monotremes animals considered to be a transitional form btwn reptiles n mammals In these animals, defecation, urination, and oviposition (egg-laying) all occur through common orifice, the cloaca Ex: platypuses and echidnas cloaca the body orifice in monotremes which defecation, urination, and oviposition (egg laying) all take place Properties of the reproductive system - male and female Make gametes Secrete hormones to maintain repro organs as well as other systems Have ducts for moving gametes around Have glands for lubrication and gamete support Have complementary anatomy, so partners are held together briefly as gametes are exchanged gametes the haploid cells that when combined, make a unique human being Define genitals and gonads The genitals are all the structures of reproduction, both male and female The gonads: strucutre which produces gamates ~ testes and ovaries Properties of FEMALE reproductive system that males cannot do fertilization (union of gametes) implantation (attachment of embryo to uterus) parturition (labor and delivery) urology the medical specialty that treats disorders and diseases of the male reproductive system Anatomical features found in male Testes Ducts Accessory sex glands Urethra (shared btwn repro and urinary system) Penis (shared btwn repro and urinary systems) Anatomical features found in female Ovaries Uterine (Fallopian) tubes Uterus Cervix Accessory sex glands Vagina Explain what they do:  Testes Ducts Male accessory sex glands Testes: produce continuous supply of sperm; also make testosterone & other androgens Ducts: transport, store, and assist in maturation of sperm Accessory Sex glands: secrete bulk of seminal fluid What all does the penis do? encloses urethra as passageway for excretion of urine Penis and urethra used to introduce semen into female by coitus and ejaculation What do the ovaries do produce oocytes, progesterone, estrogens, inhibin, and relaxin stores and matures eggs What does the uterine tubes do "Fallopian" tubes transport oocyte to uterus is site of fertilization What does the uterus do site of implantation of fertilized ovum and supports development of fetus What do the FEMALE accessory sex glands do secrete fluid during coitus What all does the vagina and cervix do Vagina receives penis during coitus Cervix and vagina are passageways for childbirth spermatogenesis the making of sperm spermatozoa or simply sperm the gametes produced by the male are produced in the hundreds of millions Made in the testes, mature in the epididymis, then upon demand travel through ducts to be ejaculated What is one single sperm called spermatozoon scrotum a loose sack of skin loosely attached to the body wall house the testes the loose attachment is important as sperm production is highest at a temp about 2-3° lower than body temp has 2 muscles: dartos & cremaster spermatic cord a canal which carrie nerves, blood vessels, and the "vas" from inside the abdomen to the scrotum ductus deferens also called the vas deferens the ducts which carry sperm from seminiferous tubules to prostate one on each side, lead to midline urethra at prostate gland and end there dartos one of two muscles of the scrotum that helps support the testes, spermatic cord and spermatogenesis  surrounds the scrotal sac subcutaneously In cold conditions, causes the scrotum to become firm, drawing the testes toward body will cause wrinkles to appear in the sac when the muscle contracts **Lets dart inside, it's cold Cremaster one of two muscles of the scrotum that helps support the testes, spermatic cord and spermatogenesis  surrounds the testical; either draws the testes higher into the scrotal sac to protect them from danger or allows it to hang down **HAHA, I am your master, you will hang when I say you can hang Describe the inside of the testes Each testis is divided into compartments called lobules Each lobule contains 1 - 3 seminiferous tubules where sperm are produced tunica albuginea fibrous septum (collagen) which divides the testes into lobules What kind of cell actually makes spermatozoa spermatogenic cells Sertoli cells also called sustentacular cells support the function of spermatogenic cells basically make nursery environment for baby cells inside basement membrane stimulated by FSH from the pituitary **Sed (Syd) likes making babies in a tent (sustentacular cells). But Sadie said "Fuck Syd to Hell" (FSH hormone) androgens hormones which support the male metabolism and secondary sexual characteristics (Ex: things that are typically male but are not scrotum or penis) Leydig cells cells which produce androgens (primarily testosterone) also called interstitial cells outside basement membrane stimulated by LH from the pituitary sustentacular cells another name for sertoli cells interstitial cells another name for Leydig cells seminiferous tubules within each testis a series of tubules which lead to a central network; which then lead into the epididymis The tissue lining within generates gametes from a stem cell population; approx 600 per mm of tubule per day epididymis where spermatozoa are stored, and undergo final maturation closely associated w testis inside each scrotal sac erectile tissue consists of sponge-like venous passages which fill up with congested blood to make penis erect Has 3 chambers in penis Three chambers which become engorged by erection Corpus spongiosum ~ a midline structure that surrounds the urethra (keeping it open during  arousal) and also makes up bulk of glans penis Corpora cavernosa ~ paired (left and right), each lie in the body of the penis prepuce "foreskin" found on uncircumcised men partially covering the glans Summarize path of spermatozoa through duct system; from testes to ejaculation Released into lumen of seminiferous tubules of testes Mature in epididymis, wait for ejaculation Upon sexual stimulation leading to ejaculation, travel via ductus deferens  Critical fluids from seminal vesicles and prostate added Ejaculation through urethra of erect penis blood-testes barrier a basement membrane which separates the capillaries of the testes & interstitial cells from the lining of the seminiferous trubule spermatogonia stem cells found along the basement membrane of the seminiferous tubules, farthest from the luminal surface constantly divideing to either make more stem cells) new spermatogonia OR differentiated cells (primary spermocytes) What's the process of "making" a spermatozoon Gametes mature progressively as they move from basement membrane to lumen: Spermatogonia (mitosis) Primary spermatocyte   (meiosis I) Secondary spermatocyte  (meiosis II) Early spermatid Late spermatid   (maturation) Spermatozoa (sperm cell) Summarize the "sperm itinerary" Starts w male gametes formed in seminiferous tubules They collect together in rete testis (network of testicle) effterent ducts ⇒ ductus epididymis ⇒ ductus deferens Explain how spermatozoa are motile Sperm are only cells in human body with flagella Obviously, it allows them to be motile Spermatozoon is basically a "missile" (mitochondria for rocket fuel + flagellum) with a "payload" of paternal DNA rete testis created by seminiferous tubules collecting together After being produced in seminiferous tubules of testes, sperm move through here and cross imaginary border into the epididymis bulbourethral glands another name for Cowper's glands efferent ducts in the epididymis, sperm use this passage to enter ductus epididymis ductus epididymis Where sperm wait up to 14 days to mature If sperm are there longer than 14 days, they will resorb During maturation, they acquire mobility and ability to fertilize ovum How does sperm get into the ductus deferens When sexual activity occurs, a smooth muscle "shell" around epididymis contracts expelling sperm into the ductus Cowper's glands activated when spermatozoa are forced into ductus They secrete a small amount of alkaline fluid to lubricate and buffer pH of urethra Also called bulbourethral glands lie just inferior to prostate, on either side of urethra Where does the ductus meet the urethra? the ejaculatory duct (at the prostate) Here, secretions from the seminal vesicles and prostate are added Now the fluid is semen and can now be ejaculated Explain process of ejaculation Is a sympathetic reflex coordinated by lumbar spinal cord Internal urethral sphincter closes to prevent leakage of urine and backflow of sperm Contractions of muscles at root of penis result in emission Summarize the organs involved in semen production Sperm from testes and epididymis secretions from seminal vesicles and prostate gland also a small contribution from bulbourethral glands Semen facts: How much spermatozoa/day How much semen in average ejaculate How many spermatozoa per mL What's the pH Approx 600 spermatozoa/day Approx 2.5 to 5 mL semen in average ej. About 100 million spermatozoa per mL (below 20 mill/mL is defined as infertility) Is slightly alkaline @ 7.2 - 7.7, this helps neutralize acidity of male urethra and female vagina Explain clotting factors and reliquification of semen clots about 5 minutes after ejaculation ~ no one knows why, is from different clotting proteins than blood After about 10-20 minutes, semen liquefies PSA is one anti-clotting agents PSA prostate-specific antigen one of the major anti-clotting agent in semen also used to detect prostate cancer in men; however it's controversial how to use PSA levels to detect cancer as there is no evidence to support the relationship What's the purpose of the seminal fluid it nutrients semen provides a buffer is a fluid medium for delivery of ejaculate What does the seminal vesicles secretions contribute to seminal fluid helps w pH prostaglandins, and fructose (which is major nutrient which powers sperm motility) Seconday spermatocyte vs. secondary oocyte the secondary spermatocyte in the male is the haploid secondary oocyte is the "egg" What does prostate secretions contribute to seminal fluid contributes zinc, citrate and the enzyme acid phosphatase (used in forensic testing) Also gives semen a milky quality ovum the female gamete coitus sexual intercourse btwn male and female vulva collective term for the externally visible parts of female reproductive system Includes: mons pubis (mount of adipose tissue) labia majora (labia = lips) - outer lips (similiar to scrotum in male) labia minora - inner lips (spread exposes vestibule), forms prepuce of clitoris, covers 2 openings: urethral opening and vaginal opening external urethral orifice clitoris vaginal orifice hymen found on younger women a membranous structure which partially or completely covers the vaginal orifice A girls "cherry" Pelvis inflammatory disease refers to disease of the upper reproductive organs recall cervix helps keep unwanted organisms out of uterus & upper reproductive organs STD usually happen at the cervix ectopic pregnancy Recall the need for the uterine tube to have enough space for the oocyte and sperm to move around.  If there is any obstruction, such as scar tissue, there can still be enough room for a spermie to move past, but not enough room for an embryo Therefore, the egg attaches to the uterine tube. This is dangerous oophorsalpingohysterectomy the removal of ovaries, uterine tubes, and uterus What's the "egg" in the female the oocyte ova ovum - plural female gametes begin as oocytes they mature in the ovaries follicle a collective term referring to the structure (w/in the ovary) that encloses an oocyte, along w all the surrounding cells that help it grow and mature In general, the female repro system matures only one follicle per menstrual cycle Also, as more follicles develop, there will be an increase in estrogen production When do female reproductive years lie? Btwn menarche (first menstrual period) and menopause ( the time of last menstruation) primary oocytes describes the precursors to ova which undergo their last cell division before birth and remain in a quiescent (dormant) state until after menarche What influences a follicle (which surrounds a primary oocyte) to begin to change? under the influence of pituitary hormones and w hormonal feedback from the overaries and uterus Identify the stages of follicular development in the ovary Primordial follicles Primary follicles Secondary follicle Mature (Graafian) follicle Ovulation → secondary oocyte expelled Corpus luteum Degenerating corpus luteum Corpus albicans (scar tissue) primordial follicle The very beginning... :-) the smallest follicle contain a primary oocyte, and a single layer of follicular cells (which, as they develop, will be the estrogen producing cells) primary follicle a primordial follicle that has further developed: still has primary oocyte now there's multiple layers of follicular cells (granulosa cells- in several concentric layers) supporting the egg w hormones & nutrients secondary follicle (was a primary follicle) Is filling with follicular fuild & now has developed a follicular fluid-filled pocket (an antrum) The fluid will not only provide the oocyte with nutrients, but it will also help in the detachment of the egg from the wall of the follicle so it can be released antrum the follicular fluid-filled pocket, or space, that develops in a primary follicle after it's formed, the follicle is now a secondary follicle What happens to the primary oocyte right before it is released (via ovulation) it finishes meiosis I Graafian follicle another name for a mature follicle, also referred to as the tertiary follicle refers to a follicle that was a secondary follicle, but now the fluid predominates Thus the follicle is due to rupture (ovulation) In this phase the oocyte undergoes it's first mitotic division What happens to all the other follicles They are lost... will always have one dominant follicle The rest disintegrate and are reabsorbed *In the case of having twins, there were two dominant follicles. So it can happen; these would be fraternal twins, since it was from two different eggs ovulation a process in which a mature follicle ruptures In response to a surge of luteinizing hormone (LH) released from the anterior pituitary once each month, the mature follicle ruptures and releases a secondary oocyte **LORD HAve mercy.... What essentially is responsible for stimulating this whole process that works toward ovulation HaHa... it's mother nature's evil trick on females Once a gal hits puberty, it sends pulses of hormones (Gonadotropin releasing hormone) from the hypothalamus *Recall  hormones with "releasing" in it's name comes from the hypothalamus recall how LH and FSH hormones are released LH = luteinizing hormone FSH = follicle-stimulating hormone BOTH released from the anterior pituitary The hypothalamus releases GnRH (gonadotropin releasing hormone) into the hypohpyseal portal system; thus the anterior pituitary responds FSH: follicle-stimulating hormone released from the anterior pituitary is released early in the menstrual cycle stimulates development of the follicle in the ovary: promotes the maturation of a primary follicle into a secondary follicle, then into a mature follicle Therefore, FSH levels rise early in reproductive cycle How does the follicle respond to LH a burst of LH causes the mature follicle to rupture, releasing the oocyte secondary oocyte an oocyte that has been released from a ruptured follicle ovarian cycle refers to the changes in the ovary with each menstrual cycle estrogens secreted by secondary and mature follicles corpus luteum An endocrine structure which is the remnants of the follicle after it has ruptured & released the oocyte a yellowish, waxy substance  fills the follicle It secretes estrogen and progesterone IF CONCEPTION HAPPENS, corpus luteum stays intact and continues to secrete hormones  IF CONCEPTION DOESN'T HAPPEN, it begins to atrophy & turn into a hunk of scar tissue What job is progesterone and estrogen responsible for to maintain the lining of the uterus and prepare the womans body for implantation of the fertilized ovum If fertilization does not occur, or if embryo does not implant, menstruation proceeds corpus albicans a knot of scar tissue with no endocrine function, gets reabsorbed results from the corpus luteum "burning out" if conception doesn't happen after 14 days; it no longer secretes hormones The sudden drop in hormone output is what begins the next menstrual cycle w the sloughing off of the endometrium menstrual flow Summarize the "ovarian" cycle Day 1-14 pre-ovulatory Day 14 - 28 post-ovulatory Summarize follicular development in the ovary primordial follicle primary follicle secondary follicle mature (Graafian) follicle ovulation - secondary oocyte expelled corpus luteum degenerating corpus luteum corpus albicans (scar tissue) fimbriae Latin for "fringe" Long "fingers" of the uterine tube acts to "sweep up" the secondary oocyte and send it on it's journey along the uterine tube takes about a week for the oocyte to traverse the length of the tube What CAN occurs to the secondary oocyte as it travels through the uterine tube It can encounter sperm here if it does, the secondary oocyte rapidly undergoes a cell division to become an ovum The ovum can now be fertilized by the spermatozoa and become a zygote zygote a female gamete that was fertilized by a spermatozoa and genetics combine after fertilization, the zygote continues it's journey out of the uterine tube and into the uterus, where it will find an inplantation site Name layers of the uterus 3 layers: endometrium: inner layer myometrium: is thickest, middle layer (is smooth muscle) perimetrium: is outer, connective tissue layer (serosa layer, nearest the pelvic cavity) endometrium the inner lining of the uterus, nearest the lumen Has 3 layers:  simple columnar epithelium stratum functionalis stratum basalis *The stratum functionalis is shed monthly in menstrual cycle *The stratum basalis is the tissue from which the stratum functionalis generates from Identify the blood supply of the uterine wall Blood flows from: the internal iliac arteries → uterine arteries → arcuate and radial arteries The radial arteries branch into spiral arterioles, (which are shed along w the stratum functionalis) and straight arterioles (in the basalis, which are not shed) ** I Usually Aint Right... Slap me Silly Describe venous drainage of the uterus Simply drains into the uterine veins and then into the internal iliac veins summarize what happens after ovulation A secondary oocyte is released from ovary at ovulation Swept up by fimbriae of uterine tube Oocyte may encounter sperm in uterine tube IF IT DOES, secondary oocyte undergoes the final meiotic division to form an ovum If spermie & ovum unite, zygote is formed Zygote travels to uterus where it implants Clarify: secondary oocyte vs. ovum vs. zygote A female ovulates & releases a secondary oocyte When sperm enters egg, and egg finishes meiosis II, THEN it's an ovum When sperm and egg nuclei actually unite, then it's a zygote Describe the uterine cycle Generally the menstrual cycle is 28 days w menstruation lasting 7 days 3 "stages" : proliferative phase secretory phase menstruation *menstruation and proliferative phases are pre-ovulatory secretory is post ovulatory How is "day 1" of the uterine cycle marked? The menstrual cycle begins with the sloughing off of the previous cycles tissue (the menstrual flow) The constriction of the arteries leading into the stratum functionalis causes that layer to die and slough off What happens during menstruation the stratum functionalis and its associated blood vessels (spiral arterioles and venules) are lost w layer of endometrium Day 1 of menstrual cycle marked by the sloughing off of tissue that was build during previous cycle, flow can last 7 days depending on person Proliferative phase of uterine cycle Time in which the stratum functionalis is rapidly rebuilt, along w arterioles and venules Begins when menstruation ends, Goes up through about day 14 *Recall main hormone coming from follicle during this time (approx day 5 - day 14) is estrogen, therefore estrogen is in direct correlation of menstrual flow If one cycle has more estrogen (for whatever reason) there will be an increase in flow Explain estrogens job It's influence is pre-ovulation follicles produce estrogen, estrogen causes rapid growth of stratum functionalis Other jobs: ~Promote development/maintenance of female repro structures, 2ndary sex characteristics, breasts ~Increase protein anabolism ~Lower blood cholesterol ~Moderate levels inhibit release of GnRH, FSH, and LH **I Love Rough Sex Inside secretory phase of uterine cycle occurs at ovulation, ideally at day 14 the venules and spiral arterioles in endometrium enlarge this is in preparation for the implantation of the zygote  Hormone that is post-ovulatory coming from corpus luteum is progesterone ~if embryo does implant in uterine lining, will occur about day 21. It will need rich blood supply to build placenta and feed embryo ~If no implantation happens, around day 26 the endometrial lining loses hope and menstruation begins So what is the job of progesterone It's influence is post-ovulation Is secreted by the corpus luteum Causes the endometrium to mature in preparation for implantation of a zygote make "potting soil" pro- in favor of; -gestation Also: ~works w estrogens to prepare for implantation ~Prepares mammary glands to secrete milk ~Inhibits release of GnRH and LH menorrhagia abnormal bleeding (menstrual) While the average is  36mL per cycle, more than 80mL is considered abnormal How are the ovarian and uterine cycles synched? Hormones secreted by pituitary , follicle, corpus luteum and endometrial glands are used to coordinate ovarian and uterine cycles Summarize what is happening in the ovarian and uterine cycles early in the menstrual cycle During last half of menstruation, FSH released from anterior pituitary causes one lucky primordial follicle in ovary to start developing.  It becomes a primary follicle As FSH remains high, the primary follicle develops into a secondary follicle at the beginning of endometrial proliferation phase Summarize what is happening in the ovarian and uterine cycles in proliferation phase up to ovulation At beginning of proliferation, a secondary follicle was formed As it further develops into a mature follicle, it begins secreting estrogens to help maintain the growth & development of the stratum functionalis  At midpoint of cycle, approx day 14, a burst of FSH and LH triggers ovulation which marks  beginning of secretory phase summarize spikes of hormones throughout cycle At beginning of cycle, FSH spikes a little to encourage follicle development As follicles develop, a increase in estrogen occurs At ovulation, LH suddenly spikes to release egg, which then drops back off That's when progesterone increases, along with a slight increase in estrogen, from the corpus luteum Once progesterone drops (if not fertilization occurs) triggers menstration Inhibin hormone secreted by corpus luteum Inhibits release of FSH (mostly) and, to lesser extent, LH Simply keeps body from starting another cycle before it's ready Relaxin hormone secreted by corpus luteum Inhibits contractions of uterine smooth muscle to allow easier implantation (from cycle to cycle) Plays key role during labor= increases flexibility of pubic symphysis & dilates uterine cervix, also relaxation so baby can drop parturition childbirth Why is estrogen always referred to in the plural sense? There are 3 different chemicals call estrogens: E1 estrone is main form found in body during menopause and later E2 17β-estradiol is the predominant estrogen found in nonpregnant females E3 estriol is main estrogen during pregnancy & is made by fetal liver SRY Sex-determining region Y All 5 wk embryos start out w indifferent gender After that, a small region of the Y chromosome kicks into action (SRY) IF SRY is present & active & not mutated, then embryo develops male gonads *oddly, is only important gene on Y chromosome hermaphrodites more modern term is intersex describes individuals who had errors in the SRY gene Therefore, they developed gonads somewhere btwn "SRY-on" and "SRY-off" Describe analogous structures btwn male & female The same embryonic structures develop into one thing if SRY is active, another if it's not Therefore, the same lump of tissue will develop into one thing if its male, another if it's female Describe analogous structure: gonads Male: testes Female: ovaries Describe analogous structure: paramesonephric (Müllerian) ducts Male: [degenerate] Female: uterine tubes, uterus, vagina describe analogous structure: glans area of genital tubercle Male: glans penis, corpora cavernosum Female: clitoris Describe analogous structure: urethral folds of genital tubercle Male: penile urethra Female: labia minora Describe analogous structure: labioscrotal swellings of genital tubercle Male: Penis, Scrotum Female: Labia majora Male: corpus spongiosum Female: pubocervical fascia, vestibular bulb other analogous structures btwn male and female Male: prostate Female: Paraurethral glands (G-spot) Male: bulbourethral glands Female: greater vestibular glands Both contribute to lubrication perineum the region surrounding the genitals and anus one area where males & females differ (duh) Traditionally divided into 2 regions: urogenital triangle and anal triangle spermatic cord the channel through which the descent of the male testes from the embryonic position in the abdomen, into the scrotal sac (approx 7 months gestation) Is a mechanically weak point and common place for inguinal hernias for males Describe hormonal control in the male for gamete production Similar to females, GnRH is secreted (from hypothalamus) which acts to secrete FSH or LH *No follicles in males, duh FSH acts as stimulant to spermatogenic cells and Sertoli cells of testes LH acts on Leydig cells of testes, which secrete testosterone...which may be converted to the active form DHT DHT dihydrotestosterone a male hormone that alters secondary sexual characteristics How is spermatogenesis promoted? In the presence of FSH, testosterone and androgen-binding protein (from Sertoli cells) promote spermatogenesis What does the hormone "inhibin" do in males Controls a negative feedback loop which ensures that sperm are not over-produced Recall mitosis Is the reproduction of somatic cells; where DNA content is doubled (during S phase) and then divided equally btwn 2 daughter cells retains it's ploidy (chromosome content) Therefore, somatic cells are diploid diploid refers to a cell which has two copies of every chromosome Ploidy vs  n number The ploidy of a cell refers to the number of copies of each chromosome present in the cell nucleus The n number refers to the number of copies of each unique DNA strand in the nucleus As each chromosome contains 1 or 2 strains of DNA at different stages of the cell cycle (whether mitotic or meiotic) these numbers do not always coincide haploid refers to mature gametes that have only one copy of each chromosome Therefore, haploid gametes w one DNA strand per chromosome are said to be 1n In some stages of cell cycle, diploid cells also have 1 DNA strand per chromosome, and hence are  2n  During earlier stages or meiosis or mitosis, each chromosome of a diploid cell has 2 strands of DNA (has a sister chromatid)= 4n crossing over an important feature unique to meiosis In prophase of meiosis I, genetic recombination occurs (scrambling of pieces of chromosome) Ensures twins are not born years apart Differences btwn mitosis & meiosis: daughter cells Mitosis is cell division where DNA of daughter cells is exactly the same sequence as parents (daughters are clones) Meiosis involves tetrad formation and crossing over Differences btwn meiosis & mitosis: reduction division or multiplication? Mitosis preserves the ploidy & n # of cell. Always diploid, and alternates btwn 2n and 4n. Multiplication of n number during S phase, division during M phase. Meiosis is a reduction division. The precursors of gametes are diploid (2n). The resulting cells are haploid. It's when 2 haploid cells meet, it returns to being diploid. Differences btwn meiosis & mitosis: cycles or non-cycles Mitosis is a cyclical process. It repeats Meiosis is a "one-way street"; once cells become gametes, they cannot ever reproduce new cells except by joining another gamete in fertilization Describe correlation btwn spermatogenesis with mitosis Recall in males, gametogenesis begins with the stem cell, spermatogonia Spermatogonia undergo mitosis to produce a clonal population As long as they stay near the basement membrane, they remain a stem cell and divide by mitosis  Describe the correlation of spermatogenesis and when/how they go through meiosis If a spermatogonia leave the basement membrane of seminiferous tubule, they begin the process of differentiation. They become primary spermatocytes (diploid, 4n) Primary spermatocytes undergo meiosis I to become secondary spermatocytes (haploid, 2n) In meiosis II, they split their DNA into individual chromatids (1 copy DNA per cell), so they end up haploid, 1n spermatids They continue further differentiation but no further changes in DNA content is made, so they end up as haploid, 1n spermatids Explain meiosis I in oogenesis OOgonia undergo their last mitotic division in female fetus Meiosis I begins at that time, generating primary oocytes The primary oocytes lie suspended halfway through meiosis I for 10-50 years. Each month after menarche, 5-12 primary oocytes respond to hormonal signals  In general, only 1 progresses to 2ndary oocyte remaining material becomes first polar body polar body first polar body: the remaining genetic material that is "tossed in the garbage disposal" after a primary oocyte progresses all the way through meiosis 1 to form a secondary oocyte second polar body: only formed is a spermatozoon penetrates the egg, and the 2ndary oocyte is able to complete meiosis II to become an ovum. Again, the left over genetic material from the reduction division In what circumstances does a 2ndary oocyte complete meiosis II Once a primary oocyte completes meiosis I and forms a secondary oocyte, that secondary oocyte begins, but doesn't complete, meiosis II.  Meiosis II is only completed is a spermatozoon penetrates the 2ndary oocyte. Then it completes meiosis II and becomes an ovum (this also generates the second polar body) pronuclei describes the female DNA (n DNA content) and male DNA (n) after an ovum is produced (via penetration of sperm into egg) They remain separate as male and female pronuclei Eventually they will fuse to form the diploid zygote (2n) time zero - of embryonic development refers to the fusion of the male and female pronuclei to form a zygote Summarize meiosis I for female During fetal development, meiosis I begins After puberty, primary oocytes complete meiosis I, which produces a 2ndary oocyte and a first polar body that may or may not divide again summarize meiosis II for female The secondary oocyte begins meiosis II A secondary oocyte (and first polar body) is ovulated After fertilization, meiosis II resumes. The oocyte splits into an ovum and a second polar body Differences btwn male and female gametogenesis Male: spermatogonia continuously undergo mitosis to generate primary spermatocytes Meiosis 1 generates 2ndary spermatocytes Meiosis II generates spermatids continues throughout lifetime Female: All oogonia generated b4 birth Primary oocytes start meiosis I After completion of meiosis I, just b4 ovulation, Primary oocyte becomes 2ndary oocyte; meiosis II begins Meiosis II only completed at fertilization What marks the onset of puberty for both sexes Males: spermatogenesis Females: menarche Also, both are marked by development of 2ndary sexual characteristics Primary sexual characteristics Male: penis, scrotum, associated glands Female: vulva, ovaries, uterine tubes, uterus, associated glands They define gender Secondary sexual characteristics those that are different btwn genders but not definitive Ex: males tend to be more muscular w deeper voices Male: body hair on face, chest, pubic region, arms and legs, deeper voice, adams apple Female: body hair in pubic region, arms and legs, larger breasts, wider hipds Name some factors that may be responsible for the change in average age of menarche internal cues external cues increased obesity ~adipose tissue acts as an endocrine organ and may alter the developmental clock penile plesmythograph an instrument for measuring penile erection Components of sexual arousal There are at least 2: reflexive, mechanical dimension ~ which is obviously easier to study than the other mentioned... also easiest to study in men spiritual dimension Who started the study of human sexuality Thanks be to the landmark studies in 1948 by: Kinsey, Pomeroy and Martin They began the field of study Masters and Johnson advanced the field greatly in the 1960's Nerves of sexual response Primarily controlled by autonomic nervous system  Incoming sensory info from structures which produce sexual arousal: S2-S4  Outgoing striated motor and parasympathetic autonomic also S2-S4  Outgoing sympathetic autonomic at T10-T12 The brain clearly influences this basic reflex pathway What process cause penile erection Penile erection results from congestion in the corpora cavernosa 3 processes working together: ~relaxation of smooth muscle in corpora cavernosa, allowing blood to fill open spaces in this spongy tissue ~increase in arterial blood flow to penis ~restricted flow of blood out of the penis (venous congestion) What is released via stimulation of nerves S2-S4 NO (nitric oxide) VIP (vasoactive intestinal polypeptide) CGRP (calcitonin gene-related peptide prostaglandin What effects on erection does NO play ~ nitric oxide Promotes dilation of blood vessels through out body In turn, promotes penile erection by stimulating all 3 processes sildenafil Viagra causes penile erection by inhibiting an enzyme which breaks down an NO-related signaling molecule (PDE5) Therefore, Viagra blocks PDE5 and prolongs smooth muscle relaxation What areas in the female are consistently engorged in sexual arousal only 2 have been found: the clitoris and vestibular bulb vestibular bulb the area surrounding the female introitus introitus the entrance to the vagina what female tissues are homologous to the corpus spongiosum penis in males the vestibular bulb the pubocervical fascia (Halban's fascia) and the paraurethral glands (Skene's glands) sexual neutrality the idea that women engage in sexual intercourse because of desire for emotional closeness Models of female sexual arousal 3 competing models: Masters n Johnson: based on "male", hydraulic model of sexual arousal Kaplan: motivational motel Basson: sexual neutrality The Masters and Johnson model of female sexual response: 4 stages of sexual arousal excitement plateau orgasm resolution Focus is on physiological response; based on modification of male sexual response Kaplan model of female sexual response is a modification of Masters and Johnson, but w an additional phase added at beginning & 4 stages compressed to only two 1. Desire ~ a psychological motivation to engage in sexual behavior 2. Excitement ~ similar concept as in Masters and Johnsons model 3. Orgasm ~ reflexive component, w reflexive pelvic muscle contractions Basson model of female sexual arousal Based on "sexual neutrality" posits that emotional intimacy is primary motivator Once search for intimacy leads to sexual behavior, the physically pleasurable aspects take over, and sexual arousal occurs sperm capacitation takes place in the uterine tube flagella are stimulated to beat more vigorously # of chemicals (cholesterol, glycoproteins, and proteins) r removed from spermatozoa in preparation to fuse w secondary oocyte acrosome the "head" of the sperm profilactin unpolymerized actin in acrosome of spermatozoon acrosomal reaction the process of converting profilactin into actin this helps spermatozoon penetrate the secondary oocyte describe dizygotic twins fraternal occur when 2 oocystes are shed, usually one from each ovary monozygotic twins occure when the zygote splits into two embryos in an early division identical twins What happens in the rare case 2 spermies penetrate an oocyte fertilization doesn't occur This is POLYSPERMY... the idea that it's possible for more than one sperm to enter the oocyte blocks to polyspermy there are at least 2: Block to polyspermy One is fast (which is very detailed), the other is slow (which involves the cortical reaction) Two layers surrounding the oocyte which sperm must penetrate corona radiata zona pellucida corona radiata "radiant crown" made by granulosa cells from the follicle partially surround the ovulated secondary oocyte outer layer zona pellucida the inner layer surrounding the ovulated secondary oocyte sperm must penetrate is a thick, clear layer cortical reaction caused by the penetration of the oocyte by the 1st spermatozoon causes Ca++ to be released from cortical granules in the oocyte This lifts the zona pellucida off egg, making it impossible to pass Unless the zona pellucida is in close contact w oocyte, sperm can't penetrate Define fertilization When the sperm and egg unit Forms a diploid = zygote Is the moment which starts out developmental "clock" Describe first week after fertilization the embryo travels from uterine tube, where fertilization almost always occurs near distal end of tube,  Along the way, it continues the process of mitotic cell division two-cell embryo results from the first division of the zygote, resulting in two symmetrical, equal cells *the splitting of the cell at this point will result in monozygotic twins forming four-cell embryo next division of embryo, takes place on day 2 produces 4 equal, almost identical cells morula the stage after four-cell embryo; seen at day 4 when simple pattern of cell division is lost "raspberry" blastocyst when the embryo forms a hollow, fluid filled ball seen about day 5 What leads to implantation happens about day 6 blastocyst makes contact w endometrium of uterus Inner cell mass develops Problem: embryo is "foreign issue (half of genes not from mom) so involves evading mother's defense mechanisms (since dad's DNA is foreign) Inner cell mass develops when the point of contact btwn blastocyst and endometrium causes uterus to release chemical factors implantation days 8 - 12 Upon implantation, the blastocyst divides into three parts: ~trophoblast ~innercell mass→ embryonic disc ~yolk sac The endometrial lining becomes the decidua By day 12, embryo is completely covered by endometrial tissue Gastrulation Happens approx day 16 the process by which an embryo folds in on itself to form 3 layers: ectoderm ~ becomes skin & nervous system mesoderm ~ becomes connective tissue, muscles and bones Endoderm ~ becomes gut tube carcinoma vs. sarcoma When cancer occurs, it's named by tissue of origin Carcinoma refers to tissue from the ectoderm Sarcoma refers to the tissue from the mesoderm Name ectoderm derivatives: epidermis teeth jaws nervous system posterior pituitary **Every Tom & Joe Needs Pussy Name Mesoderm derivatives: Somites Kidneys Heart Reproductive system Gonads **Sadly Kissing Happened Regularly, George Name endoderm derivatives Lungs  bladder Thyroid Liver Pancreas Lining of digestive tract **Please... Let The Bitch Lie Longer?? What is the breakdown of somites (from the mesoderm derivatives) Look like little "speed bumps" of the mesoderm, when form into: dermatome = dermis sclerotome = vertebrae myotome = skeletal muscles, appendicular skeleton decidua term used for the uterine lining during pregnancy extraembryonic membranes represent a collaboration btwn mom & baby Deals with the fact that the embryo is different from mom's tissues (is foreign) and also convinces mom to feed and protect embryo The joint project is called the placenta placenta & function a joint project btwn mother and baby is half embryonic tissue & half maternal Placenta will: provide food to embryo Provide oxygenated blood to embryo Protect embryo from invaders w maternal antibodies (only IgG antibodies can pass placental border) How does the placenta begin With the development of lacunae (open spaces) which form immediately after implantation chorionic villi (pl), chorionic villus (sing) loops of blood vessels formed by embryonic tissue important as the first structures of developing embryo that can be biopsied to detect genetic defects of the embryo Since this is completely derived from embryonic tissue, and not maternal tissue, and chromosomal abnormalities can be fully attributed to embryo Most common detected is trisomy 21 (downs) Chorion the circular "wall" around the entire embryonic project area nondisjunction chromosomal abnormalities, can occur during meiosis I or Meiosis II Recall w meiosis, all 4 chromatids r suppose to arrive in different daughter cells In nondisjunction, chromatids fail to separate and both go to the same cell: one gamete get two copies of chromatid 21 Therefore, at fertilization, Dad contributes one copy, Mom contributes 2, so child ends up with 3 copies What resulting X & Y combinations can there be with Trisomy 21 Resulting embryo can be XXX, XXY, XO, or YO YO embryos do not survive List blood flow btwn mom and baby maternal circulation ⇛ maternal endometrial arteriole ⇛ fetal blood vessels in chorionic villi ⇛ umbilical vein (IS OXYGENATED BLOOD) ⇛ embryo ⇛ umbilical artery (IS DEOXYGENATED BLOOD) ⇛ fetal blood vessels in chorionic villi ⇛ maternal endometrial venule Anlagen The initial clustering of embryonic cells from which a part or an organ develops organogenesis The time when individual organs start to develop from precursor tissues found in the appropriate layer begins once gastrulation has occurred & 3 embryonic layers are formed Day 20-28 neural folds a prominent feature of the dorsal surface of embryo, forming a distinct groove The lips of this groove meet to form a neural tube, which will twist and fold to form the brain critical period time when systems are sensitive & can be harmed by teratogens when a system can be changed during the embryonic period teratogens substances that can cause birth defects Ex: rubella ("german measles") toxoplasma (cat feces) radiation cytomegalovirus embryonic period defined as fertilization to 8 weeks After this time, the fate of most organ systems is set Fetal period 9 weeks to 40 weeks There is growth and development, but most of fetal period involves the organs carrying out developmental plan set out during the embryonic period 4 hormones that are released directly by the placenta hCG (human chorionic gonadotropin) relaxin hCS (human chorionic somatomammotropin) CRH (corticotropin-releasing hormone) hCG human chorionic gonadotropin - hormone released by placenta released by chorionic membrane, acts on gonads Supports the function of the corpus luteum, keeping it "alive" for about 3 more months Basis for home pregnancy testing relaxin hormone released by placenta that helps at childbirth by making pubic symphysis more flexible, and aiding in dilation of cervix during labor hCS human chorionic somatomammotropin - hormone released from the placenta alters maternal metabolism, increasing protein synthesis to enhance growth decreasing glucose use and increasing fatty acid use for ATP CRH corticotropin-releasing hormone - released from placenta establishes the time of birth and increases cortisol secretion from the adrenal cortex Hormone Levels vs. gestational age Spike of hCG is earliest, peaking btwn 8-10 wks Slow rise in progesterone and estrogens from maintenance of corpus luteum: levels of estrogens rise steadily through pregnancy levels of progesterone rise steadily, but begin to drop slightly at end of pregnancy Cardiovascular changes during pregnancy increased blood flow to placenta (duh) ⇧ stroke volume ⇧ cardiac output ⇧ heart rate ⇧ blood volume compression of inferior vena cava, leading to edema in legs and varicose veins compression of renal artery may lead to renal hypertension Respiratory changes during pregnancy ⇧ tidal volume ⇧ ventilation ⇧ total oxygen consumption ⇩ expiratory reserve volume dyspnea possible Urinary changes during pregnancy increased urination due to fetus sitting on bladder, duh increased glomerular filtration rate toxemia of pregnancy pre-eclampsia cardial signs are rapid rise in BP to hypertensive levels & proteinuria HELLP syndrome Life-threatening condition Hemolytic anemia, Elevated Liver enzymes, Low Platelet count 3 stages of labor dilation stage expulsion stage placental stage dilation stage of labor From onset of labor to dilation of cervix Lasts about 6-12 hours regular contractions Usually rupturing of amniotic sac Ends w complete diation  The estrogen/progesterone ratio, increased maternal oxytocin release, and increased fetal oxytocin release probably play a key role in initiating parturition Expulsion stage can last 10 minutes to several hours begins w dilation of cervix, ends with delivery Placental stage The final stage to labor can last 5 to 30 minutes Ends w expulsion of placenta Powerful uterine contractions expel placenta and help control bleeding Describe feedback loop of labor Is rare example of positive feedback loop Input: stretching of cervix sends sensory info to brain Processing & output: brain interprets signal, releases oxytocin from posterior pituitary Oxytocin causes uterus to contract more forcefully This pushes baby further into cervix, increasing stretch Delivery of baby stops feedback loop *Synthetic oxytocin (Pitocin) can be used to stimulate this homeostatic loop milk let-down reflex another positive feedback loop associated with childbirth allows newborn to suckle Only involves releasing stored milk Input: baby sucks nipple Processing & output: hypothalamus and posterior pituitary  Releases oxytocin which stimulates "milk let-down reflex" Cycle continues until baby stops suckling mammary glands are modified sudoriferous (sweat) glands which produce milk Alveolar glands w/in fat tissue of breast are surrounded by myoepithelial cells, which contract in response to oxytocin This ejects milk from alveoli summarize breast structure Bulk of breast is adipose tissue, embedded within are alveolar glands 15-20 lobes per breast, separated by fat tissue lobes have lobules that contain alveoli Coopers ligaments also referred to as suspensory ligaments maintains structure of breast become stretched throughout life Whats the probability of concenption from a single, unprotected act 2-4% Peak probability of conception if at days 12-14 Sperm survive 3 days, so intercourse slightly after ovulation has higher probability of conception than intercourse after ovulation