week 11 (2)

• Reproductive system


  A collection of organs and a network of hormone production that work together to create life
• Male reproductive system

  • Testes (produce sperm)
  • Penis
  • Epididymis
  • Vas deferens
  • Ejaculatory ducts
  • Urethra
• Female reproductive system

  • Ovaries (produce eggs)
  • Fallopian tubes
  • Uterus
  • Cervix
  • Vagina
  • Vulva
• Both the male and female reproductive systems must be functioning properly for a couple to conceive naturally
• A problem with the structure or function of either reproductive system can cause infertility
• Reproductive system function


  Enables a man to impregnate a woman who gives birth to a child
• During conception, a sperm cell from the man fuses with an egg cell in the woman, creating a fertilized egg (embryo) that implants and grows in the uterus during pregnancy
• Abnormalities or damage to reproductive organs and malfunction of the hormone production and delivery system that governs reproduction are common causes of infertility in men and women
• Hypothalamus


  Brain center that produces gonadotropin-releasing hormone (GnRH) to regulate the production and release of FSH and LH in the pituitary gland
• Pituitary gland


  Brain center that releases FSH and LH, the two gonadotropic hormones involved in both male and female reproduction
• Menstrual cycle regulation

  1. FSH from pituitary stimulates ovarian follicles

  2. Follicles produce estrogen

  3. Estrogen signals LH surge from pituitary

  4. LH triggers ovulation

  5. Corpus luteum produces progesterone
• Estrogen


  Hormone that regulates the menstrual cycle
• Progesterone


  Hormone that supports pregnancy
• FSH


  Stimulates testes to produce sperm
• LH


  Signals testes to produce testosterone, which enhances sperm maturation
• Testosterone


  Primary male sex hormone
• Functions of female reproductive system

  • Produce eggs
  • Incubate and nourish a fertilized egg
  • Produce female sex hormones
• Female reproductive organs

  • Ovaries
  • Fallopian tubes
  • Uterus
  • Cervix
  • Vagina
  • Vulva
• Parts of vulva/external genitals

  • Labia majora
  • Labia minora
  • Clitoris
  • Vaginal opening
  • Hymen
  • Opening to urethra
• Male reproductive system functions


  Produces, maintains and transports sperm and protective fluid (semen)<|>Discharges sperm within the female reproductive tract during sex<|>Produces and secretes male sex hormones
• Male reproductive organs

  • Penis
  • Scrotum
  • Testicles
  • Epididymis
  • Ductus (vas) deferens
  • Ejaculatory ducts
  • Urethra
  • Seminal vesicle
  • Prostate gland
  • Bulbourethral (Cowper's) glands
• Testosterone


  Main sex hormone in people assigned male at birth, helps develop certain characteristics
• Testosterone


  Increases touch sensitivity in the penis, primes brain areas to release dopamine during sexual arousal
• Seminal vesicle


  Produces fructose that provides energy to the sperm as they seek an egg
• Prostate gland


  Produces a fluid that helps the sperm move more quickly through the female reproductive system
• Bulbourethral/Cowper's glands


  Make a fluid for protecting the sperm on its way through the urethra
• Testosterone


  Essential for male sexual arousal, acts partly by increasing touch sensitivity in the penis
• Testosterone's effects


  1. Binds to receptors that increase responses in parts of the hypothalamus

  2. Primes the MPOA and several other brain areas to release dopamine

  3. MPOA neurons release dopamine strongly during sexual arousal, and the more dopamine they release, the more likely the male is to copulate
• Castrated male rats


  Produce normal amounts of dopamine in the MPOA, but they do not release it in the presence of a receptive female, and they do not attempt to copulate
• Levels of testosterone


  Correlate positively with men's sexual arousal and their drive to seek sexual partners
• Married/committed men


  Have lower testosterone levels than single, unpaired men of the same age
• Decreases in testosterone levels

  Generally decrease male sexual activity
• Low testosterone is not the usual basis for impotence, the inability to have an erection. The most common cause is impaired blood circulation, especially in older men
• Sildenafil (Viagra)


  Increases male sexual ability by prolonging the effects of nitric oxide, which increases blood flow to the penis
• Menstrual cycle

  1. Anterior pituitary releases FSH, which promotes the growth of a follicle in the ovary

  2. Follicle produces estrogens

  3. Increased estradiol causes an increased release of FSH and a sudden surge in the release of LH

  4. LH and FSH cause the follicle to release an ovum

  5. Corpus luteum releases progesterone, which prepares the uterus for implantation

  6. If not pregnant, estradiol and progesterone decline and the lining of the uterus is cast off (menstruation)
• High estradiol and progesterone levels during pregnancy

  Cause fluctuating activity at the serotonin 3 (5HT3) receptor, which is responsible for nausea
• Birth control pill


  Prevents the surge of FSH and LH that would otherwise release an ovum, thickens the mucus of the cervix, and prevents an ovum from implanting in the uterus
• Estradiol and progesterone


  Most effective combination for enhancing sexual behavior in female rats
• Estradiol


  Increases the sensitivity of the pudendal nerve, which transmits tactile stimulation from the vagina and cervix to the brain
• Most women report a decrease in sexual desire after menopause or surgical removal of the ovaries, which decreases estradiol levels