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142 Cards in this Set
- Front
- Back
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gametes
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cells in sexual reproduction that contains a copy of half of his/her genetic material.
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male gamete
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spermatozoa
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female gamete
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ova
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zygote
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fertilized ovum before cleavage.
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diploid
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2 sets of chromosomes (2n)
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sperm
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male gonads
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ovum
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female gonads
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parturition
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birth
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secondary sex characteristics
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external features that distinguish the sexes from each other (facial hair, widening of hips)
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puberty
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period of sexual maturation that usualy occurs between ages 10-14 to mid to late teens
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reproductive tract
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system of interconnecting passageways through which gametes are transported after leaving the gonads
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meiosis
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series of two cell divisions following only a single replication of DNA, thereby generating daughter cells with half the normal chromosome number.
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sister chromatids
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Original DNA is replicated in a cell, yielding exact copies of all 46 chromosomes (2n x 2). Two copies of each chromosome remain joined together at a structure called a centromere.
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crossing over
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when portions of homologous chromosomes begin to exchange segments with each other during meiosis
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independent assortment
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random grouping of maternal and paternal chromosomes during meiosis. pairs of homolgous chromosomes line up along a plane bisecint the cells so that maternal and paternal chromosomes is present on either side of the cell.
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gonad functions
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*produce gametes
*secrete sex hormones (promote gameteogenesis, growth and maintenace of reproductive organs, development of secondary sex characteristics) |
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sex determination and factors
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role of genes determing a person's sex. XX or XY. srY gene (codes for testis-determining factor found on Y chromosome).
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sex differentiation and factors
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the role of hormones, testerone and MIS (Mullerian inhibiting substance) in the development of sexual characteristics.
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Gametes
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Gametes are haploid
23 chromosomes: 22 autosomes, 1 sex Fertilization-->zygote Diploid 46 chromosomes: 44 autosomes, 2 sex |
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Sex chromosomes
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come in 2 forms: X and Y
Genes not all paired X chromosome found in all individuals Has essential genes Y chromosome only in males Has genes essential for developing into male |
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Autosomes
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come in pairs : 22 pairs
Each in a pair carries same complement of genes |
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Gametogenesis
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production of gametes from undifferented germ cells
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Mitosis
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normal cell division
DNA replicated once Cells undergo division once |
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Meiosis
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cell division to produce gametes
DNA replicated once Cells undergo division twice |
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Reproductive System
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all organs involved in mating, gametogenesis, or other functions involved in producing offspring
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Organs of Reproductive System
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Gonads
Accessory Reproductive Organs |
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Accessory Reproductive Organs
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1) organs of reproductive tract, a system of interconnecting passageways through which gametes are transported after leaving the gonads
2) various glands that secrete fluids into the reproductive tract. |
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Sex hormones
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Testes: androgens
Ovaries: estrogens and progesterone |
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Adrenal Cortex
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produces sex hormones
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Events Following Fertilization
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Copulation = act of mating
Sperm deposited into female to fertilize ovum After fertilization = pregnancy or gestation First two months: embryo After two months: fetus About nine months: parturition or birth |
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Y chromosome
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srY gene (sex-determining region on Y)
If srY gene present – testes If srY gene absent – ovaries |
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First 2 Weeks of Sex Differentiation
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First 2 weeks: embryo sexually indifferent
Wolffian ducts (precursor to male tract) Müllerian ducts (precursor to female tract) |
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Testes present (due to srY gene)
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testes will secrte testerone and Mullerian-inhibiting substance (MIS). testerone is responsible for wolffian ducts to be active, and those will become the male reproductive structures. MIS causes degeneration of Müllerian ducts
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No tests (no srY)
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Absence of testerone will cause the wolffian ducts to regress. lack of MIS allows mullerian ducts to form which will form female reproductive structures.
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Puberty
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(starts at 10-14 years, later in boys):
*Sexual maturation *Reproductive organs mature (can produce gametes) *Secondary sexual characteristics develop |
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Female Sexual Maturation
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female reproductive system cycles. lose the ability to reproduce around ages 45-50.
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Male Sexual Maturation
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Can continually produce sperm throughout entire life.
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Testes
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*Male gonads
*250-300 compartments *Seminiferous tubules--> highly coiled hollow tubes responsible for sperm production. |
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Spermatocele
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a benign cystic accumulation of sperm that arises from the head of the epididymis.
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Testicular Torsion
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spermatic cord that provides the blood supply to a testicle is twisted, cutting off the blood supply, often causing orchalgia (pain in testes or scrotum). Prolonged testicular torsion will result in the death of the testicle and surrounding tissues.
It is also believed that torsion occurring during fetal development can lead to the so-called neonatal torsion or vanishing testis, and is one of the causes of an infant being born with monorchism (one testicle). |
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Testicular Mass
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*cancer
*experts recommend regular monthly testicular self-examination after a hot shower or bath, when the scrotum is looser. Men should examine each testicle, feeling for pea-shaped lumps. Symptoms may include one or more of the following: a lump in one testis or a hardening of one of the testicles, pain and tenderness in the testicles build-up of fluid in the scrotum,a dull ache in the lower abdomen or groin, an increase, or significant decrease, in the size of one testis, blood in semen |
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Cells of Testes
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Leydig (interstitial), Sertoli(epithelial),smooth muscle, blood-testes barrier.
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Sertoli Cells
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*Support sperm development
*Secrete luminal fluid in which sperm develop *Secrete androgen-binding protein :androgen buffer, elps maintain steady androgens in lumen. *Target cells to testosterone and FSH :Secrete chemicals that stimulate spermatogenesis *Secrete inhibin :hormone of negative feedback loop for FSH *Secrete MIS (embryonic only) |
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Leydig Cells
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interstitial cells that secrete testerone.
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Smooth Muscle of testes
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peristalsis to propel sperm
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blood-testes barrier
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has tight junctions,luminal compartment, and basal compartment
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Penis
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external male genitalia. male copulatory organ.
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Male Reproductive Tract
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seminferous tubules-->rete testis-->efferent tubules-->exits testes-->epididymis--> vas deferenes-->meet with seminal vesicle, now called ejaculatory duct-->prostate gland-->urethra--> bulbourethral glands.
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bulbourethral glands
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pair of rounds, pea-sized shaped glands located beneath prostate. secretes a fluid containing viscous, sticky mucus that is released prior to ejaculation and functions as a lubricant.
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Male Accessory Glands
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Seminal Vesicles
Prostate Gland bulbourethral glands |
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Seminal Vesicles
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Secrete alkaline fluid with fructose, enzymes, and prostaglandins
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Prostate Gland
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Secrete citrate and enzymes
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Vasectomy
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permanent birth control method for men. in some conventional clinics part of the vasa deferentia are surgically removed
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Hormonal Regulation of Reproductive Function in Males
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*Gonadotropins:
FSH – stimulates gametogenesis LH – stimulates androgen secretion *Androgens (including testerone) *GnRH (gonadotropin releasing hormone) |
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Gonadotropins
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hormones secreted by the anterior pituitary and and act on gonads (FSH and LH)
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FSH
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acts on sertoli cells to stimulate spermatogenesis
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LH
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stimulates secretion of androgens by Leydig cells
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Androgens (testerone)
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lipophilic; therefore readily diffusable from Leydig cells to all testicular tissues including sertoli cells. Function as paracines--> in testes works with FSH to promote spermatogenesis.
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Actions of Testerone
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*stimulate spermatogenesis
*promote development of secondary sex characteristics during puberty and maintenance of these characteristics in adult life *increase sex drive *promote protein synthesis in skeletal muscles *stimulate GH secretion, which permits bone growth during adoloscence *promotes development of male reproductive structures during embryonic life. |
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GnRH
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hypothalamic tropic hormone that stimulates secretion of gonadotropins. Acts on anterior pituitary to release FSH and LH.
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Negative Feedback Control of Gonadotrophins
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When testerone levels are high, it acts with the hypothalamus to stop GnRH release, which stops FSH and LH release.
Sertoli cells secrete inhibin to supress FSH by anterior pituitary. |
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Sperm
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*Head
-Chromosomes -Acrosome (enzymes necessary for fertilization) *Mid-piece -Mitochondria *Tail -Whip-like movements propel sperm |
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Sperm Maturation
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*Spermatozoa released into lumen of seminiferous tubules. They are immotile for 20 days.Move to epididymis by peristaltic contractions and flow of lumenal fluid. Now acquire motility.
*Move to vas deferens by peristalsis. Remain in vas deferens until ejaculation |
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Sexual Maturation
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*Controlled by autonomic nervous system
*Spinal Reflexes--> stimulation act on interneurons of spinal cord changing activity of autonomic nervous system. *Phases -Erection – parasympathetic nervous system -Emission – sympathetic nervous system -Ejaculation – sympathetic nervous system |
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erection
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parasympathetic--> arterial vasodilation, increases blood flow to erectile tissue. dilation also compresses veins to reduce outflow of blood.
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ejaculation
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sympathetic--> triggers strong contractions in epididymis, vas deferens, and ejaculatory ducts, secretion of fluids by seminal vesicles and prostate gland.
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emission
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mixture of sperm and semen into urethra. following emission smooth muscle of urethra and skeletal muscle at base of penis undergo contractions that expel semen through urethral opening. also triggers closure of urethral sphincter at base of bladder to prevent urine from mixing with semen during ejaculation.
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Erectile Dysfunction (ED)
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*impotence
*Inability to maintain an erection sufficiently rigid to permit sexual intercourse *Affects ~ 10 to 15 million American men *Result of vascular or connective tissue damage in penis as part of aging *Psychological |
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Possible Causes of ED
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Testosterone deficiency
Kidney disorders Multiple sclerosis Atherosclerosis Diabetes mellitus Tobacco and/or EtOH |
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Medications that may cause ED
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Antihypertensive agents
Antidepressants Tranquilizers |
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Characteristics of Female Reproductive System
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*Cyclic changes in activity
-Menstrual cycle *Restricted periods of fertility -Ovulation *Limited gamete production -Pool established at birth |
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Mittelschmerz
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*Abdominal pain occurring at the time of ovulation
*Results from irritation of the peritoneum by bleeding from the ovulation site *Typically occurs on day 14 of cycle |
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Female Reproductive Organs
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*Gonads: ovaries
*Reproductive tract: uterus, uterine tubes, vagina *External genitalia: vulva |
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Follicles
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*develop in ovary
*contain one ovum *start as a primordial follicle with a single layer of follicle cells. As it develops, the cells increase to more than one layer and it then referred to as granulosa cells. Granulosa cells proliferate and the outermost layer is transformed into theca cells. |
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Granulosa Cells
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*Target cells of estrogen and FSH :Secrete chemical messengers in response
*Secrete inhibin :Provides negative feedback to FSH secretion *Transport nutrients to oocytes through gap junctions *Secrete estrogens *secrete antral fluid *secrete substance that forms zona pellucida |
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Uterus
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*center of pelvic cavity
*functions to house and nourish developing human *fetus is held in upper portion known as the body *lower portion has cervix with a cervical canal that leads to the vagina |
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birth canal
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cervical canal and vagina
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Wall of uterus
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*endometrium- innermost layer, epithelial cells and underlying connective tissue. numerous glands that secrete fluid that bathes uterine lining.
*myometrium- smooth muscle layer. contractions help to expel fetus from uterus. *perimetrium -outer layer. epithelial cells and connective tissues. |
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Vagina
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*Female organ of copulation
*Wall contains smooth muscle *Inner surface bathed in acid fluid secreted from uterus or glands in cervix Protects against bacterial infections |
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Uterine Tubes (aka fallopian tubes aka oviducts)
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*Ova transported from ovaries to uterus
*Site of fertilization *Infundibulum (tunnel like structure where uterine tube terminates) *fimbriae (fringed fingerlike projections that partially envelop the ovary) -Pick up released ovum |
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Movement of ovum through uterine tube after being released by ovary
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Initially – peristaltic contractions
Mostly – ciliary actions Duration – 4 days to uterus |
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Tubal Ligation
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Permanent female method of contraception. But uterine tubes and seal cut ends shut.
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Ova and Their Development
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*Females: number of oogonia is fixed prior to birth
*Meiosis of gametes begins in fetal life, but not completed until after fertilization |
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Menstrual Cycle
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*The Ovarian Cycle
*The Uterine Cycle *Hormonal Changes During the Menstrual Cycle -regular, periodic changes in secretion of hypothalamic, anterior pituitary, and ovarian hormones. *lasts about 28 days |
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Ovarian Cycle
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*Follicular phase
-Menstruation--> ovulation -~14 days *Luteal phase -Ovulation-->before menstruation -14 days -coincides with remainder of menstrual cycle |
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menustration
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shedding of blood and tissue from the surface of the uterine lining.
marks beginning of menstrual cycle. |
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ovulation
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release of an egg.
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Follicular Phase
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*Few follicles begin to develop from primordial follicle
*Oocyte grows, granulosa cells proliferate *Zona pellucida and antrum form *dominant follicle continues development, others regress *corona radiata develops *Graafian follicle=mature *ovulation |
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zona pellucida
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membrane between granulosa cells and oocyte.
granulosa cells secrete noncellular material that forms that forms this membrane |
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antrum
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fluid filled cavity that increases in size and surrounds follicle.
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Hormonal Control of Follicular Phase
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FSH and estrogens stimulate follicle growth and development
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Ovulation
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*wall of Graafian follicle ruptures
*Antral fluid with oocyte flows to ovary surface *Released *Ova enters fimbrae |
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Luteal Phase
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*Ruptured follicle-->gland = corpus luteum
*Corpus luteum secretes estrogens and progesterone *Corpus luteum reaches max activity 10 days, then degenerates in no fertilization occurs |
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Hormonal Control of Ovulation
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LH surge triggers ovulation and development of corpus luteum in luteal phase
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corpus albicans
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corpus luteum degenerates if not fertilized to this scar tissue. causes a decline in plasma estrogen and progesterone that sets the stage for menustration and beginning of next follicular phase.
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Fraternal Twins
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*Two or more follicles may become dominant and released at ovulation
*If both are fertilized – fraternal twins *Also called dizygotic twins (develop from 2 zygotes) |
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Uterine Cycle
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occurs in concert with ovarian cycle: 3 phases:
*Follicular Phase (from menstrual cycle) -Menstrual Phase(Days 1-5) -Proliferative Phase (menstruation-14) *Luteal Phase (from menstrual phase) -Secretory Phase (15-28) |
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Menstrual Phase
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*Shedding of uterine lining
*Blood flow to tissue decreases *Tissues die and slough into vagina causing menstrual flow |
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Hormonal Control of Menstruation Phase
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*Triggered by decreased estrogens and progesterone
*Hormones decrease when corpus luteum degenerates |
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Proliferative Phase
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*uterus renews itself in preparation for a possible pregnancy.
*endometrial tissues that were spared from destruction in menstrual phase being to grow. *smooth muscle in underlying myometrium thickens *endometrial glands enlarge. *cervical canal secretes mucus that bathes inner surface (facilitates sperm migration) |
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Hormonal Control of Proliferative Phase
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Estrogens stimulate development of uterine lining
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Secretory Phase
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*Endometrium prepared for implantation
*Blood supply increased Glands enlarge and secrete glycogen-rich fluids (which embryo uses an an energy rich source it early phases of growth) *Cervical secretions more sticky forming a plug (isolates uterus from microorganisms in outside environment that could harm embryo). |
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Hormonal Control of Secretory Phase
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progesterone (due to action of corpus luteum).
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Uterine Fibroid Tumors
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*Most common pelvic tumors in women
*Occurring in approximately 30% of women over the age of 35. |
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Uterine Fibroid Tumor Symptoms
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*excessive bleeding leading to iron deficiency anemia
*pain and pressure sensations even obstruction of the bowel or urinary tract *Women with fibroids often complain of painful intercourse *may result in pregnancy loss *Each year approximately 200,000 hysterectomies are performed in the United States for uterine fibroids |
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Hormonal Changes During Menstrual Cycle
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*Estrogen secreted from follicle 1st, then corpus luteum
*Progesterone secreted from corpus luteum *LH and FSH secreted from anterior pituitary *Estrogens and progesterone inhibit LH and FSH secretion (negative feedback inhibition) |
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Regulation of Hormone Secretion Mid-Follicular Phase
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*estrogen and progesterone levels decline, which normally inhibit gonadotropin release; therefore, the anterior pituitary will excrete FSH and LH.
*FSH stimulates follicles to develop and grow. *LH stimulates theca cells (have LH receptors) to secrete androgens taht travel to granulosa cells and is converted to estrogen. *estrogen affects the hypothalamus and anterior pituitary causing supression of GnRH, LH, and FSH. *LH remains fairly steady *FSH falls due to inhibin being released by granulosa cells--> causes atresia of non-dominating follicles. |
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Estrogen Functions
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*uterine changes characteristic of proliferative phase
*work with FSH to promote oogenesis and follicular growth *promote changes htat prepare body for subsequent events of menstrual cycle *induce of expression of LH receptors *induce expression of progesterone receptors on endometrial cells, which primes endometrium to respond to progresterone during luteal phase. |
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Long Term Regulation of Female Reproductive Function
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*Puberty
-Estrogen – secondary sex characteristics *Reproductive years -Estrogen levels high to maintain secondary sex characteristics *Menopause -Estrogen levels decrease -Reversal of some secondary sex characteristics -Hot-flashes -Increased risk of heart disease and osteoporosis |
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Fertilization, Implantation, and Pregnancy Stages
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*Events of Fertilization
*Early Embryonic Development and Implantation *Late Embryonic and Fetal Development *Hormonal Changes During Pregnancy |
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Fertilization
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*Fertilization usually takes place in uterine tube
*Sperm must be introduced into female reproductive tract within five days before ovulation -Sperm viable for 5 days -Oocyte viable for 12-24 hours *Sperm initially incapable of fertilization -Requires capacitation |
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capacitation
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sperm unable to fertilize with oocyte at first. must be in tract for several hours.
*change in pattern of tail movement to move faster; plasma membrane altered so fertilization can occur. |
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Oocyte movement in Uterine Tube
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*At ovulation, fluid movement causes oocyte to enter fimbriae of uterine tube
*Peristaltic contractions move oocyte toward uterus for several minutes *Cilia move oocyte toward uterus for few days *Entire trip takes 4 days |
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Ectopic Pregnancy
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fertilized egg has implanted outside the uterus, usually in the fallopian tubes
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Ectopic Pregnancy Symptoms
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*Cullen’s sign
-Black and blue bruising around umbilicus *Also seen with -Abdominal trauma -Acute pancreatitis |
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Events of Fertilization
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*Several sperm generally reach ovum and try penetrating corona radiata
*Once penetrated they bind to sperm-binding protein *Acrosome reaction triggered, with acrosomal enzymes released *Enzymes break through zona pellucida allowing sperm to access oocyte *First sperm to access oocyte binds to receptor on oocyte plasma membrane *Sperm transported into cytoplasm = fusion *Sperm-binding proteins become inactivated and zona pellucida hardens preventing polyspermy |
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Fertilization after Fusion
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*Fusion stimulates 2nd meiotic division of oocyte
oocyte-->ovum *Sperm plasma membrane disintegrates *Chromosomes from sperm and ovum migrate to center DNA replicated-->zygote |
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Early Embryonic Development and Implantation
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*Mitotic divisions-->morula
Cell cleavage (no increase in overall size) *Totipotent up to 16-32 cell stage |
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Identical Twins
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When cells totipotent, division of morula results in identical twins aka monozygotic twins
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Blatocyst
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*Lost zona pellucida
*Outer cell layer = trophoblast will become fetal placenta *Inner cell mass will become embryo *Fluid-filled cavity = blastocoele |
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Implantation
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*Occurs 6-7 days post-fertilization
*Trophoblast responsible for implantation *Secretes enzymes that digest endometrial cells to provide nourishment for embryo *Secretes paracrines that stimulate decidual response *Infiltrates endometrial tissue to develop into placenta |
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decidual response
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an increase in number of capillaries, which helps increase the delivery of oxygen and nutrients in area
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Blastocyst Attaches to Endometrial Lining
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Endometrium swells, increases glycogen stores
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Trophoblast Penetrates Endometrium
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Trophoblast and endometrial cells will form placenta
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Late Embryonic and Fetal Development
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By 5 weeks, placenta functioning, heart beating
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Placenta Development
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*Fetal component
-Chorionic villi *Maternal component -Endometrial tissue *Blood flow to placenta -Maternal uterine artery and vein -Fetal umbilical artery and vein located in umbilical cord |
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Parturition
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Babies head wedges cervix open.
Baby born head first. Expulsion of placenta=afterbirth |
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Labor and Parturition
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Oxytocin secretion from
anterior pituitary strenghthens uterine contractions for birth. Pressure of fetus against cervix will weaken contractions. |
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Trigger for Parturition
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*Unknown, but current theory suggests signal comes from fetus
*Fetal placenta -CRH-->fetal ACTH-->DHEA *DHEA-->Estrogens -Enters maternal blood stream *Estrogen-->parturition |
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Lactation
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*Inhibit lactation
-Estrogen -Progesterone *Stimulate lactation -Prolactin -Oxytocin |
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Colostrum
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Watery milk produced 1st few days after birth. Proteins, few nutrients.
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Later milk
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Nutrients, growth factors, hormones, and antibodies
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Mammary Glands
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*Prolactin – milk synthesis
*Oxytocin – milk ejection |
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Suckling Reflex
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*Tactile receptors in nipples
*hypothalamus causes: PRH secretion to increase and PIH secretion to decrease. PRH stimulates anterior pituitary to secrete prolactin, and milk secretes by alveoli in breasts. -activity in neurosecretory cells stimulate posterior pituitary to release oxytocin, which causes contraction of myoepithelial cells in breasts, and milk ejects. |
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chorionic villi
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chorion sends fingerlike projections that cotain both capillaries of fetal circulation and cells that secrete paracrines that alter the structure and function of the surrounding endometrial tissue.
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umbilical cord
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fetal blood carried to placenta by paired umbilical arteries and back to fetus for general circulation by umbilical vein.
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DHEA
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dehydroepiandrosterone. androgen from adrenal cortex that is manufactured to placental estrogens of developing fetus
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Estrogen Functions During Pregnancy
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*growth of mammary glands
*prolactin secretion to prepare mammary glands for lactation *growth of enhanced contractile responsiveness of uterine smooth muscle; increases responsiveness of oxytocin in uterine smooth muscle. |
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Progesterone Functions During Pregnancy
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*growth of glandular tissue
*suppression of contractile activity in uterine smooth muscle *maintenance of secretory-phase uterine conditions |
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CRH
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corticotropin releasing hormone
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PRH
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prolactin releasing hormone
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PIH
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prolactin inhibiting hormone
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