Lesson #2: Menstruation and fertilization Objectives: Draw, label and explain the menstrual cycle. Explain how and when human fertilization occurs

Menstruation: Phase 1 (day 1-4) Lining breaks down: Body realizes that there is no baby and progesterone decreases, causing the uterine lining to disintegrate (menstruation) Phase 2 (day 5-13) Lining builds up: Estrogen causes the lining of uterus to build up. Phase 3 (day 14) Ovulation: Egg is released from the ovaries and begins to travel down the fallopian tubes. Phase 4 (day 15- 28) Lining is maintained: Progesterone keeps the uterus lining healthy and intact, waiting to see if the egg is fertilized.

What is semen? 1) Provides a watery environment in which the sperm cells can swim while outside the body. 2) Provides nutrients for the sperm cells (fructose, amino acids and vitamin C) 3)Protects the sperm cells by neutralizing acids in the female's sexual tract -

Any questions?