Reproductive system Flashcards
1
Q
basic structure + function of reproductive systems
A
- gonads = produce gametes (males - testes produce spermatozoa, females - ovaries produce oocyte)
- ducts that receive + transport gametes
- accessory glands + organs that secrete fluids involved
- perineal structures - external genitalia
2
Q
define meiosis
A
production of haploid cells (23 chromosomes) from diploid cells
3
Q
describe the structures involved with sperm production and secretion
A
testes = produce spermatozoa
epididymis = maturation of sperm (18hrs -10 days) + storage
ductus deferens = stores sperm / conduit for sperm delivery
urethra = passageway for urine from bladder / spermatozoa/semen from ejaculatory duct
4
Q
describe the accessory glands involved in sperm production + secretion
A
- seminal glands = secretes largest quantity of fluid for semen production / ducts drain into ductus deferens
- prostate gland = produces prostatic fluids that mix w/ seminal fluids in the urethra
- bulbourethral glands = mucous secreting glands located at base of penis
5
Q
describe the process of spermatogenesis
A
- begin as stem cell (spermatogonium)
- divide by mitosis to produce daughter cells (one is stem cell, other differentiates into primary spermatocyte)
- spermatocytes undergo meiosis to form gametes (divide into secondary spermatocytes then into spermatids)
- spermatids mature to spermatozoa -> released into lumen
6
Q
epididymis function
A
- maturation + storage of spermatozoa
- monitors + adjusts fluid composition
- acts as recycling centre
7
Q
ductus deferens function
A
- storage of inactive spermatozoa
- accessory glands aid w/ creation of semen when spermatozoa moved to ejaculatory duct
8
Q
seminal glands function
A
- make up 60% volume of semen
- alkaline to neutralise prostate + vaginal acids
- contains prostaglandins, fructose + fibrinogen
9
Q
prostate gland function
A
- 20-30% volume of semen
- secretes acidic, prostatic fluid
- contributes to sperm motility + viability
10
Q
bulbourethral glands function
A
- secrete thick, alkaline mucous
- neutralises urinary acids + lubricates penis
11
Q
what is semen + how much sperm is released in it
A
- thick whitish fluid containing sperm, seminal fluid + enzymes
- 2-5ml/ejaculation
- 20-100 mil. sperm/mL
12
Q
6 functions of nurse cells
A
- maintenance of blood-testis barrier
- supports mitosis + meiosis
- supports spermiogenesis
- secretion of inhibin (neg. feedback loop -> depress FSH + GRH to prevent overproduction)
- secretes androgen-binding protein
- secretes mullerian inhibiting factor (important for descent of testes)
13
Q
function of interstitial cells of leydig
A
secretes androgens - testosterone
14
Q
function of testosterone
A
- released in response to LH from pituitary
- controls development, growth + maintenance of male sex organs
- stimulates bone + muscle growth
- sexual behaviour
- final maturation of sperm
- stimulates descent of testes
15
Q
what 5 hormones ultimately control the production + maturation of sperm
A
- GnRH
- LH
- FSH
- inhibin
- testosterone
16
Q
function of the ovaries
A
- production of oocyte via meiosis
- oocytes grow + mature in follicles until ovulation
17
Q
function of fallopian tubes
A
transportation + nourishment for oocyte
-> 3 -4 days to move through
18
Q
uterus function
A
- mechanical protection, nutritional support + waste removal for embryo/foetus
- contraction during childbirth
19
Q
what are the 3 main layers of the utuerus
A
- perimetrium = outer serosal wall
- myometrium = muscular layer
- endometrium = grows + provides attachment location for oocyte
-> stratum basalis
-> stratum functionalis
20
Q
mammary glands function
A
- milk production for infant nourishment after birth
- controlled by hormones such as oxytocin + prolactin
21
Q
ovarian cycle definition
A
monthly series of events associated w/ maturation of an ovum
22
Q
menstrual cycle definition
A
series of changes in the endometrium of a non-pregnant female
23
Q
describe the 6 steps of the ovarian cycle
A
- primordial follicles in egg nest = primary oocytes in clusters -> activated from puberty
- formation of primary follicles = oocytes X completed first stage of meiosis / thecal + granulosa cells surrounding oocyte produce estrogens
- formation of secondary follicles = meiosis 1 stays suspended but oocyte begins to grow
- formation of mature graafian (tertiary) follicles = meiosis 1 complete / meiosis 2 halts in metaphase
- ovulation = tertiary follicles releases secondary oocyte / wall of follicle ruptures releasing contents -> oocyte moves to fallopian tube
- formation of corpus luteum + corpus albians = progesterone + estrogen released -> ready uterus for possible pregnancy / no pregnancy results in hormones declining - menses
24
Q
describe the 3 steps of oogenesis
A
- mitosis of oogonium (stem cell) = primary oocyte forms (all occurs before birth)
- meiosis 1 = primary oocyte prepares to undergo meiosis - halts in prophase until puberty when 1 oocyte per month completes meiosis 1 + divides into secondary oocyte
- meiosis 2 = secondary oocyte enters meiosis 2 + halts in metaphase until fertilisation
25
summarise the ovarian cycle in regards of days
1. during foetal development
2-4. (days 1-13) follicular phase of each ovarian cycle
5. (day 14) ovulation
6-7. (days 15-28) luteal phase
26
summarise the menstrual cycle in regards to days
- proliferative phase (day 8-14) = replacement of functional zone
- ovulation (day 14) = marks change to new phase of menstrual cycle
- secretory phase (day 15-28) secretion/thickening of functional zone
- menses (day 0-7) = will take place if there is no fertilisation of the oocyte w/ a spermatozoa
27
function of estrogens
- control female secondary sexual characteristics eg. breasts + uterus
- causes proliferation of uterine endometrium
- inhibits FSH production as levels rise + triggers LH production
28
function of progesterone
- only act on tissues which have previously been affected by estrogen
- causes endometrial growth + secretory changes in lining of uterus
- makes body temp ruse by 0.5*c after ovulation
29
describe the hormones regulation occurring in days 15-28 of both cycles
- LH released under GnRH control until progesterone levels increase
- estrogen levels decline
- if no fertilised ovum, all hormone levels decline whilst GnRH begins to ready the production of FSH + LH for a new cycle
30
describe the hormone regulation of the luteal phase of the ovarian cycle
- LH causes formation of corpus luteum + secretion of progesterone
- GnRH stimulates more LH than FSH which maintains structure of corpus luteum
- as progesterone levels rise estrogen levels fall slightly
- corpus luteum disintegrates + forms corpus albicans as cycle ends
- hormone levels decline at day 28 + new cycle begins
31
describe the hormone regulation of the secretory phase of the menstrual cycle
- progesterone secreted, preparing uterus for pregnancy
- enhances blood supply + uterine glandular secretions increase
- endometrial layer thickens in preparation for pregnancy
- day 28 if no fertilised oocyte implants, hormones decline + menses begin
32
describe how the contraception pill works
- minute doses of estrogens + progesterone
- slows the hypothalamic-pituitary actions
-> neg. feedback decreases GnRH release
-> inhibits follicular development + prevents ovulation
-> increases cervical mucus to inhibit sperm
33
describe what occurs during menopause
- cessation of ovulation + menstruation after around 450 ovarian cycles
- decreased estrogen + progesterone, decreased responsiveness of ovaries to FSH + LH
- increased conc. of GnRH which increases FSH + LH
- failure of follicles to mature
34
pre embryo definition
conceptus from fertilisation until 2 weeks old
35
embryo definition
conceptus during 3rd to 8th week
36
foetus definition
conceptus from 9th week through to birth
37
describe the trimesters of gestation
1st trimester = rudiments of major organ systems appear
2nd trimester = development of foetus + organ systems
3rd trimester = rapid foetal growth + deposition of adipose tissue / organ systems become fully functional
38
how long are oocytes + sperm viable for
oocyte = 12-48 hrs
sperm = 24-72 hrs
39
describe the steps to sperm penetration
- ovulated oocyte encapsulated by corona radiata + zona pellucida
- sperm break bonds b/t corona radiata cells
- sperm binds to the zona pellucida -> digests path through to oocyte surface where they fuse
- binding of one sperm prevents other sperm from fusing
40
describe the steps of meiosis II completion + fertilisation
- when sperm enters, secondary oocyte completes meiosis II
- ovum + sperm nuclei swell + 2 nuclei come together
- cell undergoes first cleavage + yield 2 daughter cells (blastomeres)
- morula formation occurs up to 72 hrs + reaches uterus ready for implantation
41
describe the blastocyst of the pre-embryo
- single layer of trophoblasts (which provide nutrients to developing embryo)
- an inner cell mass (eventually becomes embryo)
42
describe the steps to implantation
6-7 days after ovulation:
- trophoblast erodes path through uterine wall
- inner cell mass separates from trophoblast
-> forms embryonic disc
-> amniotic cavity forms on one side, yolk sac on other
43
function of amniotic cavity + yolk sac
amniotic cavity = provides buoyant environment, homeostatic temp for foetus development
yolk sac = primary nutrient source for early embryo until placenta takes over
44
what is gastrulation
where the 2-layered embryonic disc becomes a 3-layered embryo
45
describe what occurs by day 12 in terms of gastrulation
blastocyst develops into gastrula w/ 3 germ layers
- ectoderm
- mesoderm
- enderderm
-> layers form different body systems
46
describe placentation
formation of placenta from:
- embryonic trophoblastic/mesoderm tissues
-> vessels develop in embryonic tissues to supply nutrients for development (no mixing of maternal/foetal blood occurs)
47
describe what happens to the chorion during placentation
chorion = chorionic membrane
- become vascularised
- extend to embryo as arteries + veins
- embryo, amnion + yolk sac float in fluid filled chamber
- attached to placenta by body stalk (becomes umbilical cord)
48
describe process of embryogensis + organogenesis
- after gastrulation, body of embryo starts to separate from rest of embryonic disc
- body of embryo + organs start to form
-> wk 4 = head + tail folds form
-> organogenesis est. in first trimester + continues until 3rd trimester
49
role of hCG
function resembles LH - keeps corpus luteum functional for 3-4 months
50
role of estrogens + progesterone in pregnancy
- produced by corpus luteum + placenta
- maintain pregnancy + endometrium then stimulate labour + delivery
51
hPL + placental prolactin function
preparation of mammary glands
52
relaxin function
- increase pelvic flexibility (while baby grows)
- increases cervical dilation (delays oxytocin until uterine contractions should begin)
53
describe the metabolic changes during pregnancy + the hormone responsible
from human placental lactogen (hPL)
- glucose sparing effect (more for baby)
- 10-30% increase in nutritional requirements
54
describe the CV changes during pregnancy
- increased blood volume + Q
- decreased BP
-> b/c of blood flowing to placenta
55
describe the renal system changes during pregnancy
- dilation + enlargement of kidneys/ureters
- increased urine production
56
describe the respiratory system changes during pregnancy
- increased V + O2
- decreased CO2
57
describe the gastrointestinal changes during pregnancy
- morning sickness b/c of increased estrogen + progesterone
- decreased motility + gastric emptying
58
describe the changes to the mammary glands during pregnancy
- growth + development for lactation due to hormones
59
describe the uterine changes during pregnancy
- increased size + weight
- changes occur through hypertrophy of existing cells (myometrium smooth muscle fibres enlarge)
60
describe the events leading up to labour
- estrogen peaks in last weeks of pregnancy causing myometrium irritability
-> weak braxton-hicks contractions occur
- oxytocin + prostaglandins cause uterine contractions as birth nears
- emotional + physical stress activates hypothalamus + sets up +ve feedback loop releasing more oxytocin
61
describe the dilation stage of labour
- onset of labour
- cervix dilates
-contractions begin + increase slowly + frequency
- 'water breaks' late in stage
62
describe the expulsion stage of labour
- begins when cervix fully dilated (10cm)
- contractions increase in intensity, duration + length
- continues until foetus has been delivered
63
describe the placental stage of labour
- after delivery of newborn
- muscle tension builds up in walls of partially empty uterus
- contractions tear connection b/t placenta + endometrium
- ejection of placenta occurs
64
describe the foetal circulation changes after birth
- 3 vascular shunts shut off after lungs inflate + pattern of blood flow + pressure is changed suddenly
- creates normal circulatory system of human body
65
describe how a newborn baby starts to breath
- CO2 builds up after umbilical cord cut
- lungs inflate + surfactant in alveolar fluid helps reduce surface tension
- ductus arteriosus closes -> isolates pulmonary + systemic trunks
-> foramen ovale closes = 2 separate atria, 2 separate circuits
66
describe the hormonal control of lactation
- estrogen, progesterone + lactogen stimulate hypothalamus to release PRH
-> anterior pituitary responds by releasing prolactin
67
benefits of breast milk for the infant
- contains important nutrients eg. AAs + sugars
- has antibodies
