Reproductive Health

Describe the events of fertilization (7)

1) Sperm surround ovum 2) Cap (of sperm) releases acrosomal enzyme, protective 3) One sperm penetrates oocyte - only 1 can make it, then it is sealed 4) Oocyte completes meiosis II 5) Sperm and egg nuclei fuse 6) Zygote formed 7) Happens in fallopian tubes upon its release (eggs don't live that long, while sperm does) in which a series of cellular divisions occur before implantation of zygote in uterus

How many pairs of chromosomes does the nucleus of a fertilized egg have?

23 pairs of chromsomes

How long is sperm viable?

48-60 hrs

How long is an egg viable?

6-24 hrs

Define seminal vesicles

@ base of bladder, produce viscous/alkaline fluid which provides sperm energy

What main event occurs in the follicular stage?

A follicle matures into an egg

What are the changes to an unfertilized egg in ovary from days 1-4?

A new egg begins to mature while the old egg is shed during menstruation.

What is the human diploid number made up of?

A pair of sex chromosomes and 22 pairs of autosomes

Why does the uterine lining thicken if fertilization occurs?

A thick uterine lining allows an embryo to grow/develop. It provides nourishment for the embryo as well.

Define progestin. Changes this brings? (2)

A variety of chemicals, both natural and synthetic, that produce characteristic secretory and glandular endometrium changes

Define urethra

After vas deferens - urinary bladder where sperm ejaculated - runs from bladder to end of penis

What events produce new combinations of parental genes? (3) When do these occur?

Crossing over in Prophase I Meiosis I Independent assortment/random allignment (Metaphase I) Chance meeting (of sperm and egg)

On what day does progesterone reach its peak concentration?

Day 20-21

What occurs in the luteal phase as far as hormones and their effects? (3)

Estrogen produced Increase in progesterone by corpus luteum causes endometrium thickening/secetions to build up in preparation for fertilized ovum If no implantation or fertilization by 24th to 26th day of cycle, corpus luteum regresses and there can be no implantation. This causes progesterone to decrease, which begins menstruation.

Define thelarche

First sign of puberty in girls w/breast development

What part of the body releases GnRH? What does the release of GnRH cause?

Hypothalamus Release of GnRH causes release of FSH and LH

Why is the chromome number decreased in oogenesis?

In order for the mom and dad chromosomes to equal 46 in fertilization/development of a baby

Where does fertilization occur?

In the fallopian tubes

Does the placenta prevent or allow direct exchange between the blood of the fetus and the blood of the mother?

It prevents direct exchange of blood b/t the fetus and mother

How does meiosis alter the diploid number?

It reduces it by half Each daughter cell recieves half the amount of DNA that the parent cell had

What happens to the corpus luteum if fertilization does not occur? (2) If fertilization does occur? (2)

It stops producing progesterone and begins to break down. Declining progesterone levels cause the uterine lining to breakdown and menstruation will occur. If fertilization and implantation do occur, the corpus luteum is maintained until the placenta takes over the hormone producing functions. During this time the corpus luteum continues to secrete both estrogen and progesterone.

While progesterone stays at a high level, what happens to the lining of the uterus?

It thickens and maintains it if pregnancy occurs

What organ secretes LH?

Pituitary gland

What is the function of progesterone?

Prepares and maintains the uterus for pregnancy. Every month, levels of progesterone rise and stimulate the thickening of the uterine lining (endometrium). If pregnancy doesn't occur, these levels drop off and menstruation begins, renewing/restarting the function. Progesterone balances with estrogen. There are also many other functions!

What hormone prevents the corpus luteum from breaking down if fertilization has taken place?

Progesterone

What hormone causes the corpus luteum to develop? After the corpus luteum develops, what happens physically and hormonally if pregnancy does or does not occur?

Progesterone Progesterone remains at high levels until pregnancy may be occuring, and remains at high levels until pregnancy takes over. If no pregnancy occurs, the corpus luteum disintegrates and the body starts producing GnRH again.

Define prostaglandins

Related to steroid hormones, bioactive compounds

What is the third phase of the endometrial cycle? (3)

Secretory Phase Glands of endometrium dilate and fill up with secretions Endometrium gets ready for pregnancy Positive and negative feedback loops occur

Define penis

Sex organ used for urination

What happens from days 15-21 to the egg if fertilization does occur?

Sperm cells fertilize the egg in the oviduct at day 15. At day 20, the embryo buries itself into the uterine lining.

What happens from days 15-28 to the egg if fertilization does not occur?

The egg moves to the oviduct on day 15, then ot the uterus on day 19, and is ready to be shed by day 26.

What happens to the egg follicle in the ovary as FSH rises (days 1-12)?

The follicle grows/matures.

What is the difference between a follicle and the corpus luteum? What is the function of the corpus luteum?

The follicle ruptures to become the corpus luteum and releases the secondary oocyte in ovulation.

What is the role of the placenta once it forms/takes over from the corpus luteum? (2) What is the role of the corpus luteum at this point?

The placenta secretes estrogen to support the pregnancy, and progesterone to support the pregnancy and produce milk. Role of corpus luteum becomes minor.

What happens on days 21-266 if fertilization does occur?

The uterus thickens as the embryo grows, by day 90 the embryo is considered a fetus and continues to grow. THe pregnancy is considered full term at day 266.

What happens to the uterus lining during days 1-12, as estrogen is rising? After? (2)

Thickening of the endometrium Estrogen will maintain the endometrium if pregnancy occurs

What does the release of GnRH in men trigger?

Triggers Leydig and Sertoli Cells which leads to spermatogonia, which is sperm production

What is the endometrium?

Uterine lining

Where does the endometrial cycle take place?

Uterus

Define graafian follicles

matured primordial follicles

What is estrogen and the most common forms? (3)

"Female hormones" including estradiol, estriol, and estrone

How long is the fertility period in a 28-day cycle?

12-16 days

Define labia majora

2 folds of skin that protect the inner parts of the vulva

Define epidydimus

20 ft. long coiled tube, sperm come here aftter maturing in seminiferous tubules

How long is the average menstrual cycle?

28 days

At the end of oogenesis, what is produced?

3 polar bodies and 1 egg

The normal developmental process of a human baby from her last menstrual period (LMP) through birth is how many weeks long?

40 weeks long

What happens to the egg during the menstrual cycle on day 14?

A/the mature egg is released from the ovary.

When/how does the corpus luteum form?

After ovulation, the follicle heals over and forms the corpus luteum in the luteal stage of the menstrual cycle.

Define ovulation

After the follicle matures, it ruptures releasing the egg - this process is called ovulation (day 14)

Define cholesterol

Basic building block for the synthesis of steroids, necessary for sex steroid formation of all endocrine tissues

Why are humans said to have a menstrual cycle?

Because during this cycle, there are periodic changes to the uterine lining (endometrium).

Why is the process called a "cycle"?

Because there are cyclic changes to the uterus/ovaries depending on the hormone fluctuation that continues each month if fertilization/pregnancy does not occur.

What are chromosomes made up of?

DNA molecules packaged into them (they are made up of DNA molecules)

What day does FSH reach its peak concentration?

Day 12

What day does estrogen reach its peak concentration?

Day 12

On what day does LH reach its peak concentration?

Day 13

What will become the embryo?

An inner cell mass

Define testosterone

Androgen produced by interstatial cells of male testes

Define androgen

Any compound w/masculinizing effects

Define vestibule

Area enclosed by labia minora

Around what day do LH levels peak?

Around day 13

How does follicle growth influence the amount of estrogen it produces? What other effects does this increase have? (2)

As the follicle grows the amount of estrogen it produces increases. Higher estrogen levels cause the pituitary to decrease the production of FSH and a sharp rise in the production of LH by the pituitary.

What is the total chromosome number in a body cell called? What is this number in humans?

Diploid number 46

What happens to the egg in the ovary on Day 14 after LH levels reach their peak?

Egg breaks through the wall.

When are eggs arrested? When are they unarrested?

Eggs are arrested at Prophase I of Meiosis I They become unarrested when menstruation begins

Why is only one egg formed from meiosis/oogenesis?

Eggs need a lot of cytoplasm and organelles

What hormone causes the follicle to develop?

Estrogen

What hormone does the developing follicle produce?

Estrogen

What hormone peaks and causes ovulation?

Estrogen

What changes are brought on by estrogen in the follicular phase? (3) What is the function of these changes?

Estrogen causes the cells of the endometrium to thicken and get longer. The cells increase in size and number for several days out of each menstrual cycle. The endometrium eventually doubles in thickness. These changes prepare the endometrium and increase the odds that a fertilized egg will be able to implant and develop.

What are the primary sex steroids? (3)

Estrogen, progesterone, and testosterone

What pituitary hormone stimulates the development of a primary oocyte into an egg?

FSH

Define vulva

Female external genitals, includes labia majora/minora, clitoris, vestibule, urethra/vaginal openings

Define ovum. What does this contain?

Female gametes, arrested in development as primary oocytes, which contains follicles

Define ovaries

Female gonads that produce gametes and hormones suspended in the pelvic cavity

Define menarche

First period

FSH =

Follicle Stimulating Hormone

What is the first phase of the ovarian cycle? What occurs in this phase? (2)

Follicular Phase Follicle grows and matures Maturation of oocyte

How many haploid sperm are created at the end of Meiosis? Are they duplicated or unduplicated?

Four haploid sperm, unduplicated

What does meiosis produce?

Gametes

Are gametes haploid or diploid? What does this mean?

Gametes are haploid - means half the original

Define prostate

Gland that surrounds urethra as it leaves the bladder

What hormones are released during the follicular phase/what are they stimulated by? (4) What are their functions?

GnRH is released by hypothalamus at the beginning of the phase in response to low estrogen. This causes the anterior pituitary to release FSH and LH. FSH stimulates follicles in the ovary LH causes estrogen secretion by the follicle LH surge causes ovulation to occur

What is GnRH?

Gonadotropin releasing hormone

From days 5-13, what happens to an unfertilized egg in ovary? (2)

At day 9, the egg is almost fully mature. On day 13, the mature egg is released from the ovary.

When is Meiosis I complete?

At ovulation when an egg is released

Once progesterone dereases if there is no fertilization, what happens to the lining of the uterus?

It begins to shed

Why is the corpus luteum important?

It secretes progesterone and some estrogen.

Define vas deferens

Joined w/gland from seminal vesicle to form 2 ejaculatory ducts

How often does sperm production occur in males?

Throughout life

Define puberty

Transition from childhood to adulthood when physical and mental changes occur for reproduction

Define cervix

Lower, constricted portion of uterus that projects into the vagina and has an opening to the vagina (external os) and an opening to the uterine cavity (internal os)

LH =

Lutenizing Hormone

Define testes

Male gonads, produce gametes and hormones (mainly testosterone)

In human egg formation, where does Meiosis I begin? Where does Meiosis I complete? Where/when does Meisosis II complete?

Meiosis I begins in the embryo Meiosis I completes at ovulation Meiosis II completes at fertilization

What is the first phase of the endometrial cycle? What occurs duing this phase? (2) When do these events occur?

Menstrual/Proliferative Phase Menstruation occurs when the endometrium sloughs off (first 3-5 days of cycle) Endometrium breakdown and buildup - regeneration occurs 3-5 days later

Define menstrual synchronity

Menstruation of women in close proximity with each other around the same time each month

How often does a sexually mature woman produce a mature egg?

Once every 28 days, on day 14 of a 28 day cycle

When is Meiosis II completed?

Only at fertilization

What organ secretes estrogen?

Ovaries

Where does meiosis occur in females?

Ovaries

Where does the ovarian cycle take place?

Ovaries

What is the second phase of the endometrial cycle? What events occur in this phase?

Ovulation. Same events as described above.

Define ejaculation

Release of semen from male from reproductive tract

How many follicles mature each month/into what?

Several follicles begin to mature each month, but usually only one completely matures into an egg.

What is the trophoblast? What does this later form?

Surface layer of cells of the blastocyst, later forms placenta.

Where does sperm production and meiosis occur in males?

The seminiferous tubules

Estrogen increases the sense of smell/taste. How would this be an adaptation to increase chances of conception and when?

The senses would be higher from days 6-18 when estrogen is 100 units/mL or higher, and highest on the days surrounding/closest to day 12. This could increase chances of conception due to an increased noticing of pheremones.

Define uterus

Hollow, muscular organ that houses fetus development during gestation

Define inhibin. When does it act?

Hormone that suppresses FSH secretion from the pituitary gland during the follicular phase to regulate follicle dev.

What occurs on day 14 of the menstrual cycle hormonally? What is this triggered by?

Hormones, mainly LH, trigger ovulation

What happens to the uterus lining from days 1-4?

The uterus lining is shed during menstruation.

Why does the uterine lining no longer need to be thick if fertilization does not occur?

There is no embryo to develop/grow that needs to be nourished.

What organ secretes FSH?

Hypothalamus

What are the functions of meiosis? (2)

1) Produce gametes 2) Increase genetic variation

Females are fertile on a cyclical basis. Where do these rhythmic changes occur (2) and what hormones are causing these changes (the major players) (4)?

Ovariesand Uterus Estrogen, Progesterone, FSH, and LH

What is the second phase of the ovarian cycle? What occurs in this phase? (2) When do these events occur?

Ovulation Mature follicle ruptures relasing secondary oocyte/egg (triggered by LH surge) Release of oocyte from ovary (day 14 of 15 before the beginning of next period, can vary + or - 4/5 days)

Define hymen

Below urethral orifice/around vaginal opening is this small membrane

Define basal body temperature (BBT)

Body temperature upon waking up before physical activity. The temp is raised in the 1-3 days of/before ovulation

What is the role of sexual intercourse in reproduction?

Brings together sperm and eggs permitting fertilization and conception.

Describe the hormonal events of the menstural cycle. (6)

1) GnRH prods anterior lobe cells to secrete FSH and LH 2) In ovary, FSH and LH promote follicle growth and oocyte maturation, estrogen production, priming of endometrium, and other reproductive events. 3) Blood level of estrogens rises and stimulates a surge in LH secretion 4) Midcycle surge of LH triggers ovulation, then formation of corpus luteum 5) Progesterone and estrogen secreted by the corpus luteum will maintain the endometrium if pregnancy occurs 6) The rises in progesterone/estrogen will inhibit FSH/LH secretion during last phase of cycle

What is the third phase of the ovarian cycle? What ocurs during this phase? (2)

Luteal Phase Corpus luteum forms from remnants of the ruptured follicle, but releases it's own hormones. It would give off progesterone if pregnancy occurs. Placenta would later take over. Endometrium gets ready for pregnancy.

Define clitoris

Originates from the same embryonic tissue as the penis, it is made of erectile tissue that fills with blood during sexual intercourse - it is mostly internal, but wraps around vagina and urethra

What process occurs b/t days 3-6? (2)

Mensturation/a new egg is maturing in the ovary.

Define pelvic floor

Muscles that form lower wall of pelvis that can become damaged/strained leading to urinary/fecal incontinence

Define vagina

Muscular tube passing upwards to uterus

Define progesterone. Produced by... (2)

Naturally occuring progestin in vertebraes produced by the ovaries after ovulation has occured and by the adrenal glands

Define fallopian tubes

Next to uterus, divided into 4 sections: uterine portion, isthmus, ampulla, and infundibulum

If two sets of twins get together and have children, will the cousins look the same? Why or why not? (4) When do these events occur?

No, because of crossing over, random assortment (in metaphase I), and chance meeting. Also, how the twins look would depend on dominant/recessive alleles.

From days 5-13, what happens to the uterus lining?

On day 5, the uterus lining is thin because of the blood and tissue lost during menstruation. By day 11, the uterus lining is thickening once again.