Reproductive System Review Sheet PDF

**REPRODUCTIVE SYSTEM REVIEW SHEET** **Two sexes**: male & female gametes(cells) combine genes to form a **fertilized egg(zygote)** **Primary sex organ**: produces **gametes (testes/ovaries)** **Secondary sex organs:** genitalia (male: penis, urethra, ducts + glands) & (female: uterus, vagina) *...

**REPRODUCTIVE SYSTEM REVIEW SHEET** **Two sexes**: male & female gametes(cells) combine genes to form a **fertilized egg(zygote)** **Primary sex organ**: produces **gametes (testes/ovaries)** **Secondary sex organs:** genitalia (male: penis, urethra, ducts + glands) & (female: uterus, vagina) **Sex chromosomes**: 23pair (46total)=22 pairs of autosomes, one pair of sex chromosomes (XY&XX) **Gonads(**testes/ovaries): develops \~6weeks. Indistinguishable sexes. **SRY(sex-determining region of Y):** determines biological sex. In **males**, the SRY gene codes for a protein (testes-determining factor), which initiates the formation of testes. In females, without the SRY gene, gonads develop into ovaries. **Androgen-insensitivity syndrome(AIS)** occurs when an individual has XY chromosomes(male) but develops a female appearance due to a defect in androgen receptors. The body cannot respond to the hormone because the target cells lack functioning androgen receptors. **Complete AIS** leads to a feminine appearance and no male genitalia despite the individual having an XY chromosome. **Descent of Gonads**: abdominal cavitypelvic cavity(ovaries) or scrotum(testes) \~6 weeks: **Testes** pass into the scrotum by the **gubernaculum.** BV, lymphatics, nerves, & ducts also adjust. **Ovaries** descend less & settle in lesser pelvic. The gubernaculum supports the ovary and uterus. **Cryptorchidism**-undescended tests (\~3% of male births). **MALE REPRODUCTIVE SYSTEM** **External organs:** penis & scrotum **Internal organs:** testes, epididymis, vas deferens, seminal vesicles, prostate gland, bulbourethral glands, and urethra **Penis**: reproduction; introducing sperm into the female body. **Testis:** oval organ located in the scrotum, covered by tunica albuginea(white fibrous capsule) **\*Functions:** spermatogenesis, hormone production (testosterone), storage **\*Seminiferous tubules:** tubes inside the testes where sperms are produced. Drains into a network called **rete testis**. \*Houses two cells: **interstitial cells(testosterone) + sustentacular cells (supports + regulates spermatogenesis**) **Sustentacular cells:** nourish germ cells, blood-testis barrier, androgen-binding protein, phagocytosis **Scrotum:** sac that houses the testes. **Temp regulation**: testes need to stay slightly cooler than body's core temp for spermatogenesis **Duct system**: tubes that transport sperm from the testes to the outside of the body during ejaculation. **Efferent Ductules**: a first pathway for sperm exiting testes. They connect to the head of the epididymis. It has [cilia] to help move immature sperm. SEMINIFEROUS TUBULESRETE TESTISEFFERENT DUCTULESEPIDIDYMISVAS DEFERENSEJACULATORY DUCTSURETHRA(mixes with accessory glands to form semen)expelled out of the body. **Accessory glands**: seminal vesicles, prostate gland, bulbourethral glands **Puberty:** surge of pituitary gonadotropins(triggered by GnRH) } 10-12boys & 8-10girls **Hormones:** Testosterone in men: development in secondary sexual organs(muscle, scent, etc) **GnRH**: by hypothalamus. Stimulated by the anterior pituitary gland. Secretes **FSH + LH** **Male**: LH stimulates interstitial cells to make testosterone FSH: stimulates sustentacular cellsspermatogenesis **Female:** FSH stimulates follicles to make estrogen + progesterone. Ripens egg and prepares uterus **Aging:** decline in testosterone (by age 80). Rise in FSH & LH secretion after age 60 (menopause): mood changes, hot flashes, "illusions of suffocation" **Impotence(erectile dysfunction):** as your age increases **Menopause:** midlife changes + no menstruation \~52years old Less secretion of estrogen + progesterone b/c follicles lose their functions. Atrophy of the uterus, vagina, and breasts. Risks of CV disease increase, hot flashes, **(HRT=low dose estrogen & progesterone therapy)** **Mitosis:** produces 2 genetically identical daughter cells: in tissue repair + embryonic growth **Meiosis:** produces [gametes(reproductive cells).] Carries half of the genetic info(haploid) needed to form a new individual when combined with another gamete. **Two cell divisions: Miosis I (2 haploid cells) & Miosis II (4 haploid cells)** **Miosis I: Early prophase Imid-late Prophase Imetaphase I anaphase I Telophase I** **Diploid (2n)** **Early Prophase: chromatin condenses & forms visible chromosomes.** **Mid-late prophase I: chromatids break& cross over. Centrioles produce spindle fibers.** **The nuclear envelope breaks down.** **Metaphase I: terads align at the center with the centromere with spindle fibers attached** **Anaphase I: chromosomes separate & migrate to opposite poles of the cell.** **Telophase I: A new nuclear envelope forms around chromosomes. Cell goes under cytokinesis(cell divides into two daughter cells) =2 haploid** **Miosis II: Prophase IIMetaphase IIAnaphaseTelophase IIfinal product (4 haploid)** **Prophase II:** **Spermatogenesis:** making immature germ cells(spermatids) into mature sperm cells (spermatozoa) in seminiferous tubules of testes. **Hormone involved**: gonadotropin-releasing hormone(GnRH) **GnRH** acts on the anterior pituitary to stimulate the release of two hormones: **LH & FSH** **FSH & LH** are released into the bloodstream. LHinterstitial cells of testes & produces testosterone FSHsustentacular cells in seminiferous tubules & secrete inhibin **Testosteronespermatogenesis**: t[estosterone] produced by interstitial cells promotes **meiosis** in **PRIMARY SPERMATOCYTES(diploid cells),** triggering their division into **SECONDARY SPERMATOCYTES(haploid cells)** - **Testosteronespermiogenesis (**final maturation of spermatids into functional sperm, including development of tail for motility) - **Inhibin and testosterone** =negative feedback to regulate FSH, LH, and GnRH level **Spermiogenesis**: final step of spermatogenesis (**spermatidsspermatozoa**) **[Shape changes]**: spermatids develop tail(flagellum) & elongated shape for swimming **Nucleus condenses** and becomes more compact to reduce the size of the sperm head **Acrosome:** cap-like structure forms on top of sperm cells and helps sperm penetrate the egg during fertilization. **Cytoplasm** is removed, leaving behind a streamlined cell. Sperm gains a long, whip-like tail to help it move. **FEMALE REPRODUCTIVE SYSTEM** **Ovaries, fallopian tubes, uterus, cervix, vagina, and external genitalia** **Ovaries:** produces **eggs** and female hormones: **estrogen + progesterone** **Anatomy of the ovary:** - **Outer layer:** germinal epithelium - **Tunica albuginea:** fibrous CT layer beneath the germinal epithelium. - **Cortex:** outer functional region of ovary. **\*\*Ovarian follicles:** house eggs in various stages of maturity **\*\*corpus luteum:** temporarily forms after ovulation, progesterone production - **Medulla:** inner region on ovary; BV, nerves, lymphatic vessels - **Hilum:** a small region where BV, lymphatics, and nerves enter & exit the ovary. **Fallopian Tubes**: muscular tube with ciliated cell - Isthmus, ampulla(body) , infundibulum **Uterus:** a muscular chamber that opens into the roof of the vagina, harbors the fetus - **Fundus(superior), body(corpus)& cervix** - **Histology:** perimetrium, myometrium, and endometrium **PAP Smear**: medical procedure to test for cervical cancer or precancerous changes in the cervix (lower portion of the uterus) **Vagina/Birth Canal**: Reproduction & Excretion(urethra) Oogenesis: a process where ovaries create egg/ova **Before birth:** PRIMORDIAL GERM CELLS arise in the embryo and migrate to the ovaries. Reaching OVARIES, they differentiate into OOGONIA(immature egg cells). Through MITOSIS, oogonia goes through division & increases its number. Oogonia stops dividing and begins MEIOSIS. They enter PROPHASE I and become PRIMARY OOCYTES. At the same time, each primary oocyte becomes surrounded by granulosa cells, which becomes a PRIMORDIAL FOLLICLE. They pause their development until puberty. **Adolescence to menopause**: several hormones(**GnRH, LH & FSH**) trigger the follicles to continue developing. LH: triggers ovulation and supports luteum formation FSH: stimulates follicle growth in the ovaries **MEIOSIS I** resumes and completes the phase under the influence of **LH.** As a result, a SECONDARY OOCYTE forms and also a POLAR BODY, which eventually degenerates. Around day 14 of the menstrual cycle, the mature follicle ruptures and releases the se **Human Development:** **Sperm migration** Majority of sperm do not make it to the egg -- destroyed by [vaginal acid (low pH)]\ -- fail to penetrate the [cervical mucus] -- go up the [wrong uterine tube] Assisted by female physiology -- uterine contractions, chemotaxis chemical attraction **Capacitation** (a process that sperm undergo after entering the female reproductive tract, enabling them to fertilize an egg) - **[Spermatozoa]** can reach the uterine tube within 10 minutes of deposition/ejaculation - cannot fertilize the egg until undergoes capacitation - Capacitation takes about ten hours to complete\ -- sperm membrane becomes fragile & more permeable to Ca2+ (calcium ions). Allows sperm to undergo [acrosome reaction] where enzymes are released to penetrate the egg's protective layers. - **Sperm fertile** for 48 hours in the female body - **Conception** is optimal if sperm are deposited 48 hours before ovulation or 14 hours after ovulation. **Fertilization = process where sperm + egg meet to form a zygote** **Acrosomal reaction**: sperm binds to the zona pellucida(a glycoprotein layer surrounding the egg). This triggers the release of enzymes from the acrosome. These enzymes (hyaluronidase & acrosin) enables the sperm to reach the egg membrane & fuse with it. **Fusion Reaction**: once the sperm penetrates the zona pellucida, its membrane fuses with the egg's plasma membrane. The sperm nucleus & other contents are released into the egg's cytoplasm. This allows the transfer of sperm's genetic material to the egg. **Cortical reaction**: sperm entry triggers Ca^2+^ influx within the egg. This calcium wave causes cortical granules (vesicles inside the egg) to release their content. These contents modify zona pellucida, hardening it and making it impermeable to other sperm. **Prevention of polyspermy** To ensure only 1 sperm fertilizes the egg, the egg employs two mechanisms to block additional sperm)\ 1. **fast block** = depolarization of membrane (by the opening of [Na+ channels]) prevents binding of second sperm. Occurs immediately after sperm entry\ 2. **slow block** = sperm penetration triggers [Ca+2 inflow]. this causes a **cortical reaction**, where the vesicles near the egg membrane release enzymes that harden the zona pellucida. This makes the zona pellucida impenetrable to other sperm. **The secondary oocyte** is arrested in metaphase II. Fertilization triggers oocyte to complete meiosis IImature ovum & a second polar body which degenerates. After the sperm enters the egg: the sperm nucleus swells, becoming the **male pronucleus.** The **female pronucleus** forms from the egg's nucleus after **meiosis II**. The pronuclei from the sperm + egg migrate toward each other. They **rupture,** allowing the chromosomes from the sperm and egg to intermingle. - The [chromosomes of sperm(haploid,23) and egg (haploid,23) combine to make a diploid set (46 chromosomes) ] - Once the chromosomes have mixed, the fertilized egg is officially called a **zygote.** the zygote begins a series of [mitotic (cleavage) divisions] as it travels down the fallopian tube towards the uterus. **Pre-embryonic stage (first 2 weeks after fertilization)** - **Cleavage** (days 1-3): rapid mitotic divisions of the zygote without growth in size, resulting in smaller cells called blastomeres. - 30 hours=zygote divides into 2 cells (**blastomeres**). 72 hours structure becomes **morula**, a solid ball of small cells. Morula free in the uterine cavity for 4-5 days. - **Blastocyst formation**: The morula develops into a blastocyst, a hollow structure. - **Trophoblast**: the outer layer of cells that will contribute to the formation of the placenta - **Embryoblast** (inner cell mass): a group of cells inside the blastocyst that will develop into an embryo **Twins** **Dizygotic (fraternal) twins**\ -- 2 eggs are ovulated and fertilized (2 zygotes) -- as different as any other siblings ** Monozygotic (maternal) twins**\ -- 1 egg is fertilized (1 zygote), but the embryoblast splits into two\ -- genetically identical siblings (must be same sex) **Implantation of blastocyst** Attaches to uterine wall 6 days after ovulation\ **Syncytiotrophoblast formation**-- trophoblast (outer layer of blastocyst) differentiates into the syncytiotrophoblast, a multinucleated mass that : - grows "roots" to invade the endometrium. - secretes [**human chorionic gonadotropin (HCG**): a hormone that maintains corpus luteum to continue progesterone, preventing menstruation] (detectable by urine test kit) syncytiotrophoblast expands and contributes to the formation of **chorion**, which will become part of placenta. [Chorion is a membrane that surrounds a developing placenta.] Endometrium encloses implanting embryo **Steps of embryogenesis** **Fertilization of zygote blastocyst formationformation of germ layers (days 15-16)** **Blastomere** has 3 primary germ layers : - **ectoderm**: forms the skin, nervous system and sensory organs - **mesoderm**: develops into muscles, bones, b.v, and CT. - **endoderm**: lines digestive, respiratory and urinary systems - **Amniotic cavity**: part of extra embryonic membranes, which include amnion, chorion and yolk sac. This cavity is filled with amniotic fluid which provides protective environment for the developing embryo. **Ectopic pregnancy** - Blastocyst implants somewhere other than uterus ( 1 out of 300 pregnancies) - Most cases occur in **uterine tube** (tubal pregnancy) but can happen in ovary, cervix. - Tube cannot expand enough and [ruptures by 12 weeks], leading to internal bleeding and potentially life-threatening consequences for the mother. - In rare cases, conceptus may reimplant in the abdominopelvic cavity. **Embryonic Stage (weeks 2-9)** Begins with all 3 primary germ layers are present Embryo begins receiving its nutrients from the placenta. **Germ layers differentiate into organs** : presence of organs marks the beginning of fetal stage Nutrition: first 8weeks, conceptus is nourished by digestion of endometrial cells. Placental nutrition: conceptus is nourished from mother's bloodstream through placenta **Placentation:** formation occurs from 11days -- 12 weeks Chorionic villi: extensions of syncytiotrophoblast within endometrium Placental sinus: pools of maternal blood that emerge and surrounds villi, blood stimulates rapid growth of chorionic villi