Urinary System Lecture Notes Part 4

–Uterine tubes –Uterus –Vagina •External genitalia The external sex organs Ovaries Uterine (fallopian) tubes •Held in place by several ligaments •Ampulla •Fundus, Body, Isthmus –Ovarian ligament –Infundibulum - distal expansion near ovary –Suspensory ligament •Cervix: narrow neck to vagina –Usual site of fertilization •Cervical canal connected to Fallopian- fertilization –Vagina via external os •Ciliated fimbriae of infundibulum create currents to move oocyte into uterine tube –Uterine body via internal os –Mesovarium •Broad ligament: supports the (female duct system) ● Uterine(fallopian) tubes or oviducts, ● Uterus ● Vagina •Follicle –Oocyte surrounded by Granulosa cells •Stages of development –Primordial follicle –Primary follicle –Secondary follicle –Late secondary follicle •Graafian follicle –Fluid-filled antrum forms •Ovulation –Ejection of the oocyte •Corpus luteum •Isthmus: constricted region where tube joins uterus •Oocyte is carried along by peristalsis and ciliary action Uterus •Cervical glands secrete mucus, blocks sperm entry except during mid cycle Supports of the uterus •Mesometrium: lateral support: part of broad ligament •Lateral cervical ligaments: cervix to pelvis •Uterosacral ligaments: uterus to sacrum •Round ligaments: to anterior wall –develops from ruptured follicle The usual site of fertilization is the __________. Uterine tube Uterine wall Vagina •Three layers 1.Perimetrium: visceral peritoneum 2.Myometrium: smooth muscle 3.Endometrium: mucosal lining •Birth canal and organ of copulation •Labia majora: outer fatty skin folds •Layers of wall •Labia minora: inner skin folds Endometrium •Stratum functionalis (functional layer) –Changes in response to ovarian hormone cycles 1.Fibroelastic adventitia 2.Smooth muscle muscularis 3.Stratified squamous mucosa •Mucosa near the vaginal orifice forms an incomplete partition called the hymen Hymen- incomplete partition –Is shed during menstruation •Stratum basalis (basal layer) –Forms new functionalis after menstruation –Unresponsive to ovarian hormones The uterine layer shed with each monthly cycle is the __________. Functional layer of endometrium Which male structure is homologous to the female's clitoris? Penis External Genitalia –Vestibule: recess between labia minora •Greater vestibular glands –Release mucus into the vestibule for lubrication •Clitoris –Contains erectile tissue –Glans clitoris: exposed The muscular wall of the uterus is called the __________. Myometrium The __________ is shed during menstruation. stratum functionalis Oogenesis: production of female gametes •Begins before birth –Oogonia (2n ovarian stem cells) multiply by mitosis and store nutrients –Primary oocytes develop in primordial follicles –Primary oocytes begin meiosis but stall in prophase I •One oocyte is selected each month, after puberty, to resume meiosis I •Result is two haploid cells –Secondary oocyte –First polar body •The secondary oocyte arrests in metaphase II and is ovulated •If penetrated by sperm the second oocyte completes meiosis II, yielding –Ovum (the functional gamete) –Second polar body Which cell type is actually ovulated from the ovary? Secondary oocyte Which of the following hormones causes the oocyte to mature? FSH The basic difference between spermatogenesis and oogenesis is that __________. One mature ovum is produced in oogenesis, and four mature sperm are produced in spermatogenesis. In oogenesis In humans, the secondary oocyte must complete meiosis II before it can be fertilized. Ovarian cycle •Monthly series of events associated with the maturation of an egg •Two consecutive phases (in a 28-day cycle) –Follicular phase: period of follicle growth (days 1–14) –Ovulation occurs mid cycle –Luteal phase: period of corpus luteum activity (days 14–28) •Corpus Luteum secretes Progesterone and Estrogen Which of the following is MISMATCHED? follicular phase; maturation of a primordial follicle to form a secondary oocyte ovarian cycle; monthly series of events associated with maturation of an egg luteal phase; characterized by decreased progesterone levels ovulation; secondary oocyte is released Within the ovary, progesterone is produced by the __________. Corpus luteum Ovulation in a typical, or "average," cycle usually occurs on day __________. 14 What hormone is responsible for the secondary sex characteristics found in women? Estrogen Uterine Cycle Menstrual cycle Proliferative phase Ovulation Secretory phase •Cyclic changes in endometrium in response to ovarian hormones •Three phases 1.Days 1–5: menstrual phase –The growing ovarian follicle produces estrogen –Estrogen levels prompt generation of new functional layer i.e. the endometrium rebuilds itself –Preparation for implantation –Corpus luteum secretes progesterone and estrogen –Progesterone levels prompt •Proliferation of blood vessels 2.Days 6–14: proliferative (preovulatory) phase •Secretion of glycogen for developing embryo 3.Days 15–28: secretory (postovulatory) phase (constant 14-day length) •If no fertilization – cycle begins again •Menstrual phase –Ovarian hormones are at their lowest levels –Stratum functionalis is shed and the menstrual flow occurs In which uterine phase does the functional layer of the endometrium start to rebuild? Proliferative Sexually transmitted infections (STIs) •Bacterial Infections –Gonorrhea –Syphilis –Chlamydia •Viral –Genital Warts (HPV) –Genital Herpes Menopause •Has occurred when menses(blood) have ceased for an entire year ( bleeding stops for menstruation •Declining estrogen levels → –Atrophy of reproductive organs and breasts –Irritability and depression in some –Hot flashes as skin blood vessels undergo intense vasodilation –Gradual thinning of the skin and bone loss –Increased in blood cholesterol Interstitial cells (leydig)- makes testerone Seminiferous tubules- site of sperm fallopian tubes B. generally the site of fertilization of the ovulated oocyte fimbriae A. finger-like projections that brush over the ovary uterus E. receives, retains, and nourishes a fertilized ovum vagina C. thin walled structure that connects the uterus to the body exterior ovaries D. house and form the female gametes Pregnancy Egg-to-embryo-to-fetus •Pregnancy: Events that occur from fertilization until the infant is born •Conceptus: Developing offspring •Gestation period: Last menstrual period to birth •Preembryo: Fertilization to 2 weeks old •Embryo: 3rd through the 8th week •Fetus: 9th week through birth __________ refers to events that occur from the time of fertilization (conception) until the infant is born. Pregnancy Fertilization process •Definition: Sperm fuses with an egg & forms a zygote •Gamete Characteristics: •Oocyte: Viable for 12-24 hours •Sperm: Viable 24-72 hours •For fertilization to occur, coitus must occur no more than 3d before to 24 hrs after ovulation For successful fertilization to occur, coitus must occur no more than __________ and no later than __________. 2d, 24 hours Sperm- transport and capacitation •Fates (ejaculated sperm) –1) Leak out, destroyed by acid, fall short, fall prey to uterine phagocytes –2) Reach the uterine tubes! •Sperm must undergo capacitation within the female reproductive tract before they can penetrate the oocyte The process of implantation generally begins __________, and is usually completed by __________. six to seven days after ovulation; the twelfth day after ovulation Human chorionic gonadotropin (hCG) levels spike within the first two months of pregnancy and then sharply decline by four months. True By the end of the third month of pregnancy, the placenta is usually fully functional as a nutritive, respiratory, excretory, and endocrine organ. True Acrosomal reaction and sperm penetration •Ovulated oocyte is encapsulated by: •Corona radiata •Made of granulosa cells • Zona pellucida •Binding of sperm to Binding and fusion the zona pellucida •Sperm membrane triggers the acrosomal binds to oocyte reaction sperm-binding •Enzymes from the receptors acrosomes of many •Sperm and oocyte nearby sperm digest membranes fuse holes in the zona allowing sperm pellucida contents to enter •A path is cleared to the oocyte membrane Block of Polyspermy •Entry of sperm causes oocyte membrane depolarization and triggers the Cortical Reaction –Exocytosis of cortical granules Result: •Zona Pelucida hardens •Sperm receptors removed from membrane Block of Polyspermy •Only one sperm is allowed to penetrate oocyte - monospermy •2 mechanisms ensure monospermy –Fast block to polyspermy: Plasma membrane depolarization prevents other sperm from fusing with oocyte –Slow block to polyspermy: Cortical granules release enzymes destroying sperm receptors (sperm already bound to receptors detach) All EXCEPT which of the following prevent polyspermy? the release of Ca2+ after the sperm has entered the ova natural elimination of an embryo with too much genetic material the spilling of enzymes into the extracellular space beneath the zona pellucida a decrease in zonal inhibiting proteins Completion of meiosis II and fertilization •Upon entry of sperm: –The secondary oocyte completes meiosis II & –Casts out 2nd polar body •Fertilization: –Swollen pronuclei come together & fuse Cleavage: zygote to Blastocyst •1st cleavage →two daughter cells (blastomeres) •Morula: 16+ cell stage (72 hours) •Blastocyst: Fluid-filled hollow sphere (100+ cell stage) - composed of: –Trophoblast layer (aids placenta formation) –Inner cell mass (becomes the embryonic disc) After fertilization the zygote goes through a rapid period of cell divisions called __________. clevage •Begins 6-7 days after ovulation: When trophoblasts adhere to endometrium •Implanted blastocyst surrounded by endometrial cells •Process completed by 12th day after ovulation Implantation is usually completed after __________. Implantation of embryo Associated Hormone Production: •Corpus luteum: Maintained by human chorionic gonadotropin (hCG) so it can produce progesterone & estrogen •Placenta: Takes over from corpus luteum (helped by chorion [trophoblast derivitive]) between 2nd & 3rd month & assumes nutrient supply & waste removal duties Placenta •Formed from combination of Embryonic trophoblastic tissues & Maternal endometrial tissues •Placenta fully formed & functional by end of 3rd month (including hormone production) Which of the following is NOT a function of the placenta? waste elimination urine formation hormone production nutrient transfer respiratory gas transfer What is the function of the hormone hCG (human chorionic gonadotropin)? It signals the corpus luteum to continue producing estrogen and progesterone Embryonic development: embryonic membranes Amnion Yolk sac Allantois Cells form a transparent membrane filled with amniotic fluid Cells form a sac on ventral surface of embryo Small outpocketing at –Primitive tissues caudal end of yolk from which all body sac organs develop –Will form part of digestive tube –Structural base for umbilical cord (becomes part of urinary bladder) –Provides buoyant, protective environment for embryo –Helps maintain constant homeostatic temperature –Makes earliest RBCs & vessels (source of primordial germ cells) Primary germ layers –Ectoderm, Mesoderm & Endoderm –Amniotic fluid: From maternal blood (later, fetal urine) The outermost embryonic membrane is the __________. Chorion In humans, the extraembryonic membrane that comprises the structural base for the umbilical cord is the __________. allantois Events of embryonic development: gastrula to fetus •Germ Layers –During implantation, blastocyst begins conversion to gastrula •Inner cell mass develops into embryonic disc •Three primary germ layers form; extraembryonic membranes develop Gastrulation •Occurs in week 3 •Embryonic disc three-layered embryo with primary germ layers present –Ectoderm, mesoderm, and endoderm •Begins with appearance of primitive streak, raised dorsal groove; establishes longitudinal axis of embryo •Ectoderm, mesoderm, endoderm Organogenesis •Embryo begins as 昀氀at plate → •Cylindrical body resembling three stacked sheets of paper folding laterally into tube, and at both ends Specialization of endoderm •Primitive gut formed from endodermal folding –Forms epithelial lining of GI tract –Organs of GI tract become apparent, and oral and anal openings perforate •Mucosal lining of respiratory tract forms from pharyngeal endoderm (foregut) Specialization of ectoderm •Neurulation –First major event of organogenesis –Gives rise to brain and spinal cord –Induced by chemical signals from notochord –Ectoderm over notochord thickens, forming neural plate –Neural plate folds inward as neural groove with neural folds •By 22nd day, neural - primitive tissues from which all body organs derive •Epithelia cells –Ectoderm → nervous system; skin epidermis –Endoderm → epithelial linings of digestive, respiratory, urogenital systems; associated glands •Mesenchyme cells –Mesoderm → everything else The process that transforms the embryo into a three-layered stage is called __________. Gastrulation The process by which the three primary germ layers form is known as __________. Gastrulation the first major event of organogenesis is __________. Neurulation The first major event in organogenesis is gastrulation. False The ectoderm is the primary germ layer from which the digestive, respiratory, and urogenital systems and the associated glands form. False- endoderm folds fuse into neural tube –Anterior end → brain; rest → spinal cord •Neural crest cells migrate widely → cranial, spinal, and sympathetic ganglia and nerves; adrenal medulla; pigment cells of skin; contribute to some connective tissues •Brain waves recorded by end of second month the heart begins to beat in the developing offspring __________. at about 3 1/2 weeks Which of the following occurs eight weeks into pregnancy? The head of the fetus is nearly as large as the body. Which of the following occurs 17-20 weeks into pregnancy, during the fetal period? Quickening occurs. Effects of pregnancy Anatomical Changes •Breasts enlarge & areolae darken, uterus expands, Lordosis is likely, pelvic ligaments & pubic symphysis relax (Typical weight gain: ~29 lbs.) Metabolic Changes •Placenta secretes hormones to stimulate breast maturation, ↑maternal metabolism (↑ PTH ensures a positive calcium balance) Physiological Changes •GI tract: Morning sickness (↑ estrogen & progesterone) •Urinary tract: ↑ urine production (↑ work & pressure) •Respiratory: Sometimes Dyspnea (difficult breathing: late term) •Cardiovascular system: ↑ blood vol. (25-40%) –Maternal venous pressure: Impared in lower limbs --> varicose veins Which hormone produced by the placenta causes the mother's pubic symphysis to loosen and widen? Relaxin __________ and __________ are both hormones and powerful uterine muscle stimulants that cause contractions to become more frequent and more vigorous. Oxytocin; prostaglandins Which of the following is NOT a common metabolic/physiological change that occurs in pregnant women? Low blood pressure Homeostatic imbalance •Preeclampsia –Insu昀케cient placental blood supply → fetus starved of oxygen –Woman → edematous, hypertensive, proteinuria –Believed due to immunological abnormalities •Correlated with number of fetal cells that enter maternal circulation Hormonal induction of labor The hormone that induces labor and controls labor via a positive feedback mechanism is __________. Oxytocin Parturition: action of giving birth Which sequence shows the correct order of the stages of labor? dilation, expulsion, placental Stages of labor: expulsion stage •Vertex position – head-first –Skull dilates cervix; early suctioning allows breathing prior to complete delivery •Breech position – buttock-first –Delivery more difficult; often forceps required, or C-section (delivery through abdominal and uterine wall incision) Extrauterine life 1-5 minutes after birth: •Infant's physical status is assessed based on five signs (0-2): heart rate, respiration, color, muscle tone, reflexes •Apgar score: Total score of above scores (8-10 healthy) •First breath: Difficult! - lungs initially collapsed! Lactation (Breast Milk) •Milk from mammary glands (other hormones lead to Prolactin release --> milk production) •Colostrum: 1st 2-3 days, (vitamin A, protein, minerals, & IgA antibodies (later:true milk) Stimulation • After birth, milk production is stimulated by the sucking infant, crying (emotional stimulus) Advantages of breast milk •Fats & iron better absorbed & a.a.'s better metabolized than a.a.'s of cow's milk •Beneficial chemicals: IgA (& other immunoglobulins), complement, lysozyme, interferon •Natural laxatives help cleanse bowels of meconium The Apgar score range that indicates a healthy baby is __________. 8-10 Prolactin causes __________. milk production by the breast tissue Meconium is __________. sloughed epithelial cells, bile, and other substances