A&P Reproductive system
Ovulation vs spermatogenesis
At birth, all the eggs she will ever have Ovum availability: puberty->menopause Oogenesis interrupted twice: at birth: stuck in the 1st meiotic division at ovulation: stuck in 2nd meiotic division 1st meiotic division completed at ovulation 2nd meiotic division completed at fertilization 1 (2n) oocyte-> 1 viable fertilized egg + 3 non-viable polar bodies, all (n)
occurs in the male with rising levels of testosterone acting on the hypothalamus and anterior pituitary to inhibit the release of GnRH, FSH, and LH. The Sertoli cells produce the hormone inhibin, which is released into the blood when the sperm count is too high.
Describe the negative feedback loops in the control of sperm and testosterone production.
around week 3- after pronuclei approach each other and mitotic spindle forms between them. THEN chromsomes intermix and fertilization is accomplished
Fertilization does not technically occur when the sperm penetrates the oocyte. When technically does fertilization occur?
The ovum released from the ovary is captured by the fimbria of the fallopian tube and transported by ciliary action toward the uterus. Each fallopian tube is about 10 cm long, and the fallopian tubes are the usual site of fertilization. The vaginal canal connects the uterus with the external genitalia.
How does the ovulated oocyte end up in the fallopian tube?
24 hours
How long does the secondary oocyte remain viable after ovulation?
40-50 minutes Morula- 3 days blastocyst- 4 days
How many hours post-fertilization are the following structures observed: 2-celled stage, morula, blastocyst.
Primary follicle /primary oocyte secondary follicle/ secondary oocyte mature vesicular follicle/ secondary oocyte they are 2n
In the follicular phase, the follicle changes from primordial to ____ to ____ and finally to the ________ follicle which is the most mature and is seen just prior to ovulation. What is the name of the oocyte during all of these follicular stages? Is it n or 2n?
the pituitary gland releases follicle stimulating hormone (FSH) and luteinizing hormone (LH) seminal gland secrete fluid that partly composes the semen. Bulbo- urethral gland add fluids to semen during the process of ejaculation( neutralizes acidic urine) Prostate Gland ~ Milky, slightly acidic, Citrate Nutrient, Fibrinolysin Dissolves clotted
Indicate the 4 endocrine glands involved in hormonal control of sperm Production.
1. Pituitary Gland 2-3.theca cells to produce androstenedione 4-5.androgens to estrogen
LH and FSH from the ___ target the ovary and act upon the developing follicle. LH stimulates _____ cells to produce ______. FSH then facilitates the conversion of the_______ into ________ within the granulosa cells. This last hormone then acts upon the uterus to develop the functional layer of the endometrium.
head - Acrosome & enzymes, genetic material, DNA midpiece- many mitochondria flagellum- motility
Name the 3 parts of the sperm and indicate the function of each part.
Mitosis-16 days meiosis- a few hours spermiogenesis- 24 days
Name the 3 phases of spermatogenesis. How long does it take to go through these phases?
If pregnancy AND IMPLANTATION occurs the secondary oocyte secrete human chorionic gonadotropin (HCG) BECOMES FETUS If it does not occur the endometrium is sloughed off and the cycle begins again
Notice the second meiotic division is halted before its conclusion, thus leaving a functional secondary oocyte. What are the potential fates of this oocyte depending on whether pregnancy occurs or not?
Following puberty, during each menstrual cycle, pituitary gonadotrophin stimulates completion of meiosis 1 the day before ovulation (day 14) the product is 1 polar body a 1 secondary oocyte polar body can divide 1 more time into 2 polar bodies but then there degenerate. secondary oocyte goes on to be fertilized and splits after meiosis 2 to make 1 polar body and 1 ovum (fertilized egg) BOTH have 23 chromosomes and are haploid
Once puberty is reached, the first meiotic division is completed and the second one is begun. What triggers this progression? When in the monthly cycle does this occur? The products of the first meiotic division are ___ and___. What is the difference between these? Both of these have a ___ complement of chromosomes and thus are ____.
Before birth- Chromosomes of the oogonium duplicate to become 2 primary oocyte childhood- Meiotic resting phase begins until puberty puberty- activates stage 1 of meiosis which triggers the primary oocyte to split into 2 secondary oocytes and then is paused again until fertilization. Fertilization activates stage 2 of meiosis which creates 1 egg (ovum) and 2 polar bodies. 1 oogonium produces 2 egss in the end vs spermatogenesis where 1 spermatogonium produces 8 sperm
Oogenesis- divided into 3 time frames: Before birth, Childhood, and Each Month Puberty-to-Menopause.
follicular phase Luteal phase
The _______ phase traces the changes in the follicle and the ______ phase follows the formation and changes of the corpus luteum (which is what remains of the follicle after ovulation).
urethra
The corpus spongiosum contains what tubular structure?
Postate, seminal vesicle, and bulbourethral gland
The male reproductive system/what organ, ducts and glands produce sperm & hormones?
scrotum helps to regulate the temperature to slightly 2.5 - 3 degrees lower in temp- spermatogenesis is most efficient at 34 degrees Celsius
There are several adaptations which keep the temperature of the testes at the proper temperature for sperm production. What are these adaptations?
epididymus (head, body, tail), testis, vas deferens, seminal vesicle, seminiferous tubule, tubulus rectus, prostate, bulbourethral gland, rete testis, spermatic cord, urethra (prostatic, membranous, spongy), and ejaculatory duct.
Trace the structures sperm encounter as they first develop until they leave the body
A little blood enters the corpus spongiosum; the remainder engorges the corpora cavernosa, which expand to hold 90% of the blood involved in an erection, increasing both in length and in diameter. The function of the corpus spongiosum is to prevent compression of the urethra during erection.
What are the corpora cavernosa?
After release of the ovum, the remaining cells of the granulosa and theca interna form the corpus luteum. The center contains the remains of the blood clot that formed after ovulation. corpus luteum produces progesterone
What becomes of the remains of the Graafian follicle after ovulation? What hormones does this structure produce?
cumulus cells.
What cells from the Graafian follicle are ovulated besides the oocyte?
Trophoblast celss- forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. I-The inner cell mass of the blastocyst is composed of two kinds of cells: those that will become the mature organism (the epiblast), and those that will develop into the placenta, the chorion, and the amniotic membranes. The cells that will develop into the completed embryo are called embryonic stem cells (ESCs).
What develops from the trophoblast cells? Inner cell mass?
Estrogen is high and progesterone is low, which rebuilds the endometrium DAY 5-14
What does estrogen do in the proliferative phase?
High progesterone and low estrogen- nourish endometrium DAY 14-28 Progesterone also stimulates the glands in the uterus to secrete substances that maintain the endometrium and keep it from breaking down
What does progesterone do in the secretory phase?
- LH - if pregnancy doesn't occur, corpus luteum shrinks into scar tissue - if pregnancy occurs The corpus luteum secretes progesterone and estrogen that cause the uterine lining, or endometrium, to thicken and be able to nourish a fertilized egg. Corpus Albicans-the regressed form of the corpus luteum.
What hormone from the anterior pituitary maintains the activity of the corpus luteum? What happens to this structure of the luteal phase if pregnancy does not occur? If pregnancy does occur? What is the corpus albicans?
the fertilization of an egg by multiple sperm, and the results of such unions are lethal. prevent by: Sperm head enters oocyte which causes the Release of intracellular Ca++ which Release of cortical granules from within oocyte to outside of oocyte Granules attract water, swell, push sperm away (physical blocking) Enzymes in granules inhibit sperm receptor molecules in the plasma membrane
What is polyspermy and what 2 mechanisms act to prevent it?
the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis.This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. - takes 64-72 days -starts at puberty and ends at death - begin with 1 diploid spermatogonium (2n) and end with 4, viable, haploid, non-identical spermatozoa
What is spermatogenesis? Where does it take place? When does it begin and when does it end?
Acrosomal enzyme, hyaluronidase, digests "cellular glue" between granulosa cells and through zona pellucida. Many sperm required to create a "path" to the oocyte 1st sperm there is not likely the one to fertilize
What is the acrosomal reaction? Why is the first sperm to reach the ovulated oocyte most likely not the sperm to fertilize it?
The penis is the male sex organ, reaching its full size during puberty. In addition to its sexual function, the penis acts as a conduit for urine to leave the body.
What is the function of the penis?
luteal phase (day 14-day 28) Follicular Phase (day 1-14)
What is the name of the phase of the ovarian cycle that occurs after ovulation?
Some leak out of vagina Others killed by macrophages Acidic environment of vagina slows them Thick cervical mucus blocks them
What obstacles do sperm encounter in attempting to reach the fallopian tube?
OVARIAN FOLLICAL in the proliferative phase Corpus luteum in secondary phase
What ovarian structure is hormonally functional during the uterine proliferative phase? The uterine secretory phase?
Luteinizing hormone and follicle-stimulating hormone, which are produced by the pituitary gland, promote ovulation and stimulate the ovaries to produce estrogen and progesterone.
Where does each hormone of the ovarian cycle act, when does it act, and what are the consequences of it action?
3-4 days- fallopian tube 5-6 days- isthmus 6-7 days - lumen(cavity) of the uterus 7-14 days - endometrium/ implanted in the wall
Where in the reproductive tract is the developing fertilized oocyte 3-4 days post-ovulation, 5-6 days post-ovulation, 6-7 days post ovulation, 7-14 days post-ovulation?
Progesterone
Which ovarian hormone is responsible for building-up the endometrium? Which form maintaining it? In the disintegration of the functional layer?
In embryology, cleavage is the division of cells in the early embryo. The process follows fertilization, with the transfer being triggered by the activation of a cyclin-dependent kinase complex... The different cells derived from cleavage are called blastomeres and form a compact mass called the morula.
With respect to immediate post-fertilization events, what is cleavage?
oogonium
Before birth, immature oocytes, called _____, are produced by mitosis.
1. FIRST meiotic division 2. Primary oocytes 3. second (46 chromosomes) 4.a diploid AT BIRTH: 5 MILLION OVA PUBERTY: 300,000OVA PUBERTY THRU MENOPAUSE: 500 OVA
Before birth, the oogonia begin the 1. ____ meiotic division, do not complete it and are arrested in this beginning stage until puberty. These are called 2. ____and have a 3. ___ complement of chromosomes, that is 4. _____. How many of these are present at birth and how many are released during the reproductive period of a female?
Weakening of acrosomal membrane due to loss of cholesterol in membrane=capacitation Allows for release of acrosomal enzymes Takes 2 - 6 hours
Capacitation must occur for sperm to fertilize the oocyte. What is capacitation?
Parasympathetic system helps the male to relax so they can get an erection. Nitric oxide ( NO) is a vassodiolator cGMP helps the penis to maintain an erection phosphodiesterase (PDE) helps to break down cGMP to relax viagra blocks action of PDE to keep the erection going
Describe the role of the parasympathetic system, nitric oxide (NO), cGMP, phosphodiesterase (PDE), and viagra in erection.
Estrogen and Progesterone support endometrium bulit up- before ovulation Nourished- after ovulation maintained- if pregnancy occurs sloughed off- no pregnancy occurs
During which phase of the uterine cycle is the endometrium built-up, maintained, and sloughed-off, respectively?
48 hours for male 24 hours female
For fertilization to occur, intercourse must take place no more than ____ hours before ovulation (male limits) or ____ hours after fertilization(female limits).
the basal (close to the basal lamina) and adluminal (towards the lumen) compartment. Large molecules cannot pass between the basal and adluminal compartment - this is called the blood-testis barrier. CELLS- (in the wall) Spermatogenic cells- become sperm Sertoli cells- help sperm develope (between tubules) Interstitial cells- secrete testosterone
Into what compartments is the seminiferous tubule divided and what cells divide it into these compartments?
second meiotic division non functional polar bodies are formed and 1 OVUM
It is only upon fertilization that the ___ meiotic division is completed. If pregnancy occurs, two more non-functional ___ are produced and one____.
CELLS- (in the wall) Spermatogenic cells- become sperm Sertoli cells- help sperm develope (between tubules) Interstitial cells- secrete testosterone
Three important cell types are found in the testes. Name each type, where each is located, and the general function
abluminal membrane
Meiosis occurs in which compartment of a male?
(tunica vaginalis) Basal spermatogonial stem cells.
Mitosis occurs in the ____ compartment and produces many cells destined to become sperm which are called what?
Estrogen main hormone secreted by ovary in follicular phase (Days 1-14) by follicle Progesterone (lots) and estrogen (some) secreted in luteal phase by corpus luteum (Days 14-28)
Ovarian Hormones
LH targets thecal cells to secrete androgens Androgens diffuse into granulosa cells FSH helps convert androgens in granulosa cells to estrogen Estrogen is the hormone secreted by follicle during follicular phase
Pituitary LH & FSH
ovulation phase during the menstrual cycle Day 14 when LH surge happens, and estrogen is highest and progesterone is lower
Pregnancy is most likely to occur during what phase of the uterine cycle?
anterior pituitary, hypothalamus, and ovaries
What 3 glands are involved in the hormonal control of the ovarian cycle?
fructose, fibrinogen, prostaglandins
What substances do the 3 glands structures contribute to the semen?
spermatogonia spermatids spermatozoa (haploid) lumen
Summarize the trends within the seminiferous tubule as you proceed from the margin to the lumen.
Haploid cells used in sexual reproduction, gametes, are formed during meiosis, which consists of one round of chromosome replication and two rounds of nuclear division. Meiosis I is the first round of meiotic division, while meiosis II is the second round.
gamete formation there is 1 DNA replication and 2 nuclear divisions.
What is the function of the reproductive system?
keep the species going
*Consumes excess cytoplasm during spermiogenesis *Provides fluid for sperm transport *Provides nutrients for developing sperm *Secretes inhibin and androgen binding protein (ABP) Provides blood-testis barrier
name the many functions of the sertoli cells
The ovaries, fallopian tubes (fimbriae, ampulla), uterus (myometrium. endometrium—basal layer and functional layer), cervix, vagina.
the organs of the female reproductive system.
testes tube system
The male reproductive system is anatomically divided into:_____, which produce sperm and hormones and____________ which assist in the delivery of viable sperm to the female reproductive tract.
Follicular phase- Day 1-14 Luteal Phase - day 14- 28 Ovulation occurs on day 14
The monthly ovarian cycle considers the development of the follicles within The ovary, which includes the maturation of the oocyte and the changes in the supporting cells around it. The follicle includes the oocyte and these supporting cells. There are 2 separate phases of the ovarian cycle separated by ovulation. These phases are ___ and ____ which occur between days ___ and ____, respectively, with ovulation occurring around Day ___.
*Sperm survive up to 48 hours in female tract *Oocyte survives 24 hours after ovulation For fertilization to occur, intercourse: 48 hr before-->ovulation--> 24 hrs after (Male limits) (female limits)
How long do sperm remain alive in the female reproductive tract after being deposited?
120 million sperm per day -survive 5 days in female reproductive tract -survive 14 days in epididymus to fully mature
How many sperm are produced daily, and how long do they survive in the epididymus compared to the female reproductive tract?
corpus lueum
If pregnancy does not occur, the ____ oocyte degenerates.
Once Meiosis I ( completed by one primary oocyte each month in response to LH surge) second at meiosis II (only if sperm penetrates oocyte)
In the female, the nuclear divisions are interrupted twice if carried to completion.
infundibulum of Fallopian tube
In what part of the female reproductive tract does fertilization usually occur?