Reproductive system

Question 1

Why we have a tendency for declining reproductive health?

Answer 1

The number of chemicals registered
for commercial use now 30 percent increase since
1979.

Exposed through industrial releases,
contaminated food, household
products and cosmetics, and the
workplace
• Coinciding with this rise are
increased rates of infertility,
decreasing sperm counts and higher
rates of birth defects

Question 2

Increase in progesterone during pregnancy can lead to

Answer 2

Hypospadias

Hypospadias is a common variation in fetal development of the penis in which the urethra does not open from its usual location in the head of the penis.

Question 3

Hypospadias ( apart form progesterone can be caused by)

Answer 3

Phthalates and BPA are found in toys,
food containers, cosmetics, and many
other consumer products. PBDEs are
used as flame retardants in household
furniture and electronics

Plastics

Question 4

of couples are infertile and infertility is
increasing due to reduced sperm counts, exposure
to environmental toxicants, obesity and delayed
parenthood

Answer 4

15-17%

Question 5

How many men are recognized infertile with a cause

Answer 5

4%

Question 6

Who is born more in the last 30 years

Answer 6

girls

Question 7

What is happening with a sperm

Answer 7

Numbers are declining, as well as quality, 85% if sperm produced in a men is DNA-damaged

Question 8

Where the spermatogenesis happen

Answer 8

In testes, more specific in seminiferous tubule

Question 9

What is the structure of seminiferous tubule

Answer 9

On the periphery there are spermatogonium, which are immature sperm cells .

Specific cell types:
Sertoni-support spermatogenesis and respond to FSH, nourishment and nursing

Leydig cells - outside the tubule, respond to LH,secrete testosterone

Question 10

Stages in spermatogenesis

Answer 10

On the periphery there are spermatogonium, which are immature sperm cells . As they move towards the center they undergo different stages of meiosis and then when they are near the lumen , they will receive the tails, and now sperms

Spermatogonium divide by mitosis and one of the cell is selected to produce primary spermatocyte (the other stays as a sem cell and is continued to divide by mitosis), then after meiosis I it becomes secondary spermatocyte, then mitosis 2 ->spermatids-> receive tails->spermatozoa

Question 11

Oocytes can only contain____

Answer 11

x chromosome

n=23

Question 12

Recall meiosis

Answer 12

Meiosis I: involves the
separation of homologous
chromosomes and recombination
• Meiosis II: involves the
separation of sister chromatids

Question 13

Structure of spermatozoa

Answer 13

Head (where the genetic material is found), on the tip in acrosome that contains enzyme to digest the layer of oocyte
The midpiece, where a lot of mitochondria is found to propel the tail
and tail (flagella)

Question 14

describe the pathway of hormonal regulation of spermatogenesis

Answer 14

GnRH ( gonadotropin release hormone) in hypothalamus activates the secretion of FSH from anterior pituitary and LH form posterior

FSH is going to bind sertoli cells, and by second messengers activate spermatogenesis

LH is going to stimulate Leydig cells,->release of testosterone

Testosterone will bind to androgen-binding protein (ABP), that was produced under FSH stimulation and promote spermatogenesis, as well as testosterone will have the effect on secondary male characteristics , and stimulate sertoli cells

When FSH activates the pathway of spermatogenesis, it produces also inhibin that will stop the secretion of FSH from pituitary

Testosterone will feeback GnRH and LH secretion

Question 15

Is testicular cancer is treatable

Answer 15

Relatively yes

Question 16

Two main parts of the uterus

Answer 16

The cervix and the body of the uterus

Also have fundus of uterus, follopian tibes, ovaries

Question 17

Connection of ovary and follopian tubes is called

Answer 17

Infundibulum of the uterine tube

Question 18

Where fertilization usually occurs

Answer 18

isthmus-Ampulla junction of uterine tube

Question 19

Connection of the tube to the body of uterus

Answer 19

Isthmus

Question 20

What is ectopic pregnancy

Answer 20

Ectopic pregnancy—development of the fetus in a place other than the
uterus- 95% in the fallopian tubes

Question 21

When the girls is born what does she have already

Answer 21

All oocytes in meiosis 1

Question 22

What happens at puberty with oocytes

Answer 22

Under the influence of FSH, they are going to grow from primary follicles->secondary follicles->graffian follicle (mature) and then ovulation, the follicle is arrested in meiosis 2

Question 23

What will happen with cell development of oocyte with conception

Answer 23

It will undergo meiosis 2

Question 24

The ovaries are endocrine
organs that secrete
the female sex hormones
(____)

Answer 24

estrogens and progesterone

Question 25

Each uterine tube has three divisions

Answer 25

isthmus, ampulla, and infundibulum.

Question 26

3 layers of uterus

Answer 26

endometrium myometrium (mascular layer) perimetrium ( the outter layer)

Question 27

Histology of oviduct

Answer 27

Ciliated columnar cells

Question 28

What is pelvic inflammatory disease

Answer 28

sexually transmitted diseases can cause scarring and infertility Destruction of cells lying the oviduct, lacking cilia-> may result in ectopic pregnancy If a pelvic infection occurs in the tubes this can block the passage, scar tissue, pus outside the tube can spread the infection to other organs • Cause of 1 in 4-ectopic pregnancy • Pain upon palpation, may be discharge, fever some pelvic discomfort

Question 29

What is menstruation

Answer 29

spongy uterine wall breaks down. The degenerating tissue, blood, and unfertilized egg are passed out as menstrual flow. Lasts 4-7 days

Question 30

Stages in menstrual cycle

Answer 30

Follicular Stage - Ovulatory phase Luteal phase

Question 31

How control pill work

Answer 31

A spike in LH is the key to induce ovulation. Constant high levels of estrogen (eg. Birth control pill) block the LH surge and block ovulation.

Question 32

Explain follicular phase

Answer 32

Day 1 - bleeding. at the same time FSH causes several ‘follicles’ to rise on the surface of the ovary. These fluid filled “bumps” each contain an egg. Eventually, one of these follicle becomes dominant and within it develops a single mature egg; the other follicles shrink back. If more than one follicle reaches maturity, this can lead to twins or more. The maturing follicle produces the hormone estrogen, which increases over the follicular phase and peaks in the day or two prior to ovulation. The lining of the uterus (endometrium) becomes thicker and more enriched with blood in the second part of this phase (after menstruation is over), in response to increasing levels of estrogen. High levels of estrogen stimulate the production of gonadotropin-releasing hormone (GnRH), which in turn stimulates the pituitary gland to secrete luteinizing hormone (LH). On about day 12, surges in LH and FSH cause the egg to be released from the follicle. The surge in LH also causes a brief surge in testosterone, which increases sex drive, right at the most fertile time of the cycle.

Question 33

Explain ovulatory phase

Answer 33

The release of the mature egg happens on about day 14 as a result of a surge in LH and FSH over the previous day. After release, the egg enters the fallopian tube where fertilization may take place, if sperm are present. If the egg is not fertilized, it disintegrates after about 24 hours. Once the egg is released, there is a left over of the follicle which is called the corpus luteum Peak in FSH and LH

Question 34

Describe luteal phase

Answer 34

After the release of the egg, levels of FSH and LH decrease. The corpus luteum produces progesterone with the sti,ulation of LH. If fertilization has occurred, the corpus luteum continues to produce progesterone which prevents the endometrial lining from being shed. If fertilization has not occurred, the corpus luteum disintegrates, which causes progesterone levels to drop and signals the endometrial lining to begin shedding ``` If pregnancy occurs the embryo produces the pregnancy recognition hormone hcg ( human chorionic gonadotropin) this maintains the CL and progesterone levels which prevent a return to the estrous cycle ```

Question 35

Inhibin role in menstrual cycle

Answer 35

Inhibin is secreted by the maturing follicle In the first half of the cycle moderate Estrogen levels and inhibin instructs the pituitary to inhibit FSH (through a negative feedback mechanism

Question 36

Meiosis in developing the egg

Answer 36

Mitosis which is completed before birth oogonium is divided into anothe oogonium anf primary oocyte (2n) which later will enter meiosis Primary oocyte undergoes prophase of meiosis I ( before the birth) that's how they are arrested until puberty (2n) At puberty , when the follicle is selected to mature it will continue the meiotic division primary oocyte will form secondary oocyte (n) and first polar body (n)- it may divide , but will nit a mature egg Primary oocyte will continue division until it becomes mature ovum ( if only fertilized)

Question 37

The difference between meiosis in men and females

Answer 37

males -4 sperm with n | 1 primary egg

Question 38

Lifestage of gametogenesis in male and female

Answer 38

Male-begins at puberty | Female- begins with mitotic division before birth, resumes at puberty

Question 39

Frequency of occurrence of gametogenesis in male and female

Answer 39

Male-constant after puberty | Female-monthly from puberty until menopause

Question 40

What is the mechanism of combined birth control pills

Answer 40

Synthetic estrogen and progestin Combined oral contraceptive pills were developed to prevent ovulation by suppressing the release of gonadotropins. ... Estrogen negative feedback on the anterior pituitary greatly decreases the secretion of FSH, which inhibits follicular development and helps prevent ovulation

Question 41

Minipill action principle

Answer 41

It keeps progesterone at the same level inconsistently inhibit ovulation in ~50% of cycles and rely mainly on their progestogenic effect of thickening the cervical mucus around the cervix, thereby reducing sperm viability and penetration

Question 42

•Why synthetic hormones? in birth control

Answer 42

Natural hormones are broken | down by the liver very rapidly

Question 43

What are implants and patch contraceptives

Answer 43

Implants ex Implanon, release P last up to 3 yrs | • Patch change 1X a week, release E and P

Question 44

What is PCOS

Answer 44

``` Endocrine disorder, common cause of infertility due to anovulation • Incidence is 1/10 • PCOS-follicles develop but do not ovulate- cystic follicles • More than an ovary issue as associated with metabolic disruption and high risk of developing type 2 diabetes ```

Question 45

Symptoms of PCOS

Answer 45

Prevalence of hirsutism , acne , androgenic alopecia , menstrual disorders , overweight , obesity , and infertility Can go hand in hand with hypothyrodism

Question 46

Hormonal disruption in PCOS

Answer 46

highly irregular cycles, elevated testosterone, abnormal FSH, LH, and excess Conversion of T to DHT

Question 47

How to diagnose PCOS and treat

Answer 47

blood tests, ultrasound • Treatment: contraceptive pill, surgery, Weight loss, exercise, diabetes medication metformin

Question 48

___ (time) for sperm to reach the egg in the | ampulla

Answer 48

5-10 minutes

Question 49

How propulsion of sperm is achieved

Answer 49

Transport of the sperm is aided by mucosal secretion, prostaglandins in the seminal fluid from prostate stimulate contractions of the uterus, a few hundred to thousand sperm reach the ampulla

Question 50

What happens in conception

Answer 50

Sperm must penetrate corona radiate (granulosa cells), then bind and penetrate the zona pellucida • One the sperm has entered, MII is completed and second polar body is extruded

Question 51

What is an acrosome reaction

Answer 51

``` Once the sperm binds to the ZP it releases acrosomal contents (acrosome reaction)-proteases • This permits its entry into the perivitelline space then egg • Calcium rapidly rises by stimulating Phospholipase C, activates the egg • Block to polyspermy involves changes to ZP to prevent other sperm from entering egg ```

Question 52

How long can the gg last

Answer 52

24 hours after ovulation

Question 53

Do eggs age? Why are there greater risks with maternal | age?

Answer 53

More errors in division | Eggs are exposed to anything we put in

Question 54

Aneuploidy is

Answer 54

of 1500 first trimester miscarriages 61% have abnormal chromosome. It is the most frequent cause of miscarriage and the risks of aneuploidy increase as women age.

Question 55

How many percent of embryos will miscarry after implantation And in IVF?

Answer 55

31% 70%

Question 56

What happens after fertilization

Answer 56

After fertilization within 3-5 days the zygote travels to the uterus. • Aided by the cilia which always beat towards the uterus • Rapidly increasing P from CL binds receptors on the smooth muscle cells of the fallopian tubes and causing a relaxing effect promoting entry of the egg into the uterus. • On entry into the uterus called a blastocyst

Question 57

8 vell zygote is called

Answer 57

morula • Morula—solid mass of cells formed from zygote; takes approximately 3 days; continues to divide

Question 58

prenatal period is

Answer 58

Begins with conception and continues until the birth of a child

Question 59

Parts in blastocyst

Answer 59

Trophoblast which will form the placenta Inner cells - that will form the fetus and blastocyst cavity

Question 60

What is a cleavage

Answer 60

Mitotic division of zygote

Question 61

What is a blastocyst

Answer 61

Blastocyst—by the time developing embryo reaches uterus • Implants into uterine lining • Approximately 5-7 days pass from fertilization until implantation in uterine lining; can detect hcg (day 20-22)

Question 62

Integrin secreted when

Answer 62

Integrin expressed on epithelium in window of implantation-at time of implantation-day 10 or in late secretory phase nonpregnant day 21 Plays role in implantation

Question 63

Placenta is and important for

Answer 63

Acts as a barrier between the mother and the baby ``` Anchors fetus to uterus and provides “bridge” for exchange of nutrients and waste products between mother and baby • Also serves as excretory, respiratory, and endocrine organ • Placental tissue separates maternal and fetal blood supplies • Has important endocrine functions—secretes large amounts of human chorionic gonadotropin (hCG), which stimulates the corpus luteum to continue its secretion of estrogen and progesterone ```

Question 64

Organization of the mature placenta

Answer 64

``` In humans, fetal chorionic epithelium is bathed in maternal blood because chorionic villi have eroded through maternal endothelium • Classification-Hemochorial ```

Question 65

Gestation period: length, how it is divided

Answer 65

``` period—approximately 39 weeks; divided into three 3-month segments called trimesters • Embryonic phase extends from fertilization until the end of week 8 of gestation • Fetal phase—weeks 8 to 39 ```

Question 66

What is the role of relaxin

Answer 66

To relax joints, to make them more flexible

Question 67

What is thought to be one of the major onset of labor

Answer 67

Fetal cortisol

Question 68

How hormones change before child's birth

Answer 68

Progesterone blocks uterine contractility this drops before labor Fetus pituitary secretes oxytocin, fetal adrenal glands secrete cortisol, membranes release PGF-all can act to increase intensity of uterine contractions Irritation of or stretch of cervix-increase oxytocin

Question 69

Stages of labor

Answer 69

``` Stage one —period from onset of uterine contractions until cervical dilation is complete Stage two —period from maximal cervical dilation until the baby exits through the vagina Stage three —process of expulsion of the placenta through the vagina ```

Question 70

Birth is controlled by __ feedback

Answer 70

Positive More uterine contractions-> more cervical stretch->more oxytocin from posterior pituitary ->prostaglandins from uterine wall-> more uterine contractions

Question 71

Environmental exposures and reproductive health

Answer 71

Deodorants, bodycream, perfumes accumulation of lipophylic chemicals (DDT/DDE-pestisides) Inhalation exposure (plasticisers,heavy metal) some in the breast milk (lipophylic) oral exposure (plastics, food contamination)

Question 72

What is the trend on sex of the babies born

Answer 72

Twice as many girls as boys are being born in remote communities North of the Arctic Circle (2:1) • Across much of the Northern hemisphere in US and Japan the gender ratio has skewed towards girls