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163 Cards in this Set
- Front
- Back
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What is the function of the reproductive system? |
To produce new offspring for species survival |
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What are female's function in the reproductive system? |
Gamete fusion Embryonic/fetal development Delivery of newborn Nourishment of newborn |
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What occurs during sexual reproduction in humans that produces a unique offspring? |
DNA from two genetically-distinct individuals is combined |
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Sex cells are produced through what? |
Meiosis, using recombination of DNA to rearrange the original gene combination |
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What occurs during meiosis that re-orders parental DNA |
Alignment of homologues |
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What does gene recombination allow for over time? |
increased adaptation under changing conditions |
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Does meiosis produce diploid or haploid sex cells with new gene combination? |
Haploid |
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What are the phases in Meiosis I? |
Early Prophase I Mid- to Late Prophase I Metaphase I Anaphase I Telophase I |
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What occurs during Meiosis I, Early Prophase I? |
Chromosomes form with two sister chromatids |
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What occurs during Meiosis I, Mid- to Late Prophase I? |
During synapsis, homologous chromosomes form tetrads and crossing over occurs |
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What occurs during Meiosis I, Metaphase I? |
Tetrads align randomly at equator (random orientation) |
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What occurs during Meiosis I, Anaphase I? |
Random orientation in metaphase I leads to independent assortment |
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What occurs during Meiosis I, Telophase I? |
Cytokinesis may follow, resulting in two genetically different haploid cells with sister chromatids still attached |
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What are the phases in Meiosis II? What occurs in each phase? |
Prophase II: chromosomes remain condensed Metaphase II: Chromosomes line up along equator
Anaphase II: Sister chromatids separate
Telophase II: Cytokinesis follows |
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What is the difference between Mitosis and Meiosis? |
Mitosis produces 2 diploid cells that are genetically identical to the mother.
Meiosis produces 4 haploid cells that are genetically different from the mother and each other. |
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Function of testes |
1. Produce sperm (seminiferous tubules) and testosterone (interstitial cells) 2. Suspended by spermatic cord 3. Protected by tunica vaginalis (serous membrane) 4. Cremaster muscle adjusts testicular position for thermoregulation |
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Function of epididymis |
Sperm maturity and storage Acidic fluid keeps sperm inactive until ejaculation |
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Function of the scrotum |
Protects and supports testes |
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Function of ductus deferentia |
Ejaculation of sperm during orgasm |
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Function of seminal glands |
1. Produce alkaline fluid for semen and fructose for sperm motility 2. Alkaline secretion neutralize acidic secretions of vagina & epididymis 3. Prostaglandins stimulate smooth muscle contractions in female |
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Function of prostate gland |
Produce alkaline fluid for semen |
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Function of bulbourethral glands |
Secretes lubricating fluid to facilitate insertion of penis into vagina Alkaline secretions neutralize acidic pH of urethra |
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Function of the penis |
1. Composed of 3 cylindrical masses of erectile tissue (2 cavernosa, 1 spongiosum) 2. Engorgement with blood causes erection 3. Inserted into female during intercourse to release sperm & semen during orgasm 4. Micturition of urine via penile urethra |
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What event requires a lower temperature in the testes compared to the core of the body? |
Spermatogenesis |
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How are the testes temperature maintained? |
By a countercurrent heat exchanger, whcih transfers heat form arteries entering the testes to exiting veins |
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How many degrees lower do the testes need to be compared to the core temperature? |
2-3 degrees lower |
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What does the cremaster muscle do? |
Lowers or raises the testes to regulate testicular temperature |
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What does the dartos muscle do? |
Wrinkle or smooth the scrotum to regulate testicular temperature |
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What is Spermatogenesis? |
The process of sex cell production in males |
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What type of division does spermatogenesis & oogenesis use? |
Meiotic division |
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5 steps in Spermatogenesis |
1. Spermatogonium undergoes mitosis to produce diploid primary spermatocytes 2. One primary spermatocyte undergoes Meiosis I to produce 2 haploid secondary spermatocytes 3. Two secondary spermatocyte each undergo Meiosis II to produce 4 haploid spermatids 4. Spermatids elongate as they begin spermiogenesis 5. Spermatids continue to undergo spermiogenesis to eventually become mature sperm cells |
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What does the blood-testis barrier maintain? |
A controlled chemical environment for spermatogenesis |
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What does the blood-testis barrier prevent? |
Immune activity against the genetically different sperm cells |
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What is a mature sperm composed of? |
Head Midpiece Tail |
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Function of the sperm head |
Contains haploid nucleus; acrosome with digestive enzymes |
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Function of the sperm midpiece |
Abundant mitochondria; drive portion of flagellum |
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Function of the sperm tail |
Flagellum for motility |
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How long does sperm live for once ejaculated into the female reproductive tract? |
3-5 days |
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Which chromosome lasts longer? |
X chromosomes is heavier and swims slower (~5 days) |
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A typical ejaculate contains what? |
Glandular of secretion from the seminal and prostate glands 40-750 million sperm and supportive nutrients |
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What does the sticky consistency of ejaculate promote? |
Adherence to the vaginal wall and cervix |
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Alkaline secretions promote what? |
Motility in the sperm and neutralize the naturally acidic vaginal pH |
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What thins the cervical mucus plug? |
Prostaglandins |
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What does the acidic pH in the vagina do to the acrosome of a sperm? |
It capacitates the acrosome to allow release of its digestive enzymes |
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A. Hypothalamus releases GnRH B. Anterior pituitary detects GnRH and secretes FSH and LH C. LH simulates testosterone production from interstitial cells; FSH stimulates sustentacular cells to secrete ABP. D. ABP binds testosterone E. Testosterone simulates spermatogenesis & development of male characteristics F. As levels of Testosterone & inhibin rise, secretion of GnRH, FSH, & LH decreases |
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What male item induces smooth muscle contactions in the female? |
Prostagladins |
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Male or female? Dramatic increase in terminal hair |
Male |
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Male or female? Larynx enlarges and vocal cord thicken |
Male |
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Male or female? Integument thickens and oil secretion increases |
Male |
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Male or female? Increase in Basal Metabolic Rate (BMR) |
Male |
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Male or female? Increased growth, especially skeleton and muscle Shoulders typically broaden |
Male |
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Male or female? Increase in hematopoiesis |
Male |
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Male or female? Increased simulation of libido |
Male |
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Male or female? Oogenesis advances in a cyclic basis |
Female |
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Male or female? Menarche - first menstrual period |
Female |
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Male or female? Moderate increase in terminal hair |
Female |
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Male or female? Mammary glands develop |
Female |
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Male or female? Integument becomes more vascular |
Female |
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Male or female? Increased adipose deposition in breast, thighs & butt |
Female |
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Male or female? Moderate increase in skeletal & muscle tissue Hips broaden |
Female |
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Male or female? Sperm production begins |
Male |
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4 steps of male arousal (erection phase) |
1. Parasympathetic neurons trigger the release of nitric oxide (NO); occurs with physical/sensory stimuli 2. NO causes vasodilation in arterioles supplying erectile tissues of the penis 3. Increased blood flow engorges the penis while compressing exciting veins 4. Erect penis can be inserted into vagina |
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3 steps of male arousal (ejaculatory phase) |
1. As arousal escalates, sympathetic neurons release norepinephrine 2. Smooth muscle contracts in glands and ducts propel semen into the penile urethra 3. Smooth muscle contactions in the penis expel semen into the vagina |
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What do males experience as they age? |
Climacteric |
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What is climacteric? |
Testosterone levels steadily decline and sperm count declines |
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What 2 factors makes male arousal more difficult with age? What can it lead to? |
Reduced testosterone Psychological effects Can lead to impotence |
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What enlarges as males age? What does it affect? |
Prostate Affects urination |
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Males are encouraged to have what exam as they age? |
Prostate exam via Digital rectal exam (DRE) |
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Function of the ovaries |
Produce ova, estrogen & progesterone Anchored and supported by suspensory, ovarian and broad ligaments |
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What are the primary organs in human reproduction? |
Testis & ovaries |
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Function of uterine tubes |
1. Movement of sperm towards ovum 2. Location of fertilization of ovum 3. Movement of ovum/conceptus to uterus (ciliated epithelium & smooth muscle) |
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Function of uterus |
1. Development of embryo/fetus; delivery of baby (smooth muscle contractions) 2. Smooth muscle myometrium provides labor & menstrual contractions 3. Highly vascularized mucous endometrium provides nourishment to developing embryo/fetus 4. Mucus plug of cervix prevents bacteria entry 5. Anchored and supported by uterine ligaments |
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Function of the vagina |
1. Receives penis and semen during intercourse 2. Birth canal during delivery 3. Menstrual flow during menstruation 4. Acidic pH maintained by Lactobacillus |
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Function of mons pubis |
Fatty padding protects pubis and pubic symphysis
Pubic hair traps pheromones & emphasizes vulva |
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Function of labia majora |
Protects urogenital openings Secretes pheromones |
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Function of labia minora |
Protects urogenital openings Secretes lubricating fluids |
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Function of clitoris |
Erectile tissue for female arousal Engorgement with blood causes erection |
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Function of breasts |
Produce (Prolactin-stimulated) and secrete (Oxytocin-stimulated) milk to nourish child |
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What is oogenesis? |
Process of sex cell production in females |
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Steps in oogenesis |
1. Oogonium undergoes mitosis 2. Meiosis begins and makes a primary oocyte (arrested in prophase I) 3. During puberty primary oocyte continues Meiosis and gets rid of 1st polar body 4. Secondary oocyte (arrested in metaphase II) 5. Ovulation 6. Sperm fertilizes oocyte 7. Secondary oocyte completes Meiosis 8. 2nd polar body (degenerates) 9. Fertilized ovum |
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In females, when do oogonia become primary oocytes? |
Prior to birth |
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Uneven division of the cytoplasm produces what? |
One ovum Up to 3 polar bodies |
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Where does most of the cytoplasm from uneven division remain? |
With the ovum |
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Spermatogonium vs oogenesis Time of onset |
Spermatogonium: begins at puberty Oogenesis: begins before birth |
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Spermatogonium vs oogenesis What happens at puberty? |
Spermatogonium: begins and continually produces sperm cells Oogenesis: continues Meiosis and release an immature gamete (the second oocyte) each month |
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Spermatogonium vs oogenesis Number of cells produced |
Spermatogonium: produces millions of small, motile sperm each day Oogenesis: produces one large oocyte each month |
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Spermatogonium vs oogenesis When process ends |
Spermatogonium: continues until death
Oogenesis: continues until age 45-55 |
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Spermatogonium vs oogenesis Duration of Meiosis |
Spermatogonium: continues throughout life Oogenesis: pauses twice; at prophase I from prophase development to puberty, and at metaphase II from ovulation to fertilization |
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First 3 steps of female arousal and orgasm |
1. Parasympathetic neurons trigger the release of nitric oxide; occurs with physical/sensory stimulus 2. Nitric oxide causes vasodilation in arterioles supplying several female organs 3. Increased blood flow engorges the clitoris and labia |
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Last 3 steps of female arousal and orgasm |
4. Vagina dilates and sweats to provide lubrication; the uterus extends upwards to align with the vagina 5. The vestibular bulbs constrict to provide friction on the penis 6. Sympathetic stimulation triggers orgasm |
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What does a female orgasm cause? |
Causes the cervix to dip into the pool of semen to facilitate sperm entry into the uterus Also triggers peristaltic contractions in the vagina, uterus and uterine tubes |
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What do ovaries need to do each month? |
Release a minimal number of oocytes per month |
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What does the uterus need to prepare for? |
The possible arrival of a conceptus |
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What happens to the ovarian and uterine cycle if fertilization occurs? |
They are interrupted and the uterine cycle must be maintained |
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What occurs in the cycle if fertilization doesn't occur? |
The uterus must be renewed and the ovaries must begin a new cycle |
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What's the relationship between the ovarian cycle and the uterine cycle? |
Estrogen secretion peaks during ovulation Progesterone secretion peaks during secretory phase Uterine lining is thickest during progesterone secretion |
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A. Hypothalamus releases GnRH B. Anterior pituitary releases LH and FSH in response to GnRH C. LH causes ovaries secrete androgen. Ovaries convert androgen to estrogen and secrete estrogen and inhibin in response to FSH D. Estrogen simulates a dominant follicle to mature to a vesicular follicle The new vesicular follicle produces large amounts of estrogens, triggering an LH surge The LH surge and FSH trigger ovulation |
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What is the positive feedback for hormonal regulation of the female? |
Estrogen from the vesicular follicle triggers an LH surge from the anterior pituitary |
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What's the negative feedback for hormonal regulation of ovarian function? |
Estrogen inhibits GnRH and LH secretin Estrogen and inhibin decreases FSH secretion |
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3 steps in the uterine cycle |
1. Menstruation phase: uterus sheds the stratum functionalis, resulting in menstruation 2. Proliferative phase: a new stratum functionalis develops with endometrial glands and spiral arteries and veins 3. Secretory phase: the spiral arteries convert the stratum functionalis to secretory mucosa and endometrial glands secrete uterine milk |
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During menstruation phase what hormones start to rise? What occurs by day 5? |
LH & FSH Ovarian follicles increase estrogen production |
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During the proliferating phase, what does estrogen rise stimulate? |
LH & FSH surges which triggers ovulation |
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During the secretory phase, why does LH & FSH drop? |
Because of negative feedback on the anterior pituitary |
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Are ovarian hormones low or high during the beginning of the menstrual phase? |
Low |
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Why does progesterone levels rise after ovulation? |
Because of the corpus luteum |
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What phase does progesterone levels rise? When do they drop? |
Secretory phase Drops around day 24 if fertilization doesn't occur |
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What is a girls first menstrual cycle called? |
Menarche |
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What is the minimum amount of body fat required for Menarche to occur? |
About 17% body fat |
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What is meant when a cycle is anovulatory? |
Oocyte are still being developed 2-3 months before ovulation |
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How long after menarche does the menstrual cycle and ovulation become stable? |
About one year |
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What is premenstrual syndrome? |
PMS a range of physical, emotional and psychological symptoms that many women experience during the luteal phase Most notably due to rising progesterone |
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Symptoms of PMS |
Fluid retention Cramping Irritability |
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What can make PMS worse? |
Caffeine and nicotine |
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Why would phototherapy be used to treat symptoms of PMS? |
Because of elevated melatonin levels |
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What occurs during menopause? |
Follicles stop responding to FSH & LH Estrogen levels drop drastically |
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Symptoms of menopause |
Hot flashes Vaginal dryness Decreases sexual arousal Decreased bone density (Later age) secondary sex characteristics atrophy |
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What develops during the prenatal period? |
Cells specializes Tissues, organs and systems develop |
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What happens to the baby during the postnatal period? |
Increase in size Some development Lots of learning |
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When does fertilization occur? |
When fusion of sperm and ovum nuclei produce a diploid zygote |
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What is the development stage of the Pre-embryonic period? Events? |
Blastocyte Week 1-2 Zygote divides mitotically many times to produce a multicellular blastocyte that implants in the uterus |
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What is the developmental stage of the embryonic period? Events? |
Embryo Week 3-8 Blastocyst grows, folds and reforms rudimentary organ systems
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What is the developmental stage of the fetal period? Events? |
Fetus Weeks 9-38 Grows larger and develops until it's organ systems can function without assistance from the mother |
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8 steps of fertilization |
1. Sperm undergo capacitation as they migrate to oocyte 2. Acrosomal reaction releases enzymes 3. Sperm binds to the plasma membrane of the oocyte 4. Sperms entry stimulates cortical reaction, which destroys sperm binding receptors 5. Additional sperm cells are rejected 6. Sperm nucleus swells to form a male pronucleus 7. Oocyte completes Meiosis II and the ovum nucleus swells to form female pronucleus 8. Spindle fibers form between male and female pronuclei and chromosomes intermix |
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How many autosomes and sex chromosomes does the child receive from each parent? |
22 pairs of autosomes 1 pair of chromosomes Each parent provides one of the homologues in a pair |
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What chromosomes do males and female have? |
X: female Y: male |
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A child receives how many copies of most coding genes? |
2 copies, one from mom and one from dad |
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How many genes are needed for expression for dominant and recessive alleles? |
Dominant: one copy Recessive: both copies |
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Are genetic disorders mostly dominant or recessive? |
Recessive |
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Faulty genes found on the sex chromosome affect which sex more? Why? |
Males because they receive only one x chromosome and males are the only ones that can receive a y chromosome |
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What is cleavage? |
Rapid cell division after fertilization has occurred |
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What's a morula? |
Solid ball of cells produced after cleavage |
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What's a blastocyte? |
Hollow ball composed of a Trophoblast: outer layer of cells Inner cells mass: inner cluster of cells |
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Trophoblast produces what? |
Placenta |
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Inner cells mass produced what? |
Embryo |
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Cells at the Blastocyst stage are considered what? |
Pluripotent and can differentiate into any cell line |
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9 steps of the pre-embryonic period: fertilization through implantation |
1. Secondary oocyte 2. Fertilization and formation of pronuclei 3. Zygote 4. 2-cell stage 5. 4-cell stage 6. 8-cell stage 7. Morula 8. Blastocyte hatched from Zona pellucida 9. Blastocyte is implanted |
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Once the conceptus reaches the uterus, what is secreted from the trophoblast? Why? |
Enzymes. To mildly digest the endometrium to allow the Blastocyst to implant into the uterine lining |
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Trophoblast secretes hormone hCG to: |
1. Stimulate corpus luteum to maintain endometrium 2. Stimulate development of placenta 3. Decrease immunity against the embryo |
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Once placenta develops, placental estrogen and progesterone will do what? |
1. Moderate gestation to promote breast development 2. Inhibit FSH & LH secretion from anterior pituitary 3. Maintain uterine lining 4. Prevent uterine contraction |
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4 significant events that occurs during embryonic development includes: |
1. Formation of primary germ layers 2. Formation of the extraembryonic membranes 3. Development of the placenta 4. Early development of all organs
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What are the 3 primary germ layers of the inner cell mass? |
Ectoderm Mesoderm Endoderm |
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Ectoderm produces? |
Nervous system Skin Special senses |
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Mesoderm produces? |
Muscular & skeletal system Kidneys Gonads Heart Blood vessel |
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Endoderm produces? |
Epithelia of the digestive, respiratory and urinary tract |
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4 extraembryonic membranes |
Anion Yolk sac Chorion Allantois |
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Function of amnion |
Filled with amniotic fluid to cushion the child |
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Function of yolk sac |
Hematopoietic stem cells Spermatogonia Oogonia |
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Chorion functions |
Forms the fetal placenta |
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Allantois function |
Forms umbilical cord |
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What is the placenta formed from? |
Fetal portion of the trophoblast
Maternal portion of endometrium |
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What is exchanged between the mother and child prior to birth? |
Nutrients Oxygen CO2 Waste |
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Will a mother and baby's blood ever mix? |
No |
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What appears in the skeleton of a fetus as it develops? |
Ossification centers |
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Hypodermal adipose is deposited when? |
During fetal development |
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When do neural networks form? |
During fetal development |
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2 primary reasons why the fetus has special blood flow patterns |
Lack of air to the lungs Exchange through the placenta |
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What is different about fetal hermaglobin compared to adult hermaglobin? |
Fetal hermaglobin has a greater binding affinity towards O2 |
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Flow of blood through fetal circulation 8 |
1. Fetal placenta 2. Umbilical vein 3. Ductus venosus 4. Inferior vena cava 5. Foramen ovale (right to left atrium) 6. Ductus arteriosum (pulmonary trunk to aorta) 7. Iliac arteries 8. Umbilical arteries |
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Summarized events of gestation |
1. Fertilization: sperm and secondary oocyte unite in uterine tube 2. Pre-embryonic period: chromosomes from male & female pronuclei combine to form zygote. Cleavage produces blastocyte. Blastocyte implants in uterine endometrium. 3. Embryonic period: 3 germ layers are formed in blastocyte. Extraembryonic membranes form. Differentiation of the 3 germ layers result in organogenesis. 4. Fetal period: placenta completes development. Umbilical cord provides nutrients. Fetus grows rapidly. Tissue & organs contribute to grow until gestation ends at 38 weeks. |
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Hormones involved with parturition in a positive feedback mechanism 5 steps |
1. Fetal adrenal cortex produces cortisol, stimulates placenta to secrete high levels of estrogen 2. Estrogen simulates uterus to form oxytocin receptors 3. Fetal&maternal hypothalamus secrete oxytocin, which stimulates placenta to secrete prostaglandins 4. Prostaglandins dilate the cervix and with oxytocin, increase strength of uterine contractions 5. Positive feedback begins when cervical stretching triggers release of more oxytocin and prostagladins |
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4 stages of labor |
1. Normal position of fully developed fetus before labor begins 2. Dilation stage: cervical canal dilates to 10 cm. Ruptured amnion. 3. Expulsion stage 4. Placental stage |
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What changes occur in a baby's circulatory system when they are born? |
Ductus arteriosus & venosus constrict Foramen ovale closes Umbilical vessels degenerate into ligaments |
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Hormonal regulation of lactation 5 steps |
1. Infant suckling triggers maternal hypothalamus to produce oxytocin and the anterior pituitary to produce & release prolactin. 2. Oxytocin simulates myoepithelial cells of the breast to contract (let down reflex) 3. Prolactin simulates the mammary glands to produce additional milk 4. A positive feedback mechanism is responsible for continued production of milk a long as infant suckles |
