Presentation on theme: "Ch. 28. Male Reproductive System Objectives Describe location, structure, and function of the organs of the male reproductive system. Discuss the process."— Presentation transcript:
Male Reproductive System Objectives Describe location, structure, and function of the organs of the male reproductive system. Discuss the process of spermatogenesis in the testes.
Organs of the Male Testes – produce sperm and secrete hormones System of ducts (epididymis, ductus deferens, ejaculatory ducts, and urethra) – transports and stores sperm, assists in maturation Accessory sex glands (seminal vesicles, prostate, and bulbourethral glands) – adds fluid to semen Supporting structures – scrotum and penis – delivery and support
WORD BANK Vas deferens Scrotum Urethra Prostate Epididymus Bladder Teste Seminal Vesicle
Organs Scrotum (bag) – supporting structure for testes Loose skin Internally scrotum is divided into two sacs – one for each testis Location of testes is vital to sperm survival 2-3 degrees below normal body temperature In cold – muscles pull the scrotum closer to the body to keep sperm warm In warm – opposite occurs
Organs Testes or testicles Descend during 7 th month of pregnancy Where sperm are made during spermatogenesis Epididymis Comma-shaped organ along the border of each testis Site of sperm maturation – sperm acquire motility and ability to fertilize (14 days) Stores sperm for up to several months
Organs Ductus deferens or vas deferens Along border of epididymis and up around bladder Pushes sperm during arousal toward the urethra Also stores sperm for several months Ejaculatory ducts Eject sperm and seminal vesicle secretions before release of semen Urethra Passageway for urine and semen
Organs Seminal vesicles Pouch like structures at base of bladder Secrete alkaline fluid with fructose, clotting proteins, prostaglandins Alkaline fluid neutralizes female acidity in vagina Fructose is for ATP production in sperm for their swim Clotting proteins help semen coagulate after ejaculation Prostate Doughnut shaped, golf ball sized organ Secrete antibiotic for bacteria in urethra or vagina
Organs Bulbourethral glands or Cowper’s glands Secrete alkaline fluid into urethra that protects sperm from urine Secretes mucus for lubrication of external penis and urethra
Semen Mixture of sperm and seminal fluid Seminal fluid from seminal vesicles, prostate, bulbourethral glands Contains mL of fluid with million sperm/mL 20 million/mL or lower is considered infertile Slightly basic ( ); milky appearance, sticky consistency Seminal fluid provides sperm with nutrients, transportation, protection
Penis Contains urethra and passageway for ejaculation of semen and urine Glans penis – head of penis Erection – result of increased blood supply to penile tissue
Circumcision – removal of foreskin Cleaner and decreases risk of infection or disease Vasectomy Sterilization of males Portion of ductus deferens is removed Ducts are cut and tied with stitches Sperm production continues, but sperm cannot reach exterior of penis
Spermatogenesis Takes days Begins with spermatogonia (stem cells) Undergo meiosis – 4 spermatids Spermiogenesis When spermatids become spermatozoa
Review Describe the function/structure of the following: Testes Epididymis Ductus deferens Ejaculatory ducts Urethra Seminal vesicles Prostate Bulbourethral glands Scrotum Penis What is spermatogenesis?
Female Reproductive System Objectives Describe the location, structure, and functions of the organs of the female reproductive system. Discuss the process oogenesis in the ovaries.
Organs of the Female Ovaries – produce eggs and hormones Uterine (fallopian) tubes or oviducts – transport egg to uterus, site of fertilization Uterus – site of implantation of fertilized egg, development of fetus, labor Vagina – receives penis, passageway for childbirth External organs (vulva) Mammary glands – synthesize, secrete, and eject milk for newborn
Cervix Fallopian Tubes Vagina Ovary Uterus WORD BANK
Organs Ovaries Paired glands, almond sized Produce Gametes (egg cells) Hormones (progesterone and estrogen, inhibin, relaxin) Uterine tubes (fallopian) or oviduct Extend away from uterus Provide route for sperm to reach ovum Transports eggs and fertilized eggs to the uterus from the ovary Have cilia at the ends to “coax” egg from ovary Fertilization occurs here Up to 24 hours after ovulation – sperm can survive for 3 days Egg enters uterus 6-7 days after ovulation
Organs Uterus (womb) pear-shaped Pathway for sperm deposition into vagina to reach fallopian tubes Site of implantation for fertilized egg Growth of fetus during pregnancy Labor Source of menstrual flow
Organs Uterus Fundus Body Cervix
Organs Cervical mucus Water, glycoproteins, lipids, enzymes, salts More hospitable to sperm during ovulation Helps protect sperm on passage to uterus Vagina Fibromuscular canal Receptacle for penis Outlet for menstrual flow Passageway for childbirth
Organs Vulva - External genitals of female Mons pubis – adipose tissue, skin, hair Labia majora – two folds, covered by pubic hair Labia minora – two folds, underneath labia majora, no hair Clitoris, glans – erectile tissue and nerves, sexual excitement in females
Organs Mammary glands Breast Nipple – where milk emerges Areola – darkened area around nipple Mammary gland – modified sweat glands
Disease/Medical Ovarian cysts Fluid-filled sac in or on ovary Usually noncancerous, can go away on their own Uterine prolapse When uterus is outside the vagina Occurs with age, disease, traumatic vaginal delivery, difficult bowel movements, coughing Can be put back with surgery
Disease/Medical Hysterectomy Removal of uterus Episiotomy Fetus stretches perenial region Performed to prevent tearing Straight, tearing is jagged
Review What is the function/structure of: Uterus Ovaries Fallopian tubes Vagina Mammary glands Describe oogenesis.
Objectives Describe the hormones that are important to the reproductive cycle. Summarize female reproductive cycle. Describe various methods of birth control.
Female Reproductive Cycle Ovarian Cycle – events in the ovaries that occur during and after the maturation of an oocyte Menstrual Cycle – changes in the endometrium (lining) of the uterus to prepare for the arrival of a fertilized ovum that will develop until birth Female reproductive cycle includes both of these
Hormones of Cycles Gonadotropin-releasing hormone (GnRH) Secreted by hypothalamus Stimulates release of FSH and LH Stimulate release of egg from ovaries Estrogens Secreted by ovaries Promote development of sex characteristics Progesterone Secreted by ovaries Prepare and maintain endometrium for implantation Prepare mammary glands for milk secretion
Hormones of Cycles Relaxin Relaxes the uterus by inhibiting contractions Increases flexibility of pubic symphysis Helps dilate cervix Inhibin Secreted after ovulation Inhibits secretion of FSH and LH
Summary Cycle is counted from 1 st day of last period Menstruation lasts 4-5 days Proliferative phase (13 days) Endometrium fills will tissue and blood Ovulation occurs around day 14 Secretory phase (10 days) If egg is fertilized, tissue stays to care for fetus If egg is not, menstrual phase begins again
Birth Control Oral contraceptives (the pill) – inhibits FSH and LH from being released, ovulation doesn’t occur, no egg for fertilization – close to 100% effective “morning-after-pill” – causes shedding of lining (induces period) to prevent implantation IUD – prevent implantation in uterus by changing lining Spermicides – kill sperm, more effective with use of condom or diaphragm
Birth Control Barrier methods – prevent sperm from getting into uterus (condoms, diaphragm); also helps protect against STD’s Periodic Abstinence – couple learns “cycle” and abstains during that time
Review Describe various methods of birth control. Describe the hormones that are important to the reproductive cycle. Summarize the reproductive cycle.