Reproduction Flashcards
1
Q
what 2 factors set human reproduction apart from animals?
A
mate for pleasure & procreation, females are sexually receptive outside fertile window
2
Q
what 3 factors of human reproduction are similar to animals?
A
internal fertilization, mating/courtship rituals, internal fetal development
3
Q
what is the benefit of internal fertilization?
A
motile, flagellated sperm remain in an aq enviro
4
Q
what are 2 benefits of internal fetal development?
A
protects embryo from dehydration, cushioned from mech damage
5
Q
what is sexual dimorphism?
A
physical/sexual distinction btwn males and females
6
Q
what is reproduction?
A
perpetuation of a species via production offspring (important for species but not individual survival)
7
Q
what determines the sex differentiation of the embryo?
A
sex hormones
8
Q
what do the gonads produce?
A
sperm/ovum (gametes) and sex hormones
9
Q
how many weeks after the production of a zygote is it considered an embryo then fetus?
A
embryo: 0-8 weeks
fetus: 8-birth
10
Q
what are the 3 “structures” of male/female sex organs?
A
gonads (testes/ovaries), internal genitalia (connect gonads to ext enviro), external genitalia
11
Q
what are 3 sex/steroid hormones? and ex?
A
androgens (testosterone, DHT), estrogen (estradiol), progesterone
12
Q
t/f: androgens are only present in males, and estrogen/progesterone are only found in females
A
false, all are found in both males and females
13
Q
what are developing gametes aka?
A
germ cells
14
Q
how many chr do gametes contain?
A
23 (not in pairs, one set)
15
Q
when do females vs males undergo germ cell mitosis? (primary oocyte/spermatocyte)
A
females: fetal development
males: embryonic stage
(both in utero)
16
Q
what is a diff btwn female vs male germ cell mitosis?
A
female: mitosis completed before birth
males: significantly begins at puberty and continues throughout life
17
Q
what is the process of female gametogenesis (include 1N, 2N, 4N)? (4)
A
oogonium/germ cell (2N) undergoes mitosis and begins meiosis w/ DNA repl’n to generate primary oocyte (4N) as embryo, meiosis 1 occurs at puberty generating 1st polar body and secondary oocyte (egg, 2N), egg released at ovulation, if fertilized: undergoes meiosis 2 (1N) and generates 2nd polar body and zygote (2N), unfertilized: degenerates
18
Q
t/f: one primary oocyte yields 2 eggs
A
false, meiosis 1 of primary oocyte generates only 1 egg (polar body disintegrates)
19
Q
what is the process of male gametogenesis (include 1N, 2N, 4N)? (4)
A
spermatogonium/germ cell (2N) begins mitosis as embryo, meiosis begins w/ DNA repl’n at puberty (mitosis continues) to generate primary spermatocyte (4N), meiosis 1 generates secondary spermatocytes (2N), meiosis 2 generates spermatids (1N) which develop into sperm
20
Q
t/f: one primary spermatocyte generates 2 sperm
A
false, one primary spermatocyte generates 4 sperm (meiosis 1 and 2)
21
Q
how many chr is 1N, 2N, and 4N?
A
1N: 23 chr (no pairs/homologs)
2N: 46 chr (23 pairs/homologs)
4N: 46 (sister chromatids)
22
Q
what is sex chromatin/Barr body?
A
one X of XX is non-functional, condenses to form sex chromatin (aka Barr body)
23
Q
where is sex chromatin/Barr body contained? (2)
A
cheek mucosa cells and WBCs
24
Q
how can genetic sex abnormalities be found?
A
by karyotyping (tissue culture)
25
what do XXX, XXY, YO, and XO genotypes all result in?
XXX: female
XXY: male
YO: non-viable (need X)
XO: female, Turner's syndrome
26
what scenario can cause sexual phenotype to not match chr composition?
atypical sex differentiation (≠ XX/XY)
27
what can atypical sex differentiation result in?
intersex or ambiguous genitalia
28
what is required for proper sex differentiation? (2)
genes on chr, secretions from gonads (testes primarily)
29
what week do gonads remain undifferentiated until?
6th week
30
what week do testes develop?
week 7
31
what gene on the Y chr mediates development of testes?
SRY (Sex-determining Region Y) gene
32
which cells express SRY gene?
urogenital ridge cells
33
what protein does SRY gene encode for?
TDF (testes determining factor)
34
what do both male and female gonads derive from?
urogenital ridge
35
what cells does TDF trigger development of?
Leydig and Sertoli cells (in testes)
36
what occurs if Y chr/SRY gene is absent?
testes don't develop, and ovaries do in same region
37
what does the undifferentiated fetal reproductive tract contain? (3)
wolffian ducts, mullerian ducts, common opening for ducts/urine
38
what duct system persists in males?
wollfian
39
t/f: duct systems can give rise to external genital structures
false, only give rise to internal structures
40
what does ultimate development of male internal and external structures depend on?
presence of functional, fetal testes
41
what do Leydig vs Sertoli cells secrete?
Leydig: testosterone
Sertoli: mullerian-inhibitng substance/H (MIS)
42
what induces MIS gene?
SRY protein
43
what does MIS do?
degenerates mullerian duct system
44
what does testosterone do for fetal development?
differentiates wolffian ducts into epididymis, vas deferens, ejaculatory ducts and seminal vesicles
45
what hormone forms penis and scrotum, and degenerates urogenital slit?
testosterone-derived DHT
46
what does absence of DHT cause?
intersex (required for external genitalia)
47
what hormone stimulates testes to descend?
testosterone
48
what is failure to descend testes called?
cryptochordism (remain in abdomen)
49
what can cryptochordism result in?
decr sperm production
50
why does cryptochordism cause decr sperm production?
proper sperm development requires lower than core body temp, if testes remain in abdomen, too hot for proper development
51
what triggers degeneration of wollfian ducts?
absence of testes, SRY gene, and thus MIS and testosterone (mainly)
52
what does mullerian duct system develop into?
Fallopian tubes and uterus
53
what triggers development of mullerian duct system?
absence of testes, SRY gene, and thus MIS and testosterone (mainly)
54
what does lack of testosterone-derived DHT cause?
persistence of urogenital slit
55
t/f: embryonic ovaries secrete hormones that trigger development of external genitalia
false, vagina/female external genitalia development is not influenced by ovaries
56
what does androgen exposure during period of female genital development cause? and after 13th week of gestation?
development: develop male structures
| after 13 weeks: female genitalia virilized (enlarged)
57
what is the process of male embryonic sexual development? (4)
SRY gene in embryonic germ cells produces TDF, which initiates differentiation of gonad medulla into a testis, interstitial/Leydig cells secrete testosterone which directs development of internal and external (DHT) genitalia, Sertoli cells secrete MIS which causes regression of Müllerian duct
58
What is the process of female embryonic sexual development?
lack of SRY gene causes differentiation into fetal ovaries, no MIS initiates internal genital development, no testosterone causes regression of Wolffian ducts and development external genitalia + vagina
59
what is androgen insensitivity syndrome?
impaired testosterone binding in XY genotype causes degeneration of mullerian ducts (MIS present) and Wollfian ducts (no testosterone activity), therefore are infertile
60
when is androgen insensitivity syndrome detected?
at puberty when menstrual cycle fails to initiate
61
what is congenital adrenal hyperplasia?
overproduction of androgens in fetus causes virilization of XX fetus and ambiguous genitalia
62
what causes androgen insensitivity syndrome?
mutation in androgen receptor gene
63
why is androgen insensitivity syndrome aka "testicular feminization"?
testes present but ext. female genitalia
64
what causes congenital adrenal hyperplasia?
mutation in cortisol gene synthesis causes incr ACTH and androgen production
65
what is a treatment for congenital adrenal hyperplasia?
cortisol replacement (normalizes ACTH but not ext. genitalia)
66
what is the general synthesis pathway for DHEA? where is it secreted?
cholesterol forms pregnenolone to form DHEA; adrenal cortex
67
what is the general synthesis pathway for estrone and estradiol? where are they secreted?
cholesterol forms pregnenolone to form progesterone which forms androstenedione that can be converted to estrone by aromatase or testosterone, aromatase converts testosterone to estradiol; ovaries
68
what is the general synthesis pathway for DHT?
cholesterol forms pregnenolone to form progesterone which forms androstenedione that is converted to testosterone, secreted by testes to target tissue where 5-a-reductase converts it to DHT
69
where is progesterone secreted in females?
ovaries
70
where are androgens synthesized? (2)
testes mainly but also adrenal cortex
71
t/f: androgens from the adrenal cortex are enough to sustain male reproduction functions
false, adrenal androgens are not potent enough
72
are adrenal androgens also secreted by women?
yes, from ovaries in small amounts
73
is DHT a more potent form of testosterone?
yes
74
what are estrogens vs estrogen?
estrogens: family of steroid hormones
estrogen: used interchangeably with estradiol
75
where are estrogens secreted from? (2)
ovaries and placenta
76
what is estradiol?
predominant estrogen in plasma
77
what individuals are estrone vs estriol mainly found in?
estrone: post-menopausal
estriol: pregnant women
78
where is estriol produced?
placenta
79
what are estrogens produced from? how?
androgens; aromatization
80
what enzyme is responsible for aromatization of androgens into estrogens?
aromatase
81
are estrogens found in males?
yes, released from testes
82
where are androgens converted to estrogens in males?
in non-gonadal tissues by aromatase
83
what is the HPG axis for sex hormones?
hypothalamus produces GnRH, GnRH stimulates ant pit to produce FSH and LH (gonadotropins), FSH and LH stimulate sex hormones
84
what can sex hormones do in HPG axis? (3)
stimulate gametogenesis, or any organ w/ a receptor, or negative feedback (or positive for females) on hypo (GnRH) ant pit (FSH and LH)
85
what cells secrete GnRH?
neuroendocrine cells in hypothalamus
86
t/f: impaired function of hypo/ant pit results in failure of gonads to secrete steroids/gametogenesis
true
87
what secretes progesterone in anatomical females?
ovaries and adrenal gland
88
what is the major secretory product of placenta during pregnancy?
progesterone (also during specific times during menstrual cycle)
89
t/f: progesterone is not present in males
false, progesterone is present in males as it's a precursor/intermediate for adrenal steroids/androgens and estrogens
90
what is the action of gonadal steroids in a target cell?
diffuse into cells (lipid-soluble), bind to intracellular receptor to form complex, binds DNA in nucleus and modifies mRNA formation, protein synthesis, and circulating levels of protein
91
what are the 2 actions of gonadal steroids (not gametogenesis)?
development of accessory reproductive organs (ducts, breasts), and secondary sex characteristics (hair, body shape/height)
92
what does LH do in gonads? (2)
stimulates endocrine cells to produce steroid/sex and peptide hormones, stimulates gametogenesis in females
93
what does FSH do in gonads?
stimulates gametogenesis
94
in what scenarios does estrogen exhibit positive vs negative feedback in HPG axis?
positive: high levels of estrogen
negative: low to moderate levels
95
what is the pattern of secretion of GnRH?
pulsatile (every 1-3hrs)
96
is the pulsatile secretion of GnRH in males and femlaes?
yes
97
what hypothalamic region generates pulses of GnRH?
GnRH pulse generator
98
why is GnRH secreted in pulses?
steady, high levels of GnRH down-regulates GnRH receptors on gonadotropin cells, ant pit cant respond to GnRH
99
t/f: children with a GnRH deficiency can still mature sexually
false, GnRH deficiencies cause lack of sexual development (treated w/ PULSATILE GnRH)
100
what occurs directly after pulsatile GnRH secretion?
FSH and LH are stimulated/secreted
101
what is a clinical application of GnRH?
treatment for prostate/breast cancer (stimulates FSH/LH at first, then ant pit desensitizes)
102
what is kisspeptin?
peptide hormone critical in generating pulsatile secretion of GnRH
103
t/f: kisspeptin is essential for upstream mechanisms initiating timing of puberty
true
104
how can kisspeptin affect GnRH neurons?
can exhibit positive and negative feedback onto GnRH neurons from estrogen and sex steroids resp.
105
t/f: FSH and LH have different structures in each sex
false, same structure in each sex
106
what are inhibins?
peptides from gonads that affect ant pit
107
what are 4 enviro factors that can affect reproduction? (females > males)
stress, nutrition, day-light cycle (travelling, shift work, melatonin), environmental estrogens (endocrine disruptors)
108
what are 6 ex of enviro estrogens (endocrine disruptors)?
phytoestrogens (plants: soy), synthetics (plastic, pesticide, chemicals, pharmaceuticals: hormonal replacement/contraception)
109
what are 4 effects of enviro estrogens (endocrine disruptors)?
bind estrogen receptors and have positive or negative effects, accumulate in adipose, compromise gamete quality, disrupt developing embryos
110
where is the prostate?
encircles urethra
111
what is the effect of cancerous enlargement of the prostate?
impedes urination
112
where is the urethra in the penile shaft?
ventral side, surrounded by corpus spongiosum
113
what comprises the penile erectile tissue? (3)
corpus spongiosum, corpora cavernosa (2)
114
what is the glans?
tip of penis covered in foreskin (unless circumsized)
115
where are the testes located?
suspended outside abdomen in scrotum (2 sacs)
116
when do the testes descend from the abdomen?
7th month of pregnancy (w/ testosterone)
117
what is cryptorchidism? effect?
1 or both testes fail to descend and remain in abdomen; decr spermatogenesis but normal testosterone production
118
what does the spermatic cord do?
binds testicular blood vessels and nerves
119
why is vascular counter current exchange in the penis essential?
facilitates heat exchange btwn warm arterial and cool venous blood which maintains normal temp for spermatogenesis
120
t/f: normal testosterone production and secretion can occur at core body temp
true (not spermatogenesis)
121
where is the site of spermatogenesis?
seminiferous tubules in testicles
122
what encases bundles of seminiferous tubules?
outer fibrous capsule
123
what does the interstitial tissue of the testes feature?
blood vessels and Leydig cells
124
what does the spermatic cord pass through to get to testes?
inguinal canal
125
what do the seminiferous tubules converge into? (4 -> urethra)
sem. tubules -> rete testis -> efferent ductules -> epididymis -> vas deferens -> urethra
126
what are 4 of the contents and functions of accessory gland secretions?
nutrients (for sperm), protective buffers (neutralize acidic urine in male urethra and vaginal secretions), seminal vesicle chemicals (prostaglandins: incr motility?), mucus (lubrication)
127
where is mucus secreted from in male repro tract?
bulbourethral glands (for later semen passage)
128
what is another purpose for male secretions (other than sperm viability)?
protect from pathogens (antibacterial)
129
what is seminal plasma?
nonsperm portion of semen (99%)
130
what metal is present in semen?
zinc (unsure function)
131
how is a constant supply of undifferentiated sperm maintained?
one clone produced by each spermatogonium germ cell drops out to re-enter mitotic pathway (staggered development)
132
what occurs in the final phase of spermatid differentiation into sperm/spermatozoa?
cell remodelling and elongation
133
approx. how long does spermatogenesis take?
2 months
134
what surrounds each seminiferous tubule?
basement memb
135
what 2 types of cells are in the seminiferous tubule wall?
developing sperm and Sertoli
136
what is at the center of each seminiferous tubule?
lumen w/ mature sperm
137
where are the Leydig cells?
around/btwn seminiferous tubules in connective tissue
138
t/f: sperm-producing and testosterone-producing functions of the testes are carried out by the same structure
false, Leydig cells produce testosterone and sem tubules produce sperm (Sertoli cells)
139
t/f: Sertoli cells don't require and can't receive testosterone from Leydig cells
false, testosterone can freely diffuse into Sertoli cells and they require it
140
what is the "Sertoli-cell" barrier?
ring of Sertoli cells from basement memb to lumen of each sem tubule (blood testes barrier)
141
what are the 2 compartments of the sem tubule? what separates them?
basal and central; Sertoli ring
142
when are the Leydig cells quiescent vs active?
active in fetus, quiet after birth, reactive at puberty
143
what can Leydig cells also do w/ testosterone?
convert to estradiol w/ aromatase
144
what is the hormonal control of spermatogenesis? (5)
hypo releases GnRH, ant pit releases FSH and LH, LH stimulates Leydig cells to release test, test stimulates body for 2ndary effects and diffuses across blood-testis barrier into Sertoli cells, FSH stimulates Sertoli cells to produce cell products
145
what are 3 products of Sertoli cell stimulation?
inhibin (neg feedback of FSH), nourish developing sperm, androgen binding protein (ABP) (luminal secretions)
146
what is androgen binding protein (ABP)? purpose?
protein that binds Leydig-derived testosterone to cross Sertoli cell barrier into sem tubule lumen (allows high conc)
147
where does mitosis of sperm cells occur in sem tubule?
basal compartment btwn Sertoli cells
148
what occurs to defective sperm in sem tubule?
Sertoli cells phagocytose them
149
t/f: Sertoli cells produce chemical messengers in response to local testosterone
true, Leydig cells stimulate spermatogenesis and inhibin release (in Sertoli cells) via paracrine signals
150
when do sperm cells unbind from apical membrane of Sertoli cells?
when transformation is complete
151
where does final maturation of sperm occur?
epididymis
152
what occurs to sperm during final maturation in epididymis?
lose cytoplasm and develop tail
153
what are the 3 portions of a sperm cell?
head, midpiece, tail
154
what is the head of a sperm cell?
almost all nucleus, covered by acrosome
155
what does the acrosome contain?
protein-filled vesicle w/ enzymes necessary for fertilization
156
what is the midpiece of a sperm cell?
formed by mitochondria (E to move)
157
what is the tail of a sperm cell?
mostly flagellum (propels sperm)
158
what stores sperm until ejaculation?
vas deferens and epididymis
159
what prevents engorgement of epididymis? benefit?
fluid can be absorbed from lumen; concentrates sperm
160
what propels sperm to urethra during ejaculation?
peristaltic movements of vas deferens and epididymis
161
what is a vasectomy?
removal of segments from each vas deferens so sperm cant travel from epididymis
162
t/f: vasectomies result in fluid build-up
false, sperm break down and are reabsorbed
163
t/f: testosterone and Leydig cells are unaffected in a vasectomy
true
164
t/f: sperm production halts w/ a vasectomy
false
165
what is the passive process of sperm movement?
Sertoli cells produce secretions and incr P in sem tubule and push sperm as far as the epididymis (sperm not motile)
166
what are 8 factors that negatively affect sperm?
heat/P on scrotum, caffeine/nicotine/alcohol/marijuana, enviro toxins, hair growth stimulants/OTC drugs, laptops/phones (heat), saliva (acidic), lube/douche, estrogens in plastic (BPA)
167
how do estrogens in plasticizers (BPA) negatively affect male repro?
incr negative feedback in HPG axis which decr testosterone production
168
what 3 ways are negative effects exhibited by sperm?
decr sperm count, abnormal morphology, abnormal motility
169
what is the general process of penile erection? (6)
3 cylindrical compartments flaccid, sexual excitation, dilation of small arteries, incr BF and engorgement of vascular compartments, passive compression of adjacent veins (no outflow, maintains engorgement), erection
170
which ANS system and NT(s) are responsible for flaccid vs erect penis?
flaccid: sympathetic, NA/E (contract/vasoconstriction)
erect: parasymp, ACh and NO (relax/vasodilation)
171
what 2 processes must occur for vasodilation/relaxation in erection?
inhibition of sympathetic input, activation of non-adrenergic, non-cholinergic (NO, para) autonomic neurons to arteries
172
what are some primary stimuli (and pathway) for erection? (5, 4)
mechanoreceptors in penis, higher brain centre input such as thoughts, emotions, sights, and odours -> incr afferent neuron firing -> (lower) spinal reflex -> changed efferent neural outflow
173
what is ejaculation?
spinal reflex that discharges semen w/ stimulation of penile mechanoreceptors
174
what is the 1st phase of ejaculation?
emission: sympathetic activity contracts epididymis, vas def, ejaculatory ducts, prostate and seminal vesicles, moving semen into urethra
175
what is the 2nd phase of ejaculation?
ejaculation: semen expelled from urethra by contractions of urethral smooth muscle and skeletal muscle at base of penis
176
what prevents retrograde ejaculation?
closure of sphincter at base of bladder during ejaculation phase
177
what is an orgasm? what follows it?
muscular contractions, pleasure and systemic physiological changes (incr HR, BP) that is followed by a latent/ref period (no erection possible)
178
what is erectile dysfunction (ED)?
consistent inability to achieve/maintain an erection sufficient for penetration (not called impotence anymore)
179
when is ED most common?
40-70 yrs old (>10%)
180
what are 5 other causes (not nerve/vasc. impairment) of ED?
endocrine disorders (decr test), drug use, alcohol, diseases, psych factors (stress/trauma)
181
what is the most common cause of ED?
damage/impairment of efferent nerves that control vasculature (needed for erection)
182
what are 3 drug treatments for ED?
NO supplementation, PDE5 inhbitors, Alprostadil
183
how does NO supplementation treat ED? (3)
NO incr GMP -> cGMP in smooth muscle cell, which decr Ca and causes smooth muscle relaxation/vasodilation
184
how do PDE5 inhibitors treat ED? (3)
PDE5 breaks down cGMP so inhibition incr cGMP in smooth muscle cell, which decr Ca and causes smooth muscle relaxation/vasodilation
185
how does Alprostadil treat ED? (3)
activates prostaglandin E (PGE1) receptors which incr ATP -> cAMP in smooth muscle cell, which decr Ca and causes smooth muscle relaxation/vasodilation
186
what occurs to testosterone in the prostate vs brain, liver, and adipose?
prostate: conversion to DHT by 5 a-reductase
| brain/liver/adipose: conversion to estradiol by aromatase
187
what does a deficiency in 5 a-reductase and aromatase suggest?
testosterone deficiency
188
t/f: androgens don't mediate libido
false, they do
189
what are functions of DHT (4) vs estradiol (2) vs testosterone (6) in males?
DHT: facial/body hair, acne, scalp hair loss, prostate growth
estradiol: bone formation, breast tissue
testosterone: muscle mass, skeletal growth, spermatogenesis, sexual function, libido, erection
190
what is a possible treatment for prostate cancer and male pattern baldness?
5 a-reductase inhibitors (decr DHT) but can neg affect fertility
191
what are 4 effects of decr testicular function/testosterone synthesis from castration or drugs?
decr size of accessory organs, decr secretion from glands (decr semen, sperm viability), decr smooth muscle activity of ducts (decr ejac.), decr sex drive/erection
192
what is a treatment for decr testicular function/testosterone synthesis?
testosterone treatment
193
when does puberty occur in males?
12-16 yrs old
194
how are first signs of male puberty detected?
secretion of adrenal androgens (not gonadal)
195
what stimulates first signs of male puberty?
ACTH from ant pit (stimulates adrenal glands)
196
what occurs during the first stages of male puberty?
development of pubic and auxiliary hair, beginning of growth spurt (mitigated by adrenal androgens)
197
after first stages (stimulated by adrenal androgens), what controls other events in male puberty?
HPG axis
198
what are 2 hypothesized initiators of male puberty?
decr sensitivity of brain to neg feedback of gonadal hormones (low secretion), incr spontaneous activity of kisspeptin neurons in hypo
199
what is the general process of male puberty? (5)
possible initatiors (kisspeptin neurons), incr activity (f and conc.) of GnRH, incr ant pit gonadotropins, stimulate sem tubules and testosterone secretion, 2ndary sex characteristics/accessory organs/sex drive)
200
what is growth of 2ndary male characteristics dependent on?
DHT and testosterone
201
what are 6 ex of male 2ndary sex characteristics?
growth of larynx, thick skin oil gland secretions, masculine fat distribution, androgen-stimulated bone growth, androgen-stimulated muscle growth, androgen-stimulated erythropoietin secretion from kidneys
202
what stimulates and terminates male bone growth in puberty?
androgens via GH secretion; testosterone stimulates closure of epiphyseal plates
203
what is the effect of androgen-stimulated erythropoietin secretion from kidneys in male puberty?
incr hematocrit in males (incr RBCs)
204
What are 2 positive and 3 negative effects of using synthetic androgens?
Pos: incr muscle mass and athletic performance
Neg: overstimulation of prostrate, aggression, decr GnRH, LH and FSH
205
Why is decr GnRH, LH, and FSH from using synthetic androgens problematic? (3)
Decr endogenous testosterone production and spermatogenesis in Sertoli cells, decr testicular size and sperm count, addictiveness (brain function?)
206
how do synthetic androgens decr endogenous testosterone production?
through neg feedback on GnRH and gonadotropins (can't cross blood-testis barrier)
207
What is a possible male birth control pill?
Low dose anabolic steroids (decr fertility but other neg side effects)
208
What is hypogonadism?
Decr testosterone release from testes
209
What’s the diff btwn primary and secondary hypogonadism?
Primary: caused by testicular failure
Secondary: caused by decr stimulation of testes by LH/FSH or GnRH (disorder w/ hypo/ant pit)
210
What is the effect of having hypogonadism before puberty?
Failure to develop secondary sex characteristics and normal sperm
211
What is an ex of a primary cause of hypogonadism?
Klinefelter’s syndrome (genetic: XXY)
212
What causes Klinefelter’s syndrome?
Failure of chr to separate during meiosis (in parents)
213
How does Klinefelter’s syndrome present itself? (4)
Before puberty: normal
After puberty: small, poorly developed testes (decr Leydig and Sertoli cell function), absence of 2ndary sex characteristics, incr breast size, high FSH/LH
214
What is the effect of having decr Leydig and Sertoli cell function in Klinefelter’s syndrome? (3)
Poor Leydig function: decr [testosterone] -> abnormal sem tubule development, decr sperm production
215
What is the cause of having high LH/FSH in Klinefelter’s syndrome?
Loss of inhibin and androgen neg feedback
216
What is a treatment for Klinefelter’s syndrome?
Androgen replacement therapy
217
What are 3 causes of secondary hypogonadism?
Hyperprolactinemia, hypopituitarism, GnRH deficiency
218
What is hyperprolactinemia and how does it cause secondary hypogonadism?
Secretion of prolactin from pituitary gland cells (lactotrophs, tumour?); inhibits LH and FSH secretion from ant pit (paracrine)
219
What is hypopituitarism and how does it cause secondary hypogonadism?
Loss of ant pit function (head trauma, infection/inflammation), decr secretion of LH and FSH
220
What are 3 possible treatments for hypopituitarism?
Testosterone replacement, cortisol, thyroid hormone
221
What are 3 effects of male castration in adulthood?
Same 2ndary sex characteristics, decr androgen sensitive tissues, decr size of accessory ducts and testes
222
What is andropause?
Steady decr in testosterone levels at ~40yrs (not as drastic as menopause)
223
What causes andropause? (2)
Deterioration of testicular function, failure of gonads to respond to ant pit gonadotropins (decr sensitivity to LH/FSH)
224
What are 3 effects of andropause?
Decr libido, decr sperm motility/viability, depression
225
T/f: males stop being fertile after andropause
False, sperm production does not decr immediately w/ testosterone decr (remain fertile for years afterwards but then decr)
226
What are fallopian tubes aka?
Oviducts
227
What is at the end of each oviduct (not uterus)?
Fimbrea (brush over ovaries)
228
What are the components of the female internal genitalia?
2 ovaries, 2 oviducts, 1 uterus, cervix, and upper portion of vagina
229
What is the female external genitalia collectively referred to as?
Vulva
230
What are the components of the female external genitalia?
Mons pubis (fatty tissue at top), labia majora, labia minora, clitoris, vaginal vestibule (opening), vestibular glands
231
What are the female analogues to the male penis and scrotum?
Penis-clitoris
| Scrotum-labia majora
232
What is the hymen?
Thin fold of mucous memb that partly overlies vaginal vestibule (considered ext genitalia)
233
What are 4 main functions of the ovaries?
Fetal oogenesis, oocyte maturation (birth), ovulation (puberty), sex hormone secretion (endocrine function)
234
What 3 sex hormones are secreted from the ovaries?
Estrogen, progesterone, inhibin
235
What is considered endocrine tissue in the ovaries?
Corpus luteum (differentiated eggless follicle)
236
Where do ova/eggs exist in the ovaries?
In follicles
237
What are the 5 stages of ova development?
Primordial follicle, primary follicle, preantral follicle, early antral follicle, mature/Graafian follicle
238
When can primordial follicles progress into preantral and early antral stages?
Throughout infancy, childhood, and menstration (not just after puberty)
239
What is the structure of the primordial follicle?
Primary oocyte surrounded by granulosa cells
240
What do granulosa cells secrete?
Estrogen, progesterone and inhibin
241
What is the structure of the primary follicle?
Fully grown oocyte separated from granulosa cells by zona pellucida
242
What does the zona pellucida contain? why?
Glycoproteins; help w/ fertilization by binding sperm to egg surface (after ovulation)
243
What is the structure of the preantral follicle?
Oocyte surrounded by multiple layers of granulosa cells, has early theca cells
244
What is the antrum? When and how is it generated?
Fluid-filled space; in early antral follicle by granulosa cells
245
What is the theca?
Differentiated connective tissue (ovarian stroma) around granulosa cells that synthesizes estrogen
246
How do theca cells work w/ granulosa cells to produce estrogen?
Theca cells secrete androgens in response to LH, which diffuse into granulosa cells which respond to FSH and convert them to estrogen (via aromatase)
247
How do inner granulosa cells associate w/ and support oocyte?
Form gap junctions via cytoplasmic process and can exchange nutrients and chemical messengers
248
What is the structure of the Graafian follicle? (3 major contents)
Mature follicle w/ cumulus oophorus, many layers of theca cells, and large antrum (allows major enlargement)
249
What is the cumulus oophorus?
Extension of granulosa cells that surround oocyte (to separate from rest of follicle) “egg on a cloud”
250
What occurs to 99.99% of ovarian follicles present at birth?
Atresia (breakdown)
251
What occurs to follicles at beginning of menstrual cycle?
cohort of ~10-25 preantral and early antral follicles develop into larger antral follicles
252
What occurs to follicles in the 1st week of menstrual cycle?
Largest antral follicle from cohort is selected to develop further and non-dominant follicles undergo atresia
253
How is the dominant follicle selected?
By local estrogen secretion (has most granulosa cells to respond to FSH and secrete estrogen)
254
What occurs to the Graafian follicle at ovulation? (5)
Emerges from meiotic arrest to undergo 1st meiotic division to 2ndary oocyte, cumulus separates from follicular wall (floats in antral fluid), follicle physically distends from surface of ovary, thin wall btwn follicle and ovary rupture (enzymatic digestion), P from antral fluid pushes 2nday oocyte (surrounded by zona pellucida, gran cells, cumulus) onto ovarian surface
255
T/f: if more than one folllicle reaches maturity, multiple eggs can be ovulated
True, multiple births -> fraternal twins (different sperm)
256
how is the corpus luteum formed?
after mature follicle discharges egg+antral fluid, remaining granulosa cells enlarge (change pheno)
257
what does corpus luteum secrete (endocrine)?
estrogen, progesterone and inhibin
258
what occurs to the corpus luteum if fertilization does not occur? (2)
degenerates by apoptosis to form corpus albicans, loses endocrine function which initiates menstruation (max development ~10 days)
259
what are 2 phases of menstrual cycle (ovarian)? separated by?
follicular and luteal; ovulation
260
what occurs during the follicular vs luteal phases (ovarian)?
follicular: mature follicle and 2ndary oocyte develop
luteal: formation of corpus luteum (until degen wo/ fertilization)
261
how do hormone patterns during menstrual cycle regulate ovarian/HPG events? (1st week: 2, 2nd week: 5, before ov: 3, ov: 1, luteal: 4)
1st week: low estrogen (loss of corpus luteum) causes incr LH and FSH (decr -FB), low prog
2nd week: multiple follicles develop, incr estrogen, FSH decr (est -FB), non-dom follicles degenerate, low prog
before ovulation: incr est now has +FB, estrogen decr, slight prog incr
during ovulation: LH surge (est +FB)
luteal: corpus luteum incr estrogen and prog, decr LH/FSH (-FB), est/prog decr rapidly wo/ fertilization, LH/FSH incr
262
t/f: LH and prog levels are somewhat stable during the follicular phase
true
263
What hormone receptors do granulosa vs theca have at first vs later in menstraul cycle?
Gran: at first: only FSH, later: FSH and LH
Theca: only LH (never FSH)
264
What stimulates multiplication, estrogen production and secretions for antrum in granulosa cells?
FSH (estrogen can exhibit further +FB)
265
What male cells are the female counterparts for theca and granulosa cells?
Granulosa: Sertoli (germ cell enviro, stim by FSH/sex H)
Theca: Leydig (produce androgens, stim by LH)
266
How does the dom foll have incr sensitivity to FSH when it decr in 2nd week of menstrual cycle?
Has incr FSH receptors
267
T/f: FSH and LH stimulation of the dom foll is enough to produce estrogen to support incr plasma conc in 2nd week of menstrual cycle
True
268
What does estrogen have -FB on?
Ant pit: decr FSH and LH (in response to GnRH)
| Hypo: decr amplitude of GnRH pulses and total secreted
269
What decr more from estrogen -FB? Why?
FSH > LH; inhibin (from granulosa cells) primarily inhibits FSH
270
how long does estrogen peak last in the late follicular phase?
1-2 days
271
how could GnRH incr during the estrogen peak? (2)
+FB on hypothalamus directly (incr GnRH) or activate kisspeptin neurons (upstream of GnRH)
272
t/f: estrogen +FB is necessary for normal menstrual cycles and ovulation
true
273
what accounts for the decr in estrogen and slight incr in progesterone right before ovulation?
granulosa cells decr estrogen and begin to release progesterone
274
what are 7 functions of granulosa cells?
nourish oocyte, secrete chem messengers to oocyte and theca cells, secrete antral fluid, follicle development via estrogen and FSH in early/middle follicular phase, convert androgens to estrogen via aromatase, secrete inhibin to inhibit FSH, react to LH for ovulation and conversion to corpus luteum
275
what stimulates conversion of theca and granulosa cells into corpus luteum?
drop in LH (after surge)
276
how long does the corpus luteum function for?
10-14 days
277
what does the corpus luteum secrete?
estrogen, progesterone, inhibin
278
what does progesterone from corpus luteum do? (2)
inhibits gonadotropins (through ant and hypo), and prevents LH surge in luteal phase
279
t/f: plasma gonadotropin levels are high in the luteal phase
false they are low (don't want to waste energy stimulating follicle when ovulation has already occurred)
280
what is day 1 of the menstrual cycle?
first day of menstrual flow
281
what occurs during the menstrual phase (uterine)? (2)
bleeding, degeneration of endometrium
282
what occurs during the proliferative phase (uterine)?
growth of endometrium and myometrium w/ incr estrogen (from developing follicle - overlap w/ follicular phase)
283
when is the proliferative phase?
between cessation of menstruation and ovulation (~10 days)
284
what occurs during the secretory phase (uterine)? (6)
endometrium converts to secretory tissue (changes pheno) in response to progesterone from corpus luteum, glands become coiled, highly vascularized, accumulate enzymes, and secretes glycogen (in glandular epithelium), then secretes glycoproteins and mucopolysaccharides (primes endometrium for possible implantation)
285
when is the secretory phase?
after ovulation until next period
286
What ovarian phases correspond to what uterine phases?
Follicular: menstrual and proliferation
Luteal: secretory
287
What induces expression of progesterone receptors on endometrial cells in proliferative phase?
Incr estrogen levels
288
Why is it important for endometrium to begin expressing progesterone receptors in the proliferative phase?
So it can respond to progesterone in secretory phase and become secretory tissue
289
What are 2 functions of progesterone?
Inhibits myometrial contractions and opposes stimulatory actions and estrogen + prostaglandins
290
Why is progesterone needed to inhibit myometrial contractions and oppose estrogen/prostaglandins?
Ensures safe implantation and maintains uterine ‘quiescence’ (prevents premature birth)
291
What could be a reason for recurrent miscarriages?
Low progesterone
292
What modulates production and consistency of cervical mucous?
Sex hormones
293
How, when and why does estrogen affect cervical mucous?
Makes it abundant, watery, and clear during ovulation to facilitate sperm movement
294
How, when, and why does progesterone affect cervical mucous?
Makes it thick and sticky after ovulation to form a plug that protects uterus and embryo from bacteria (and further sperm if fertilization already occurred)
295
What is involution of the corpus luteum?
Degeneration of corpus luteum if fertilization does not occur
296
What are 3 effects of corpus luteum involution?
Decr estrogen and progesterone, loss of hormonal support for endometrium, menstruation (day 28 to 1)
297
What are 4 events in menstruation?
Construction of uterine blood vessels, disintegration of uterine lining, rhythmic contractions of uterine muscle, dilation of endometrial arterioles
298
What causes uterine blood vessels to constrict during menstruation?
Prostaglandins produced by endometrium in response to decr estrogen and progesterone (inhibit prostaglandins)
299
What is the purpose of constricting uterine blood vessels during menstruation?
Deprives endometrial cells of O2 and nutrients
300
What causes rhythmic contractions of uterine smooth muscle?
Overproduction of prostaglandins
301
What causes dysmenorrhea and systemic symptoms (GI issues) during menstruation?
Overproduction of prostaglandins (constrict blood vessels and contractions)
302
What is disintegrated during menstruation?
All but a thin, base layer to regenerate endometrium for next cycle
303
What cause dilation of endometrial arterioles during menstruation?
Previous hypoxia (from constriction) causes incr CO2 and dilation
304
What causes hemorrhage through endometrial capillary walls? Effect?
Dilation of endometrial arterioles; expulsion of blood and endometrial tissue through vagina
305
how do hormone patterns during menstrual cycle regulate uterine/HPG events? (1st week: 3, 2nd week: 3, 3rd week: 3, 4th week: 3)
1st week: decr est and prog (corpus luteum degenerates), uterine lining sloughs, incr LH and FSH
2nd week: est incr (dom foll), endometrium develops, cervical mucous clear and watery
3rd week: corpus luteum secretes est and prog, endometrium becomes secretory, cervical mucous thick and sticky
4th week: corpus luteum involution, est and prog decr, endometrium sheds
306
How does estrogen exhibit “pro-progesterone” effects? (Estrogen priming)
Incr synthesis of progesterone receptors in tissues (including endometrium) and thus responsiveness to progesterone
307
What does a peak in progesterone suggest?
Ovulation occurred (incr basal body temp, inhibits vaginal cell proliferation)
308
How does progesterone exhibit “anti-estrogen” effects?
Decr estrogen receptors (for uterine “quiescence”)
309
what is the only direct measure of ovulation?
Clinical pregnancy confirmation (incr basal body temp is indirect/neural)
310
What is a difference btwn female and male puberty?
Female initiates earlier (10-12 y/o)
311
What is leptin? and how does it play a role in female puberty?
an adipokine (hormone from fat); stimulates GnRH production
312
how do low GnRH, gonadotropins, and estrogen (strong -FB) affect female characteristics before puberty? (4)
no follicle maturation beyond early antral stage, no menstrual cycle, accessory organs remain small and non-functional, minimal secondary sex characteristics
313
what is amenorrhea?
failure to have menstrual flow/menses
314
what is primary vs secondary amenorrhea?
1': failure to initiate menarche
| 2': loss of previously normal menstrual cycles
315
what are some causes for primary vs secondary amenorrhea?
1': anorexia nervosa (body fat/leptin?)
| 2': pregnancy, menopause, anorexia nervosa
316
how does female athleticism affect their sex characteristics? 4 effects?
exercise considered a stressor that inhibits the HPG axis; pre-pubertal appearance, minimal body fat (decr leptin?), hypogonadism, possibly amenorrhea (if consistent)
317
what is the optimal time frame for fertilization?
5 days before and 1 day after ovulation
318
why is the optimal time for fertilization 5 days before and 1 day after ovulation?
sperm are viable for 4-6 days after ejaculation (can stay in female repro tract) and ovum is only viable 24-48 hours after ovulation (key limiting factor)
319
what is capacitation?
removal of cholesterol, carbs, and proteins from sperm head after several hours in female repro tract (its secretions) that is necessary for sperm's ability to fertilize
320
how does capacitation affect sperm? why? (2)
changes wave-like to whip-like tail movements (incr propulsion) and alters pmemb (incr fusion w/ egg pmemb)
321
where and when does fertilization occur?
in fallopian tube; 24-48 hours after ovulation
322
what do the many sperm cells move between to try and fertilize egg?
corona radiata (layers of granulosa cells around egg)
323
what do sperm bind to on egg?
zona pellucida
324
what does zona pellucida contain that binds to sperm?
glycoproteins that act as sperm receptors (proteins exposed w/ capacitation)
325
what does sperm binding to zona pellucida trigger?
acrosome reaction
326
where does the acrosome reaction occur?
in bound sperm
327
what is the acrosome reaction?
alteration of sperm pmemb which exposes acrosomal enzymes to zona pellucida, enzymes digests zona and allows sperm to advance w/ tail movements
328
what is the "race against time"?
many sperm compete to reach egg and fuse both pmembs
329
what part of the sperm enters egg cytosol?
head (midpiece and tail can enter but are destroyed)
330
what is the "block to polyspermy"?
prevention of multiple sperm fertilizing an egg to preserve zygote viability (can occur - abnormal)
331
how is "block to polyspermy" ensured?
w/ the cortical reaction (changes membrane potential when egg and sperm pmembs fuse)
332
what is the cortical reaction?
fusion of 1st sperm w/ egg releases cortical granules (cytosolic secretory vesicles) into space btwn egg pmemb and zona pellucida, enzymes in granules enter and harden zona pellucida which inactivates further sperm binding (are released/rejected)
333
t/f: many sperm can undergo acrosome reaction
true, fusion of one w/ egg pmemb causes fertilization
334
what are the steps to embryogenesis after fertilization? (6)
egg completes second meiotic division hours after fertilization, 2nd polar body extruded and disintegrates, DNA of pronuclei (23 chr of egg and sperm) replicated, pronuclear pmembs degenerate, pronuclei fuse, cell prepared for mitosis (completes fertilization and zygote formation)
335
what occurs to the ovulated egg if fertilization did not occur?
egg degenerates and is phagocytosed by cells lining the uterus, lost w/ menses (doesn't complete 2nd meiotic division)
336
how long is the conceptus housed in the fallopian tubes? Why
3-4 days; contains nutrients important for conceptus viability
337
what ensures the conceptus stays in the fallopian tube for a few days after fertilization?
estrogen causes contraction of smooth muscle at junction btwn fallopian tube and uterus
338
what allows conceptus to move to uterus?
incr plasma progesterone levels relax smooth muscle btwn fallopian tube and uterus (opposes estrogen)
339
t/f: cell undergoes multiple meiotic division in fallopian tube wo/ any change in overall size
true, 16-32 cell conceptus reaches uterus approx. same size as fertilized egg
340
how long does conceptus float freely in intrauterine fluid? Why?
~3 days; fluid has nutrients
341
t/f: conceptus undergoes cell division up to 100 cells in uterine fluid and enters blastocyst stage
true
342
what is a feature of the blastocyst stage?
cells of conceptus are no longer totipotent (undergo differentiation)
343
what are 3 parts of the blastocyst?
trophoblast (outer cell layer), inner cell mass (gives rise to human), central fluid-filled cavity
344
t/f: trophoblast surrounds the embryo and fetus throughout development
true
345
what does the trophoblast do? (2)
contributes nutrition and hormone secretion
346
when is the blastocyst stage w/ in the menstrual cycle?
day 14-21 (luteal/secretory)
347
when does the blastocyst implant into the endometrium?
day 21 (7 days after ovulation)
348
what is the orientation of the blastocyst when it embeds in the endometrium?
has cell mass towards endometrium
349
what allows the blastocyst to implant?
stickiness of trophoblast cells
350
what provides metabolic fuel and raw materials to embryo for first few weeks after implantation?
endometrial cells
351
what is placentation?
formation of placenta by interlocking fetal and maternal tissues
352
what is the purpose of the placenta? (3)
takes over embryonic and eventual fetal nutrition (after endometrium), oxygenation, and waste removal (site of exchange)
353
what are the 3 portions of the placenta?
embryonic (chorion), chorionic villi, maternal (endometrium)
354
What is the chorion?
Outer layer of trophoblast cells (embryo)
355
What are the chorionic villi?
Rich capillary network that is part part of embryonic circulation and projects into endometrium
356
t/f: there is mixing of maternal and fetal blood in chorionic villi
False
357
What do chorionic villi secrete? Why?
Enzymes and paracrine factors that alter endometrium; creates pockets in endometrium for blood exchange
358
What are pockets in endometrium filled w/ maternal arteriole blood that surround each chorionic villi called?
Sinus
359
What forms the amnion/amniotic sac?
inner cell mass
360
What is the amnion/amniotic sac?
epithelial lining
361
Where is the amniotic cavity?
Between inner cells mass and chorion
362
What does the amnion fuse with?
Inner surface of chorion
363
What is the fetal ECF? (when amnion fuses w/ chorion)
Amniotic fluid
364
What are 3 purposes of amniotic fluid?
Buffers mechanical disruption, temperature fluctuations, prevents dehydration
365
What state is the fetus in for last 8 months of pregnancy?
Free-floating in amniotic fluid, attached to placenta by umbilical cord
366
What are the hormonal changes throughout pregnancy?
Estrogen and progesterone continue to increase throughout pregnancy
367
What are the functions of estrogen and progesterone during pregnancy? (2, 2)
Est: stimulates growth of uterine muscle, supplies contractile force for parturition
Prog: inhibits uterine contractility (opposes estrogen) and prevents premature delivery
368
What produces most of the estrogen and progesterone during first 2 months of pregnancy?
Corpus luteum
369
What maintains the corpus luteum during pregnancy?
Human chorionic gonadotropin (hCG)
370
What secretes hCG at endometrial invasion stage?
Trophoblast cells
371
T/f: hCG produced by trophoblast cells is enough to be detected in moms plasma/urine by a pregnancy test
True
372
How can a pregnancy test give a false positive?
If test was taken too early (hCG not high enough)
373
T/f: placenta has enzymes needed for progesterone synthesis during 2nd and 3rd trimester
true
374
How does placenta produce estrogen during 2nd and 3rd trimesters? (3)
Since it doesn't have enzymes to synthesize androgens, gets androgens from ovaries/adrenal glands/fetal adrenal glands, then can convert to estrogen w/ aromatase
375
What is parturition?
Childbirth
376
How long is a full term human pregnancy?
40 weeks
377
When is a pregnancy term started from?
First day of last menstrual cycle (2 weeks before conception)
378
How many weeks from ovulation and conception does a full term childbirth occur?
38 weeks
379
When does parturition occur? What does it culminate in?
Final weeks of pregnancy; delivery of baby and placenta
380
What maintains integrity of cervix (firmness) and loose connections of myometrial smooth muscle cells (SMCs) during pregnancy?
Progesterone
381
What does incr in estrogen (>> prog) do late in pregnancy? (3)
Softens cervix, connect SMCs (via connexins), expresses oxytocin receptors on myometrium
382
What is the purpose of SMCs connexins towards end of pregnancy? (Via est)
Permits coordinated contractions of smooth muscle
383
What does cervix softening, SMC connexins, and myometrial oxytocin Rs via est late pregnancy ensure?
Strong, rhythmic contractions of myometrium
384
When do mini contractions begin? Aka?
Week 30; Braxton Hick’s
385
T/f: Braxton Hick’s contractions move the fetus though female repro tract
False
386
What occurs to the fetus in the final month of pregnancy?
Move downwards in contact w/ cervix (and other uterine contents)
387
What are 7 steps of labour and delivery?
Amniotic sac ruptures (enzymatic breakdown), amniotic fluid flows out of vagina, powerful uterine contractions (10-15 min intervals then shorten), cervix dilated and forced open (max. 10cm), contractions move fetus through cervix and vagina (bearing down incr P), delivery and constriction of umbilical and placental vessels, placental delivery
388
T/f: medical intervention is usually needed during labour and delivery
False, usually it isn’t unless forceps or C-section is required
389
What position are 90% of births in?
Baby is head-first
390
What are 4 controllers of parturition?
Properties of myometrium, uterine prostaglandin secretion, oxytocin, progesterone (during pregnancy)
391
How do properties of myometrium control parturition?
SMCs have auto rhythmic response to fetal stretch (reflex contraction)
392
How does uterine prostaglandin secretion control parturition?
Stimulates smooth muscle contraction
393
How does oxytocin stimulate parturition?
Stimulates uterine muscle to incr contractility and prostaglandin synthesis (incr oxytocin Rs from previous est incr)
394
Where and how is oxytocin released?
Reflex secretion from posterior pituitary in response to cervical stretch
395
How does progesterone control parturition?
DURING PREGNANCY, prog decr uterine contractions by decr myometrial sensitivity to estrogen, oxytocin and prostaglandins
396
T/f: progesterone withdrawal does not occur in humans
True
397
What is the positive feedback mechanism in parturition? (5) how does it stop?
As baby drops lower in uterus to initiate labour, incr cervical stretch (hypo input) stimulates oxytocin release, incr uterine contractions, pushes baby against cervix which incr cervical stretch; delivery stops cervical stretch input to hypo
398
What is lactogenesis?
Lactation, production, and secretion of milk by mammary glands
399
What occurs to mammary glands during pregnancy?
Incr in size and number
400
What is the site of milk secretion?
Alveoli (converge into nipples)
401
What are 2 cells and diff functions in breast alveoli?
Epithelial cells: responsible for milk secretion (line inner surface of alveoli)
Myoepithelial: contractile cells that deliver milk (around alveoli)
402
What hormone stimulates milk production?
Prolactin
403
Why is there no milk secretion during pregnancy if there is high prolactin, large and developed breasts?
Very high levels of estrogen and progesterone inhibit action of prolactin at mammary glands
404
What releases milk production from estrogen and progesterone inhibition during pregnancy?
Delivery of placenta removes source of estrogen and progesterone so prolactin can now act on mammary glands to stimulate milk production
405
How is milk production maintained (PRL and OXY) during breastfeeding? (5)
Suckling stimulates nipple mechanoreceptors, input to hypo for incr PRF/H and oxytocin (post pit) release, PRF/H stimulates prolactin release from ant pit, prolactin stimulates mammary epithelial cells to incr milk synthesis, oxytocin stimulates contraction of myoepithelial cells around alveoli to eject milk
406
What is the “milk ejection reflex”/“milk letdown”?
Contraction of myoepithelial cells w/ OXY stimulation to eject milk from alveolar lumen into ducts (secreted into lumen w/ PRL)
407
How do higher brain centres exhibit effects on milk ejection reflex?
Nursing mother can eject milk by hearing baby’s cry or thinking about nursing (reflex OXY secretion from post pit)
408
What is colostrum?
Watery, protein-rich fluid that is the first substance secreted from breasts after delivery
409
What is in colostrum? Purpose?
Antibodies and leukocytes that mediate newborns immune system (required for LT activation)
410
What are 9 components of breast milk?
Water, proteins, lipids, lactose (carb), minerals, vitamins, Abs/WBCs, hormones (growth factors), NTs (opioids)
411
What is the purpose of growth factors/hormones in breast milk?
Aid tissue development and maturation in newborn
412
What is the purpose of neuropeptides/endogenous opioids in breast milk?
Shapes infants brain and behaviour
413
What ensures newborn does not denatures proteins consumed in breast milk?
Low gastric acidity (higher pH)
414
What ensures newborn absorbs proteins in breast milk?
Intestinal epithelium more permeable to proteins (vs adult)
415
T/f: all components of breast milk are from mom’s circulation
False, some synthesized by breast tissue and transported from maternal blood to milk
416
What else can be passed through breast milk? (3)
Infectious agents (HIV), drugs and alcohol
417
What is contraception?
Birth control methods that work before implantation (preventative)
418
T/f: abortion is considered contraception
False, is not considered preventative (reactive)
419
Where do oral contraceptives, IUDs vs barrier devices (condom) target?
Oral: ovaries
IUD: uterus
Condom: cervix
420
What are 8 ex of contraceptives?
Vasectomy, condom, tubal ligation, vaginal diaphragm, vaginal cap, spermicides, IUD, birth control pills
421
What is abortion?
Death of embryo or fetus after implantation
422
What are abortifacients?
Drugs that induce abortion (not contraceptives)
423
What do oral contraceptives do and their effects? (3)
Contain estrogen and progesterone that inhibit pituitary gonadotropins (prevent ovulation), thicken cervical mucous (decr sperm movements), inhibits proliferation of endometrium by estrogen (decr receptivity)
424
What are 2 types of oral contraceptives?
Estrogen and progesterone (combination); progesterone only (mini-pill)
425
What is a reason to take the mini-pill?
Lack of estrogen allows a nursing mother to lactate (estrogen inhibits PRL release)
426
What do oral contraceptives mimic?
Luteal phase of menstrual cycle (keep est and prog steady, decr gonadotropins/LH surge)
427
T/f: estrogen in oral contraceptives is high enough to exhibit +FB effects
False
428
When is post-coital/emergency contraception taken?
Within 72 hours of intercourse
429
What do emergency contraceptives interfere with? (3)
Ovulation, transport of conceptus to uterus (inhibit cilia in Fallopian tube), implantation (decr endometrial receptivity)
430
What are 2 approaches to emergency contraceptives? Diff?
High dose est and prog: -FB inhibits ovulation
| Mifepristone (RU486): progesterone antagonist (in uterus)
431
How does Mifepristone (RU486) work? (2)
Binds to progesterone receptors in uterus (antagonist) causing: endometrium erosion and incr contractions of Fallopian tube and myometrium (incr prostaglandins) -abortifacient/contraceptive
432
When is onset of menopause?
50-52 years old
433
What is the initial stage of menopause called?
Perimenopause
434
How is menopause onset detected?
With irregular menstrual cycles
435
T/f: menopause is more abrupt than andropause
True, est decline >> test decline
436
When is menopause “declared”?
W/ cessation of menstrual cycles for 12 months
437
Why are there psychological changes in menopause?
Accepting reproductive life has ended
438
What is the cause of menopause? 3 effects?
Ovarian failure; decr responsiveness to gonadotropins, follicles lost to atresia, decr estrogen and inhibin decr -FB on HPG so incr GnRH and gonadotropins (no foll to respond to)
439
T/f: the adrenal gland can still produce androgens after menopause
True
440
Are adrenal androgens (converted to estrogen in tissues w/ aromatase) adequate to maintain estrogen-dependent tissues?
No, estrone (form prominent in post-menopausal women) is not sufficient to support estrogen-dependent tissues
441
What are 5 physiological effects of decr estrogen activity in post-menopausal women?
Atrophy of breast and reproductive organs, osteoporosis, hot flashes (perimenopause), incr risk of CV disease, thinning and drying of vagina
442
What is a possible treatment for menopause? Pro and con?
Hormone replacement therapy; pro: can manage symptoms during perimenopausal period, con: incr risk for CV disease
