Reproductive System

• Reproduction


  Ensures perpetuity of life
• Types of reproduction


  • Asexual
  • Sexual
• Asexual reproduction


  • Results in new organisms formed by mitotic cell division producing offspring that are genetically similar to their parents
• Sexual reproduction


  • Involves the fusion of gametes or sex cells from 2 parents which are produced through meiosis, resulting to genetically unique offspring
• In Vitro Fertilization


  Forming offsprings in a lab, considered as Sexual reproduction because of the involvement of gametes
• Types of asexual reproduction

  • Binary fission
  • Budding
  • Spore formation
  • Fragmentation
  • Vegetative reproduction
  • Parthenogenesis
• Binary fission


  Divisions of cells common in bacteria; multiple fissions are type of binary fissions that produce 3 or more daughter cells
• Budding


  e.g. Hydra
• Vegetative reproduction


  e.g. plants through roots, stem cuttings, leaves
• Parthenogenesis


  Virgin birth, only female is involved in the reproduction
• Types of sexual reproduction

  • External fertilization
  • Internal fertilization
• External fertilization


  Occurs in aquatic animals where gametes are released from both male and females animals, and the fusion takes place outside the body
• Internal fertilization


  Among terrestrial animals, a strategy used to prevent dehydration of gametes on lands, enhances the fertilization of eggs by a specific male, survival rate is higher
• Functions of the male reproductive system

  • Production of sperm cells
  • Sustaining and transfer of sperm cells
  • Production of male sex hormones
• Testes


  Primary sex organ, production of sex hormones - testosterone, spermatogenesis
• Male reproductive structures


  • Series of ducts
  • Epididymides
  • Ductus deferens
  • Urethra
  • Accessory glands
• Epididymides


  Where sperm will travel first, site for cell maturation, sperms will learn how to swim ability to bind to secondary oocyte
• Ductus deferens


  45 cm long; main sperm duct
• Divisions of urethra


  • Prostatic
  • Membranous
  • Spongy
• Seminal vesicles


  Sac shaped, produces viscous alkaline part of the semen
• Scrotum


  • Sac-like containing the testes
  • Composed of skin, connective tissue, dartos muscle, cremaster muscle
  • Testes were once inside the body as a fetus
  • Descends before being born, suspended by the scrotal sac
  • Facilitates spermatogenesis by keeping testes 2 degrees lower than normal body temp
• Dartos muscle


  Contracts when temp is low, relaxes when temp is high
• Cremaster muscle


  Pulls the testes up when temp is cold, relaxes when temp is high
• Penis


  • 3 columns of erectile tissue: 2 corpora carvenosa, corpus spongium
  • Glans penis - most sensitive part due to abundance of sensory receptors
• Prepuce/Foreskin


  Covers the glans penis in uncircumcised individuals
• External Urethral Orifice


  Opening where sperm and urine is expelled
• Ejaculatory duct


  • 1 inch, prostate gland that converge from seminal vesicle and ampulla of dd; ejects spermatozoa into urethra
• Testes/male gonads


  • Oval organs, each about 4-5 cm long
  • Seminiferous tubules - site of spermatogenesis
  • Interstitial cells/Leydig cells - produce testosterone
• Lobules


  Tiny compartments inside the testes, separated by septa, contain highly coiled seminiferous tubules
• Spermatogenesis


  Spermatogonia (near tubule walls) undergo meiosis to become spermatocytes, then spermatids, then sperm cells
• Mature sperm cell


  • Acrosome, nucleus with 23 chromosomes, centriole, mitochondria, tail
• Seminal fluid components


  • 60% from seminal vesicles
  • 30% from prostate gland
  • 5% from bulbourethral gland
  • 5% from urethra
• Seminal fluid


  Thick, mucus-like fluid with fructose, proteins, enzymes, prostaglandins
• Semen


  • Mixture of sperm and seminal fluid
  • Normal volume is 2-5 ml
  • Contains 100 million sperm/ml
• Series of Reflexes in the Male Sexual Act


  1. Erection

  2. Secretion

  3. Emission

  4. Ejaculation

  5. Orgasm

  6. Resolution
• Functions of the Female Reproductive System


  • Production of the oocyte (ovaries)
  • Reception of sperm cells from the male (vagina)
  • Nurturing the development of (uterus) and providing nourishment for the new individual (mammary glands)
  • Producing of female sex hormones (ovaries)
• Oogenesis


  Production of estrogen and progesterone
• Mammary glands (in breasts)

  • Where milk is secreted and produced
  • Areola (colored area)
  • Each breast has a nipple
  • Each with 15-20 glandular lobes possessing a single lactiferous duct
  • Lobules
  • Alveoli
  • Myoepithelial cells – surrounds the alveoli and contract to expel milk
  • Suspensory ligaments – supports
• Ovary


  • 1 pair
  • Primary female organ
  • Site for oogenesis
  • Begins in a 4 mo. fetus
  • Contains 5 million oogania (where oocytes developes)
  • 2m at birth
  • 300 – 400 k from birth to puberty
  • 400 – will complete its development and be released
  • 12 – every year are released
  • Women start menopausing in their 50's
  • Outer part – ovarian follicle each containing oocyte
  • Inner part – loose connective tissues, blood vessels, lymphatic vessels, and nerves
  • Secretion of estrogen and progesterone
• Fallopian Tube/Uterine Tube/Oviduct


  • Site for fertilization
  • Site for meeting of the sperm cell and egg cell
  • Ampulla – where fertilization occurs (zygote – fertilized egg)
  • Fimbriae (fimbria – singular) – long, thin processes at its opening; w/ cilia that sweeps oocyte from ovary to UT