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90 Cards in this Set
- Front
- Back
sexual reproduction
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fusion of haploid gametes forms a diploid cell
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zygote
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diploid cell formed by sexual reproduction
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egg
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female gamete
large, nonmotile cell |
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sperm
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male gamete
much smaller, motile cell |
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asexual reproduction
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generation of new individuals without fusion of egg and sperm
-mostly relies entirely on mitotic cell division |
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fission
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separation of a parent organism into 2 individuals of approximately equal size
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budding
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new individuals arise from outgrowths of existing ones
ex: coral and hydra |
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fragmentation
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breaking of body into several pieces
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regeneration
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regrowth of lost body parts
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parthogenesis
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form of asexual reproduction in which egg develops without being fertilized
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sexual reproduction pros
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enhances reproductive success/survival
-unique combination of parental genes -speed up adaption -allow population to rid itself of sets of harmful genes more readily |
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ovulation
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release of mature eggs
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hermaphroditism
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individual has both male and female reproductive systems
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fertilization
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union of sperm and egg
-either external or internal |
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external fertilization
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female releases eggs into environment where male then fertilaze them
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internal fertilization
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sperm are deposited in or near female reproductive tract and fertilization ovvurs within the tract
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spawning
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individuals clustered in same area release gametes into water at same time
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phermones
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chemicals released by one organism that can influence the physiology and behavior of other indiciduals of the same species
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gonads
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organs that produce gametes in most animals
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external female reproductive structures
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clitoris and 2 sets of labia
-surround clitoris and vaginal opening |
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ovarie
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female gonads that flank the uterus and held in place in obdaminal cavity by ligaments (pair of them)
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follicles
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oocyte surrounded by group of support cells found in outer layer of each ovary packed in
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oocyte
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partially developed egg
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oogenesis
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formation and development of an ovum
-born w/ 1-2 million follicles, only 500 mature -prior to ovulation follicle produce estradiol |
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corpus luteum
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growth of residual follicular tissue w/in ovary after ovulation
-secretes additional estradiol and progesterone, (helps maintain uterine lining during pregnancy) -degenerates if egg cell not fertilized |
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oviduct
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fallopian tube
extends from uterus toward each ovary -at ovulation egg released into abdominal cavity near funnel-like opening of oviduct -cilia on epithelial lining of duct help collect egg by drawing fluid from body cavity into oviduct -diameter near uterus extremely narrow |
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uterus
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womb, thick muscular organ that can expand during pregnancy to accomadate 4kg fetus
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endometrium
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richly upplied with blood vessel
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cervix
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neck of uterus, opens into vagina
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vagina
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muscular but elastic chamber
-site for insertion of penis and deposition of sperm during copulation |
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vulva
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collective term for external female genitals
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labia majura
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pair of thick fatty ridges
-encloses and protects rest of the vulva |
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labia minora
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pair of slender skin folds that border cavity of the vaginal opening and seperate opening of the urethra
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hymen
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partly covers the vaginal opening in humans at birth and reptures during vigorous physical activity/intercourse
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clitoris
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located at upper intersection of labia minora consists of short shaft supporting rounded glans
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glan
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head covered by prepuce
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prepuce
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small hood of skin
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mammary glands
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-pressent in both sexes but normally produce milk only in females
-low level of estradiol in male limits development of fat deposits (remain small) |
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testes
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male gonad, consist of highly coild tubes surrounded by several layers of CT
-semineferous tubules -leydig cells -scrotum -testicle |
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seminferous tubules
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tubes where sperm form
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leydig cells
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scattered btween semineferous tubules, produced testosterone and other androgens
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scrotum
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fold of body wall
-maintains testis temp about 2 degrees below that in abdominal cavity |
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testicle
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tetis within a scrotum
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epididymis
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takes 3 weeks for sperm to pass thru 6m-long tubules
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ejaculation
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sperm are propelled from each epididymis through a muscular duct
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vas deferns
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muscular duct, extends around and behind urinary bladder and joins duct from seminal vesicle
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ejaculatory duct
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opens into urethra
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urethra
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outlet tube for both the excretory system and reproductive system
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semen
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fluid that is ejaculated
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seminal vesicles
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2
contribute around 60% volume of semen -thick yellowish, alkaline -contains mucus, sugar fructose (promotes most of sperm's energy), coagulating enzyme |
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prostate gland
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secretes products directly into urethra thru several small ducts
-fluid is thin and milky -anticoagulant enzyme and citrate -->enlargement of prostate occurs in more than 1/2 of all men over 40 -->almost all men over 70 |
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bulbourethral glands
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pair of small glands along urethra below prostate
-before ejaculation secrete clear mucus that neutralizes many acidic urine remaining in urethra -carries some sperm (why withdrawl is not adequate birth control) |
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penis
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contains urethra and three cylinders of spongy erectile tissue
-main shaft covered by relatively thick skin, head/glans has thinner covering (more sensitive to stimulation) -prepuce/foreskin |
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prepuce
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foreskin
fold of skin covers human glans-may be removed by circumcision |
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vasocongetion
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filling of a tissue with blood
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myotonia
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increased muscle tension
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4 phases of sexual response cycle
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excitement, plateau, orgasm and resolution
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excitement phase
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continue as result of direct stimulation of genitals
-females: outer third vagina vasocongested, inner 2/3 slightly expands -->forms depression for recieving sperm at back of vagina |
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orgasm
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chacterized by rhythmic, involuntary contractions of reproductive structures
males: emission, ejaculation female: uterus and outer vagina contract |
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emission
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glands and ducts of reproductive tract contract, forcing semen into urethra
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expulsion/ejaculation
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urethra contracts and semen is expelled
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resolution phase
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reverses responses of earlier stages
-organ return to normal size and outer muscles relax -female no refractory period |
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gametogenesis
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production of gametes
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spermatogenesis
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formation of development of sperm
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spermatogonia
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formed from stem cells developed in embryonic testes that have differentiated
-->generate spermatocytes, also by mitosis |
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spermatocyte
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gives rise to 4 spermatids through meiotic cell divisions (reduce chromosome numbers from diploid to haploid)
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semineferous tubules and stem cell differentiation
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stem cells near outer edge->closer as spermatogensis proceeds mature sperm released into lumen->epididymis->motile
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acrosome
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special vesicle on head which contain enzymes that help sperm penetrate the egg
-tail=flagellum |
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spermatogenesis pathway
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primordial germ cell in embryo->mitotic division->spermatogonial stem cell (2n)->mitotic divisions->primary spermatocyte (2n)->meiosis I->2 secretory permatocyte (n)->meiosi II->4 early spermatid (n)->differntiation (sertoli cells provide nutrients)->sperm cell
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oogenesis
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development of mature oocytes (eggs)
-immature eggs form in ovary of female embryo but do not complete development til years later |
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oogonia
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divide mitotically to form cells that begin meiosis, but stop process at prophase I
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primary oocytes
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contained w/in small follicles they arrest development before birth
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secondary oocyte
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released at ovulation, arrested in metaphase of meiosis II
-follicle breaks down -only if sperm penetrates oocyte does meiosis II resume |
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oogenesis pathway
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primordial germ cell->mitotic diviion-->oogonium (2n)-->mitotic divisions->primary oocyte(2n, present@ birth, arrested in prophase of meiosis I)-> completion of meiosis I and onset of meiosis II-> firt polar body and secondary oocyte (arrested at metaphase of meiosis II, n)--> ovulation, sperm entry--. completion of meiosis II-->second polar body (n), fertilized egg (n)
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spermatogenesiss vs. oogensis
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1. only in spermatogenesis do all 4 products of meiosis develop into mature gametes
-in oogenesis, cytokinesis during meiosis is unequal -almost all cytoplasm segregated into single -daughter cell secondary oocyte, large cell destined to become the egg, other products are polar bodies and degenerate 2. spermatogenesis including mitotic divisions of stem cells and differentiated spermatogonia, occurs throughout adolescence and adulthood -->oogenesis, mitotic divisions are completed before birth and production of mature gametes causes at about age 50 3. spermatogenesis produces mature sperm from precursor cells in a continous sequence, whereas oogenesis has long interruptions |
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sertoli cells
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within semineferous tubules and help nourish developing sperm
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leydig cells
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located in intersitital space between semineferous tubules
-secrete testosterone and other androgens which promote spermatogenesis in tubules |
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inhibin
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hormone that males produce by sertoli cells
-acts on anterior pituitary to reduce FSH secretion |
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menstruation
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cyclic shedding of the endometrium from the uterus (occurs in flow through the cervix and vagina)
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menstrual cycle
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changes int he uterus
average 28 days in length |
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ovarian cycle
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cyclic events that occur in the ovaries
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ovarian cycle pathway
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-begins with release of GnRH from hypothalamus
-stimulates anterior pituitary to secrete small amounts of FSH and LH -follicle stimulating hormone stimulates follicle growth aided by LH -cells of growing follicles start to make estradiol -follicular phase -low levels of estradiol inhibit secretion of pituitary hormones (keeping levels of FSH and LH relatively low) -high concentration of estradiol has opposite effect-->stimulates gonadotropin secretion by acting on hypothalamus->increase in GnRH (positive feedback) -final maturation of the follicle -follicular phase ends at ovulation, about day after LH surge -peak in LH level->follicle and adjacent wall ov ovary rupture->releases secondary oocyte -luteal phase: follows ovulation -->LH stimulates follicular tissue left behind in ovary to transform into corpus luteum (glandular structure) -corpus luteum secretes prgesterone and estradiol -excites negative feedback on hypothalamus and pituitary -->reduces secretion of LH and FSH to very low levels |
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follicular phase
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part of ovarian cycle during which follicles grow and oocytes mature
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uterine menstrual cycle pathway
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-prior to ovulation, ovarian steroid hormone stimulates uterus to prepare for support of an embryo
-estradiol signals endometrium to thicken -follicular phase of ovarian cycle coordinated with proliferative phase -estradiol and progesterone continue development and maintenance of uterine lining -->enlargement of arteries and growth of endometrial glands-secrete nutrient fluid that can sustain early embryo even before it implants in uterine lining -luteal phase coordinated with secretory phase -disentigration of corpus luteum->rapid drop in ovarian hormone levels->arteries in endometrium constrict->uterine lining disintegrates->mestrual flow phase |
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endometriosis
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disorder in which some cells of the uterine lining migrate to an abdominal location that is abnormal
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ectopic
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abnormal because cells migrated to location such as an oviduct, ovary or large intestine
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menopause
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cessation of ovulation and menstruation
btwn ages 46-54 -ovaries lose reponsiveness to FSh and LH resulting in decline in estradiol production by ovary |
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estrous cycles
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absence of a pregnancy the uterus reabsorbs endometrium and no extensive fluid flow occurs
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conception
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fertilization, occurs when a perm fuses with an egg in the oviduct
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blastocyst
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sphere of cells surrounding a central cavity
-several days after impass into endometrium |