The Reproductive System

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The Reproductive System

• Chapter 19

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Introduction

• Reproduction process by which genetic material
  is passed from one generation to the next

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Introduction (contd.)

• Meiosis produces sex cells
• Sperm from male and egg from female join to form
  zygote
• Zygote develops into embryo
• Embryo develops into fetus

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The Male Reproductive System
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Introduction

• Testes produce sperm and male sex hormones
• Accessory glands produce secretions
• Accessory organs scrotum
• Penis transporting and supporting structure

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Introduction (contd.)
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The Scrotum

• Outpouching of abdominal wall
• Supports the testes
• Divided internally by a septum
• Scrotal sac elevates and descends

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The Testes

• Tunica albuginea capsule covering with lobules
• Convoluted seminiferous tubules
• Spermatogenesis

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The Testes (contd.)

• Spermatogenesis
• Spermatogonia gt primary spermatocytes gt secondary
  spermatocytes gt spermatids gt spermatozoa
• Sertoli cells supply sperm cells with nutrients

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The Testes (contd.)

• Interstitial cells of Leydig produce testosterone

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The Testes (contd.)
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The Anatomy of the Spermatozoa

• Three hundred million produced daily
• Anatomy
• Head contains genetic material and acrosome
• Acrosome has enzymes that aid sperm in
  penetrating covering of ovum
• Middle piece contains mitochondria
• Tail propels sperm

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The Anatomy of the Spermatozoa (contd.)

• Anatomy of a sperm cell

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The Functions of Testosterone

• Controls development, growth, and maintenance of
  male sex organs
• Stimulates muscle buildup and bone development
• Causes sperm maturation
• Causes thyroid cartilage enlargement
• Produces body hair patterns

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The Ducts of the System

• Seminiferous tubules transport sperm cells
• Rete testis network of ducts
• Ductus epididymis site of sperm cell maturation
• Epididymis located on posterior border of testis

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The Ducts of the System (contd.)

• Vas deferens straightened portion of epididymis
• Enclosed in spermatic duct
• Ejaculatory duct ejects spermatozoa into urethra

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The Ducts of the System (contd.)

• Urethra terminal duct
• Prostatic urethra, cavernous urethra, urethral
  orifice

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The Accessory Glands

• Seminal vesicles produce viscous part of semen
• Prostate gland produces fluid part of semen
• Bulbourethral glands produce mucus

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Semen

• Mixture of sperm cells and secretions
• Provides energy to the sperm via fructose
• Neutralizes acidity of vagina
• Acts as a transport medium
• Contains enzymes that activate sperm
• Average volume is 2.5 to 6 mL
• Seminalplasmin destroys certain bacteria

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The Penis

• Delivers spermatozoa to female reproductive tract
• Glans penis end of the shaft
• Prepuce loose skin covering glans penis
• Circumcision removal of prepuce

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The Penis (contd.)

• Contains masses of spongy tissue with sinuses
• Sinuses fill with blood resulting in erection
• Compress veins so blood is retained
• Help penis penetrate vagina
• During ejaculation, sphincter at base of urinary
  bladder is closed

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The Female Reproductive System
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Introduction

• Primary sex organs
• Ovaries
• Accessory organs
• Uterine tubes, uterus, vagina, external genitalia
• Accessory glands produce mucus

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Introduction (contd.)
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The Ovaries

• Held in position by ligaments
• Covered by germinal epithelium
• Tunica albuginea cortex contains ovarian
  follicles
• Ovarian follicles eggs in various developmental
  stages
• Primary follicle contains oocyte

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The Ovaries (contd.)
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The Ovaries (contd.)

• Oogenesis
• Begins in developing female fetus (700,000
  produced)
• Puberty ovarian cycle begins
• Primary oocyte first meiotic division
• Mature egg second meiotic division

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The Uterine or Fallopian Tubes

• Transport ova to the uterus
• Infundibulum funnel-shaped end with fimbriae
• Cilia sweep an ovum into uterine tube
• Egg moved by peristalsis toward uterus
• Fertilization occurs in upper third of tube

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The Uterus

• Site of menstruation, egg implantation and labor
• Pear shaped
• Uterine cavity interior of the body
• Cervical canal interior of the cervix
• Uterine wall endometrium, myometrium, perimetrium

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The Menstrual Cycle

• Menstrual phase
• Endometrial lining shed along with blood and
  mucus
• Ovarian follicles begin development
• Preovulatory or proliferative phase
• Secondary follicle matures into graafian follicle
• Ovulation is rupturing of graafian follicle

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The Menstrual Cycle (contd.)

• Postovulatory or secretory phase
• Corpus luteum develops
• Secretes estrogen and progesterone
• If fertilization and implantation do not occur
• Corpus luteum degenerates and new cycle starts
• If fertilization and implantation occur
• Corpus luteum maintained for four months

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Animation Ovulation
Click Here to Play Ovulation Animation
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The Functions of Estrogen

• Development of female secondary sex
  characteristics
• Breast development, pubic hair, fat deposits,
  widening of the pelvic bone
• Enlargement of
• Uterine tubes, uterus, vagina, external genitalia

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The Vagina

• Passageway for menstrual flow
• Receptacle for the penis
• Lower portion of birth canal
• Fornix surrounds vaginal attachment to cervix

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The External Genitalia of the Female

• Vulva external genitalia
• Labia majora and minora
• Clitoris erectile tissue
• Vestibule vaginal and urethral orifices
• Glands Skenes and Bartholins

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The External Genitalia of the Female (contd.)
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The Perineum
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The Perineum (contd.)

• Diamond-shaped region at inferior end of trunk
  between buttocks and thighs
• Divided into
• Anterior urogenital triangle containing external
  genitalia
• Posterior anal triangle containing anus

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The Anatomy and Function of the Mammary Glands
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The Anatomy and Function of the Mammary Glands
(contd.)

• Produce milk in females
• Contain 15 to 20 lobes with lobules
• Lobules contain milk-secreting cells
• Milk is conveyed through series of tubules
• Areola circular pigmented area around nipple

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The Anatomy and Function of the Mammary Glands
(contd.)
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Pregnancy and Embryonic Development
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Pregnancy and Embryonic Development (contd.)

• Egg fertilization 12-24 hours after ovulation
• Zygote fertilized egg
• Moves down uterine tube into uterus
• Blastula
• Zygote embeds in endometrium, placenta develops

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Pregnancy and Embryonic Development (contd.)

• Primary germ layers
• Ectoderm skin and nervous system
• Mesoderm muscles and bones
• Endoderm linings of organs and glands
• Amnion fluid-filled sac
• Attached to embryo by umbilical cord
• Parturition childbirth

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Summary

• Discussed the organs of the male reproductive
  system
• Discussed the role of testosterone
• Described the process of spermatogenesis
• Discussed the organs of the female reproductive
  system

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Summary (contd.)

• Discussed the role of estrogen
• Described the process of oogenesis
• Described the phases of the menstrual cycle
• Discussed pregnancy and embryonic development