Reproductive Flashcards
1
Q
organs of reproductive system
A
gonads
pathway of gamete transport
accessory reproductive organs/glands
2
Q
function of gonads
A
gamete production
secrete sex hormones
3
Q
function of male reproductive system
A
production of gametes
organs for mating
fertilization
propagation of species
4
Q
anatomy of male r.s.
A
testis (gonads) → epididymis → vas deferens
glands: seminal vesicle, prostate, bulbo-urethral
5
Q
testes
A
male gonads
housed in scrotum (outside of body)
250-300 compartments; tightly packed seminiferous tubules
6
Q
spermatic cord
A
collection of tube structures through which vessels, nerves, + vas deferens pass
counter directional blood flow = helps temp regulation
7
Q
descent of testes
A
3 months in development
7 months → starts to descend
at birth
process regulated by testosterone
spermatogenesis requires temperatures 2 degrees below core body temp
8
Q
cryptorchidism
A
abnormality - testes remain in abdomen
can be rectified by surgery after birth
9
Q
seminiferous tubules
A
site of sperm production
packed in testes, converge from compartments into rete testis = network
separate into efferent ductules that join together to become vas deferens
10
Q
mumps
A
viral infection that causes infertility
attacks germ cells that will develop to produce gametes = larger lumen of seminiferous tubules, smaller cells
preventable by childhood vaccine
11
Q
leydig cells
A
interstitial cells
secrete testosterone
12
Q
sertoli cells
A
epithelial cells lining s. tubules
support sperm development
linked by tight junctions
13
Q
myoid cells
A
smooth muscle lining outside of s. tubule
peristalsis = propel sperm
14
Q
blood-testis barrier
A
tight junctions between sertoli cells form basal and luminal compartments
keeps sperm safe from blood-carried pathogens
15
Q
local role of sertoli cells
A
- trophic effect to support sperm development
- secrete luminal fluid for sperm housing
- secrete androgen-binding protein = buffer to maintain steady [androgens] in lumen
16
Q
endocrine role of sertoli cells
A
- act as target cells for testosterone + FSH → secrete paracrine factors that stimulate spermatogenesis
- secrete inhibin = negative feedback for FSH
- secrete paracrine factors that affect Leydig cell function
- phagocytosis of old and damaged sperm
- site of immunosuppression (blood-testis barrier)
17
Q
male gonads
A
production of sperm
production of hormones
18
Q
scrotum
A
temperature regulation of optimal sperm production
19
Q
epididymis
A
maturation of sperm following production
temporary storage site for sperm
20
Q
vas deferens
A
conduit
storage site for sperm
21
Q
male accessory sex glands
A
production of seminal fluid
22
Q
corticosteroid synthesis in males
A
cholesterol → progesterone → androgens
conversion to androgens in the gonads (also in adrenal cortex)
lipophilic hormones → cross membrane to intracellular receptors = slow response
23
Q
production of testosterone in males
A
low levels in childhood to onset of puberty = inability to reproduce
androgens (testosterone) → carried by blood to peripheral tissues:
- direct action
- converted to DHT, estrogen, or inactive molecules
24
Q
male puberty
A
onset at 10-14
sexual maturation = males can continuously produce sperm
reproductive organs mature = can produce gametes
secondary sexual characteristics develop
25
plasma testosterone levels in males
peaks at:
- mid-fetal development = descent of testes
- neonatal (after birth)
- onset of puberty
levels rise from puberty until adulthood and remain high
small decline at old age
sperm production parallels rise at puberty + adult levels
26
hypothalamic-pituitary - Leydig cell axis
higher centres trigger hypot. to release GnRH → stimulates release of LH from anterior pituitary → stimulates Leydig cells to release testosterone → effects at onset of puberty
testosterone has negative feedback at anterior pituitary + hypot.
27
puberty changes in males
growth spurt = ↑ muscle mass
↑ body hair
voice changes
pubic hair grows + genitals develop
28
effect of androgens in males
stimulate spermatogenesis
promote development of secondary sex characteristics during puberty + maintenance throughout adulthood
increase sex drive
promote protein synthesis in skeletal muscle
stimulate growth hormone secretion = permits bone growth during adolescence
promote development of male reproductive structures during embryonic life
29
testosterone anabolic action
promote protein synthesis in skeletal muscle
30
spermatogenesis
production of gametes
begins at onset of puberty
occurs in s. tubules → from basement membrane to lumen; in space between adjacent sertoli cells
mitosis of spermatogonia = primary spermatocytes → meiosis I = secondary spermatocytes → meiosis II = spermatids → differentiate into spermatozoa
takes ~64 days after mitosis
31
mitosis (males)
ensures continuous supply of spermatogonia
one daughter cell continues differentiation + other restarts mitosis to maintain germ line
32
meiosis (males)
chromosome number becomes half
33
spermatogonia
2n chromosomes
34
primary spermatocytes
2n x2 chromosomes
35
secondary spermatocytes
n x 2 chromosomes
36
spermatids
n chromosomes
37
differentiation of spermatozoa
specialization for transport + delivery of proper genetic material
38
spermiogenesis
differentiation of spermatid to spermatozoa = ~24 days
acrosomal vesicle migrates to nucleus = enzymes to support sperm head during fertilization
elongation of tail
mitochondria migrate to middle
shed cytoplasm
39
structure of a sperm
head:
- nucleus = chromosomes
- acrosome = enzymes for fertilization
midpiece:
- mitochondria = energy source
tail:
- movement of cell; slow wave becomes whiplike to propel
40
sperm maturation
spermatozoa released into lumen of s. tubules = immotile; ~20 days
fluid secreted by Sertoli cells generates pressure to push sperm into epididymis = reside 6-12 days; aquire motility; fluid is reabsorbed + sperm is concentrated
move to vas deferens by peristalsis → remain until ejaculation
41
defects in sperm maturation
affected sperm structure or count can cause infertility
optimum number = 300 million sperm/ejaculation vol (3 mL)
42
gonadotropins (males)
FSH = stimulates gametogenesis/spermatogenesis in sertoli cells
LH = stimulates androgen secretion from Leydig cells
43
hypothalamic-pituitary testicular axis
hypot. = pulse generator → releases GnRH in pulses
stimulates anterior pituitary to release LH + FSH
testosterone + androgen-binding protein combine to effect local actions in s.tubules
44
pulse generator
active at onset of puberty
pulses of GnRH secretion is sufficient to stimulate pituitary release of hormones (one large secretion is insufficient)
frequency + amplitude of pulses change every 90 min for males
45
testosterone negative feedback
at hypot. = ↓ amplitude of GnRH released
at ant. pit. = ↓ responsiveness of cells to GnRH
works to regulate rate of spermatogenesis
46
seminal vesicle
gland that releases seminal fluid into vas deferens (join before entering urethra
secretes alkaline fluid with fructose, enzymes, and prostaglandins
47
prostate gland
organ that empties secretions through pores into urethra; below entry of vas deferens
secretes citrate + enzymes (prostate specific antigen = PSA)
48
seminal fluid
dilutes sperm
provides energy (fructose)
forms semen clot
49
PSA levels
increased by hypertrophy or cancer in prostate gland
= biomarker for cancer detection
50
bulbourethral gland
secrete viscous fluid with mucus into seminal fluid
below prostate gland
51
semen
sperm + seminal fluid
52
male sexual response
controlled by autonomic nervous system
active = parasympathetic control
external stimulation or various neural inputs → reflexes at T, L, S spinal levels
1. erection = parasymp. → relaxation of vasc smooth muscle = ↑ blood flow to erectile tissue
2. emission = symp. stimulation to smooth muscles of ducts = contraction
3. ejaculation = somatic spinal reflexes → contraction of skeletal muscle for semen expulsion
53
parasymp. control of erection
stimulation → SC → ↑ activity in parasymp. neurons → relaxation of smooth muscle of arteries supplying blood to erectile tissue
= ↑ blood flow = ↑ blood vol and pressure
positive feedback (compression of veins = ↓ outflow of blood = ↑ blood vol + pressure)
54
vasodilation
activation of parasympathetic nerve = ↑ Nitric oxide (NT) = ↑ cGMP (2nd messenger) → vasodilation = ↑ blood flow
55
viagra
"sildenafil"
inhibitor of phosphodiesterase enzyme that breaksdown cGMP = higher concentration
treatment for erectile dysfunction
56
sperm numbers through female tract
200x10^6 deposited
100,000 reach uterus
100 reach ampulla = site of fertilization
many die because of high acidity, or don't have energy to move forward, cervix leakage
57
capacitation
final maturation of sperm
occurs in female tract (upper body of uterus)
uterine secretions cause changes:
destabilization of sperm surface membrane → multiple fusions, changes in cholesterol = allows for binding with female gamete
activation also changes tail movement from wave-like to whiplash
58
characteristics of the female reproductive system
cyclic changes in activity = menstrual cycle
restricted periods of fertility = ovulation
limited gamete production = pool established at birth
59
female reproductive activity
sexual maturation (early teens+)
phase leading to onset of puberty is not a fixed time period
60
menarche
onset of puberty
first menstrual bleeding
variable age
61
menstruation
female reproductive cycle
62
menopause
after last cycle, females lose ability to reproduce
~ age 45-50
63
female reproductive organs
gonads = ovaries
reproductive tract = uterus, uterine tubes, vagina
64
ovaries
site of ova maturation (produce gametes + reproductive hormones)
consists of connective tissue with follicles
separate from reproductive tract
65
fallopian tubes
uterine tubes/oviduct
site of fertilization
transports ova from ovaries to uterus
infundibulum + fimbriae sit on top of ovary and pick up released ovum
66
movement of ovum through uterine tube
initially = peristaltic contractions (smooth muscle)
mostly = movement of cilia lining tubules
duration: 4 days to reach uterus
67
ectopic pregnancy
implantation of zygote occurs in f. tube instead of uterus = not viable → surgically removed
abnormal + rare (1-2%)
untreated = maternal mortality
can be caused by chlamydia (damages cilia)
68
uterine wall
site of fetal development
outer layer = perimetrium
middle layer = myometrium
inner layer = endometrium
69
perimetrium
epithelial cells and connective tissue
70
myometrium
thickest layer
smooth muscle
= large contractions during parturition
71
endometrium
layer of epithelial cells with numerous glands → slough + grow every cycle
glands secrete glycogen to maintain embryo
layer of connective tissue
72
cervix
canal leading to vagina
birth canal = cervix + vagina
73
oocyte
female gamete ("egg")
develop within follicles and released from mature follicle
74
ovarian cycle
follicular phase + luteal phase
75
follicular phase
day 1-14 (variable length)
day 1 = start of menstrual bleeding
follicles grow
76
luteal phase
day 14-28 (always 14 days)
begins once follicle releases egg
corpus luteum becomes gland that releases hormones (if fertilization/implantation don't occur, CL dies + signals to start new cycle)
77
uterine cycle
menstrual phase
proliferative phase
secretory phase
78
menstrual phase
menstruation
day 1-5 (variable)
layer of endometrium sloughs off
triggered by ↓ estrogen and progesterone (degeneration of corpus luteum)
79
proliferative phase
preparation for egg release
day 5-14
estrogen = building of endometrial layer + glands, blood vessels enter tissues to supply O2 and nutrients
smooth muscle layer thickens
cervical glands secrete a thin mucus
80
secretory phase
day 14-28
progesterone
glands release secretions: glycogen + fluid
to support zygote development if implantation occurred
↑ blood supply
cervical secretions are more sticky = forms plug
suppresses myometrium contractions
81
hormonal cycle
estrogenic stage
progestational stage
82
estrogenic stage
day 1-14
estrogen levels build as follicles grow
assists proliferative stage
83
progestational stage
day 14-28
corpus luteum releases large amounts of progesterone
= maintain secretory phase
increases body temp following ovulation
84
follicles
embedded in connective tissue
each follicle contains 1 oocyte
earliest stage: primordial follicle = single layer of granulosa cells (specialized epithelium)
growth: cells divide to form theca cells
85
stages in folliculogenesis
primordial follicle
primary follicle
preantral follicle
early antral follicle
mature (Graffian) follicle
86
primordial follicle
contains primary oocyte + single layer of epithelial cells
87
primary follicle
oocyte grows
zona pellucida (glycoproteins) develop as cell layer differentiates into granulosa cells
88
secondary follicle
cell layer differentiates
- theca cells (internal + externa)
fluid secreted by granulosa cells forms antrum
only 10-25 each month (preantral → early antral follicles)
89
Graffian follicle
large follicle (only 1 will mature)
oocyte is pushed into antrum by granulosa cells - cumulus oophorous
90
FSH → granulosa cells
FSH exerts mitotic effect
extend cytoplasmic processes through zona pellucida + form gap junctions with oocyte
delivers nutrients + paracrine factors to help growth
91
corpus luteum
follicle after oocyte is released by ovulation
secretory gland → release of estrogen + progesterone
degenerates if no fertilization occurs → corpus albicans
92
FSH effects: mid follicular phase
stimulates granulosa cell proliferation
produce estrogen
further growth of antrum
increases aromatase synthesis + granulosa cell activity
93
LH effects: mid follicular phase
stimulates theca cells to secrete androgens (coversion of cholesterol → progesterone → androgens)
androgens permeate to granulosa cells
94
aromatase
converts androgens to estrogen in granulosa cells
95
estrogen effects: mid follicular phase
further granulosa cell growth
up regulation of LH receptors on granulosa cells + progesterone receptors on uterine endometrial cells
96
late follicular phase
LH can bind to granulosa cells
chloesterol → progesterone = ↑ levels in blood
97
granulosa cells
similar to sertoli cells
provide nutrients for developing oocyte
secretes:
- antral fluid
- paracrines that support follicle development
- inhibin
- estrogens
- substance that forms zona pellucida
98
pulse generator in females
frequency + amplitude of pulses change every 24 h over course of menstrual cycle
99
estrogen
regulates gonadotropin levels through (-) and (+) feedback depending on phase of menstrual cycle
low levels = (-) feedback on hypothalamus + pituitary
high levels = (+) feedback → initiation of LH surge
100
oogenesis
oogonia →mitosis = primary oocyte → meiosis I = secondary oocyte → meiosis II = ovum
101
ovarian hormones
not required for female sexual differentiation before birth
required for sexual maturation at puberty and secondary sexual characteristics
maintaining sexual capacity in adult life
regulation of hypothalamic pituitary gonadal axis
estrogen, progesterone, inhibin
102
menstrual cycle
follicular phase = follicle development from day 1-14 = ovulation
luteal phase = corpus luteum functions and degeneration after ovulation
103
atresia
apoptosis of follicles other than dominant
occurs during follicular phase
estrogen + inhibin → negative feedback = ↓ FSH = follicle death
104
Ovarian hormone actions - ovary
estrogen:
- ↑ growth of follicles
- upregulation of E, P, FSH, LH receptors
progesterone:
- ↓ FSH-induced estrogen production
↓ estrogen receptors
105
OHAs - fallopian tube
estrogen:
↑ cell growth
↑ contractility
↑ cilia activity = mvt of oocyte
↑ secretions
progesterone:
↓ contractility
↓ cilia number
↓ sercretions
106
OHAs - uterus
estrogen:
↑ growth of endometrium + myometrium
↑ contractility
↑ blood flow
↑ sensitivity to oxytocin
progesterone:
↑ endometrial secretions
↓ contractility
↓ sensitivity to oxytocin
107
OHAs - cervix
estrogen:
↑ watery + alkaline mucus = sperm-friendly
progesterone:
small amount of viscous, cellular (WBCs) mucus = sperm-unfriendly
108
OHAs - vagina
estrogen:
proliferation + cornification of epithelium
progesterone:
WBC infiltration
↓ cornification
109
OHAs - breasts
estrogen:
↑ duct growth
↑ fat deposition
↑ size + pigmentation of areola
progesterone:
↑ alveolar growth
110
cornification
↑ keratin deposition = hardening of epithelium
111
fertilization
fusion of male + female gametes to form zygote
site = female oviduct
sperm viable = 5 days
oocyte viable = 12-24 hours
112
gestation
pregnancy
lasts 40 weeks
first two months = embryo
after 8 weeks = fetus
parturition = birth
113
sperm acrosome reaction
happens in fallopian tube prior to fertilization
triggered by zona pellucida → paracrine factors cause release of acrosomal enzymes
114
polyspermy
multiple sperm fusing with oocyte → prevented to maintain correct chromosome number
one sperm enters zona pellucida → fuses to egg plasma membrane = change in membrane potential (Ca2+) = release of enzymes from cortical (secretory) granules → enter + harden zona pellucida + inactivate sperm binding receptor
= prevent any other sperm from entering
115
fusion of sperm + oocyte
stimulates meiosis II of oocyte → ovum
sperm plasma membrane disintegrates
chromosomes from sperm and ovum migrate to center
DNA is replicated = zygote
116
zygote
fertilized ovum
surrounded by zona pellucida
early mitotic divisions = cell cleavage (net cytoplasmic content is constant - no increase in size but increase cell number)
totipotent cells
117
totipotent
stem cells
have capacity to develop into any structure
up to 16-32 cell stage
118
morula
3-4 days post fertilization
cell cleavage of zygote
totipotent cells
can move from fallopian tube to uterus
119
identical twins
division of totipotent morula cells
1 ovum fertilized by 1 sperm later divides
120
fraternal twins
non-identical
fertilization of two oocytes released during the same cycle
121
blastocyst
4-5 days post fertilization
lost zona pellucida
outer cell layer = trophoblast → will become fetal placenta
inner cell mass → embryo
fluid-filled cavity = blastocoele
totipotency is lost
122
implantation
6-7 days after fertilization
trophoblast cells on side near uterus epithelium become sticky
→ differentiate:
- cytotrophoblast = cell layer invades endometrium
- syncytiotrophoblast = fused trophoblast layer → anchors
123
decidual response
maternal endometrium response to implantation
↑ blood vessels + glands → glycogen
↑ cytokines + paracrine factors released
124
late embryonic development
embryo starts to develop at 3 weeks
placenta becomes to form
at 5 weeks: placenta is functioning + heart beats
at 8 weeks: embryo becomes fetus
125
amniotic cavity
supportive environment where fetus grows
surrounded by amnion → chorion
126
placental development
chorion extends projections into maternal endometrium = chorionic villus → contain fetal blood vessels
space around villi = sinus → contains maternal blood
no direct contact between maternal and fetal blood → close proximity in placenta = exchange of gases + nutrients
127
functions of placenta
endocrine organ = temporary gland
exchange tissue for resp gases, nutrients, and waste products
filter/immunological protection
128
human chorionic gonadotropin
hormone used to detect pregnancy
released from chorionic layer
spikes 1-3 months since start of last period; stays above 0 until birth
maintains corpus luteum for 2-3 months
similar action to LH = estrogen + progesterone rise until birth
129
human placental lactogen
hCS
see similar curve to E + P through gestation but higher level
GH-like and anti-insulin like actions in mother
keeps ↑ glucose levels in maternal blood = available to fetus
130
hormone exchange between mother - placenta - fetus
cholesterol in mother → placenta = converted to P → released to mother + fetus
P in fetus = converted to androgen → sent to placenta = converted to estrogen → sent to mother
131
control of parturition
weak uterine contractions → pressure of fetus against cervix = (+) feedback ↑ oxytocin secretion from pit. → strengthens uterine contractions
continuous (+) feedback until parturition
132
myometrial contractions
↑ by: E, prostaglandins, oxytocin, stretch
↓ by: P, relaxin
133
cervical ripening
dilation
↑ by: prostaglandins, relaxin
↓ by : P
134
relaxin
hormone secreted by corpus luteum + placenta
regulation of ↑ in body fluid vol in mother during pregnancy
(present throughout pregnancy)
135
parturition
end of pregnancy = cervix ripens
cervix dilates → labour
baby's head wedges cervix open
expulsion of placenta = after birth
136
mammary gland
before puberty: rudimentary ducts, few alveoli
puberty: E = ducts grow + branch; P = alveolar growth
deposition of fat + alveolar tissue
pregnancy + lactation = full development
- prolactin = lactogenesis
- hPL + growth factors
- oxytocin = milk ejection
137
lactogenesis
initiation of milk synthesis
prolactin + low levels of E + P
138
galactopoiesis
process of maintenance of lactation
requires prolactin
139
alveolar structure
alveolar cells = synthesize milk protein
myoepithelial cells have oxytocin receptors → suckling reflex = cells contract and eject milk from alv cells into lumen
also contains blood vessels, connective tissue, and adipose tissue
140
suckling reflex
suckling → hypothalamus → ↑ PRH + ↓ PIH secretion → anterior pituitary = ↑ prolactin secretion
↑ oxytocin secretion from posterior pituitary = contraction of myoepithelial cells
141
Jost paradigm
determination of sex:
genetic sex (sex chromosomes)→
gonadal sex (gonads)→
genital or phenotypic sex (internal + external genitalia)
142
genetic sex
determined at moment of fertilization
XX = female
XY = male
143
gonadal sex
determined by chromosomal sex
if Y chromosome is present, SRY gene dictates differentiation of bipotential gonads → become testes
no SRY gene (XX) = default to ovaries
144
bipotential gonads
cells are no longer totipotent
gonads are near mesonephros → will become kidneys
Mullerian duct = will become female internal structures
Wolffian duct = will become male internal structures
cloaca = will become internal genitalia
145
Klinfelter's syndrome
XXY (male)
presence of more than one X chromosome impairs spermatogenesis = infertility
taller, ↓ facial + body hair, gynaecomastia, osteoporosis, small testes
146
Turner Syndrome
XO (female)
lack of X chromosome (or non-functional) causes streak ovaries = many layers of connective tissue, no follicles
shorter, CV effects
147
genital sex
dictated by factors produced in the gonads
if testes develop = cells release hormones that push development towards male
without = develop as female
148
Mullerian Inhibiting Hormone
secreted from Sertoli cells in testes
stops development of Mullerian duct = regression of female development
149
testosterone - sexual differentiation
secreted from leydig cells in testes
causes development of male internal genitalia from Wolffian duct
T is converted to DHT = masculinization of male external genitalia
150
female sexual differentiation (genital sex)
absence of MIH = Mullerian duct grows into female internal genitalia
absence of T prevents development of Wolffian duct = no male internal genitalia
absence of DHT = no masculization of external
female = default
151
pseudohermaphroditism
genital sex is not always representative of genetic/gonadal sex
females: congenital adrenal hyperplasia
males: androgen insensitivity syndrome
152
congenital adrenal hyperplasia
female - XX; has ovaries but has male external genitalia
enzyme mutation prevents conversion of cholesterol into cortisol in adrenal cortex
= no negative feedback = ↑ ACTH = ↑ cortisol
converted to androgens instead → target cells = virilization
infertility
153
CAIS
complete androgen insensitivity syndrome
male - XY; has testes but has female external genitalia
MIH has inhibiting effect on female internal development
mutation of androgen receptor on Wolffian ducts + body tissues = no response to testosterone/DHT
= no male internal + no male external → female external
androgens are converted to estrogen in target tissues
infertile
154
endocrine trigger of onset of puberty
↑ secretion of GnRH from pulse generator in hypothalamus
= ↑ LH + FSH = ↑ sex steroids from gonads → pubertal changes
before puberty = low levels → suppression of axis
at puberty: kisspeptin stimulates hypothalamus pulse generator
155
kisspeptin
neuropeptide that stimulates neurosecretory cells in hypot.
triggered by leptin from adipose tissue
156
climacteric
declining endocrinal, somatic, reproductive, and psychological functions
females = starts with perimenopause
males = andropause
157
perimenopause
number of follicles falls to ~1000
↓ follicles + ↓ responsiveness to LH + FSH = ↓ estrogen + inhibin
irregularity + cessation of ovulation + menstrual cycles
158
menopause
no ovulation = no corpus luteum → ↓ progesterone
↓ estrogen, inhibin, progesterone = no negative feedback inhibition = ↑ FSH + LH levels
