Reproductive System Notes PDF

Reproductive system Reproduction is the process by which organisms create descendants.  This miracle is a characteristic that all living things have in common and sets them apart from nonliving things. Even though the reproductive system is essential to continuation of species...

Reproductive system Reproduction is the process by which organisms create descendants.  This miracle is a characteristic that all living things have in common and sets them apart from nonliving things. Even though the reproductive system is essential to continuation of species, it is not essential to keeping an individual alive. o Is it not essential for homeostasis. Function of reproductive system: Reproduction (perpetuation of species) Gametogenesis: ovum and sperm cell formation To transport and sustain these cells To nurture the developing offspring Endocrine function: sex hormone synthesis  Sexual pleasure (coitus, coupling) 1 Sex Determination  During 7th week of intra uterine life, primitive gonadal cells (PGC) are appeared.  The primitive gonadal cells are both Mullerian duct & wolfian duct  Mullerian duct  this duct raise to female accessory sex organs like vagina, uterus, & fallopian tube are developed if the sex chromosome of the embryo is XX.  Wolfian duct: this duct raise to male accessory sex organs like epididymis, vas deferens & seminal vesicles are developed if the sex chromosome of the embryo is XY. 2 o When a sperm containing a Y chromosome fertilizes an ovum, an XY pattern results and the zygote develops into a genetic male. o Male cells contain an X and a Y chromosome (XY pattern), o When fertilization occurs with an X-containing sperm, an XX pattern and a genetic female result. o female cells contain two X chromosomes (XX pattern) o The sex of individuals is determined by short arm of Y chromosome(Sex-determining Region of Y chromosome). 3 In the absence of Y-chromosome, the Primitive gonadal cells developed into ovaries. In the absence of functioning testis, no testosterone, thus the Wolffian duct regresses. but Mullerian duct develops into the female internal genitalia, (fallopian tube, uterus and the upper 2/3 of the vagina). The urogenital slit remains open and the female external genitalia develops. 4  The regulation of embryonic sexual development. 5  At 16 weeks (4th month) the genitalia are formed = sex of fetus can be identified by ultrasound at 4th month of gestation. 6 Male reproductive system  The main difference b/n the male and female depends primarily upon the ± Y-chromosome and a pair of gonads (testis and ovaries)  The functions of the male reproductive system include: Production of male gametes (sperm) Synthesis of male sex hormones such as androgens and testosterone.  Delivering of sperm into the female reproductive tract. 7 Functional structures of the male reproductive system The male reproductive system consists of: 1. Gonads (the testis)  Primary male sex stractures  Function:  Spermatogenesis (formation of spermatozoa)  Endocrine function (produces male sex hormone, testosterone, inhibin, and estrogen 2. Accessory Tubular /duct / structures (genital tracts)  Involved in transporting of sperm  These include: Epididymis: area of storage & maturation of sperm found next to somniferous tubule of testes. Vas deferens: Joins epididymis with ejaculatory duct Ejaculatory duct: Connects vas deferens with the urethra 8 3. Accessory glands :Provide fluid medium for sperm protection and nourishment These glands includes: A. The seminal vesicle: secretes fluids containing:  Fructose (to provide energy for sperm)  Protaglandins (alter the uterine environment to help sperm passage)  Coagulating enzyme (which turns semen into a bolus that can be propelled during ejaculation)  It produces 60% of the volume of the seminal plasma B. The prostate glands  Prostate secretion makes up 30% of the seminal plasma  Prostatic fluid contains: citrate (food source for sperm) and prostate specific antigen (liquefy the semen and allows sperm cells to swim freely). 9  The prostate produce thick alkaline mucus after erection but prior to ejaculation to neutralize the of acidic urine with the urethra and lubricate the glans penis. C. The bulbourethral (Cowper's) glands-secrete similar fluid with that of prostate gland 3. Supporting structures  Penis -supports the urethra  Scrotum-supports tests and epididymis  Spermatic cord -contains Blood vessel, nerves, lymphatics 10 Structures of Male Reproductive System 11  External structure of the penis contain: i. Spongy erectile tissue ii. Gland penis iii. Prepuce (foreskin removed by circumcision) » Male circumcision has significant health benefit  The penis is composed of three layers of spongy erectile tissue.  During sexual arousal the erectile tissue filled with blood from arteries.  The resultant increased pressure seals off the veins that drain the penis.  The engorgement of the penis with blood causes an erection. 12  Male Circumcision shaft sutures corona foreskin glans penis urethral opening 13 14 Testis is male gonad located out side abdominal cavity in the scrotum.  The scrotum is a sac of skin at the root of the penis.  The paired testes (male gonads) are suspended with the scrotum, separated by a connective tissue septum.  This location provides a temperature 2-30c lower than body temperature, which enhances sperm production. The cremaster muscle elevates the testes in response to cold T0 and lowers them when T0 rises. The dartos muscle adjusts the scrotal surface area in response to changes in T0. o The dartos contracts in response to cold temperature. o This decreases scrotal surface area & reduces heat loss. o The dartos relaxes in response to hot termperature. 15 Male Reproductive System 16 The testis is made up of somniferous tubules which contain: o Spermatogenic epithelium that give rise to spermatozoa. o Leydig cells that secrete testosterone o Sertoli cells (non-germinal cells to support spermatogenic cells). somniferous tubules account about 90% of testicular mass. Function of Sertoli cells:  Mechanical support and norishement of spermatozoan  Secrete inhibin and estrogen  Defence (phagocytosis) & eat old sperm cells  Act as blood testis barrier (prevents many large molecules from passing from the interstitial tissue) 17 Spermatogenesis=production of sperm cell  The spermatogonia, the primitive germ cells of the seminiferous tubules, mature into A and B primary spermatocytes by mitotic division  This process begins during adolescence.  The A primary spermatocytes stay in the peripheral rim of the somniferous tubules to maintain the population of germ cells, where as B primary spermatocytes undergo two meiotic division,  In this two-stage process, they divide into secondary spermatocytes and then into spermatids,  The spermatids mature into spermatozoa (sperms)  In humans, it takes an average of 74 days to form a mature sperm from a primitive germ cell by the orderly process. 18 Spermatogenesis 19 Maturation of spermatid in spermatozoa 20  Mature sperm cell Mature sperm cells contain the head, neck and tail. Acromosomes at the head contain enzymes, hyaluronidase or proteases Proteases are meant for effective penetration of egg during fertilization. Head Maturation of sperm cells occurs in the epididymis and requires hormone testosterone Neck Events of sperm maturation include: Acromosomal development Cytoplasmic reduction Flagellar growth Tail Discharge of organelles Condensation of nucleus 21 Hormones for spermatogenesis  Testosterone: is essential for growth and division of the testicular germinal cells, which is the first stage in forming sperm.  Luteinizing hormone: stimulates the Leydig cells to secrete testosterone.  Follicle-stimulating hormone: stimulates the conversion of the spermatids to sperm (the process of spermiogenesis)  Growth hormone, T3/T4 and prolactin are necessary for controlling metabolic functions of the testes.  Growth hormone specifically promotes early division of the spermatogonia themselves; in its absence, as in pituitary dwarfs, spermatogenesis is severely deficient or absent, thus causing infertility. 22 Semen It is the fluid ejaculated during the male sexual act. It is made up of spermatozoa and the seminal plasma which is the combined secretion of the testis, epididymis, seminal vesicles and prostate. Seminal fluid (10% is sperm and testicular fluid,60% seminal fluid and 30% prostate fluid) An average volume per ejaculation is 2 - 5 ml with 108 sperms/ml. 50% of men have sperm count 20-40x106/ml. If the sperm count is less than 20x106/ml the person will be infertile or sterile 23  Hormonal regulation of male reproduction 24 Function of testosterone  Determines the primary sexual characteristics, and secondary sexual characteristics  During puberty, hypothalamus produces GnRH that stimulates the anterior pituitary gland to produce LH and FSH, which in turn stimulate spermatogenesis and testosterone secretion=testosterone is essential for the onset of male pubertal changes.  It stimulates the brain to develop the male sexual behavior and set up.  Spermatogenesis: It stimulates spermatogenesis and required for sperm maturation 25 Function of testosterone (cont´d) General metabolic effect: It is a protein anabolic hormone, increases muscle mass and bone matrix. It facilitates fusion of epiphysal plates of bone. Increases Basal Metabolism Increase RBC Increase the reabsorption of Na+ in the distal tubules of the kidneys. Due to this, after puberty, the blood and extracellular fluid volumes increase up to 5 to 10%. Increases Protein Formation and Muscle Development 26 Male sexual act  Has 3 stages:  Erection:  It is definitely a cardiovascular phenomena  Controlled by Parasympathetic nerve system  It is initiated by psychic, visual or tactile stimulations.  Mechanism: Parasympathetic stimulation →dilation of penile arteries →entry of large volume blood to the arteries compresses the veins (outlets) →venous occlusion → stiffening of erectile tissues (corpora cavernosa and corpus spongiosum) →erection  Orgasm: (emission and ejaculation)  It is the ejection of seminal plasma containing spermatozoa out of the male ductile system.  Sympathetic stimulation to the smooth muscles of epididymis, vas deferens, prostate and seminal vesicles result emission, whereas, contraction of urethral skeletal muscles results in ejaculation 27  Ejaculation propels sperm from the epididymis to the vas deferens.  The vas deferens run from the scrotum and behind the urinary bladder.  Here each vas deferens joins with a duct from the seminal vesicle to form an ejaculatory duct.  The ejaculatory ducts open into the urethra.  The urethra drains both the excretory and reproductive systems. 28  Resolution:  Reversion of erection, sympathetic stimulation constricts arteries, blood leaves the erectile tissues, penis become flaccid Physiological changes during male sexual act  ↑Heart Rate ↑Blood Flow ↑Metabolic Rate  ↑Cardiac Out put ↑Arterial BP ↑Energy out put  Stimulation of the CNS  Hyperventilation  Sympathetic stimulation Sexual flash  Emotional excitement  Sensation of pleasure 29 Problems associated with male reproductive system Disorders of testis 1. Testicular trauma:  Even a mild injury to the testicles can cause severe pain, bruising, or swelling. Most testicular injuries occur when the testicles are strike, hit, kick, or crushed, usually during sports or due to other trauma.  Surgery is needed 2. Varicocele:  an abnormally swollen testicular vein.  Varicocele commonly develop while a boy is going through puberty.  A varicocele is usually not harmful, although in some people it may damage the testicle or decrease sperm production 30 3. Testicular cancer:  It occurs when cells in the testicle divide abnormally and form a tumor.  Testicular cancer can spread to other parts of the body, but if it's detected early, the cure rate is excellent. 4. Epididymitis: o Is inflammation of the epididymis, and the coiled tubes that connect the testes with the vas deferens. o It is usually caused by an infection, such as the sexually transmitted disease. 32 5. Hydrocele A hydrocele occurs when fluid collects in the membranes surrounding the testes. Fluid in the space between teste & tunica vaginalis Treatment usually not required Hydroceles may cause swelling of the testicle but are generally painless. In some cases, surgery may be needed to correct the condition. Surgery needed if hydrocele becomes tense and compromises testicular circulation or if scrotal mass becomes large, uncomfortable 33 Disorders of Penis  Includes:  Inflammation of the penis: Include redness, itching, swelling, and pain, which could be usually due to fungal or bacterial infection.  Hypospadias: Is condition in which, the urethra opens on the underside of the penis, not at the tip  Phimosis: This is a tightness of the foreskin of the penis and is common in newborns and young children. It usually resolves itself without treatment. If it interferes with urination, circumcision (removal of the foreskin) may be recommended. 35  Paraphimosis: when a boy's uncircumcised penis is retracted but doesn't return to the unrestricted position.  As a result, blood flow to the penis may be impaired, and results pain and swelling.  Ambiguous genitalia: when a child is born with genitals that aren't clearly male or female In most boys born with this disorder, the penis may be very small or nonexistent, but testicular tissue is present.  Micro penis: Is when the penis, although normally formed, is well below the average size, as determined by standard measurements. 36 Disorders of the male sexual act  Impotence: The inability of a male to produce or maintain an erection also called Erectile dysfunction, which could be due to Spinal damage Diabetic neuropathy Hypotension Testicular failure  Hypogonadism: A lack of function of the gonads, in regards to either hormones or gamete production.  Hypoactive sexual desire: A low level of sexual desire and interest.  Premature ejaculation: A lack of voluntary control over ejaculation.  Periapism: persistent undesired erection  Absence of emission 37 Causes of male sterility Congenital absence of testis Cryptorchidism=hidden testes(testes not descend to scrotum Infection with Sexually Transmitted Disease Destruction of the seminiferous tubules Irradiation Oligospermia, azoospermia, asthenospermia, amotile sperm Drugs, alcohol, smoking Impotence Hypogonadism Genetic defects Functional disorders of prostate and seminal vesicles Genital tract obstruction Spermatogenesis arrest due to hypovitaminosis Testicular failure 38  Abnormal infertile sperm, compared with a normal sperm on theright.. 39 Physiologyy of the female reproductive system The functions of the female reproductive system include:  Production of female gametes (ova)  Production of female sex hormones (estrogens & progesterone).  Reception and maintenance of a developing embryo and fetus.  Feeding of the new born with milk (lactation)  The female system has more complex responsibility in reproduction than male. The Structures of female reproductive system consists of 1. Gonads  2 ovaries  Function: oogenesis, and endocrine function i.e. secretion of estrogen and 40 progesteron. 2. Oviduct/fallopian tube/uterine tube Are paired organs. Each about 4 inch long. Each connects the ovary with the cavity of uterus. Lies between folder of broad ligament. It has four parts 1. Infundibulum 2. Ampulla 3. Isthmus 4. Intra mural part(uterine part) Edris A. 41  1.Infundibullum -funnel shaped lateral end that projects beyond the broad ligament and over lies the ovaries. -has finger like projection. It is funnel or trumpet shaped. Fimbriae are fingerlike processes, one of these is longer than the other and adherent to the ovary. The fimbriae become swollen almost erectile at ovulation Edris A. 42 2.Ampulla:-widest part of the tube, about 5 cm in length. -site of fertilization. -occasionally it is site for ectopic pregnancy. 3.Isthmus:-narrowest part of the tube. 4.Intra mural part:-the segment pierces the uterine wall. Edris A. 43 Function of uterine tube  Site of fertilization.  Transport ovum and sperm.  Move the zygote to site of implantation.  Receive the ovum from the ovary  Secretory function  Final maturation of gamete post ovulate oocyte maturation,  sperm capicitation Edris A. 44 3.Uterus(womb)  It is located anterior to the rectum and posterosuperior to the urinary bladder.  It is a hollow, pear shaped organ with thick muscular walls.  About 3inch long, 2 inch wide and 2 inch thick. The uterus divided in to 3 parts: funds:-rounded part lies above the enterance of the uterine tube. body:-lies below the enterance of the uterine tube. cervix:-cylindrical, narrow inferior part of the uterus that projects in to the vagina. Edris A. 45 Female Internal reproductive organs: Uterus cont……d The wall of the uterus has 3 layers 1. The perimetrium: is the outermost layer 2. The myometrium is the middle layer and is made of smooth muscle bundles. 3. The endometrium is the inner layer and is lined by a simple columnar epithelium underlain by a thick lamina propria.  The endometrium is divided into 2 sublayers.  The stratum functionalis: is superficial and undergoes cyclic changes in response to ovarian hormones and is shed during menstruation.  The stratum basalis: is the thinner and deeper layer and is unresponsive to ovarian hormones and forms a new stratum functionalis after menstruation ends. 47  Endometrium is Sub divided in to two sub layers:- a) Stratum basalae(basal layer) -abluminal  the thinner deeper layer.  Unresponsive to ovarian hormone.  Highly cellular lamina propria.  Involved in the menstrual cycle-regenerative.  Supplied with basal artery b) Stratum functionalis- adluminal  The superior layer.  Lies cellular lamina propria.  Under goes cyclic changes in response to ovarian hormone.  Shed during menstruation  Supplied with spiral artery Edris A. 49 Organization of glands and blood flow within the uterine endometrium Edris A. 50   Function of uterus:  Site of pregnancy  Growth and development of fetus  Produces pressure during labor  Site of menstruation 4. The vagina (birth canal): o Is the thin walled tube that sits between the bladder and rectum and extends from the cervix to the body exterior. o The vaginal wall contains a mucosa, smooth muscle 51 Vagina cont……d  Lined with non-keratinized stratified epithelium  Glands secrete glycogen and lactate, harbors Lactobacillus liquificious that maintains acidic pH in the wall of the vagina.  Function:  Copulatory organ of female  Birth canal  Allows passage of menstruation D. External genitalia: clitoris, labia minora and labia majora and mons pubis. N.B The ovaries, uterine tubes, uterus, and vagina constitute the internal genitalia where as, the external genitalia, or vulva, include the mons pubis, labia, and clitoris. 52  4.the vagina/ birth canal. It is thin walled tube that sites between the bladder and rectum,≈ 3 inch or ≈7-9cm long. Extender the cervix of the uterus to the vestibule (the exterior body). Serves as excretory channel for menstruation. It receives the erect penis during Coitus. Vaginal wall contains a mucosa, smooth muscle. Lined with stratified non keratinized epithelium Its glands secrete glycogen and lactate, harbors Lactobacillus liquificious that maintains acidic pH in the wall of the vagina Edris A. 53  Function of the vagina o It forms birth canal. o Allows passage of menstruation. o Copulatoy organ of female. 5.Female External genitalia/vulva/ include i. Clitoris ii.Labia majora iii.Labia minora iv.Mons pubis v.Vestibule of vagina Edris A. 54  The Clitoris The clitoris is 2 to 3 cm in length. It is homologous with penis as an erectile organ. But clitoris is not traversed by the urethra. It is located posterior to anterior labial commissure, where labia majora meet. Usually hidden by the labia when it is flaccid. 55  The clitoris will engorged upon tactile stimulation-, protrudes when erected but it does not lengthen significantly. It is highly sensitive to tactile stimulus and very important in the sexual arousal of a female. Clitoris is most sensitive part of entire genital area to bring pleasure to female during sexual arousal. 56  Bartholin’s Glands( Vestibular Glands) are located on each side of the vaginal opening. They secrete fluid that helps lubricate the vagina during sexual intercours. Sometimes the ducts of these glands become obstructed. – Fluid backs up into the gland and causes swelling (Bartholin's cyst) Edris A. 59 The Ovaries  2 ovaries attached to the peritonium with mesovarian and broad ligaments.  Has 2 roles: gametogenic and endocrine  The gametogenic potential is established early in the fetus  Endocrine role of the ovary is not realized until puberty  Has 2 structural parts  Medullary part: the central part that contains Blood Vessels, connective tissues (elastin and collagen)  Cortical part: the peripheral part that contains actively proliferating ovarian follicles 60 Oogenesis in the Ovary 61 Oogenesis: Before birth =During fetal development, oogonia (stem cells) divide by mitosis to make primary oocytes =Primary oocytes begin meiosis and stop in prophase I until puberty Primordial follicles: Support cells that surround the oocyte in the ovary 2 million present at birth 400,000 remain at puberty Edris A. 62  Oogenesis: After Puberty Each month, hormones cause several follicles to develop, which triggers the primary oocyte to resume meiosis I Polar bodies: When the cell divides, all the cytoplasm and organelles stay with one of the new cells, the other cell is just DNA, and is called a polar body and is discarded Secondary oocyte: The stage at which ovulation occurs. The secondary oocyte begins meiosis II, but stops in metaphase II The secondary oocyte is ovulated Meiosis II is completed only if it is fertilized. Edris A. 63 Oogenesis 64 Oogenesis Edris A. 65 The Female Reproductive Cycles  Monthly rhythmical changes in the rates of secretion of the female hormones and corresponding physical changes in the ovaries and other sexual organs.  This is called female reproductive cycle or menstrual cycle (menstrual referring to "monthly"). The duration of the cycle averages 28 days. o It may be as short as 20 days or as long as 45 days in some women, although abnormal cycle length is frequently associated with decreased fertility. 66 The Female Reproductive Cycles cont……..d  Two types The female sexual cycle: 1. Ovarian cycle has 3 phases:  Follicular,  Ovulatory &  Luteal phases 2. Endometrial cycle has also 3 phases:  Menstrual,  Proliferative &  Secretory phases 67 Ovarian cycle: contains 3 phases 1. Follicular phase(1-13th day)  When a female child is born, each ovum is surrounded by a single layer of granulosa cells;  The ovum, with this granulosa cell sheath, is called a primordial follicle. Throughout childhood, the granulosa cells are believed to provide nourishment for the ovum and to secrete an oocyte maturation-inhibiting factor that keeps the ovum suspended in its primordial state in the prophase stage of meiotic division. Then, after puberty, when FSH and LH begin to be secreted, the ovaries, together with some of the follicles within them, begin to grow. Then, granulosa cells are grows around the follicles; these follicles are known as primary follicles. 68 Ovarian cycle cont.....d  The primary follicles start to produce follicular fluid called liquor folliculi, which increase secretion of estrogen which facilitates growth of follicles.  Around on the 6th day, one of the follicles begins to outgrow all the others; (while the remaining are regressed, though the cause is unknown.)  A matured follicle called Graafian follicle is formed that develops into mature ova.  This phase is under the regulation of pituitary hormones (FSH &LH) 69 Ovarian cycle cont.....d 2. Ovulation phase (14th to 15th day)  The wall of the graafian follicle ruptures and the ovum + zona pellucida + one layer of the corona radiata are shed into the peritonial cavity.  Mechanism of ovulation:(LH is the hormone of ovulation)  36 hrs before ovulation, APG produces large amount of LH (LH surge). LH reaches peak level 12 hrs before ovulation.  ↑LH→ ↑antral fluid volume → ↑progesterone secretion → ↑BF to the graafian follicles → ↑follicular swelling → ↑pressure →rupture →egg released. 70 Ovarian cycle cont.....d 3. The Luteal phase (15th to 28th day)  Immediately after expulsion of the ovum from the follicle, the remaining granulosa and theca interna cells change rapidly into lutein cells.  Then under enlarged and become filled with lipid inclusions having a yellowish appearance.  This process is called luteinization, and the total mass of cells together is called the corpus luteum.  Corpus luteum stimulates secretion of ↑↑progesterone and ↑estrogen. 71  Progesterone  Make uterus ready for pregnancy (if fertilization has occurred).  Inhibits release of FSH or LH. This prevents any further follicle growth or ovulation during the next 2 weeks– in case fertilization has occurred  If ovum is not fertilized, corpus luteum begins to regress after a 14-day and replaced by an avascular scar, known as the corpus albicans.  If ovum is fertilized, the corpus luteum stays active for up to 4 months of pregnancy( until its function replaced by placenta) 72 Endometrial (Uterine) cycle  The uterine cycle refers to the cyclical changes that occur in the uterus in response to ovarian hormones.  Has also 3 phases: I. Bleeding phase =menstrual phase (1-5 days)  Is during which, plasma progesterone will decreased and the stimulus for maintaining the thick endometrium will disappear.  In response to this, the stratum functionalis will be shed and detached tissue and blood (menses) will slough out the vagina.  Loss of 50 ml (30-80 ml) of blood N.B, this is function of progesterone 73 Endometrial cycle cont…….d II. Proliferative phase(6-14 days)  During which plasma estrogen is rising.  This causes the stratum functionalis to grow thicker and become more vascular and glandular.  This is in preparation for the possibility of fertilization and pregnancy.  Estrogen also causes cervical mucus to become less viscous. This will facilitate sperm entry.  N.B, this is function of estrogen 74 Endometrial cycle cont…….d III. Secretary (Progestational) phase =15-28 Days  During which plasma progesterone rises to its peak (during the period of corpus luteum activity).  Progesterone causes even more vascularization of the stratum functionalis and causes the endometrial glands to twist, coil, and enlarge.  Progesterone will cause cervical mucus to become more viscous (i.e., it creates a cervical plug).  This helps to prevent the embryo from being attacked by any pathogens that may migrate from the vagina. 75  Menstrual cycle. 76  Phases of menstrual cycle for female with 28 day cycle. 77 Female sex hormones (Ovarian hormones)  Ovaries secrete 4 hormones  Estrogen (E1 = estrone, E2 = estradiol & E3 = estriol)  Progesterone  ↓ Androgens  ↓ Inhibin (the only peptide gonadal hormone)  Estrogen -Ovarian follicular cells -Corpus luteum  Sources -Adrenal cortex -Placenta -Testes  Rate of secretion  36 µg/day in the follicular phase  380 µg/day just before ovulation  250 µg/day in the mid-luteal phase 78 Function of Estrogen 1. Development of the body during puberty  Growth and enlargement of sex organs  Development of 2o sex characteristics 2. Growth of the uterus during pregnancy 3. Growth of the breast 4. General metabolic effects:  Enhances bone ossification  Protein anabolic  Cholesterol lowering  Salt and water retention 79 Function of Estrogen cont......d 5. Functional relations with other hormones  Estrogen has a synergestic action with progesterone on the uterus endometrium and breast acinar cells  Estrogen sensitizes the uterus to the action of oxytocin during labor  Estrogen regulates rate of secretion of LH and FSH from Anterior Pituitary  Estrogen stimulates secretion of ACTH that leads to hyperthrophy of adrenal cortex 80  Progesterone  Sources -Corpus luteum -Follicular cells -Adrenal cortex -Placenta -Testes  Rate of secretion  1 mg/ day in the early follicular phase  4 mg/day just before ovulation  25 mg/day in the mid-luteal phase  Function of progesterone 1. On uterus o Induces the progestational changes of endometrium o Inhibits excitability of myometrium o Stimulates secretion of thick, alkaline cervical mucous 81 Function of progesterone cont……d 2. On breast  Stimulates development of secretory cells  Stimulates differentiation of ductile system 3. On other hormones: inhibits secretion of LH and FSH 4. Has a thermogenic action (increases body To ) 5. Promotes urination  N.B. The female sexual response is somewhat similar to the male response.  The vaginal mucosa, clitoris, and breasts engorge with blood – analogous to erection.  Orgasm is not typically accompanied by ejaculation, but muscular tension, BP, and HR all increase. 82 Pregnancy Fertilisation  Ovum is released from graafian follicle of ovary into the abdominal cavity at the time of ovulation.  Then the ovum enters into the fallopian tubes.  After sexual intercourse and ejaculation, sperms are transported through the uterus to the ovarian end of the fallopian tube, where fertilisation takes place.  Out of 200 – 300 million sperms entering female genital tract, only a few thousand sperms reach the spot near the ovum & only one sperm can fertilise the ovum. 83 Fertilisation cont.....d The sperm enters the ovum, by penetrating the multiple layers of granulosa cells known as corona radiata present around the ovum. This is facilitated by hyaluronidase & proteolytic enzymes present in the acrosome of sperm. Though many sperms reach the ovum, only one enters it.  This is because the proteolytic enzymes from acrosome of the first entered sperm abolish the activity of other sperms entering the ovum. 84 Cleavage and Blastocyst Formation  Cleavage:  30-36 hrs. after fertilization, the zygote divides by mitosis.  About 50-60 hours after fertilization, the early embryo develops into morula.  Blastocyst develops  From the inner cell mass (Blastocyst), embryo will develop.  The remaining cells are called trophoblast which forms the embryonic part of placenta. 85 Implantation  After the fertilisation, the ovum is known as zygote. The  zygote takes 3 – 5 days to reach the uterine cavity from fallopian tube.  While travelling through the fallopian tube, the zygote receives the nutrition from the secretions of fallopian tube.  After reaching the uterus, the developing zygote remains freely in the uterine cavity for 2 – 4 days before it is implanted.  Thus it takes about 1 week for implantation after the day of fertilisation.  During the stay at uterine cavity before implantation, the zygote takes its nutrition from the secretions of endometrium. 86 Development of Placenta & Embryo  Immediately after the implantation, a cavity develops in the morula.  Along the wall of this cavity, a structure called blastocyst develops and, the blastocyst is the first stage in the development of embryo.  Simultaneously, the trophoblast cells & the other underlying cells proliferate to form the placenta. 87  Fertilization, cleavage, blastocyst formation & implantation. 88  From ovulation , fertilization to implantation. 89  Interrelations of fetal & maternal tissues in the formation of the placenta. 90  Structure of PlacentalBarrier Edris A. 91  Placenta Placenta is organ in uterus of pregnant mammal. It is vascular organ that supply food and oxygen to the fetus through the umbilical cord. It is expelled after birth. Embryo develops placental cells after attached with maternal endometrium Thus, placental cells are made-up of both fetal and maternal cells (Formed from trophoblasts of fetus & decidua tissue of endometrium) Edris A. 92 Edris A. 93  Abnormalities of the placenta Abnomalities in the size and shape:  very small placenta - is found in women suffering from chronic hypertension  very large placenta – is found in fetal hydrops - a condition of the fetus with severe hemolytic disease resulting from serological incompatibility between the mother and baby  placenta membranous - extremely thin placenta, the chorionic villi persist on the smooth chorion, which takes part in formation of the placenta (together with villous chorion)  placenta bipartita or tripartita - a placenta with two or three incomplete lobes (after delivery, one or two lobes may be retained in the uterus and may cause postpartum uterine hemorrhage or uterine infection  placenta duplex, triplex or multiplex - a placenta that is divided in two, three or more completely separate lobes  placenta succenturiata - a placenta with one main lobe and one or two small accessory lobes Abnormalities in location of the placenta within the uterus:  placenta praevia - placental attachment may partially or completely obturate the cervix is hazardous to both mother and child because with the expansion of the lower part of the uterus, the placenta is stretched and then bleeding may occur from the 20th week- most frequently in 28th week due to the position of the placenta, spontaneous vaginal delivery is a great risk Abnormalities in the placenta attachment:  placenta accreta - a basal decidua or plate is hypoplastic (poorly developed) and chorionic villi are in direct contact with the myometrium of the uterus to which they are firmly attached  placenta increta - chorionic villi penetrate the myometrium! spontaneous expulsion of the placenta is not possible (such placenta must be removed by surgery).  Amniotic fluid is a clear, slightly yellowish liquid that surrounds the unborn baby (fetus) during pregnancy. It is contained in the amniotic sac. Origin and Production of Amniotic fluid The fluid is produced by the mother’s placenta during the first trimester and the early part of the second trimester, until the baby’s kidneys are mature enough to take over the task. The baby swallows the fluid as they “breathe” and then excretes it again as urine, thus maintaining the constant circulation of the fluid. However, the urine making up the fluid is not pure waste material as the majority of the fetal waste is passed through the placenta to be filtered by the mother’s kidneys. Edris A. 96 Functions of the Amniotic fluid are: To provide a protective cushion for the fetus, Allow fetal movement, Stabilize the temperature to protect the fetus from extreme temperature changes. To permit proper lung development. Exchanges of water and chemicals, also take place between the fluid, the fetus, and the maternal circulation. Helps uniform growth of the body parts and organs of the baby. Assists with the proper bone and muscle development Edris A. 97 Collection Amniotic fluid= amniocentesis  Abnormalities of Amniotic Fluid 1) too much (polyhydramnios) >2000 ml Abnormal digestive system or CNS - esophageal atresia, - anencephaly 2) too little (oligohydramnios) 12 days Conjoined twins. Edris A. 107  Ectopic Pregnancy  Occurs when a fertilized egg or zygote doesn't travel into the uterus, but instead grows rapidly in the fallopian tube.  Women with this condition can develop severe abdominal pain and should see a doctor because surgery may be necessary.  Ovarian tumors  Women with ovarian tumors may have abdominal pain and masses that can be felt in the abdomen.  Occur rarely.  Surgery may be needed to remove the tumor. 108 Ectopic Pregnancy=implantation out side uterus 109  Ovarian cysts  Are noncancerous sacs filled with fluid or semi-solid material.  Although they are common and generally harmless, they can become a problem if they grow very large.  Large cysts may push on surrounding organs, causing abdominal pain.  In most cases, cysts will pass or disappear on their own and treatment is not necessary.  If the cysts are painful and occur frequently, a doctor may prescribe birth control pills to alter their growth and occurrences.  Surgery is also an option if they need to be removed. 110 Ovarian Cyst 111  Polycystic ovary syndrome  Is a hormone disorder in which too many hormones are produced by the ovaries.  This condition causes the ovaries to become enlarged and develop many fluid filled sacs or cysts.  It often first appears during the teen years.  Depending on the type and the severity of the condition, it may be treated with drugs to regulate hormone balance and menstruation. 112  Menstrual abnormalities  Anovulatory cycle: normal 1-2 yrs after menarche and before menopause, otherwise infertility  Dysmenorrhea:is painful periods.  Menorrhagia: is when a woman has very heavy periods with excess bleeding.  Oligomenorrhea: is when a woman misses or has infrequent periods, even though she has been menstruating for a while and is not pregnant.  Amenorrhea: is when a girl has not started her period by the time she is 16 years old or 3 years after puberty has started, has not developed signs of puberty by 14, or has had normal periods but has stopped menstruating for some reasons other than pregnancy.  Hypomenorrhea: scanty flow 113