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Ch. 41 - Reproductive Systems
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3/19/20162 I. Sexual vs Asexual Reproduction A. Asexual 1. Creation of offspring from one parent 2. No fusion of egg and sperm 3. Types of asexual reproduction: a. Budding - Hydra b. Regeneration - flatworms c. Fragmentation - occurs in earthworms, sponges & echinoderms like starfish
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Asexual Reproduction in Hydra
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Starfish Regeneration
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3/19/20165 d. Parthenogenesis Unfertilized eggs develop into a complete individual Occurs in some insects, fish, lizards In honeybees, fertilized eggs become worker bees, unfertilized ones become male drones.
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Parthenogenesis
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3/19/20167 4. Advantages of Asexual Repro. a. No need to find mates b. Quicker production of offspring c. No energy lost to make sperm & eggs 5. Disadvantages of Asexual Repro. a. Produces genetically identical populations b. Could be a problem if the environment changes and becomes less favorable to survival c. More likely to go extinct
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3/19/20168 B. Sexual Reproduction 1. Offspring created by fusion of 2 haploid gametes (eggs & sperm) a. Sperm usually small b. Ovum usually larger 2. Advantages of Sexual Repro. a. Increases genetic variability b. May allow for greater adaptability to changing environments c. More likely that some variants will survive & reproduce
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3/19/20169 C. Having it Both Ways 1. Many animals can reproduce both ways at different times: a.Rotifers - reproduce asexually during good times; sexually when it gets cold or food or water disappears
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Dioecious Sexual Reproduction (Separate sexes)
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3/19/201611 2. Hermaphroditism (monoecious) a. Individuals have both male & female reproductive systems Some can fertilize own eggs Earthworms each fertilize the other worms’ eggs
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3/19/201612 II. Types of Fertilization A. External Fertilization 1. Discharge gametes into water 2. Fertilization occurs in water 3. Occurs in fish, amphibians & most aquatic invertebrates 4. Timing is crucial so sperm contact eggs when ripe 5. Courtship rituals important
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Frog Mating Charles Bogert’s frog call recordings
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3/19/201614 B. Internal Fertilization 1. When sperm are deposited in or close to female reproductive tract 2. Gametes unite within female body 3. Generally found in terrestrial animals 4. Requires copulation. a. Usually involves male copulatory organs that are placed within the female body b. Birds don’t have such an organ. Instead get cloacas close together
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Internal Fertilization
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3/19/201616 III. Life History Strategies A. Know what all of the following words mean: 1. Oviparous 2. Yolk 3. Larva 4. Metamorphosis 5. Extraembryonic membranes 6. Viviparous 7. Placenta
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3/19/201617 IV. Male Anatomy A. See worksheet & textbook B. Brief college-style lecture only 1. Know Table 41.1 2. Know section 41.2
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Male Reproductive System
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Testis & Sperm
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Penis Anatomy
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Hormonal Control of Testes
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3/19/201622 V. Female Anatomy A. See worksheet & textbook B. Brief college-style lecture only 1. Know Table 41.2 2. Know section 41.3
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Female Reproductive System
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3/19/201624 VI. Female Menstrual / Ovarian Cycle A. Involves cyclic changes in the: 1. Ovaries 2. Uterine lining 3. Hormones from: hypothalamus, pituitary, and the ovary itself
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3/19/201625 B. 3 phases of menstrual cycle: 1. Menstruation a. Uterine bleeding b. Lasts usually 3-5 days 2. Follicular (Proliferative) phase a. Pre-ovulatory phase b. Follicle & oocyte is growing 3. Luteal ( Secretory) phase a. Post-ovulatory phase b. Follicle becomes corpus luteum
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Menstrual Cycle Levels of Hormones
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3/19/201627 C. Events of Menstrual Cycle 1. Menstruation (3-5 days) a. Day 1 of menstrual cycle is the day a woman’s “period” starts b. Endometrium (inner lining) of uterus breaks down and leaves body through the vagina c. Discharge consists of: blood, cells & mucous
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Menstrual Cycle Levels of Hormones
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3/19/201629 2. Follicular phase (9-10 days) a. Hypothalamus secretes GnRH b. This causes pituitary to release FSH and LH c. FSH causes growth of follicle in ovary A follicle is the structure in which an ovum forms d. This causes the follicle to begin to secrete estrogen e. Estrogen causes the endometrium of uterus to thicken
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Ovarian Cycle
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Menstrual Cycle Levels of Hormones
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3/19/201632 f. As follicle grows, it begins to secrete more estrogen g. Hormone levels rise abruptly just before ovulation: Estrogen reaches a peak h. This creates positive feedback on the hypothalamus, which causes a burst of FSH & LH from pituitary i. The LH peak stimulates: Completion of meiosis Follicle to rupture & release of ovum (ovulation)
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Menstrual Cycle Levels of Hormones
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3/19/201634 3. Luteal phase (13-15 days) a. LH causes the follicle to develop into the corpus luteum A solid mass of cells that becomes an endocrine gland b. The corpus luteum begins to secrete progesterone & estrogen This inhibits further release of GnRH from hypothalamus & FSH & LH from pituitary This in turn prevents new follicles from growing & developing in the ovary
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Ovarian Cycle
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3/19/201636 c. Progesterone also has an effect on the uterus It helps to mature the glands in the endometrium Ensures that the endometrium remains thick and in place (It will not slough off)
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Menstrual Cycle Levels of Hormones
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Hormonal Control of Ovaries
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3/19/201639 D. What Happens Next? 1. Depends on whether egg is fertilized or not a. Scenario 1 = Egg not fertilized Corpus luteum atrophies Progesterone levels fall Lining of uterus breaks down and sloughs off Lack of progesterone frees inhibition of hypothalamus, which secretes GnRH to start the cycle over
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3/19/201640 b. Scenario 2 = Egg IS fertilized Egg fertilized in oviduct usually Zygote begins to divide, travels to uterus & implants in endometrium (usually about 8-10 days later) Embryo secretes a hormone called human chorionic gonadotropin (HCG) (Can be detected in urine) HCG causes the corpus luteum to be maintained, which continues to secrete progesterone This keeps the endometrium intact & maintains pregnancy
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3/19/201641 V. Contraception A. See textbook B. Brief college-style lecture only 1. Know sections 41.4 a. Know names of all common birth control methods b. Which methods are highly effective (90% & above) c. Which methods are relatively ineffective (75% & lower)
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3/19/201642
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Genital Warts 3/19/201643
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Signs Symptoms Caused by HPV or human papillomavirus May have no signs at all Can cause cervical cancer in Females Can have flat lesions or raised warts NO CURE! 3/19/201644
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Genital Herpes 3/19/201645
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Signs and Symptoms Caused by Herpes simplex virus Type one of this virus causes cold sores( not this one) Type two causes genital herpes Very prevalent May exhibit no symptoms but can still be transmitted in this state May cause itching, tingling, then blisters Blisters burst and leave painful legions 3/19/201646
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Signs and symptoms Once the blisters burst they can be accompanied by fever, painful urination, swelling, and discharge in women. There is NO Cure 3/19/201647
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Chlamydia 3/19/201648
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Signs and symptoms Caused by a bacteria, can be treated May cause burning, itching, discharge In severe untreated cases can cause sterility Can be passed to baby during childbirth 3/19/201649
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Gonorrhea 3/19/201650
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Signs & Symptoms Caused by a bacteria, can be treated May cause painful urination, green/yellow discharge. Can cause PID (scaring in urethra/oviducts) Can cause sterility Can be passed to baby during childbirth Can affect eyes, skin, mouth, anus, tonsils Can spread internally and cause heart damage or arthritis 3/19/201651
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Syphilis 3/19/201652
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Signs & symptoms Caused by bacteria Three stages Can cause rash all over the body in stage 2 Can also affect cardiovascular and nervous system Can cause mental retardation, blindness, change in gate, insanity 3/19/201653
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AIDS/ HIV You need to know signs symptoms transmission treatment 3/19/201654
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