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reproductive/develop
Reproductive and Development
Question | Answer |
---|---|
GAMETES | the reproductive cells, spermatazoa in males, ova in females |
FERTILIZATION | the fusion of the male & female gamete |
ZYGOTE | the fertilized egg |
GONADS | the reproductive organs; testes in males, ovaries in females |
TESTES | produce the spermatozoa (sperm) and the male sex hormones. The testes are enclosed by the scrotum; the primary sex organ in males. |
EPIDIDYMIS | a storage space for the sperm and helps to “mature” them. |
DUCTUS DEFERENS (vas deferens) | a tube that conducts the sperm outward. The ductus deferens is within the SPERMATIC CORD |
EJACULATORY DUCT | conducts the semen to the urethra; formed by: The DUCTUS DEFERENS (VAS DEFERENS) ascends within the spermatic cord and is joined by the seminal vesicle. |
ACCESSORY ORGANS | are glands that secrete the fluid components of the semen. These include the SEMINAL VESSICLES, PROSTATE, AND BULBOURETHRAL GLANDS |
URETHRA | conducts both semen and urine to the tip of the penis. |
PENIS | an erectile organ. |
SCROTUM | a connective tissue sac that extends from the body & includes the dartos & the cremaster muscles. |
DARTOS MUSCLE | just below the skin of the testes and wrinkles the skin of the testes |
CREMASTER MUSCLE | maintains the temperature under which sperm develop by adjusting how closely the testes are held to the body. |
TUNICA ALBUGINEA | encloses the testes |
SEPTA | Extensions of the tunica albuginea form SEPTA that divide each testis into lobules |
SEMINIFEROUS TUBULES | within the lobules produce sperm. |
RETE TESTIS | The seminiferous tubules connect to the RETE TESTIS, a maze of interconnecting tubules. The rete testis connects to the epididymus. |
SPERMATOGONIA | the stem cells that divide by mitosis & meiosis during the production of sperm (SPERMATOGENESIS)--in the seminiferous tubules |
INTERSTITIAL CELLS | The seminiferous tubules also contain INTERSTITIAL CELLS that produce the main male sex hormones, ANDROGENS, mostly testosterone |
SUSTENTACULAR CELLS (Sertoli cells | The seminiferous tubules contain SUSTENTACULAR CELLS (Sertoli cells) that support and sustain the developing sperm. |
SPERMATOGENESIS | is the process to produce and mature gametes--mitosis produces millions of spermatocytes; Each spermatocyte then undergoes meiosis & produces four haploid spermatids; The spermatids then mature into spermatozoa |
Anatomy of a Spermatozoon | ACROSOMAL CAP--contains digestive enzymes, The HEAD contains the nucleus and chromosomes. The MIDDLE PIECE (NECK) contains mitochondria. The TAIL is a flagellum that whips to push the sperm forward. |
male reproductive tract | The male reproductive tract consists of the epididymus, the ductus deferens, and the urethra. |
SEMINAL VESICLES | the first (paired) glands encountered, are found dorsal to the urinary bladder, & secrete 60% of the volume of the semen & include fructose to power the sperm |
PROSTATE GLAND | single gland found just below the urinary bladder and the urethra joins the ductus deferens within the prostate. It secretes ~30% of the volume of the semen and includes an antibiotic. |
BULBOURETHRAL GLANDS | paired glands--(Cowper’s glands) are last and secretes a sticky, alkaline mucus. |
EJACULATE | A typical ejaculation (the EJACULATE) expels 2-5 ml of semen containing 20-50 million sperm per ml (~100-200 million sperm). |
Penis | contains three erectile bodies, a pair of CORPORA CAVERNOSA dorsally and a single CORPUS SPONGIOSUM ventrally |
Describe the process causing an erection. What is the role of nitrous oxide? | parasympathetic stimulation, neurons of the arteries of the penis release NO. This causes the arteries to dilate and the veins to constrict, causing blood to pool in the sinuses of the corpora cavernosa and corpus spongiosum, resulting in an erection. |
What is nitrous oxide? | a neurotransmitter |
GONADOTROPIN RELEASING HORMONE (GnRH) male | secreted by the hypothalamus and controls pituitary action |
FOLLICLE-STIMULATING HORMONE (FSH) male | from the pituitary promotes spermatogenesis by stimulating the sustentacular cells. |
LUTEINIZING HORMONE (LH) male | stimulates interstitial cells to produce testosterone--also produced by the pituitary. |
ANDROGENS | (mostly testosterone) are made by the interstitial cells and are the most important male sex hormones. |
INHIBIN--males | released by sustentacullar cells |
Testosterone | maintains all the male secondary sex characteristics and stimulates the sustentacular cells. |
CRYPTORCHIDISM | when one or both testes fail to descend |
PROSTATITIS | an inflammation of the prostate and gives symptoms similar to prostate cancer. |
PROSTATE CANCER | a malignant, metastazing tumor of the prostate that is the second leading cause of cancer deaths in men. |
OVARIES | produce the ova |
UTERINE (FALLOPIAN) TUBES | carry the ova to the uterus |
UTERUS | incubation site for the developing fetus |
VAGINA | site of deposition of sperm and the “birth canal;" muscular tube that connect the cervix to the external genitalia |
VULVA | the external female genetalia |
OOGENESIS | production of ova--occurs in the ovaries |
Oogenesis--Mitosis | Mitosis in oogenesis occurs only before birth and produces ~2,000,000 primary oocytes. This drops to ~400,000 by puberty. |
Oogenesis--Meiosis I | Each month one of the oocytes in one of the ovaries undergoes meiosis and begins development. Meiotic divisions produce only one egg and 2-3 polar bodies. |
Oogenesis--Meiosis II | Meiosis II begins in the tertiary follicle and completed only if fertilization occurs. |
Zona pellucida | region of glycoproteins--microvilli from the surrounding follicular cells intermingle with microvilli originating at the surface of the oocyte. |
Corona radiata | protective layer around an oocyte. |
INFUNDIBULUM | a funnel-shaped structure in the uterine tube--the entrance bounded by fimbriae that receives the oocytes at ovulation |
Cilia | line the lumen of the oviduct, beat to move the egg toward the uterus |
3 regions of the uterus | BODY, CERVIX & UTERINE CAVITY |
walls of the uterus | perimetrium, myometrium, & endometrium |
PERIMETRIUM | the serous membrane covering on the outside of the uterus |
MYOMETRIUM | a thick muscle layer of the uterus necessary in childbirth |
ENDOMETRIUM | the lining of the uterus that builds up each month then is lost in menses. |
UTERINE CYCLE (also called the MENSTRUAL CYCLE) | typically ~28 days long; begins with the onset of menses, the loss of the functional layer of the endometrium, and lasts 1-7 days |
MENARCHE | the term for the first menses. |
MENOPHASE | the menstrual cycles cease. |
Menstrual cycle--PROLIFERATIVE PHASE | begins following menses--hormonal regulation stimulates the remaining portion of the endometrium, the BASILAR ZONE, to repair and regrow the functional zone. |
Menstrual cycle--SECRETORY PHASE | last phase--begins when the endometrial glands become active and prepare the uterus to receive the embryo. |
HYMEN | a thin fold of epithelium covering the opening of the vagina |
Functions of the vagina | A pathway to conduct the menstrual fluid; A receptacle for the penis during intercourse; Holding the semen after ejaculation; and birth canal for the fetus |
VESTIBULE--external female genetalia | the central space bounded by the LABIA MINORA |
LABIA MAJORA | are larger folds of connective and fatty tissues and define the outer limits of the vulva. They are covered by coarse pubic hairs. |
CLITORIS | just anterior to the vestibule. The clitoris is erectile tissue that swells during sexual activity. |
PREPUCE | connective tissue surrounding the clitoris. |
MONS PUBIS | a bulge anterior to the vulva and is formed of fatty tissue |
VESTIBULAR GLANDS | keep the exposed surface of the vulva moist and are stimulated to produce more secretions during sexual arousal. |
MAMMARY GLANDS | located within the breast--specialized organs of the integumentary system, that can produce milk for mammalian babies. |
LACTATION | the process of milk synthesis and secretion by the cells of the mammary glands, only begins after childbirth. Lactation is controlled by hormones. |
PELVIC INFLAMMATORY DISEASE (PID) | a bacterial infection of the uterus, uterine tubes and ovaries; leading cause of female sterility affecting ~1 million annually; causes fever, abdominal pain, elevated WBC count. Infection is thought to be linked to sexually transmitted diseases (STDs) |
AMENORRHEA | failure to begin or continue menses. This may have an anatomical (lack or nonfunctional ovaries, lack of a uterus) endocrine, or genetic basis. Severe physical or psychological stress or dramatic weight loss (e.g. anorexia) can also cause amenorrhea |
BREAST CANCER | a cancer of the mammary gland. Tumor cells of the breast tissue may form benign lumps, though breast cancer can also be malignant and can metastasize. |
What hormones trigger ovulation? | GnRH, FSH, and LH--estrogen and progesterone are also involved |
When does meiosis I and meiosis II occur relative to ovulation? What triggers meiosis II? | Meiosis I occurs before birth and is completed after puberty. Meiosis II is completed after fertilization occurs. During oogenesis the zona pellucida and corona radiata begin to coat the ovum. |
GnRH--female | The hypothalamus releases GnRH in steady pulses (16-20/day), then dramatically increase the number of pulses (36/day) which stimulates the pituitary to release a surge of LH and FSH. |
LH and FSH -- Female | The LH and FSH are made at low levels which stimulate the development of a follicle in the ovary. The hypothalamic release of GnRH stimulates a surge in the release of LH and FSH by the pituitary, which then stimulates ovulation in the ovaries. |
LH and FSH--female--after ovulation | the corpus luteum feeds back to the pituitary to keep levels of FSH and LH low. |
Estrogen | made by the developing follicle; feed back to the pituitary to keep LH levels low until ovulation; low levels allow the endometrium to slough off at menses Increase in estrogen levels stimulate the endometrium to repair and build up again-at uterus. |
Corpus Luteum | feeds back to the pituitary to keep levels of FSH & LH low, (LH>FSH). |
Progesterone | levels peak as corpus luteum develops, estrogen levels drop; High progesterone levels maintain the thick endometrium in anticipation of receiving a fertilized egg. |
Role of GnRH in ovulation | GnRH is released from the hypothalamus and stimulates a surge in the release of LH and FSH. |
Role of LH and FSH in ovulation | FSH and LH are released by the pituitary and stimulate ovulation in the ovaries. After ovulation, the corpus luteum feeds back to the pituitary to keep the levels of LH and FSH low. |
Role of Estrogen in ovulation | made in the ovaries by the developing follicles; feeds back to the pituitary to keep LH levels low until ovulation.; low levels allows the endometrium to slough off in the menstrual flow; increase stimulates the endometrium to repair and build up. |
Role of Progesterone in ovulation | Progesterone is produced by the corpus luteum and high levels maintain the thick endometrium in anticipation of receiving a fertilized egg. Levels of progesterone drop if fertilization does not occur. |
role of inhibin in ovulation | Inhibin is secreted by the granulosa cells of ovaries, which are stimulated by developing follicles. Inhibin inhibits secretion of FSH. |
Describe the changes in the mammary gland during and after pregnancy. | before pregnancy--mammary gland is very small and only in the area immediately around the nipple, and breast is mainly composed of adipose tissue. During pregnancy the mammary gland will grow and develop, so that it can produce milk after delivery. |
What is lactation? When does lactation occur? | Lactation is the process of milk synthesis and secretion by the cells of the mammary glands, and only begins after childbirth. Lactation is controlled by hormones. |
What is the basilar zone of the endometrium? | Hormonal region that stimulates the remaining portion of the endometrium to repair and regrow the functional zone--if ovulation does not occur. |
Describe the composition of the endometrium when this lining is thickest. | 1. the secretory phase begins when the endometrial glands become active and prepare the uterus to receive the embryo. If fertilization did not occur, the endometrium begins to degenerate and menses begins again. |
Describe the changes in the endometrium during the menstrual cycle | The endometrium is the lining of the uterus that builds up each month then (secretory) is lost in menses (proliferate). The uterine cycle beings with the onset of menses, the loss of the functional layer of the endometrium and last 1-7 days. |
Fertilization | 1. In general, fertilization occurs within 1 day(s) after ovulation. Ovulation occurs at day 14 of a 28 day menstrual cycle. |
What is the role of the sustentacular (Sertoli) cells? | The seminiferous tubules contain sustenticular cells that support and sustain the developing sperm. |
What is the role of the interstitial cells? | Interstitial cells are contained within seminiferous tubules, and produce the main male sex hormones, androgens, mostly testosterone. |
Briefly describe the process of spermiogenesis. | Spermatogenesis is the process to produce and mature gametes. In spermatogenesis, mitosis produces millions of spermatocytes. Each spermatocyte then undergoes meiosis and produces four haploid spermatids. The spermatids then mature into spermatozoa. |
Why does the ductus deferens wrap up around the urinary bladder before descending into the scrotum? | wraps up around the urinary bladder before descending into the scrotum because it meets up with the ejaculatory duct, which then connects with the urethra, which extends from the bladder to the tip of the penis and is a passageway for urine and semen. |
Why is it that the first few sperm arriving at the egg cannot fertilize the egg? | The first few sperm that arrive at the egg break down the corona radiata so one sperm can enter. Once a single sperm makes contact with the oocyte membrane, and membrane fusion occurs, fertilization (meiosis II) complete, blocking further sperm entry. |
What it the role of the acrosomal cap in fertilization? | The acrosomal cap of the sperm releases digestive enzymes, hyaluronidase to loosen the cells of the corona radiata and another enzyme to digest the zona pellucida. This digestion exposes the membrane of the egg. |
What prevents a second sperm from entering an egg? | After the first sperm fertilizes the egg, a process called the cortical reaction, releases enzymes that both inactivate sperm receptors and harden the zona pellucida—preventing entry of any more sperm. |
1. List the three layers of the inner cell mass and provide two examples of organs that are derived from each layer. | ectoderm: develops into skin and glands, and all neural tissue, including the brain and spinal cord; endoderm develops into heart, blood vessels, and kidneys; mesoderm develops into the digestive system, and lungs and respiratory tract. |
What does the primitive streak form? | The primitive streak develops into the ectoderm. |
What is gastrulation? | occurs when cells in specific areas of the surface move toward yhe primitive streak; here the migrating cells leave the surface and move between the two existing layers of the inner cells mass creating the ectoderm, endoderm, and the mesoderm. |
List the four extraembryonic membranes and briefly describe the function of each? | Yolk sac: the site of red blood cell production. Amnion: encloses the amniotic fluid and contains the developing fetus. Allontois: forms part of the urinary bladder Chorion: provides circulatory support for the early embryo. |
First Trimester | The basic body plan, the foundations of all the organ systems, and the four extraembryonic membranes appear during the first trimester. |
Second Trimester | fetus will grow to .64 kg, and all organ system become more complex, approaching functional; a period of rapid growth, accompanied by the development of fetal organs that will then become fully functional by the end of the third trimester. |
Third Trimester | the rate of growth slows, but most of the body weight and length occurs here, organ systems become fully functional and some begin to function, though other systems (respiratory, liver, digestive, etc) are quiescent until birth. |
Describe how identical and fraternal twins are formed. | Identical twins (monozygotic twins) develop from the same egg that split early in development, so they have the same genetic makeup. Fraternal twins (dizygotic twins) develop from different eggs and sperm, so each will have a different genetic makeup. |
A woman who is about to give birth is 6cm dilated and 70% effaced. What does this mean? When she is ready to deliver, what will these readings be? | Being 6cm and 70% effaced means the woman is over half way ready to give birth. When she is completely ready the readings will be 10cm and 100% effaced. |
Describe what happens in the breast milk let-down reflex. | Suckling initiates a neural circuit that triggers the hypothalamus /pituitary to release oxytocin. Oxytocin stimulates the contraction of cells in the walls of the milk ducts, ejecting the milk. |
What is colostrum? | The mammary glands secrete COLOSTRUM, which is rich in proteins and low in fats as compared to breast milk. The proteins contain many antibodies from the mother. |
How is colostrum different from milk? | Milk is thinner, but rich in proteins, water, amino acids, lipids, sugars, salts, and lysozymes (enzyme’s anti-microbial properties). |
What is the human genome project? | The human genome project has sequenced more than 3.2 billion base pairs and mapped more than 15,000 genes. |
why is the human genome project important? | Genes for 1500 diseases have been identified and genetic tests have been developed for many of these disorders. The human genome mapping program opens the promise of entirely new medical care insights. |
Functions of the liver | 1. Metabolizes proteins, fats, and carbohydrates, thus providing energy and nutrients 2. Stores vitamins 3. Stores minerals 4. Stores sugars 5. Creates bile which breaks down fats |
Functions of the liver | 1. Stores extra blood that can be quickly released when needed 2. Creates serum proteins that maintain fluid balance and act as carriers 3. Helps maintain electrolyte and water balance 4. Creates immune substances such as gamma globulin |
Functions of the liver | 1. Breaks down and eliminates excess hormones 2. Provides blood clotting factors 3. Breaks down ammonia (and other toxins) 4. Helps to maintain blood pressure 5. Removes damaged red blood cells |
Functions of the liver | 1. Produces cholesterol 2. Converts essential fatty acids such as GLA, EPA, and DHA into the lipoprotein forms necessary to allow transport via the bloodstream to the 50 trillion cells requiring fatty acids |
Functions of the liver | 1. Converts lactic acid from a toxic waste to an important storage fuel. 2. Secretes bilirubin 3. Produces urea 4. Removes bacteria from the blood stream |
INFERTILITY | inability to achieve pregnancy. Problems with fertility are varied from low sperm count, abnormal spermatozoa, inadequate hormone levels, problems with oocyte production, blockage of the oviduct, abnormal oocytes, abnormal endometrium, etc. |
SEXUALLY TRANSMITTED DISEASES (STDs) | disease transmitted from individual to individual primarily or exclusively by the exchange of body fluids during intercourse. An estimated 15 million cases are diagnosed each year. |
ERECTION | caused by Physical stimulation of the genital region or even erotic thoughts triggered by parasympathetic neurons |
EMISSION | includes peristaltic contractions of the ductus deferens, contractions of the accessory glands and closing of the urethra |
EJACULATION | involves the contraction of skeletal muscle of the pelvic floor to expell semen from the urethra. Ejaculation results in the male orgasm |
IMPOTENCE | the inability to achieve or maintain an erection |
MENOPAUSE | the time when menstruation and ovulation cease |
DEVELOPMENT | the gradual modification of physical & physiological characteristics from conception to physical maturity. |
PRENATAL DEVELOPMENT | occurs before birth. |
POSTNATAL DEVELOPMENT | begins at birth & continues to maturity when SENESCENCE begins. |
DIFFERENTIATION | the creation of different cell types during development. |
INHERITANCE | the transfer of genetically determined traits from generation to generation |
GENETICS | the study of the mechanism of inheritance |
ZYGOTE | The sperm is then absorbed into the oocyte--fertilized egg |
AMPHIMIXIS | process in which the female and male pronuclei fuse |
GESTATION | the time spent in prenatal development |
TRIMESTERS | division of human gestation into 3-three month periods |
First Trimester | cleavage and blastocyst formation (cell division & early development) implantation (of the blastocyst into the endometrium) placentation (development of the placenta & extraembryonic membranes) embryogenesis (development of the embryo) |
CLEAVAGE | includes all the cell divisions that divide the cytoplasm of the zygote to form BLASTOMERES. |
BLASTOCYST | when the zygote turns into a hollow ball, composed of the trophoblast and inner cell mass |
INNER CELL MASS | inner knot of cells |
TROPHOBLAST | the outer ball of blastomeres |
IMPLANTATION | the blastocyst burrows into the endometrium; occurs about seven days after ovulation |
PLACENTA | developed as blood vessels form around the blastocyst |
CHORIONIC VILLI | grow from the embryo & invade maternal lacunae in the endometrium. |
UMBILICAL CORD | develops to connect the fetus to the placenta. |
Hormones produced by the trophoblast (placenta) | HUMAN CHORIONIC GONATOTROPIN (hCG); ESTROGENS & PROGESTERONE; HUMAN PLACENTAL LACTOGEN (hPL) and PLACENTAL PROLACTIN; RELAXIN |
HUMAN CHORIONIC GONATOTROPIN (hCG) | shows up in the blood and urine and is used in most pregnancy kits. |
ESTROGENS & PROGESTERONE | are actively secreted and stimulate the maintenance of the endometrium |
HUMAN PLACENTAL LACTOGEN (hPL) and PLACENTAL PROLACTIN | activate the mammary glands. |
RELAXIN | secreted by the placenta and the corpus luteum. Relaxin increases the flexibility of the pubic symphysis, causes the dilation of the cervix, and delays the onset of contractions |
EMBRYOGENESIS | is the process of forming the embryo |
ORGANOGENESIS | the process of organ formation. |
SOMITES | determine much of the body tissue (muscle & nerves) |
demands on the maternal system | increases respiratory rate and tidal volume, increases blood volume,increase nutritional needs by 10-30%, increase glomerular filtration rate by ~50%, dramatically increases the size of the uterus, increases the size and activity of the mammary glands |
progesterone--during gestation | released by placenta; inhibits the uterine smooth muscle and prevents extensive, powerful contractions; As delivery nears, the effects of progesterone is inhibited by rising estrogen and oxytocin levels, as well as the production of prostaglandin. |
False Labor | occasional spasms in uterine musculature, but the contractions are neither regular nor persistent--caused by the inhibition of prgesterone |
True Labor | results from biochemical and mechanical factors, is regular with increasing frequency, and continues due to a positive feedback system. |
episiotomy | a surgical incision through the perineum made to enlarge the vagina and assist the childbirth. |
dilate | make the cervical opening bigger) |
efface | make the cervix thinner |
breach birth | when the crown of the head does NOT present to the cervix |
Parturition | expelling the fetus by rhythmic contractions of the uterine muscles. |
puberty | hypothalamus increases its production of GnRH, so circulating levels of FSH & LH rise rapidly. |
GENOTYPE | an individual’s 46 chromosomes and their genes |
PHENOTYPE | the physical expression of the individual’s genotype |
Amniocentesis | A needle is inserted into the amniotic cavity & a few ml of amniotic fluid is removed |
Chorionic Villus Sampling | A thin flexible tube (catheter) through the vagina and cervix into the placenta and a portion of the placenta is removed |
Ultrasound | Pulses of high frequency sound are bounced through the abdomen and the echoes are recorded at echogram |
ALLELES | various forms of genes. |
HOMOZYGOUS | If an individual has the same allele of a particular gene |
HETEROZYGOUS | If an individual has different alleles of a particular gene |
sex chromosomes | the X and Y chromosomes; XX determines a female; XY, a male |