Set 11 (Part I) Flashcards
1
Q
Why should we care about reproduction?
A
- Having a family
- Preventing pregnancy
- Preserving fertility
- Preventing birth defects and disease
2
Q
How has the number of chemicals registered for commercial use changed since 1979?
A
30% increase
3
Q
How are we exposed to chemicals?
A
Through industrial releases, contaminated food, household products and cosmetics, and the workplace
4
Q
What does the increase in exposure to chemicals coincide with?
A
- Increased rates of infertility
- Decreasing sperm counts
- Higher rates of birth defects
5
Q
What is early puberty in women correlated with?
A
The increased risk for hormone-driven cancers
6
Q
What are phthalates and BPA found?
A
Toys, food containers, cosmetics, and many other consumer products
7
Q
Where are PBDEs found?
A
- Flame retardants
- Household furniture
- Electronics
8
Q
What abnormalities concerning male reproduction has increased in the past century?
A
- Fewer baby boys are born
- Increased number of penis abnormalities
- Increased number of mental disorders
- Average sperm count of men is half of what it was
- 85% of sperm is DNA damaged
- Damaged sperm is associated with testicular cancer
9
Q
What are organochlorines?
A
- Industrial compounds (PCBs)
- Combustion products
- Pesticides (DDT)
10
Q
The use of organochlorines has been restricted since the 1970s, but their use persists. Can you provide examples?
A
- Continued use of DDT to combat malaria in certain countries
- They are still used in Mexico and South Africa
11
Q
What causes organochlorine accumulation?
A
They are liposoluble, and thus capable of bioaccumulating and biomagnifying
12
Q
How do organochlorines exert their effects?
A
- Endocrine disruptors
- They are estrogen receptor agonists, enhancing the effects of estrogen
13
Q
What are the three consequences of organochlorines as endocrine disruptors?
A
1) Antiandrogenic activities
2) Bind the aryl hydrocarbon receptor, modulating estrogen-dependent transcription
3) Bind thyroid hormone binding protein, reducing the effects of thyroid hormone
14
Q
Which ecosystems contain unusually high levels of environmental contaminants?
A
- Northern ecosystems
- Organochlorines, such as PCBs and pesticides
- They bioaccumulate in the Arctic food chain
15
Q
What is a complex disease?
A
Disease that cannot be attributed to genetics alone, and must be environmentally-caused as well
16
Q
How does the consumption of PCBs in Inuit populations compare to Canadian populations? What is observed to be elevated in the blood and breast milk of Inuit mothers?
A
- Inuit consume 40X more PCBs than Canadians
- Elevated organochlorines are found in the blood and breast milk of Inuit mothers
- High rates of diabetes, stillbirths, birth defects, and other complex diseases
17
Q
When is the body particularly sensitive to endocrine disruption?
A
During early development
18
Q
What are the effects of maternal consumption of PCB-contaminated fish during pregnancy?
A
- Retarded gestational development
- Low birth weights
- Small head circumference
- Neurodevelopmental delays
- Weaker immune response
19
Q
To measure the effects of organochlorine in rats, how was the exposure administered? Why?
A
- Through the mouth by food
- To mimic exposure of women in Northern communities
20
Q
Describe the study design to determine the effects organochlorines in the reproductive functions of male rats.
A
1) Female rats were exposed to varying levels of organochlorines
2) Breeding with male rats that had never been exposed
3) Breeding between the rats
4) Three weeks of lactation without additional OC treatment
5) A) Some pups were sacrificed
5) B) Remaining pups were fed commercial rat chow, and aged to either 60 or 90 days
21
Q
What were the effects of higher doses of organochlorides (PCBs) in rats?
A
- Fewer pups per litter
- Fewer number of implantation sites
- Increased post-implantation mortality
- Fewer male pups
- Fewer percentage of male offspring
22
Q
What were the effects of organochlorides on reproductive organ development of male rats?
A
Affected the testes, epididymis, ventral prostate, and seminal vesicles
23
Q
How did maternal exposure to organochlorides affect sperm from adult male offspring?
A
Decreased motility and less progressive
24
Q
How does the health of the father affect the placenta?
A
The development and function of the placenta is governed by PATERNAL genes
25
What abnormalities in foetuses were produced from organochloride-exposed rat parents?
- Heart on the right side
| - Unilateral cryptorchidism (single testes descending)
26
What are the two main parts of the uterus? What shape is it?
- Pear-shaped
| - Cervix and the body
27
What does the uterus body cavity's apex constitute? What does that open into?
- Internal os
| - Opens into the cervical canal
28
What is the cervical canal form at the lower end? What is that open to?
- Lower os
| - Opens into the vagina
29
What is an ectopic pregnancy? Where does it normally occur?
- Development of the fetus in a location other than the uterus
- Occurs in the fallopian tubes 95% of the time
30
What do ovarian follicles contain?
The developing oocyte
31
What is oogenesis?
Process that results in the formation of a mature egg
32
What endocrine organs secrete the female sex hormones? What are they?
- The ovaries
| - Estrogens and progesterone
33
Where do oocytes grow? What is that structure surrounded by?
- Grow in a follicle
| - The follicle is surrounded by granulosa cells
34
What allows the granulosa cells to divide and proliferate?
Rising levels of estrogen
35
Describe the names of the follicles during maturation.
- Primary follicle
- Secondary follicle (multiple layers of granulosa cells and a fluid-filled center with growth hormones)
- Graafian follicle (mature) (fluid-filled center called the antrum)
36
What is the most important factor to occur to allow for ovulation to happen?
The rise of estrogen
37
What are the three divisions of the uterine tubes?
- Isthmus
- Ampulla
- Infundibulum
38
Where does fertilization normally occur?
IA (ampulla/isthmus) junction
39
What kind of epithelial cells are contained within the uterus?
Ciliated columnar epithelium
40
What is pelvic inflammatory disease? How may it be treated?
- Swelling of the oviduct due to a pelvic infection
| - May be treated with antibiotics
41
What happens if a pelvic inflammatory disease persists?
- Block the passage of the oviducts
- Scar tissue
- Pus outside of the tube can spread the infection to other organs
- Results in an ectopic pregnancy 25% of the time
42
What are the three phases of the ovarian cycle? How long does each last?
1) Follicular phase (1-14)
2) Ovulation
3) Luteal phase (14-28)
43
What are the three phases of the uterine cycle? How long does each last?
1) Menses (1-7)
2) Proliferative phase (7-14)
3) Secretory phase (14-28)
44
What occurs during menstruation? How long do menses typically last?
- Spongy uterine wall breaks down
- Degeneration of tissue, blood, and unfertilized egg are passed out as menstrual flow
- 4 to 7 days
45
What occurs during the follicular phase of the ovarian cycle?
1) FSH (anterior pituitary) begins to rise at the end of the luteal phase, and induce the proliferation of granulosa cells
2) Granulosa cells are stimulated to increase production of estrogen
3) Estrogen promotes the thickening (proliferation) of the uterine lining
4) The peak estrogen positively feeds back to the hypothalamus, causing the release of GnRH, and subsequently LH and FSH
5) The high peak of LH and FSH finishes off the maturation of the oocyte, causing ovulation
46
How should the rise in FSH in the follicular phase appear on the graph?
Should appear in waves
47
Why does estrogen promote the thickening of the uterine lining?
To support an embryo if fertilization occurs
48
What occurs during the luteal phase of the ovarian cycle, assuming there is no fertilization?
1) Under the influence of LH, the remaining granulosa cells in the ovary luteinize
2) Become progesterone-secreting luteal cells, forming the corpus luteum
3) Progesterone levels rise and negatively feedback to the hypothalamus, decreasing production of GnRH, and subsequent release of LH and FSH
4) If there is no fertilization, the corpus luteum regresses, decreasing progesterone levels
5) The hypothalamus is induced to secrete GnRH, and the increasing levels of FSH work on the maturation of another follicle to produce the rise in estrogen, re-starting the cycle
49
What happens during ovulation?
The mature egg is released from the follicle
50
What is the key to induce ovulation? What may potentially block ovulation through this mechanism?
- A spike in LH
| - Constant high levels of estrogen block the LH surge and block ovulation
51
What do estrogen and inhibin instruct the pituitary to do?
- Inhibit FSH
| - At the same time, release LH
52
What occurs to the uterine lining during the luteal phase?
Continued growth so that it supports a pregnancy should the oocyte be fertilized
53
LH stimulates the corpus luteum to produce what?
Progesterone and estrogen
54
What do progesterone and estrogen promote during the luteal phase?
Promote vascularization of the uterus in preparation for implantation of the fertilized egg
55
What are thecal cells? What do they produce?
- Outer layer of cells underneath the granulosa cells
| - Produce testosterone, that is subsequently converted by granulosa cells to estrogen
56
How does a high concentration of estrogen affect the hypothalamus?
Induces the release of GnRH, FSH, and LH
57
How does a low concentration of estrogen affect the hypothalamus?
Inhibits the release of GnRH, FSH, and LH
58
What is the function of inhibin?
Inhibits the release of FSH
59
How does progesterone, secreted by the corpus luteum following ovulation, affect the hypothalamus?
Inhibits the release of GnRH, FSH, and LH
60
If fertilization does occur, what allows the corpus luteum to be maintained? What is it produced by? How does it act to maintain the CL
- Human chorionic gonadotrophin (hCG)
- Produced by the placenta
- Acts to maintain the CL by binding LH receptors, promoting progesterone synthesis
61
Why is progesterone synthesis required for pregnancy?
Ensures that the uterine wall is thickened so that embryonic development can occur and pregnancy can continue
62
What occurs to follicles in polycystic ovarian syndrome?
Follicles develop, but do not ovulate
63
What are the symptoms of polycystic ovarian syndrome?
- Highly irregular cycles
- Cystic follicles
- Elevated testosterone
- Abnormal FSH and LH
- Facial hair
- Abdominal weight gain
64
What is the treatment for polycystic ovarian syndrome? How is it diagnosed?
- Blood tests and ultrasound diagnosis
- Birth control prevents the cystic follicles from dominating
- Diet and surgery
65
What causes excess hair growth in PCOS?
- Testosterone is NOT aromatized to estradiol (estrogen), as normally occurs
- Testosterone is instead converted to dihydrotestosterone (DHT), which causes hair growth and acne
66
Differentiate the combined and Mini-pill. Who should use the Mini-pill?
- Combined: synthetic estrogen and progestin
| - Mini-pill: only progestin (highly reliable, used in nursing)
67
Why are synthetic hormones used in birth control?
Natural hormones are broken down by the liver very rapidly
68
What is the mechanism behind the birth control pill?
- Constant levels of estrogen and progesterone inhibit the LH event, preventing ovulation
- Progesterone also thickens the mucus around the cervix
69
What are other options for birth control, apart from the pill?
- Implants (release progesterone and last up to three years)
| - Patch (release estrogen and progesterone and last a week)
70
Where is sperm made? Where does it undergo maturation?
- Synthesized in seminiferous tubules
| - Undergoes maturation in the epididymis (ex: gains motility)
71
What is cut when an individual gets a vasectomy?
- The vas deferens
| - Vasectomy does not affect spermatogenesis, but the plumbing
72
What are the functions of Sertoli cells?
Resorption (cleaning up dead and dying cells)
73
Where are Sertoli and Leydig cells contained, in respect to the seminiferous epithelium?
- Sertoli cells (somatic cells) are contained within the seminiferous epithelium
- Leydig cells are contained outside the seminiferous epithelium
74
What are spermatogonium?
Form the stem-cell supplier pool
75
What is the function of Leydig cells?
Produces testosterone
76
What occurs to spermatogonia during spermatogenesis?
- Undergo mitosis, which partially maintains the stem cell supplier pool
- Once they go through mitosis, they become spermatocytes
77
What occurs to spermatocytes during spermatogenesis?
- Undergoes meiosis I
| - Undergoes meiosis II to produce haploid, round, spermatids
78
What occurs to spermatids during spermatogenesis?
- Undergoes spermeogenesis
- Get rid of their cytoplasm, condense the nuclear material on their head, forming spermatozoa
- Spermatogonia --> spermatocytes --> spermatids --> spermatozoa
79
What is the most compact cell?
Spermatozoa
80
What is the function of the acrosome within spermatozoa?
Bag of enzymes, which is required to penetrate the thick protein coat of the egg
81
What is the target of LH in spermatogenesis?
Induces the production of testosterone from Leydig cells
82
What is the target of FSH in spermatogenesis?
- Induces the production of spermatocytes and androgen-binding protein (binds testosterone)
- The target is Sertoli cells
83
Why is the early diagnosis of testicular cancer crucial?
Since the doubling time of testis is estimated to be 10 and 30 days
84
Where is Bisphenol A (BPA) found?
- Rigid and translucent polycarbonate plastic
| - Canned food and beverages use BPA-resin liners
85
What has exposure of BPA in rats been associated with?
- Hormonal dysfunction
| - Prostate tumours
86
What are the consequences of long-term exposure to BPA?
- Infertility
- Early puberty
- Breast and prostate cancer
87
What chemical was banned from Canada in 2008?
The import and sale of polycarbonate baby bottles containing BPA were banned
88
What is BPA's mechanism of action? What does it possess high affinity for? What does it possess low affinity for?
- Activates non-classical membrane-bound estrogen receptors
- High affinity to estrogen-related receptor gamma (non-membrane bound)
- Low affinity binding to alpha and beta receptors
89
What was the positive control for Dr. Kimmins' BPA study?
Estrogen
90
What histological abnormalities were shown in BPA exposed rats?
- Filling of tubules with abnormal cells
| - Cells with detached membrane and increased cytoplasm (ressembles a carcinoma in situ model)
91
Transport of the sperm to the egg is aided by what mechanisms?
- Mucosal secretion
| - Prostaglandins in the seminal fluid from the prostate stimulate contractions of the uterus, which help the sperm go up
92
How do the sperm and egg adhere to each other?
Proteins expressed on their surface (adhesion proteins)
93
What must sperm penetrate and bind to?
- Penetrate granulosa cells
| - Bind and penetrate zona pellucida
94
What is a zygote? How do you know a zygote is produced?
- Fertilized ovum that is genetically complete
| - Possesses a male and female pronucleus
95
What occurs once the sperm binds to the zona pellucida? What is the effect?
- Releases acrosomal contents, such as proteases
| - Permits its entry into the perivitelline space, then the egg
96
What occurs to activate the egg once the sperm has entered?
Calcium rapidly rises by stimulating phospholipase C
97
What prevents polyspermy from occurring?
Phospholipase C release of calcium causes the hardening of the zona pellucida to prevent other sperm from entering the egg
98
What's the optimal time for fertilization?
Within 24 hours of ovulation
99
Why does the risk of aneuploidy increase with maternal age?
As eggs get older, they are more prone to errors during meiosis, which may lead to aneuploidy
100
What percentage of embryos miscarry after implantation?
31%
101
What percentage of embryos miscarry after implantation in IVF?
- 70%
| - Bypasses the normal process, forcing ovulation
102
How long does it take for the zygote to travel to the uterus after fertilization? What is its transport aided by?
- 3 to 5 days
| - Aided by cilia, which beat towards the uterus
103
What hormonal effect promotes the entry of the egg into the uterus?
- Rapidly increasing progesterone from the corpus luteum binds receptors on the smooth muscle cells of the fallopian tubes
- Causes a relaxing effect, promoting entry of the egg into the uterus
104
What are the effects of estrogen and progesterone on smooth muscles of the uterus?
- Estrogen tones the uterus (contraction)
| - Progesterone relaxes the uterus
105
What is the zygote called on entry to the uterus?
Blastocyst
106
What is the morula? How long does it take to develop?
- Solid mass of cells formed from the zygote
| - Takes approximately 3 days
107
Where does the blastocyst undergo implantation? What occurs at implantation?
- Into the uterine lining
| - Spotting may occur at implantation
108
When may hCG be detected?
- Day 20-22
| - Approximately 5-7 days after fertilization until implantation in the uterine lining
109
What is the link between the integrin AlphavBeta3, implantation, and miscarriages?
- Progesterone is required for the upregulation of adhesion proteins, such as integrins
- The presence of AlphavBeta3 is associated with proper implantation
110
What are the functions of the placenta?
- Anchors fetus to uterus
- Provides "bridge" for exchange of nutrients and waste products between mother and baby
- Also serves as a excretory, respiratory, and endocrine organ
111
What separates the maternal and fetal blood supply?
Placental tissue
112
What is the important endocrine function of the placenta?
- Secretes large amounts of hCG
| - Stimulates the CL to continue its secretion of estrogen and progesterone
113
What is the function of the yolk sac?
- Important in the beginning of pregnancy
| - Provides nutrients
114
What is the amnionic fluid contained within? What is it?
- Contained within the amnion (inside) and chorion (outside)
| - Water breaks when the amnionic fluid escapes
115
What makes a C-section required?
Bad placement of the placenta, which is frequent in older women
116
Which fetal epithelium is bathed in maternal blood? Why?
- Fetal chorionic epithelium
| - Because chorionic villi have eroded through maternal endothelium
117
How long is the gestation period? How is it subdivided?
- 39 weeks
| - Divided into three 3-month segments called trimesters
118
What is the embryonic phase of gestation?
Fertilization until week 8
119
What is the fetal phase?
Weeks 8 to 39
120
What are the functions of hCG?
- Maintains estrogen and progesterone secretion by the CL
- Prevents menstruation
- Promotes maintenance of the uterine lining
121
What occurs after 4 months when hCG levels drop?
- The placenta takes over secreting estrogen and progesterone as hCG levels drop
- The CL subsequently ceases secreting these hormones
122
What is responsible for mood changes and nausea during pregnancy?
High levels of progesterone
123
What occurs to progesterone during labour?
- Progesterone blocks uterine contractility
| - Progesterone drops before labour
124
Which hormones increase during labour to increase the intensity of uterine contractions?
- Oxytocin
- Cortisol (fetal and maternal)
- Estrogens and PGF
125
Does prolactin increase or decrease during labour?
Increases to allow the production of milk
126
What is the main factor to induce labour? What may induce early labour?
- The rise of fetal cortisol is the MAIN factor to induce pregnancy
- Stressing the baby may induce early labour
127
Which hormone is given as a synthetic hormone to induce labour?
Oxytocin
128
What is the function of relaxin during labour?
- Allows for hips to widen, and ligaments to loosen
| - But, also makes you more susceptible to injury
129
What is parturition?
- Birth
| - Transition between prenatal and postanatal periods of life
130
What is stage one of parturition?
Period from onset of uterine contractions until cervical dilation is complete
131
What is stage two of parturition?
Period from maximal cervical dilation until the baby exits through the vagina
132
What is stage three of parturition?
Process of expulsion of the placenta through the vagina
133
What positive feedback occurs from the baby dropping lower into the uterus during labour?
Cervical stretch
134
What positive feedback does the cervical stretch during labour induce?
- Uterine contractions
- Oxytocin from posterior pituitary
- Prostaglandins from uterine wall
