Reproduction

Reproduction

Reproduction Male Reproductive Sys. Hormones A. Testosterone (an androgen) -androgens promote male characteristics -produced by Leydig cells -Leydig cells-interstitial cells of the testes that are found near blood vessels (between

seminiferous tubules) Male Reproductive Sys. Hormones A. Testosterone (an androgen) -testosterone promotes: -growth -secondary sexual characteristics -activity of male reproductive organs

Male Reproductive Sys. Hormones B. FSH (follicle stimulating hormone) -stimulates production of sperm C. LH (luteinising hormone) -stimulates production of testosterone **FSH and LH are considered to be female hormones (related to menses,

but they are found in males in smaller concentrations) Male Anatomy A. Testes=gonads -made of seminiforous tubules that produce sperm -contain Leydig cells that release testosterone

Male Anatomy B. Scrotum-bag of skin that holds the testes and allows them to hang away from the body -function: keep temperature of testes below body temperature (body temp=36.7C98F) (testes temp=34.4C94F) -temperatures around normal body temp could damage sperm count -temp is controlled by contracting and

relaxing muscles that move the testes toward or away from the body Scrotum Male Anatomy C. Epididymis-after production, sperm leave the seminiforous tubules and enter the epididymis

-About 60m in length -takes sperm 20 days to travel through -while in the epididymis sperm mature (gain ability to swim and fertilize) -stored here until ejaculation Epididymis and vas deferens #1 - 6 are all parts of the epididymis #7 is the vas deferens

Male Anatomy D. Vas deferens=muscular ducts that connect the epididymis to the ejaculatory ducts -during ejaculation the walls of the vas deferens contract and propel the sperm forward to the ejaculatory duct -from here the sperm go to the urethra and are released through the penis

Male Anatomy E. Accessory glands (three of them) -add secretion to the semen -semen=all of the fluid released during ejaculation a. seminal vesicles -secretions make up 60-70% of seminal fluids volume -secretions include sugar, coagulating enzymes and proteins -found behind the bladder

Male Anatomy E. Accessory glands (three of them) b. prostate gland -stores and secretes 1030% of seminal fluid -helps expel fluid during ejaculation -largest semen secreting gland -some medical problems effecting older males *prostate cancer *enlarged prostate (this is why older men must get rectal

exams) Male Anatomy E. Accessory glands (three of them) c. Cowpers gland (bulbourethral gland) function: during arousal each gland produces a clear viscous fluid (pre-ejaculate) -flushes out residual materials and lubricates the urethra for spermatozoa

-Cowpers fluid may contain sperm **this is why the withdrawal method of birth control doesnt always work Male Anatomy F. Penis-has three cylinders of tissue -during arousal the erectile tissue fills with blood -the blood pressure causes the veins leading away from the penis

to be sealed off -this causes an erection(when the penis becomes rigid due to the erectile tissue filling with blood) Male Reproduction G. Glans penis-the head of the penis -more sensitive than other areas because the skin covering it is much thinner

H. Prepruce-foreskin -covers the glans penis -may be removed with no impact on health or hygiene Male Secondary Sex Characteristics A. Facial and chest hair B. Larger voice box/Adams apple C. More muscle/Broader shoulders

D. Fat deposits on waist E. Larger bone structure Kidneys Ureters Bladder Urethra Vas deferens Seminal vesicle Prostate gland Cowpers gland

Epididymis Testis Scrotum Penis Glans penis prepuce Female Hormones A. FSH -stimulated ripening of the ovarian follicles for ovulation -the growing follicle releases

estrogen -follicle -a small ovarian sacs containing an immature ovum; Graafian follicle Female Hormones B. Estrogen -increases thickness of the endometrium (inner wall of the uterus) -inhibits FSH production -promotes secondary sexual characteristics

-inhibits milk secretion -high levels can cause nausea -stimulates LH production Female Hormones C. LH-stimulates ovulation and formation of corpus luteum -corpus luteum -a mass of cells that are formed from an ovarian follicle after release of a mature egg

-secretes progesterone D. Progesterone-keeps the endometrium intact (unless fertilization does not occur) -inhibits FSH and LH release -inhibits ovulation and milk secretion -produced by temporary endocrine gland (corpus luteum) Female Reproduction E. If fertilization does not occur the corpus luteum degenerates

-menstruation occurs -FSH is produced again, thus stimulating another follicle Hypothalmus Pituitary gland Inhibits FSH Stimulates LH

The effects of hormones on the menstrual cycle 1 Inhibits FSH and LH

FSH LH Growing follicle Ovulation 7

Corpus luteum Estrogen Progesterone Builds up endometrium Maintains endometrium

14 28 Menstrual cycle Menstrual cycle

Order of changes in the ovary The Menstrual Cycle A. B. Occurs in women between puberty and menopause who are not pregnant Controlled by hormones FSH, LH,

estrogen and progesterone -FSH and LH-produced by pituitary gland -Estrogen and progesterone-produced by ovaries The Menstrual Cycle 1. FSH stimulates follicle development and estrogen secretion 2. Estrogen causes production of more FSH (a positive feedback circuit) 3. Estrogen levels peak and stimulate

LH secretion 4. LH peaks and causes the follicle to rupture (ovulation begins) The Menstrual Cycle 5. Estrogen secretion declines and progesterone increases (a negative feedback circuit) 6. After ovulation, LH stimulates follicle to become corpus luteum 7. Corpus luteum secretes progesterone

8. Progesterone prepares uterus for an embryo The Menstrual Cycle 9. High progesterone and estrogen stop FSH and LH secretion (negative feedback because FSH and LH stimulated progesterone and estrogen) 10. If fertilization does not occur progesterone and estrogen levels fall.

11. Eventually, they become low enough for FSH and LH secretions to begin again. 12. After menstruation the cycle begins again and FSH stimulates follicle development Female Secondary Sex Characteristics A. Breasts B. Rounder hips C. Menstruation begins (average age

=12) -can begin as early as 8 or as late as 16 Female reproductive organs Female Anatomy A. Ovaries-egg producing reproductive organ -homologous to male testes -a.k.a. the female gonads

Female Anatomy B. Follicle-made of one egg surrounded by several layers of follicle cells -function: protect the egg -women are born with their total number of follicles (between 400,000 and 1,000,000) -only several hundred follicles release

eggs (one per menstrual cycle) -follicles expel eggs by ovulation Female Anatomy Ovarian follicles Stages of follicular growth Female Anatomy C. Corpus luteum-a temporary

endocrine gland that secretes progesterone to maintain the endometrium during pregnancy -if pregnancy does not occur the corpus luteum degenerates and a new follicle matures for the next cycle Female Anatomy Female ovary with two corpus lutea

Female Anatomy Normal corpus luteum Female Anatomy D. Oviducts-the fallopian tubes -moves the egg from the ovary to the uterus -has cilia on the inside to help move egg E. Uterus-the womb -between the cervix and oviducts -a thick muscular organ

-can expand to hold a 4kg fetus (8.8lbs) F. Endometrium-inner lining of the uterus Uterus, oviducts and ovaries Female Anatomy G. Cervix-lower portion of the uterus that joins to the vagina -has a cone shape -dilates up to 10cm during birth -samples of the cervix are removed

during a pap smear to test for cervical cancer Female Anatomy H. Vagina-thin wall chamber -leads to bodys exterior -an elastic muscle about 4 inches in length and 1 inch in diameter (there is a lot of variation) -has a 45 degree angle (relative to uterus) -forms the birth canal

-where sperm is deposited during copulation Female Anatomy I. Hymen-vascular membrane that partly covers the opening to the vagina -ruptured during intercourse or strenuous physical activity -no known anatomical function -not an indication of virginity

Assignment 1. Draw and annotate a diagram of the female reproductive system. Include: Bartholins gland vagina labia majora labia minora clitoris urethra bladder

uterus ovary oviduct Birth Control (Permanent Methods) Birth control=methods to prevent conception A. Permanent methods

1. Tubal ligation-cutting or tying of the oviducts (prevents eggs from reaching uterus) 2. Vasectomy-cutting or tying of the vas deferens (prevents sperm from leaving the body) Birth Control (Barrier Methods) Condom-a sheath of rubber rolled over

the penis before ejaculation -prevents sperm from entering the vaginal canal -PREVENTS STDs -failure rate 2%-15% Birth Control (Barrier Methods) Cervical cap/diaphragm-a firm rubber cap is placed over the cervix before

intercourse -prevents sperm from entering the uterus -failure rate= about 18% Birth Control (Chemical Methods) Spermicides -creams, jellies, foams or sponges placed

inside the vagina -kill sperm cells -must be inserted 20-30 minutes before intercourse -when used alone the failure rate is 20%-30% Birth Control (Chemical Methods) The Pill (two main types)

1. combination-has estrogen and progestin -prevents ovulation (discharge of eggs from the follicle) 2. mini-pill-has progestin only (progestin=synthetic progesterone) Birth Control (Mini-Pill) -reduces amount of cervical mucous -mucous that is present thickens in order to prevent sperm from reaching the egg

-endometrium is very this, thus if an egg were fertilized the developing blastocyst would not be able to implant Birth Control (Chemical Methods) Benefits of the pill (other than pregnancy prevention) -protect against ovarian cancer and endometrial cancer -lowers risk of cysts

-useful for anemic patients with irondeficiencies Birth Control (Chemical Methods) Side effects of the pill -blood clots -stroke -heart attack -nausea -headaches -fluid retention -weight gain -irregular bleeding

Failure rates (when used correctly) -mini-pill 1-2% -combination 1-3% Failure rates (when used incorrectly) -8-10% Birth Control (Other Methods) IUD-intrauterine device -small, plastic, flexible devices that are

inserted in the uterus by a doctor Birth Control (IUD) In the U.S. only two types are available -both are T-shaped -one is covered with copper and is replaced every 8 years -the other contains progestin that is slowly released for one year, then is replaced -failure rates: 4-5%

-work by preventing implantation of fertilized egg **(this is controversial) Birth control (Other Methods) A. Withdrawal-if the man withdraws the penis before ejaculation, most sperm cells will not enter the vagina -failure rate: 4-27%

B. Rhythm method/calendar method -use of the calendar or temperature chart to determine times of ovulation -failure rate: 25% C. ABSTINENCE (failure rate: 0% ) **MOST FAILURE RATES ARE CAUSED BY IMPERFECT USE OF THE

CONTRACEPTIVE!! Family Planning A. Things to consider (arguments for contraception) 1. overpopulation 2. future of children 3. carriers of genetic illnesses 4. decrease abortion 5. women can choose whether to become pregnant or not

B. Things to consider (arguments against contraception) 1. may increase promiscuity 2. people may use abortion as contraception 3. religion (let nature take its course) 4. unknown biological effects on body Take 5-10 minutes to. . . 1. Explain how hormones control the

menstrual cycle in females. [8] Fertilization and Early Development A. B. C. D. Sexual intercourse-copulation

Semen is ejaculated into vagina Sperm swim through cervix, up the uterus and into the oviducts If an egg is present in the oviduct, a sperm fuses with it (fertilization) to produce a zygote Early Development E. Zygote-diploid product from the union of haploid gametes (sperm and egg) F. Zygotes divide by mitosis to form an

embryo -eventually, so many divisions happen that a hollow ball is formed G. Blastocyst- hollow ball of cells -about 1 week after fertilization Early Development H. During the mitotic cell divisions the embryo is transferred down the oviduct to the uterus I. The blastocyst implants into the

endometrium (the blastocyst is covered with trophoblast that makes up the outer epithelium of the blastocyst/this is the part that implants) A blastocyst embedding in the uterine wall Early Development J. The cells inside the blastocyst will

eventually form the fetus and surrounding membranes K. Fetus-at about 8 wks after fertilization -bone tissue and organs are developing -develops placenta and umbilical cord Artists depiction of fetus at 8 wks Early Development L. Placenta- a disc shaped structure of fetal tissue that invades maternal

uterine tissue through placental villi -supplies nutrients and acts as a means of excretion for the fetus -in the placenta fetal blood flows close to the maternal blood in the uterine wall -fluid exchange takes place by diffusion Early Development L. Placenta

Early Development L. Placenta -fetus picks up oxygen and other nutrients -mother picks up carbon dioxide and other excretory wastes **Mother and baby each have their own blood supply and circulation. Materials are exchanged, but blood does not mix. **Babies can have different blood types than their mothers

Early Development M. Amniotic sac- sac to maintain amniotic fluid which surrounds the fetus function: prevent fluid leakage protect from infection Early Development N. Amniotic fluid-fluid in the amniotic sac that surrounds the fetus

functions: buffers shocks and protects from mechanical harm -babies also drink the fluid and urinate in it (it is constantly produced and filtered by the mother) Early fetal development A.

Amniocentes is procedure where Amniocentesis-a medical doctors insert a needle through the mothers abdomen to take a sample from the amniotic sac B. The amniotic sac contains fetal cells C. Doctors culture the cells and test for chromosomal abnormalities D. Takes several weeks for results

E. Procedure is optional A. B. C. D. Birth

Fetus is ready for birth about 38 weeks after conception The fetus sends signals that lead to the secretion of prostaglandins Prostaglandins-initiate contractions of uterine wall Nerve endings in the uterus and cervix will report contractions to the brain, causing the pituitary gland to release oxytocin

Birth E. Uterine contractions stimulate more release of oxytocin -leads to longer, stronger contractions F. Strengthening of contractions is caused by positive feedback H. Contractions cause the babys head to press against the cervix -leads to dilation

Birth I. Amniotic sac bursts and fluid is released (when the water breaks) J. Labor=1st stage of birth -lasts many hours -concludes when cervix is dilated about 10cm Birth K. Expulsion-2nd stage of birth

-expulsion of baby -normally less than one hour -contractions push the baby through the uterus, cervix and vagina -after expulsion positive feedback circuit is broken and contractions are reduced L. Delivery of placenta-3rd stage of birth -contractions continue until placenta is expelled from the uterine wall

Birth or birth control?! In Vitro Fertilization A. In Vitro Fertilization (IVF)-procedure where egg and sperm are united outside of the body -what some refer to as test tube babies -first born from IVF in 1978-Louise

Brown In Vitro Fertilization B. The general procedure 1. woman is given hormones so that more than one follicle will ripen 2. eggs are extracted from follicles 3. sperm are donated and processed for quality 4. each egg is mixed with sperm in a petri dish

5. dishes are checked for fertilization In Vitro Fertilization B. The general procedure (continued) 6. Fertilized eggs are cultivated 7. Embryos are place in the uterus or frozen for later use 8. Pregancy test is done to find out if embryos have implanted into the endometrium

In Vitro Fertilization C. General info. -sperm of eggs can come from donors -if sperm do not fertilize egg on their own they can be injected into the egg -normally, 2-3 embryos are placed in the uterus at the same time (varies by couple) -if all embryos successfully implant, premature delivery and reduced survival could result

IVF: Egg being injected with sperm IVF: Blastocyst ready for transfer to uterus In Vitro Fertilization D. Reasons for IVF -for couples cannot conceive through intercourse -if a female has blocked oviduct

-male infertility (couple will use donor) -childless couples can have children -embryos are screened for genetic diseases before transfer to uterus *genetic diseases could be reduced In Vitro Fertilization F. Ethics against IVF -inherited forms of infertility could be passed on -more embryos are produced than needed

(extras are killed) -embryologists select embryos for implantation (decide which ones survive) -multiple births=increase health risks for children -property fight-If parents divorce before implantation, who gets the embryos? -sex check-parents can specify if they want a boy or girl by checking chromosomes In vivo vs. In vitro

A. In vivo-sperm fertilizes egg inside the body (even in the case of a sperm donor) -in vivo=in life B. In vitro-egg is fertilized outside of the body

-in vitro=in glass On a clean sheet of paper . . . 1. 2. Discuss the ethical issues of IVF in humans. [8] Outline the process of IVF in

humans. [6] Gamete production (Spermatogenesis) A. Spermatogenesis-process of producing sperm cells -mature male gametes=spermatozoa B. Occurs in testes in seminiforous

tubules C. Involves mitosis, meiosis I and meiosis II Gamete production (Spermatogenesis) D. The process 1. spermatogonia are divided by mitosis to produce more spermatogonia -spermatogonia=diploid cells (2n) that arise from primordial germ cells

-primordial germ cells are not specialized (they will be, when they become spermatogonia) Gamete production (Spermatogenesis) D. The process 2. Spermatogonia become larger cells with more cytoplasm (primary spermatocytes)

3. Primary spermatocytes enter meiosis I 4. The result is two haploid cells Primary n Secondary spermatocyte spermatocytes 2n n

Gamete production (Spermatogenesis) D. The process 5. Secondary spermatocytes enter meiosis II, producing two spermatids 6. Spermatids are haploid (n) and must undergo maturation (grow tail, thickened body and DNA packing) 7. Spermatids become associated with Sertoli cells (a.k.a. nurse cells)

Gamete production (Spermatogenesis) D. The process 8. Sertoli cells-nurture sperm through spermatogeneis by structural and secretory support -help spermatids become spermatozoa 9. Spermatozoa detach from sertoli cells -carried out of testes by fluid in

seminiforous tubules Gamete production (Spermatogenesis) 1. Basement membrane 2. Spermatogonia 3. Primary spermatocyte 4. Secondary spermatocyte 5. spermatids 6. spermatozoa

7. Sertoli cells 8. Tight juction Spermatogenisis Sperm cells A. HeadAcrosome-contains enzymes to help the sperm penetrate the egg -found at the heads tip Nucleus-haploid(n)

-contains genetic info B. Mid-section Mitochondria-organells that provide the cell with energy to move the tail and propel the sperm C. Tail Flagella-structures that aid in movement of the cell Sperm cell 1. 2.

3. 4. 5. Acrosome Cell membrane Nucleus Mitochondrio

n Flagella A. Hormonal control of spermatogeneis (a review) FSH-produced by anterior pituitary -stimulates primary spermatocytes to enter

meiosis I to form secondary spermatocytes B. LH-produced by anterior pituitary -stimulates testosterone secretion C. Testosterone-produced in testes by Leydig cells -stimulates secondary sex characteristics -stimulates development of secondary spermatocytes into mature sperm

Semen production A. B. C. D. E. Sperm from testes arrive in epididymis Finish maturation Fluid from Sertoli cells that helped

transport sperm is reabsorbed Sperm become more concentrated Sperm mixed with seminal fluid to increase volume Semen production F. Seminal fluid contains -fructose-energy for sperm -mucus-to protect sperm from acidic conditions in vagina H. Fluid from prostate gland is slightly

alkline (to neutralize acidity of vagina) -normal pH=4, with prostate fluid pH=6 Semen production H. Cowpers gland produces clear fluid to lubricate penis and aid expelling of other wastes. Oogenesis

A. Oogenesis-development of egg cells (ova) -involves mitosis, meiosis I and meiosis II -occurs in ovaries Oogenesis B. The process 1. Oogonia (germ cells) reproduce by

mitosis to form more oogonia (2n) -occurs when female is a fetus 2. Oogonia grow -form primary oocytes Oogensis B. The process 3. Primary oocytes begin meiosis I -stop at after prophase I -the primary oocyte and a layer of follicle cells form a primary follicle

4. Females are born with about 400,000 primary follicles 5. During each menstrual cycle several primary follicles develop Oogensis B. The process 6. the primary oocytes then complete meiosis I -one secondary oocyte and one polar body are formed

-both are haploid (n) -secondary oocyte has more plasma than the polar body (it is larger) Oogensis B. The process 7. Secondary oocyte starts meiosis II and stops in prophase II -follicle cells continue dividing -follicular fluid is formed -polar body degenerates

8. The follicle will rupture and release the egg (ovulation begins) -the egg is still a secondary oocyte Oogensis B. The process 9. If the secondary oocyte is fertilized during ovulation, the rest of meiosis II will take place 10. Meiosis II will produce an ovum (egg) and another polar body

-only occurs after fertilization -the egg is produced with a sperm nucleus inside it -the sperm and egg nuclei fuse to form a diploid cell -the second polar body will degenerate 2n Oogonia (germ cells) Mitosis

2n 2n Growth Oogenesis 2n First

polar body *Additional polar bodies are not formed if the first polar body degenerates.

Oogonia (germ cells) Primary oocyte Meiosis I n n Secondary oocyte Meiosis II

Additional n polar bodies n n Second polar body

n Ovum

Compare spermatogenesis and oogenesis. [7] Annotate a diagram of the ovary. Show the location and function of germinal epithelium, primary follicles, mature follicles and secondary oocyte. Draw and annotate a diagram of a mature sperm and egg. Outline the role of HCG in early pregnancy

Fertilization Fertilization-fusion of male and female gametes (n+n=2n) B. During ovulation, the secondary oocyte is surrounded by zona pellucida and the corona radiata C. Zona pellucida-a mucoprotein that is secreted by ovarian follicle cells A.

-sperm must penetrate it for fertilization to occur D. Corona radiata-layer of follicle cells surrounding the zona pellucida Fertilization Zona pellucida Corona radiata

Fertilization Fertilization E. After the sperm penetrates the egg, the sperm receptors in the zona pellucida are destroyed and the zona pellucida hardens F. No other sperm can fertilize Female reproduction 1.

2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

13. Uterus Oviducts Ovaries Cervix Vagina Urethra Bladder Ureter Kidneys

Clitoris Labia minor Labia majora Bartholins gland

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