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Creado por Marissa Alvarez
hace casi 5 años
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The REPRODUCTIVE System
Objectives:
The reproductive system consists of the gonads, reproductive tract, and accessory sex glands.
Reproduction depends on the ___ of male and female gametes.
->The reproductive systems of the two sexes are designed to enable this union.
•The female system is also equipped to house and nourish the ___ developmentally until it is able to survive on its own.
•___ reproductive organs produce gametes and secrete sex hormones:
->Male – __ (produce spermatozoa and secrete testosterone)
->Female - ovaries (produce ova and secrete estrogen and progesterone )
•A reproductive tract plus accessory ___ are found in either sex.
•Unique ___ sexual characteristics are found in each sex.
->Differences in body configuration and distribution of body hair.
->Due to ___ in male and ___ in female.
Functions and anatomy of the male reproductive tract:
•Production of ___ (_____)
•Delivery of ___ to the female
Functions and anatomy of the female reproductive tract:
•Production of ___
•Reception of ___
•___ of sperm and ova to a common site for union
•Maintenance of the developing ___
•Parturition
•Nourishing the infant
Reproductive cells each contain a HALF SET of chromosomes.
Gametogenesis occurs by ____.
–Cell division involves the division of the nucleus and the division of the ___.
–___ is cell division that maintains the chromosome number, chromosome combination, and genetic identity of the chromosomes from the dividing parent cell to the two daughter cells produced. Mitosis produces ___ cells.
–Meiosis produces ___. Only one chromosome from each chromosome pair is inherited in each of the four daughter cells produced from parent cells. The gametes have __-__ the chromosome number.
Male & Female sex determination
and sexual differentiation:
->Genetic sex depends on combination of ___ ____.
->Gonadal sex determined by presence or absence of ___ gene.
->Sex-determining region of Y
chromosome (SRY) codes for production of ___-___ ___ (__)
->NO Y chromosome = NO __ & ___
->TDF directs differentiation
of gonads into ____ .
->With no TDF, undifferentiated
gonads develop into ____ .
Male & Female sex determination
and sexual differentiation:
->Testes secret testosterone and ___ ___ ___ (__).
->Mullerian-inhibiting factor leads to degeneration of ___ ___ .
(this is in ___)
->Absence of Müllerian-Inhibiting factor leads to development of ___ ___ in females.
->Absence of testosterone leads to degeneration of ____ ___ .
(this is in ___)
->____ sex determined by presence or absence of masculinizing hormones.
External genitalia develops from the SAME embryonic tissue:
Genital Tubercle = ___ tissue
•Glans penis
•Glans clitoris
Urethral folds
•Fuse to form ___ in male
•Labia ___ in female
Genital swellings
•Fuse to form ___ and prepuce in males
•Labia ___ in females
*No dihydrotestosterone (DHT) = _____
*Presence of DHT = _____
Reproductive tracts develop from DIFFERENT embryonic tissues:
->Mullerian ducts and Wolffian ducts are present in ___ sexes before sexual differentiation.
Placental human chorionic gonadotropin stimulates:
->Testosterone – ___ Cells
->__ ___ ___ (__) – Sertoli Cells
*Testosterone → __Wolffian ducts
*MIF → ↓___ ducts
->Wolffian ducts differentiate into ___ reproductive tract
->Müllerian ducts differentiate into ___ reproductive tract.
ERRORS in sexual differentiation
•If testes fail to properly differentiate → anatomic ___, but genetic ___
•___ ____ ____ = Genetic males whose target cells lack androgen receptors are feminized even though adequate testosterone is secreted
•__-___ ___ = testosterone does not get converted to dihydrotestosterone (DHT) → genetic male with testes and male reproductive tract, but female genitalia
•___ ___ = genetically female fetus that oversecretes DHEA can cause differentiation of the reproductive tract and external genitalia along male lines
REVIEW
Male Reproductive Physiology
Testes develop from the ___ ridge in the rear of the abdominal cavity.
•During the last months of fetal life, the testes ___ from the abdominal cavity through the ___ canal into the scrotum. ->This movement is induced by ____ and usually complete by 7 months of gestation.
•Incomplete closure of canal or rupture leads to an inguinal ___.
•____ – undescended testicle(s) – bilateral or unilateral
•The scrotum provides a ___ environment that is optimal for spermatogenesis (which cannot occur at ___ ___. A spinal reflex by scrotal muscles can retract the testes into the warmer abdomen.
•The seminiferous tubules in the testis carry out _____.
•___ cells in the testis secrete testosterone. Located in interstitial tissue between seminiferous tubules.
Light micrograph of the
Semiiniferous Tubules
EFFECTS OF TESTOSTERONE
Prior to Birth:
•Masculinizes the Reproductive tract and external genitalia
•Causes ___ of the testes into scrotum
•Secretion ___ after birth
Effects on sex-specific tissues after birth (Puberty):
•Growth and maturation of the entire ___ reproductive system:
->___ = period of arousal and maturation of a previously nonfunctional reproductive system to the point of being able to reproduce
->____ = entire transition between childhood and adulthood, not just sexual maturation
•Spermatogenesis
•Accessory sex glands ___ and become active
•Penis and scrotum enlarge
•Maintenance of reproductive tract through adulthood
EFFECTS OF TESTOSTERONE
Other Reproduction Related Effects:
•Development of sexual libido
•Maintains sex ___ in adult male
•___ feedback control of ___ - ___ ___ (___) (and thus luteinizing hormone & follicle-stimulating hormone)
Effects on Secondary Sexual Characteristics:
•All SSC depends on ____
•Male pattern hair growth, deepening of the voice, thickening of the skin, male body configuration
Nonreproductive Actions of Testosterone:
•___ to protein
•Promotes bone growth
•Terminating bone growth (epiphyseal plate closure)
•May induce ____ behavior
Spermatogenesis:
the production and development of mature spermatozoa
The ___ ____ carry out spermatogenesis.
Packaging of spermatids = _____
Anatomy of spermatozoa
Nucleus – ___ material
____ – enzymes, a modified lysosome produced by the endoplasmic reticulum-Golgi complex
Tail powered by ___ concentrated in the midpiece.
Cytoplasmic ___ b/w sperms cells during development allow necessary __ chromosome support for Y-bearing sperm.
SERTOLI Cell Functions
Throughout sperm cell maturation, the cells are intimately associated with ___ cells in the wall of the ___ ____.
The FUNCTIONS of the Sertoli cells:
•____ junctions provide a blood-testes barrier
•Prevent antibody formation against highly-differentiated spermatozoa
•Provide nourishment via selective transport of materials through the blood-lumen barrier. Glut-1 transports ___ across where it’s converted to ___ for use by the sperm
•Carry out ___ (engulf extruded cytoplasm, get rid of malformed germ cells)
•Secrete a seminiferous tubule fluid which flushes sperm from lumen to ___
•Secrete androgen binding protein (maintains high __ within lumen). High luminal __ is essential for sustaining sperm production. __ also stimulates ABP production
•Acted upon by testosterone and FSH to control ____, also secrete ___ to regulate FSH secretion
•Secrete ___-___ factor
Gonadotropin-Releasing Hormone (GnRH):
•increases at the time of ___
•Do NOT have receptors for ___ or ___
•___ neurons have receptors for androgens and estrogen
•Increases to cause puberty:
->__ increase initially
->Involves __ neurons
->Likely involves other neuron types as well
____ ____ Hormone:
– enhances spermatogenesis, needed for remodeling
____ Hormone:
– stimulates testosterone production from Leydig cells
_______:
-necessary for mitosis and meiosis
-___ selectively inhibits FSH secretion from Sertoli cell
Remainder of Male Reproductive System
Reproductive tract:
-Accessory sex glands
-Penis
**All geared toward delivering ____
Epididymis:
->______ = the gaining of the ability to move and fertilize
-Sperm are ____ of mobility or fertilization when they leave the testes.
-stimulation by _____.
-They gain further ability to do so in the ____ reproductive tract.
->_____ sperm 100x
Remainder of Male Reproductive System
Reproductive tract:
Ductus Deferens:
•STORAGE
->Sperm can be stored for up to 2 months due to low ____ needs
•Empties into the ____
•____ – ligation of the ductus or vas deferens
The male accessory sex glands contribute most to semen:
____: mixture of accessory sex gland secretions, sperm, and mucus
SEMINAL VESICLES:
–supplies ___ for energy (primary energy source)
–secretes ____ for smooth muscle contraction in the tract of both male & females (transport)
–provides most (about 60%) of the semen volume, washing the sperm into the urethra and diluting the thick mass of sperm, allowing ____
–secretes ___ (precursor of ___ needed for clotting, which keeps sperm in female reproductive tract)
The male accessory sex glands contribute most to semen:
_____ Gland:
–secretes an alkaline fluid to neutralize the acidity of the female reproductive tract to increase sperm viability
–provides clotting enzymes that act on fibrinogen to cause formation of ___
–Produces __ -___ ____ (PSA). This breaks down clot of sperm inside female reproductive tract, releasing sperm for ___. (Often measured as an index of potential cancer)
–___ ___ ___ = enlarged prostate in older men
–____ = vesicles that transfer components needed to maximize use of calcium for optimal motility and efficient fertilization
->____ Gland: Secretes a mucus-like substance for lubrication during sex
There are 4 phases to the male sexual response cycle:
1) _____ :
-erection
-testicular vasocongestion
-heightened sexual awareness
2) _____ :
-intensification
-steadily increasing heart rate, blood pressure, respiratory rate & muscle tension
3) _____ :
-ejaculation
4) ____ :
return of genitalia and body systems to their pre arousal state
Erection is accomplished by ____ of the penis with blood (____).
(____ = increased pooling of blood, decreased venous drainage)
Parasympathetic mediator – ___ ___
Erectile ____ (Impotence)
-50% ages 40-70
-70% by age 70
Nitric Oxide -> Guanylate cyclase -> PDE5 cGMP breakdown -> Smooth muscle relaxation -> vasodilation
-____ inhibits PDE5 cGMP breakdown
**Parasympathetic supply to penile arterioles causes penile arterioles to ____, which leads to an erection (compressed veins).
**NO used by PNS as a ____
Ejaculation is the emission and expulsion of semen:
Accomplished by a spinal ___
Occurs in two phases:
1) ___ – sympathetic impulses cause smooth muscle contractions in prostate, reproductive ducts, and seminal vesicles, thus delivering semen into the ___
2) ____ - the expelling of the semen through the urethra. Filling of urethra triggers skeletal muscle ____ at base of penis.
->Female sexual cycle is similar except there is no counterpart to ejaculation and no ____ following orgasm
•____ – Heavy breathing, high heart rate, generalized skeletal muscle contraction, intense pleasure & gratification
•Resolution follows, including a refractory period of varying lengths, due to increased ___ input
->Average volume – 2.75 ml of 165 million sperm (<__ ___/ml - clinically infertile)
REVIEW
FEMALE REPRODUCTION
Objectives
General Male-Female Differences
->Unlike males, where sperm production is continuous and testosterone is relatively stable, release of ova is ___ & hormones display wide cycle-associated ___ in the female.
•Menstrual cycle (menstruus = ___)
->Ovaries perform the dual function of producing ___ and secreting the female sex hormones (___, ___).
•Like males, reproductive capability begins at ____
•Unlike males, it does NOT continue throughout life (____)
By month 5 of gestation – 6 to 7 million ___
-Remain ___ oocytes from birth to puberty
-Oocytes not incorporated into follicles undergo ____
-By birth – 2 million primary ___
-By puberty – 300,000 (primary follicles)
-__ will mature and release ova
-___ = degenerated follicle (99.97%)
Follicular phase about 14 days
Luteal phase about 14 days
1) LH stimulates the ___ cells in the ovarian follicle.
2) On stimulation, the thecal cells convert cholesterol into ___.
3) Androgen diffuses from the thecal cells to the adjacent ___ cells.
4) FSH stimulates the ____ cells in the ovarian follicle.
5) On stimulation, the granulosa cells convert androgen into ___.
6a) Part of the estrogen is secreted into the ___, where it exerts systemic effects.
6b) Part of the estrogen remains within the ___ and contributes to ___ formation.
7) Local estrogen, along with __, stimulates proliferation of the ____ cells.
FOLLICULAR PHASE
Estrogen and inhibin, through actions at the pituitary, COMBINE to reduce ___-___ hormone secretion
Estrogen NOT capable of fully suppressing ___ hormone release
->Kisspeptin neurons in the ___ ____ of the hypothalamus are targeted by ____ feedback
Tonic secretion (___ & graded secretion)
SURGE Secretion
GnRH surge:
•Stimulated by high ___ levels
•Estrogen acts upon ___ kisspeptin neurons to stimulate gonadotropin-releasing hormone (GnRH) secretion
•Estrogen acts upon the ___ pituitary to increase ____ hormone as well (relatively less for follicle-stimulating hormone)
•____ still inhibiting follicle-stimulating hormone but there is a follicle-stimulating hormone surge as well
Luteinizing Hormone Surge:
1. ___ estrogen synthesis
2. Reinitiates ___
3. Triggers ___ release leading to rupture of cell wall
4. Conversion of follicular cells to ___ cell
LUTEAL PHASE
Luteal Phase
•Corpus luteum maintained by ___ hormone
•Lots of ___ produced, less estrogen
•Progesterone BLOCKS any positive effects of ____ on gonadotropin-releasing hormone secretion
•_____ a very powerful inhibitor of gonadotropin-releasing hormone/___ hormone release
•Factors underlying the demise of the corpus luteum are NOT completely known, but may involve prostaglandins, estradiol, and ___ LH secretion
*Tonic secretion (slow & ___ secretion)
1 to 5, 24
•Antrum formation, ___ secreted in response to follicle-stimulating hormone and luteinizing hormone.
•Rising ___ stimulates thickening of the endometrium.
6 to 8
•Circulating and antral concentrations of estradiol rise due to increasing levels of ___ hormone.
•Estrogen and inhibin actions at the pituitary selectively lead to a decline in ___ -___ hormone.
•Decline in follicle-stimulating hormone leads to ___ in all but the dominant follicle
9 to 11
•Rising estradiol triggers the ___ -____ hormone/____ hormone surge, causing ovulation and ___ levels to plummet.
12 to 17, 25
•Follicular cells are transformed to luteal cells and secrete ____ and, to a lesser extent, estradiol.
•Progesterone strongly inhibits BOTH ___ hormone and ___-___ hormone.
•Progesterone stimulates ___ vascularization and secretory activity of the endometrium.
18 to 23
•If NOT impregnated, the ___ ___ degenerates and progesterone and estradiol ___, allowing for an increase in ____ hormone and ___-___ hormone to begin the cycle again.
•Withdrawal of progesterone & estradiol leads to ___ off of the uterine endometrium.
Changes in the uterus (menstrual cycle) occur with changes in ovarian hormones:
•Estrogen stimulates ___ and myometrial growth.
(Also stimulates ___ receptor expression in endometrium.)
•Progesterone can then act on the estrogen-primed endometrium.
–Lining becomes ___ and edematous due to accumulation of water and electrolytes
–Stimulates endometrial glands to secrete and store ___
–Causes tremendous growth of endometrial ___ ___
–Reduces ____ of the uterus
Changes in the uterus (menstrual cycle) occur with changes in ovarian hormones:
MENSTRUAL PHASE
−Characterized by ___ of blood and endometrium
−Drop in hormone levels increases ___ release and ____ (and lack of O2) to the lining
−PG also stimulates uterine ___.
Prostaglandin ___production causes menstrual ____ (dysmenorrhea)
−Blood clots in uterus then is broken down by ___ to flow out.
−Contains large numbers of leukocytes (white blood cells) that play a role in helping the raw endometrium resist infection
−Lasts about 5-7 days, concurrent with early ___ phase
PROLIFERATIVE PHASE
−Endometrium repairs itself and starts to proliferate due to ___ __ and ___ ___ hormone
-induced estrogen secretion
−Estrogen stimulates epithelium, glands, blood vessels
SECRETORY/PROGESTATIONAL PHASE
−After ovulation when a new corpus luteum is formed (luteal phase)
−Corpus Luteum secretes large amounts of ___ & ____
−Progestational secretion of ___ into uterine lumen for nourishment of embryo
Cyclical Changes in Cervical MUCUS:
FOLLICULAR phase
−Under the influence of ___, cervical mucus is clear, thin, and abundant
−Most obvious when estrogen is highest (near ovulation)
−Facilitates passage of ___ through the cervical canal
•LUTEAL Phase
−Mucus becomes thick and sticky
−Essentially __ __ the cervical opening
−This prevents ____ from entering the uterus from the vagina
−Prevents sperm ___
PUBERTY
−Changes are similar to those in males.
−___ secretion increases at the onset of puberty.
−GnRH stimulates the release of ___ hormone from the anterior pituitary, first occurring at ___ .
−Doesn’t involve ___. The role of ___ is at least permissive.
−____ release promotes many changes in the female reproductive system and in other body characteristics (fat deposition in breasts, buttocks and thighs) & eventually the preovulatory surge.
(Also closes ____ ___).
−Growth of axillary and pubic hair, pubertal growth spurt, development of libido due to increase in adrenal ____
MENOPAUSE
−Unique to females
−May involve depletion of ___, may involve hypothalamic dysfunction
−Preceded by a period of increasingly ___ cycles and ___ estrogen levels (climacteric or perimenopausal period)
−Potential ____
−Hot flashes, may be due to increased ___ ___ secretion at surface vessels
Fertilization normally occurs in the __ __ of the oviduct (___).
•Fertilization must occur within __ hours after ovulation. If not, the ovum ___.
•Sperm cells normally survive for ~ _ days in the female reproductive tract, but can last up to _. (Sperm deposited from 5 days prior to 24 hrs after ovulation may fertilize ova)
•___ pregnancy can occur when it doesn’t enter the oviduct or stays in oviduct
Sperm migration is aided by the female tract/ovum:
−____ of cervical mucus (due to high ___ near the time of ovulation) allows passage into the uterus. Sperm get through cervix under their own ___.
−contractions of the uterine myometrium (smooth muscle layer) distribute sperm throughout ___ lumen. Stimulated by high ___ and seminal ___
−____ contractions of the oviduct (induced by estrogen and prostaglandins) propel sperm to site of fertilization, fimbriae (cilia) in oviduct
Sperm migration is aided by the female tract/ovum.
-hOR17-4, ___ receptor on sperm that is attracted to ____, a chemoattractant produced by the corona radiata.
-Binding increases intracellular ___ release, allowing for increased swimming.
−____ released by cells around the ovum also serve as a chemoattractant. It binds to surface membrane receptors and opens calcium-permeable cation channels (___) in the ___ of the sperm.
->Increase in calcium causes:
1. ____ of sperm
2. Hyperactivated ____ which provides sperm with increased power needed to penetrate the corona radiata and zona pellucida
3. ___ reaction
Increased intraovum Ca2+ also causes the ___ meiotic division
Sperm activates ovum enzymes essential for early ___ development
Penetration of corona radiata by sperm: binding of __ receptors by ___
Acrosome reaction: triggered by ___ binding
REVIEW
->_____ from corpus luteum stimulates glycogen release from endometrium and ____ oviduct allowing for zygote to be expelled into ___ lumen
->Time allows for necessary nutrients to accumulate in uterine ____
->____ and uterine lining become “sticky” through expression of cell adhesion molecules
->_____ makes a hole via enzymatic breakdown, but also makes nutrients available for blastocyst
->Area of uterus that undergoes changes to accept blastocyst = _____
-Local ____ release increases vascularity, causes edema, and enhances nutrient storage
Acceptance of Fetus by Mother; fetus is actually a FOREIGN object
___ natural killer cells are unable to kill fetal cells (unlike the usual natural killer cells)
->lock decidual dendritic cells in a ___ producing state
->dNK’s and DDC’s induce apoptosis of maternal __ _ cells
->promote production of regulatory T cells
•____ cells produce a unique Class 1 MHC glycoprotein that allows them to evade interaction with killer cells
•Trophoblastic cells produce ___ ligand
->Binds fas
->Fas is a specialized receptor on the surface of activated maternal ___ _ cells (immune cells that destroy foreign cells)
->Binding triggers ___ of T cells
•Fetal portion of placenta produces indoleamine 2,3 dioxygenase (___):
->Destroys ____
->Tryptophan is critical for ___ of cytotoxic T cells
•Production of ___ T cells is doubled or tripled
->____ T cells ___ cytotoxic T cells
The placenta is the organ of exchange b/w the maternal and fetal blood.
•Glycogen from endometrium is sufficient only for a ___ weeks
•___ – begins when trophoblast layer is 2-cells thick.
•As chorion ____, it forms cavities within ___ into which maternal blood leaks. Blood is kept from clotting via an ____ produced by the chorion.
•Fingerlike projections of the chorionic tissue form placental ___ that extend into these pools of maternal blood.
•Fetal ___ project into the placental villi. Fetal and maternal blood are separated here by a thin ___ layer.
•Exchange occurs b/w the maternal and fetal blood.
•Fetal blood leaves through an ___ vein.
•Maternal blood exits through maternal ____.
In place & operational by __ weeks after implantation
Functions of the Placenta
•Digestion, Respiration, Kidneys:
->Nutrients and __ move from maternal blood to fetus
->___ and other metabolic wastes move from fetus to maternal blood
•Different substances cross in different ways:
->simple diffusion, facilitated diffusion, secondary active transport, receptor-mediated endocytosis
•Many unwanted substances can also cross
->_____ = tranquilizer that caused limbless babies
->Heroin and other drugs lead to addicted babies
->Aspirin, alcohol, agents in cigarette smoke
->AIDS virus
•Placenta is also an ____ organ
•Human chorionic gonadotropin (__) maintains the ___ ___ of pregnancy by acting in the place of ___ hormone.
•Normal ___ hormone secretion reduced by continuing ___ secretion.
•Human chorionic gonadotropin stimulates ___ ___ production of testosterone in the male fetus.
•Human chorionic gonadotropin (HCG) eliminated in the ___ and forms the basis for early detection of ___ (about two weeks following missed menstrual period).
->Estrogen not produced by placenta __ on because it lacks the enzymes needed to make it and thus has to wait on the fetal adrenal to develop the ability to produce ___.
-Major estrogen produced is ___, which can only be produced from fetal ___, so estriol in mother’s urine can be used as an index of fetal viability
Lack of early progesterone production due to ___ mass of placenta
Estrogen:
1. Grows the ___
2. Promotes development of ducts in mammary glands
Progesterone:
3. Prevent ___ by suppressing myometrial contractions
4. Promotes __ formation in cervix
5. Stimulates the development of milk glands
Changes in later gestation prepare for parturition.
*Parturition is ___. During the last trimester the uterus becomes more excitable. Mild contractions occur (___-___ contractions).
•The cervix begins to soften near parturition due at least in part to the effects of ___.
•The fetus shifts downward, with its head contacting the cervix.
•Rhythmic contractions begin at the onset of ___. There are high levels of ___ at this time.
->Estrogen increases connexons within uterine smooth muscle cells. Form ___ junctions b/w cells that allow them to be electrically linked for coordinated contractions
->Estrogen increases myometrial receptors for ____.
->Estrogen stimulates increased local ____ production to promote cervical ripening (degradation of ___). These prostaglandins also increase uterine responsiveness to ___.
•Factors triggering the onset of parturition are not well understood.
PARTUITION DIAGRAM
Uterine Involution:
->Return of the uterus to ____ state (4-6 weeks)
->Due to loss of ___ and ___ support
->Breast feeding hastens process due to release of ___ that causes uterine ____
1.) First stage of labor Cervical ____
2.) Second stage of labor: ___ of baby
3.) Third stage of labor:Delivery of ____
•Milk synthesized in ___ epithelial cells, secreted into the alveolar lumen, and ejected into a milk duct that leads to the nipple
•Estrogen promotes ___ development
•____ promotes alveolar-lobule development
•Prolactin and human ___ ______ (__) induce synthesis of enzymes for making milk & also promote growth of the fetus through stimulation of IGF-1 & IGF-2
->Breasts are capable of lactation by ___ through pregnancy. High ___ and P block prolactin from causing milk release. Thus, the drop in E and P initiate lactation.
SUCKLING REFLEXES
Advantages of Breast Feeding:
For the infant:
-Nutrients (water, fat, lactose, proteins, vitamins, Ca2+, PO4)
-Contains a host of immune cells (particularly the ___ – milk produced in the first 5 days)
-Secretory __ = protect against infectious microbes that the infant is most likely to encounter
-___ : may bind to and prevent uptake of harmful microorganisms through the intestinal wall
-___ = decreases availability of iron to harmful bacteria
-Bifidus factor = promotes growth of lactobacillus bifidus, which helps crowd out harmful bacteria
-Other factors promote maturation of the digestive tract
For the mother:
->Hastening of uterine involution
->Suppression of menstrual cycle (perhaps through prolactin)
*Milk production stops at weaning due to the lack of ___ stimulation.
REVIEW