Bio2

• Progesterone levels


  Peak about halfway through the luteal phase
• Luteal phase


  • Hormonal changes are associated with common premenstrual symptoms, such as mood changes, headaches, acne, bloating, and breast tenderness

  
• If an egg is fertilized

  Progesterone from the corpus luteum supports the early pregnancy
• If no fertilization occurs

  The corpus luteum will start to break down between 9 and 11 days after ovulation, resulting in a drop in estrogen and progesterone levels, which causes menstruation

  
• Menopause


  • A woman who stops menstruating has reached a point wherein there are no more eggs to be released, which usually happens at the age of 45-55
  • Unable to bear a child already
• Fetal development


  The process by which a fertilized egg, or zygote, develops into a fetus within the womb during pregnancy
• Fetal development stages


  1. Week 1: Zygote divides rapidly as it travels down the fallopian tube towards the uterus

  2. Week 2: Zygote implants into the uterine lining, cells differentiate into the embryonic disc and trophoblast

  3. Weeks 3-4: Neural tube, heart, blood vessels, and limbs start to develop

  4. Weeks 5-8: Organs and body systems continue to develop rapidly, embryo becomes a fetus

  5. Weeks 9-12: Major organs and structures are formed, fetus resembles a human

  6. Weeks 13-16: Fetus grows rapidly, movements become more coordinated, genitalia start to differentiate

  7. Weeks 17-20: Lanugo and vernix caseosa develop, mother can feel fetal movements

  8. Weeks 21-24: Lungs continue to develop, fetus may have sleep and wakefulness periods

  9. Weeks 25-28: Brain continues to develop, senses become more refined, chance of survival if born prematurely

  10. Weeks 29-32: Fetus gains weight, bones become harder

  11. Weeks 33-38: Organs mature further, fetus continues to gain weight in preparation for birth

  
• Birth


  Culmination of fetal development, typically occurring around 40 weeks from the start of the last menstrual period, can range from 37 to 42 weeks
• It's crucial for a mother to abstain from alcohol and substance abuse while conceiving her child to ensures the healthy development of the fetus's brain and organs
• Reproduction types


  • ASEXUAL REPRODUCTION
  • SEXUAL REPRODUCTION
• Reproductive system


  Also known as "genital system", a system of sex organs within an organism which work together for the purpose of sexual reproduction
• FSH


  Follicle Stimulating Hormone
• LH


  Luteinizing Hormone
• Hormonal regulation of reproduction

  1. GnRH from Hypothalamus

  2. FSH and LH from Anterior Pituitary Gland
• Microscopy of sperm cells
• Sperm cell flow


  Testes – ST – RT – E (H) – E (B) – E (T) – VD / DD – SV via ED – PG via U – BG / CG via U - Urethra
• Ejaculation problems
• Bladder is closed off by a muscle during ejaculation
• Scrotum relaxes and testicles settle lower when it's hot, and rise up when it's cold
• Female reproductive system is much more complex compared to male
• Hymen


  A thin membrane that surrounds the opening to the vagina and can come in different shapes
• Clitoris


  Has no function in reproduction but is the main pleasure center for females during sex, with more nerve endings than anywhere else in the body
• Urethral Orifice / Opening


  Opening of urethra where urine exits
• Cervix


  Lower end of uterus that opens into vagina, made up of strong muscle that directs sperm into uterus during coitus
• Uterus


  Site where offspring grows, receives, retains and nourishes fertilized egg
• Fertilization and implantation


  Fertilized egg (zygote) travels down and attaches to inner wall of uterus (endometrium)
• Fallopian tube


  Also known as Uterine Tubes or Oviduct, 3.9 inches long, site of fertilization where mature egg is swept by finger-like cilia
• Ectopic pregnancy is a complication where the embryo attaches outside the uterus
• Fimbrae are finger-like projections at the distal end of the fallopian tube
• Menstrual cycle


  Follicular phase (egg develops), Ovulatory phase (egg released), Luteal phase (hormone levels decrease if egg doesn't implant)
• The average menstrual cycle takes about 28 days
• Sexual reproduction


  Involves fusion of two sex cells to form a zygote, requires two parents, offspring shows variations and are not the exact copy of the parents
• Asexual reproduction


  Does not require presence of two parents, single parent produces an offspring, commonly found in lower form of organisms
• Types of asexual reproduction

  • Fission
  • Budding
  • Fragmentation
  • Parthenogenesis

  
• Fission


  1. Binary fission

  2. Multiple fission

  
• Binary fission


  Parent cell divides into two

  
• Organisms that undergo binary fission

  • Amoeba
  • Bacteria
  • Paramecium
  • Euglena

  
• Multiple fission


  Organism divides itself into numerous daughter cells

  
• Organisms that undergo multiple fission

  • Protozoa
  • Algae (both sexual and asexual)

  
• Budding


  An outgrowth (bud) arises from the body, small part of parent's body grows into new organism