Transcript Chapter 19
Chapter 19 The Reproductive System Introduction Male reproductive system Anatomy: testes, scrotum, spermatozoa, semen, penis Physiology: ducts of the system; testosterone Female reproductive system Anatomy: ovaries, fallopian tubes, uterus, vagina, external genitalia, mammary glands Physiology: menstrual cycle, estrogen Pregnancy, embryonic development Male Reproductive System Primary sex organs: testes (male gonads, aka testicles) Produce sperm as exocrine glands; hormones as endocrine glands Accessory structures Testes Paired oval glands approx 2” in length, 1” in diameter Each testis is divided into lobules, containing tightly coiled seminiferous tubules, which produce sperm by spermatogenesis Contained within scrotum Scrotum Outpouching of the abdominal wall Loose skin and superficial fascia Supporting structure of the testes Internally separated by a septum into two lateral portions Cremaster muscle located in spermatic cord contracts scrotal sac, and elevates testes Maintains temperature about 3° below body temp, for ideal sperm and hormone production Spermatozoa Mature sperm cells are produced at a rate of 300 million/day Life expectancy once ejaculated is ~ 48 hrs 3 parts Head, contains genetic material, acrosome Midpiece, contains mitochondria Tail, flagellum, locomotion Testosterone Controls development, growth, and maintenance of male sex organs Causes descent of testes from abdomen During puberty, stimulates bone growth Stimulates protein build up in muscles Stimulates maturation of sperm cells Causes enlargement of thyroid cartilage (Adam’s apple), deepening of voice Aggression, hair patterns and recession Ducts of the System Sperm cells are moves from the convoluted seminiferous tubules into straight tubules, then eventually empty into the ductus epididymis Epididymis: comma-shaped structure on posterior of testis, where sperm cells mature Sperm continues to move from epididymis into vas (ductus) deferens, then upward through spermatic cord into the abdomen Pathway of sperm Sperms travels through the vas deferens, where it joins with ducts from the prostate, and the urethra, becoming the ejaculatory duct Secretions from the bulbourethral glands join the fluid as it becomes seminal fluid (semen), which is expelled through the urethra during ejaculation. Semen A mixture of sperm cells, and secretion from the prostate, bulbourethral glands, and seminal vesicles. Milky in color, and sticky – fructose that provides energy for sperm Alkaline, pH of 7.2 – 7.6 Average volume 2.5 – 6 mL / ejaculation Penis Shaft Glans penis – distal head Prepuse – foreskin, removed during circumcision Internally, spongy sinuses engorge with blood during erection Female Reproductive System Primary sex organs – ovaries (female gonads), paired Produce ova (ovum), eggs as exocrine glands Produce estrogen and progesterone as endocrine glands Accessory structures: fallopian tubes, uterus, vagina, external genitalia Ovaries Located in upper pelvic cavity Size of unshelled almonds Held in position by suspensory ligaments Ovum Each ovary contains ovarian follicles in various stages of development Oocyte is an immature follicle Mature egg is called a graafian follicle After egg ruptures from follicle, it changes into the corpus luteum (“yellow body”) which produces estrogen and progesterone Fallopian Tubes Paired tubes, transporting ova from each ovary to the uterus Infundibulum is a funnel-shaped open end; lies close to, but not attached to, ovary Fimbriae surround infundibulum and ovary Uterus In pelvic cavity Between rectum and bladder Where fertilized egg implants Narrow opening is cervix Fundus at top Endometrium Cervix Opens into vagina Isthmus small constricted region Interior is cervical canal Internal os opens into uterine cavity External os opens into vagina Vagina Passageway for menstrual flow Organ of copulation (coitus) Birth canal Perineum – diamond shaped area between buttocks and thighs (M&F). Anterior urogenital triangle, and posterior urogenital triangle External genitalia Vulva (pudendum) Mons pubis Labia majora Labia minora Clitoris Vestibule Hymen Skene’s glands Bartholnin’s glands Mammary Glands Present in both males and females Modified sweat glands In females, alveoli cells produce milk, called lactation Estrogen causes glands to increase in size during puberty 15 – 20 lobes separated by adipose tissue Pregnancy Ovum ruptures from ovary; must be fertilized within 24 hours Ejaculated sperm viable up to 48 hours in female reproductive tract Intercourse must occur 72 hrs before, to 24 hrs after, ovulation Zygote is fertilized egg Embryonic development Zygote travels down uterine tube, becoming a blastocyst (blastula) It implants into uterine wall, consists of 100 cells, called chorionic vesicle Human Chorionic Gonadotropin Uterine tissues form placenta Embryo becomes surrounded by amniotic sac (amnion) Embryonic development II Embryo is attached by umbilical cord By 9th week, embryo looks human Uterus changes to accommodate fetus Childbirth is called parturition Fetus is expelled through process of labor Gestation (pregnancy) Trimesters Due date Estimated date of confinement Quickening – first movement Viable – when fetus is capable of living outside the mother The Mother Nulligravida – never pregnant Nullipara – never born a viable child Primigravida – during first pregnancy Primipara – born one viable child Multiparous – given birth two or more times Childbirth Parturition – labor and delivery Antepartum Dilation Effacement – thinning and shortening of cervix Amniotic sac Bag of waters Presentation Crowning Placenta Postpartum Pathology of Pregnancy and Childbirth Ectopic Pregnancy – fertilized egg is implanted and develops outside of uterus Spontaneous abortion Miscarriage Induced abortion Preeclampsia – pregnancy induced hypertenstion Eclampsia - more serious, convulsions or coma Pathology of Childbirth Abruptio placentae – placenta separates from uterine wall prematurely Placenta previa – placenta implants lower portion of the uterus Premature infant Stillbirth Diagnostic Procedures Amniocentesis Fetal ultrasound Electronic fetal monitor – monitors fetal heart rate and uterine contractions Pelvimetry – radiographic study of pelvis dimensions Pregnancy test – tests human chorionic gonadotropin hormone levels Treatment & Procedures Apgar score – evaluation of a newborns physical status Episiotomy-surgical incision through the perineum Prevent Lacerations