- lateral (cardinal) ligament: behind uterus
what are the functions of the uterus?
- provides mechanical protection of the fetus
- transports sperm from the site of deposition to uterine tubes for fertilisation
- provides suitable environment for implantation of embryo and nourishment of embryo and fetus during pregnancy
- expels the mature fetus at the end of pregnancy
what is the menstrual cycle?
series of cyclic changes in the endometrium in response to changes in levels of ovarian hormones
describe what happens on days 1-5 of menstrual cycle
- menstrual phase
- functional layer of endometrium becomes detached from uterine wall and causes bleeding (menses)
describe what happens on days 6-14 of menstrual cycle
- proliferative phase
- FSH and LH increase
- follicular development causes increase in oestrogen
- endometrium begins to proliferate and thicken; tubular glands and spiral arteries form
- stimulation of progesterone receptors synthesis in endometrial cells
describe what happens on days 13-14 of menstrual cycle
- late proliferative phase
- time of ovulation
- glands become long and tortuous due to active growth
- storm gradually becomes oedematous (getting nutrients from endometrium)
describe what happens on days 15-22 of menstrual cycle
- secretory phase
- progesterone levels rise
- enlargement of glands which begin secreting mucus and glycogen, in preparation of implantation of fertilised ovum
- increased fluid in stroma
what are the segments of the uterine tube?
- also known as the fallopian tube or oviduct
- muscular
- infundibulum: consists of fimbriae. inner surfaces contain cilia
- ampulla
- isthmus: lies next to the uterine body
how many layers does the uterine tube consist of?
4 tunicas / layers
what are the 4 tunicas/layers of the uterine tube?
- tunica serosa
- tunica muscularis
- tunica submucosa
- tunica mucosa
what are the 3 issues that can lead to female infertility?
- issue with eggs
- issue with transport
- issue with implantation
what is anovulation?
occurs when an egg is not released from the ovary during your menstrual cycle.
chronic anovulation is a common cause for infertility
what are the main causes for anovulation?
- hypothalamic dysfunction
- pituitary dysfunction
- thyroid dysfunction
- ovarian failure
- polycystic ovarian syndrome (most common cause)
what is the lifestyle intervention required for those with polycystic ovarian syndrome?
- weight loss
- this restores ovulation
what medical treatment can be used to treat polycystic ovarian syndrome?
- ovulation induction drugs
- clomiphene citrate
what is clomiphene citrate?
- ovulation induction drug
- used to treat women with irregular or absent ovulation, but have normal basal levels of estradiol
- stimulates endogenous FSH production
- FSH stimulates ovulation
what are the most common causes for hyperprolactinemia?
- prolactin-secreting pituitary tumour
- use of psychiatric medication