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72 Cards in this Set

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1. 3 stages in male sexual act
2. 4 glands that contribute to semen
3. What male sexual act can occur by parasympathetic activity?
1. Arousal, orgasm, resolution
2. Seminal vesicles, prostate, testes, & bulbourethral glands
3. Erection & lubrication (arousal only)
Diff btw emission & ejaculation?
1. Emission: movement of sperm & semen components into urethra
2. Ejaculation: movement of semen from urethra out of the body
1. Gametogenesis
2. Fusion of sperm & egg
1. Diploid germ cells undergo meiotic division to produce haploid gametes.
2. syngamy, fertilization; results in a zygote.
** sperm contributes only haploid genome.
1. Seminiferous tubule
2. Cells that give rise to spermatogonia & oogonia
1. Site of spermatogenesis.
2. Germ cells
3. Spermatogonium -> primary spermatocyte (meiosis I) -> secondary spermatocyte (meiosis II) -> spermatids (kids, immature; tales start forming) -> spermatozoa (in seminiferous tubule & epididymis)
**"cyte" - undergoes meiosis
At vas deferens
sperms become motile but remain inactive duce to vas def. inhibitory substances (low metabolic rate)
1. Spermatogonia divided by
2. How many mature sperm from a single spermatogonium after meiosis?
1. Mitosis, not meiosis (meiotic S phase: genome replication)
spermato"cyte" - meiotic division
2. 4 haploid cells from meiosis of one diploid spermatogonium
1. Mitosis & meiosis require
2. Sister chromatids are
3. Meiosis I & II involve
1. DNA replication during S phase.
2. Identical; they do not recombine.
**Meiosis I involves paring, recombination, & separation of homologous chromosomes. Meiosis II: siter chromatids separate (like mitosis)
1. Neck region of sperm contains many mitochondria; where do they get energy?
2. Acrosome
1. From fructose from seminal vesicles & vaginal secretion
2. Head of sperm containing hydrolytic enzymes for penetration of ovum
1. 2 roles of testes
2. Seminiferous tubules
1.1. spermatogenesis
1.2. Secretion of male sex hormones (androgen/teststerone) into bloos stream
2. Site of spermatogenesis
1. Ejaculation tract
2. How does ejaculation occur?
Testes -> epididymis -> vas deferens -> inguinal canal -> (ejaculatory duct) -> urethra
2. When blood accumulates at high pressure in erectile tissue
1. Seminal vesicles
2. How many ejac. duct
1. Secrete about 60% semen into ejaculatory duct.
2. 2 testes, epididimi, vas deferens, seminal vesicles. 1 ejaculatory duct
1. What is semen?
2. How is it produced?
3. What do seminal vesicles contain?
1. Highly nourishing fluid for sperm
2. Produced by 3 separate glands: seminal vesicles, prostate, & bulbourethral glands
3. Fructose & etc
1. Bulbourethral glands
2. Prostate secretion
1. Help ejaculate; secret viscous, alkaline fluid that lubricate
2. 35% of semen
** both neutralize acidity in urethra & vagina
1. Lutenizing hormone (LH)
2. What secreted LH?
1. Stimulates division of spermatogonia. Stimulate Leydig cells to secrete testosterone.
2. Anterior pituitary & reaches targets via systemic circulation.
Increated testosteron levels in blood decreases
Production of follicle-stimulating hormone (FSH) by feedback inhibition upon anterior pituitary & hypothalamus.
1. If XY genotype embryo fails to secrete testosterone, will it have testes or ovaries?
2. Characterize an embryo w/ XY genotype that lacks receptor for testosterone.
1. Testosterone is produced by embryonic testes. The development doesn't depend on testosterone.
2. Testes are present b/c of Y chromosome; external genitalia are female.
1. Androgens
2. Testosterone
1. All hormones in develop. & maintenance of male characteristics.
2. Required in testes for spermatogenesis. Required for sec. sexual characteristics (after puberty).
1. Leydig cells
2. Testosterone production controlled by
1. secrete testosterone.
**testosterone -> dihydrotestosterone (converted inside target cells.)
2. hypothalamus & anterior pituitary
1. LH acts on
2. FSH stimulates
1. Leydig cells to stimulate testosterone production
2. Sertoli cells that provide feedback inhibition of LH & FSH.
1. Endometrium responsible for
2. At time of ovulation, where does egg come from & where does it go?
3. Is estrogen production by ovaries required for deveop. of fallopian tubes and uterus?
1. Nourishing a developing embryo, producing menstrual bleeding.
2. Emerges from ovary then swept into fallopian tube by constant flow of fluid into fallopian tube by cilia.
3. No; Mullerian ducts develop into such.
1. Oogonia
2. Primary oocytes
1. Germ cells that start dividing mitotically in ovary of female embryo until born.
2. Gamete procursors that remain constant until puberty.
**single primary oocyte exist from embryonic life -> menopause
1. Polar body
2. Is 2nd. oocyte haploid?
1. The cell getting little cytoplasm as oogenesis occurs. No f(x) but carrying off half the DNA. 2 polar bodies produced during oogenesis. --> 1 gamete after oogenesis.
2. Yes. After 1st meiotic division, haploid.
1. All gamete precursors (1st oocytes) are formed while
2. 1st oocytes are frozen in
3. Each meiotic division results in
1. A female is still an embryo in her mother's womb.
2. Prophase I for decades.
3. One viable egg precursor plus one polar body that dies.
1. When meiotic cycle is reactivated
2. Many other 1st oocytes enter competition but what happens?
1. Competition occurs and only one primary oocyte succeeds. It releases 1st polar body as it matures into 2nd oocyte, which is ovulated.
2. lose and die. Thus many 1st oocytes are lost w/ each menstrual cycle.
1. 2nd oocytes don't finish meiosis II unless
2. What happens when fertilization occurs.
3. Ootid
1. They are fertilized. Fertilization occurs before egg precursor is mature.
2. Egg & sperm nuclei don't fuse until after egg gets rid of 2nd polar body & completes its maturation process.
3. A zygote-precursor cell that contains separate sperm & egg nuclei.
When oogonium undergoes meiosis, 3 cells result. How many of these are eggs, & why only three cells result?
Only 1 egg results. 3 cells: 2 polar bodies + one ovum. Only 3 b/c polar body doesn't divide.
1. Follicle
2. Immature primary oocyte surrounded by single layer of granulosa cells
comprised of 1st oocyte surrounded by granulosa cells, which assist in maturation. (spermatocytes to Sertoli cells)
2. Primordial follicle. --> primary follicle (multilayers). Follicle surrounded by thecal cells (Leydig cells in male). Only 1 mature follicle per month (Graafian follicle)
1. Estrogen
2. How does estrogen exert an effect on the cell.
1. Steroid hormone in devel. of female secondary sexual characteristics, in menstrual cycle, & during pregnancy.
2. Cytoplasmic receptor binds estrogen & binds to specific DNA elements in promoters & enhancers to regulate transcription.
1. Estrogen is synthesized by
2. Estrogen & progesterone are synthesized by
1. Follicles
2. Corpus luteum, formed by follicular cells remaining in ovary after ovulation.
** Both responsible for menstrual cycle
1. Menstrual phase
2. Proliferative phase of menstrual cycle
3. Secretory phase
1. Preparation of endometrium of uterus
2. Estrogen produced by follicle induces proliferation of endometrium.
3. After ovulation; estrogen & progesterone from corpus luteum further increase devel. of endometrium. If no pregnancy, the secretion of the hormones decrease sharply, endometrial lining sloughs out of uterus.
**
1. Follicular phase
2. Ovulatory phase
3. Luteal phase
1. Primary follicle matures & secretes estrogen, which stimulates a 1st oocyte to proceed thru meiosis I to II and causes proliferative effects of ovarian estrogen on endometrium.
2. 2nd oocyte released from ovary.
3. Estrogen & progesterone secreted by corpus luteum after ovulation stimulate endometrial secretory phase.
1. Where is 2nd oocyte during the secretory phase
2. If est. & progest. were given to a woman w/o cyclic variation, how would this affect menstruation?
1. It's traveling down fallopian tube toward uterus. If fails to implant in uterus, secretory phase ends & menstruation begins.
2. If est. & progest. kept at high levels (w/ pills), menstruation will not occur.
** Menstr. occurs b/c est. & progest. from corpus luteum decrease suddenly as it degenerates.
1. FSH & LH
2. They are inihibited by
1. Secreted by anterior pituitary, they stimulate the secretion of est & progest by follicular cells or corpus luteum.
2. By high levels of est & progest.
1. FSH helps ovarian follicular cells
2. What happens in high lvl of estrogen? In graudal increase of estrogen of follicular phase?
3. Role of LH after ovulation
1. develop during follicular phase & secrete estrogen.
2. Inhibits LH secretion. Stimulates LH secretion.
3. Induces follicle to become corpus luteum * secrete est. & progest. during secretory phase.
1. What happens when LH secretion drops?
2. If est. lvls remain high in a woman's blood for 1 month, what happens?
Corpus luteum regresses -> no secretion of est progest -> doesn't maintain endometrium & menstruation occurs.
2. The woman'd not ovulate. (birth pill)
1. Why does corpus luteum degenerate?
2. Why endometrium?
3. Why LH?
1. Due to decrease in LH (luteinizing hormone).
2. Due to decrease in est. & progest.
3. Due to feedback inhibition from high lvls of est & progest. secreted by corpus luteum.
** no rise in LH, no ovulation
Way ovulation is prevented during pregnancy.
Constant
1. What happens if fertilization takes place?
2. What is role of chorion?
Devel. embryo becomes implanted in endometrium & placenta begins to develop.
2. A portion of placenta that maintains endometrium by secreting hCG.
1. Immediately prior to menstrual cycle
2. Is meiosis I or II completed prior to ovulation?
3. When does ovulation occur?
1. Surge in luteinizing hormone release from anterior pituitary.
2. Meiosis I. Meiosis II is completed after fertilization.
3. Around day 14 of the cycle. Menstruation begins at day 1.
1. What is menopause?
2. What occurs during menopause?
1. Cease of ovulation as # of follicles in ovaries decreases.
2. In absence of est. & progest., no feedback inhibition, thus LH & FSH levels are very high & stay high.
1. Secretory phase of endometrial cycle is dependent on
2. LH lvls highest during
1. The secretion of est & progest. by corpus luteum.
2. Menstrual phase of endometrial cycle
1. Fertilization
1. fusion of spermatozoan w/ 2nd oocyte; occurs in fallopian tube. Sperm must penetrate corona radiata (protective layer of granulosa cells) & vitelline layer (just outside egg cell memb).
1. How does sperm penetrate the thick layers?
2. What happens after sperm nucleus enters 2nd oocyte?
3. Zygote
By acrosome reaction; a sperm head containing hydrolytic enzymes releaed by exocytosis.
2. In ~20 min 2nd oocyte completes meiosis II & gives rise to an ootid & 2nd polar body. Ootid -> ovum.
3. New diploid cell after sperm & egg nuclei fuse.
1. Polyspermy
2. How is it prevented?
1. Penetration of ovum by multi-sperm
2. By fast/slow block to polyspermy.
fast block: a depolarization of egg plasma membrane, perventing other spermatozoa from fusing w/ egg cell membrane.
Slow block (cortical reaction): Ca2+ influx caused by initial depolarization - swelling btw vitelline layer & plasma mem & hardening of vitelline layer.
**Ca2+ leads pH change within egg, increasing metabolism & protein synthesis (egg activation)
3 ways of infertility
1. Lack of progest. secretion during latter half of menstrual c ycle -> ovulatoin had not occured.
2. Sperm very sensitive to pH.
3. Failure to mitosis of male nucleus in ovum.
1st step of Embryogenesis
**Embrygen - proceeds slowly.
Cleavage - zygote undergoes many cell divisions to produce ball of cells (Morula).
** Morula same size as zygote, meaning dividing cells are in S & M phase, not G1 & G2.
**Meiosis does not occur in embryogenesis, so homologous chromosomes don't interact w/ eachother.
1. Blastulation
2. If 2 inner cell masses form in blatula, what happens?
Morula -> blastocyst (consists of outer & inner cell mass.
* Outer cell mass -> trophoblast -> chorion (zygote's contribution to placenta).
* Iner cell mass -> embryo
2. Embryo is lost.
1. When does developing blastocyst burrows into endometrium?
2. Trophoblast secretes
3. Trophoblast
1. A week after fertilization
2. Proteases that lyse endometrial cells.
3. Where blastocyst absorbs nutrients from
Why does secretory phase of endometrial cycle occur?
Endometrial cells store glycogen, lipids, and other nutrients so that early embryo may derive nourishment directly from endometrium.
** 1st 3 months - hCG essential for maintenance of endometrium.
Placenta
Organ that is specialized to facilitate exchange of nutrients, gases, & antibodies btw maternal & embryonic bloodstreams.
**Last 6 months, corpus luteum no longer needed b/c placenta itself secretes sufficient est. & progest.
1. What happens if corpus luteum is removed during 1st trimester?
2. Role of hCG
1. Woman menstruates & embryo's lost.
2. Substitues for LH in stimulating corpus luteum that makes est & progest, which maintain endometrium.
1. Placental villi
2. Sinuses (open spaces)
1. Chorionic projections extending into endometrium where fetal capillaries will grow.
2. Srrounds villi & filled w/ maternal blood.
1. Amnion
2. Yolk sac
3. Allantois
1. Surrounds fluid-filled cavity containing developing embryo. (water that breaks before birth)
2. First site of RBC synthesis in embryo. Mammals don't store yolk.
3. Develops from embryonic gut & forms blood vessels of umbilical cord, transporting blood btw embryo & placenta.
1. Does O2-containing blood pass from mother to fetus?
2. Endometrium
1. No, placenta is like a lung facilitating exchange of substances btw 2 bloodstreams
2. Part of mother's uterus, thus has mother's genetic information. Chorion, amnion, & yolk sac have same genome.
1. Gastrulation
2. Gastrula develops from
3. Blastula & invagination
1. 3 primary germ layers (ectoderm, mesoderm, & endoderm) becomes distinct.
2. Double layer of cells (embryonic disk)
3.1 Blastula - hollow ball of cells.
2.2 Gastrulation - invagination (ingrowth) of cells to form layers
**Endoderm, ectoderm, mesoderm. Mesoderm develops from endoderm.
** Gastrula has blastopore; blastula has no opening.
Ectoderm
1. Entire nervous system
2. Posterior pituitary, adrenal medulla
3. Cornea & lens
4. Epidermis of skin & derivatives (hair, nails, sweat glands, sensory receptors)
5. Nasal oral, anal epithelium
Mesoderm
1. All muscle, bone & connective tissue
2. Entire vascular & lymphatic system, including blood.
3. Urogenital organs (kidneys, ureters, gonads, & reproductive ducts)
4. Dermis
Endoderm
1. GI tract epithelium (except mouth & anus)
2. GI glands (liver,etc)
3. Respiratory epithelium
4. Epithelial lining of urogenital organs & ducts
5. Anterior pituitary
1. O2 must diffuse across chorionic membrane
2. Trophoblast is derived from
3. All cells of blastocyst are
1. To reach fetus from mother
2. Outer cell mass & gives rise only to chorion. Embryo derived entriely from inner cell mass.
3. Trophoblast & inner cell mass; they have diff roles.
**Trophoblast -> chorion -> placental villi
1. Neurulation
2. It proceeds by
1. Next step after gastrulation; formation of nervous system.
2. Invagination & pinching off of layer of ectoderm along dorsum (back) of embryo to form dorsal neural groove.
**Dorsal neural groove -> neural tube -> brain & spinal cord.
1. Formation of neural tube induced by
2. Neural tube gives rise to
Instructions from underlying notochord (mesodermal in origin).
2. Vertebral column.
**Other ectodermal cells migrate thru the body to form peripheral nervous system ganglia.
1. Neurulation is one component of
2. By 8th week of gestation
1. Organogenesis, development of organ systems.
2. All major organ systems present & embryo is called fetus.
**By 3rd month, fetus only 5 cm long.
1. Embryonic stage
2. Fetal stage
1. From implantation thru 8th week of development. Includes periods of phenomenal differentiation & development (organ & system formation)
2. From 8th week of devel until birth. Growth & maturation of systems formed earlier
1. When is developing human most sensitive to toxins like drugs & radiation?
2. During gastrulation, do tissues from trophoblast move inward to form lining of primitive gut?
1. 1st trimester when organs are being formed.
2. No, gastrulation involves only cells derived from inner cell mass.
1. Totipotent cells
2. Cell fate is determined b4 it's visibly differentiated. Dtermination induced by
1. Primitive cells in early embryo that have potential to become any cell type.
2. Cell's envt, like exposure to diffusable factors or neighboring cells, or preprogrammed.
1. Result of dedifferentiation in uncontrolled manner
2. Specialization of cell types is
3. Cell type w/ unique genome.
1. Cancer
2. Function of things in cytoplasm & proteins & RNA in nucleus, but no genetic changes take place during devel & diff.
3.1 B & T cells - undergo gene rearrangements in process of attaining antigen specificity.
3.2 Gametes - b/c of reductive division w/ independent assortment & recombination
1. Parturition
2. What are factors that increases uterine excitability near the end of pregnancy?
1. Birth; depends on contraction of uterine wall muscle.
2.1 Change in ratio of est to progest
2.2 Presence of hormone oxytocin secreted by posterior pituitary
2.3 Mechanical stretching of uterus & cervix
1. What occurs thruout pregnancy?
2. What begins as pregnancy reaches full term?
1. Weak contractions of uterus
2. Rhythmic labor contractions (result of + feedback reflex)
1. Positive feedback reflex
2. Stretching cervix causes posterior pituitary to
1. Increased pressure on cervix -> increase in intensity of uterine contractions -> greater pressure on cervix that stimulates stronger contraction.
2. Increase secretion of oxytocin.
3 stages of labor.
1. Dilation of cervix.
2. Actual birth, involving movement of baby thru cervix & birth canal, pushed by contraction of uterine (smooth) & abdominal (skeletal) muscle
3. Expulsion of placenta, after it separates from wall of uterus.
**Contraction of uterus after birth -> minimizes blood loss.
1. In puberty est stimulates
2. During pregnancy high lvl of est & progest
3. After parturition lvl of est & progest
1. Devel of breasts
2. Further stimulates devel of breast tissue but inhibits milk secretion.
3. Fall & milk secretion begins. (prolactin, anterior pituitary hormone secreted largely prior to parturition)
1. What happens when suckling occurs?
2. Oxytocin
1. Pituitary gland stimulated by hypothalamus to release large surge of prolactin -> milk
2. Posterior pituitary hormone that's necessary for milk let-down (release). Released when suckling occurs.