1 Adaptations for Sexual ReproductionHuman Reproduction Adaptations for Sexual Reproduction
2 Section Outline The Reproductive System Sexual DevelopmentRole of Hormones 1. Pituitary Hormones: FSH + LH 2. Testes: Testosterone 3. Ovaries: Estrogen + Progesterone C. The Male Reproductive System 1. Sperm Development 2. Sperm Release D. The Female Reproductive System 1. Egg Development 2. Egg Release E. The Menstrual Cycle 1. Follicular Phase 2. Ovulation 3. Luteal Phase Menstruation
3 Hormones and Human ReproductionHormones are powerful “chemical messengers” produced by Endocrine Glands. Hormones regulate most life activities (directly or indirectly); including the onset of sexual maturity (Puberty) The development of gametes and secondary sex characteristics are controlled by the INTERACTION of hormones produced by the Hypothalamus and Pituitary glands (brain) and hormones produced by the male and female gonads.
4 The Brain-Gonad “Connection”Hypothalamus The hypothalamus makes hormones that control the pituitary gland. In addition, it makes hormones that are stored in the pituitary gland. Pituitary gland The pituitary gland produces hormones that regulate many of the other endocrine glands. Ovary The ovaries produce estrogen and progesterone. Estrogen is required for the development of secondary sex characteristics and for the development of eggs. Progesterone prepares the uterus for a fertilized egg. ovary Testis The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics testes
5 Hormones controlling Male ReproTwo hormones produced by the Pituitary Gland (located in brain) are: FSH (follicle stimulating hormone) – “targets” testes to develop mature sperm LH (luteinizing hormone) – acts on the testes to produce testosterone Testosterone, is produced in the testes and is the primary sex hormone in males.
6 Action of TestosteroneA sudden increase in Testosterone Initiates male puberty Acts to develop secondary male sex characteristics Development of Male Sex Organs Greater Bone and Skeletal Muscle Mass/density Growth of Beard and Body Hair Lowering of Voice
11 Cross-section of OvaryFollicles at various stages of Development (photo) Follicles produce eggs, Estrogen and Progesterone ONLY one Follicle/ month will Produce the egg That’s ovulated follicle Egg
13 Human Menstrual Cycle
14 Menstrual cycle Controlled by interaction of 4 hormones FSH & LHestrogen progesterone FSH ovulation = egg release egg development corpus luteum estrogen progesterone lining of uterus days 7 14 21 28
16 Menstrual Cycle Summary ChartFollicle Stage ↑FSH Follicle develops Follicle produces Estrogen Egg Matures Estrogen Thickens Uterus lining Lasts days Low Estrogen + progesterone allows FSH to be released again from pituitary Day 14 4. Menstruation Sudden decrease in estrogen and progesterone Shedding of Uterine Lining 2. Ovulation ↑ LH released Mature egg released Ovulation Lasts days 3. Corpus Luteum Stage Ruptured follicle becomes the Corpus Luteum (yellow Body) Corpus luteum produces Progesterone Uterus lining becomes thicker, prepares For possible fertilization Corpus luteum Degenerates Causing Progesterone + estrogen to Drop
17 Fertilization Occurs In the Fallopian TubesDay 4 4 cells 2 cells Zygote Morula Day 7 Fertilization Blastocyst Day 0 Implantation of blastocyst Uterine wall Egg released “ovulation” ovary
19 The Three Germ Layers Differentiation of CellsEndoderm: Lining of Digestive And Respiratory tracts, Liver and Pancreas Mesoderm: Muscles and Skeleton, Circulatory and Reproductive systems Ectoderm: Nervous System Epidermis of skin
20 Multiple Births Fertilization is the fusion of a sperm and an egg to form a zygote, the single cell from which all cells of the human body are derived. When an egg is fertilized, the remarkable process of human development begins. 1. If two eggs are released during ovulation, each can be fertilized by a sperm. What do you think would be the result? Explain your answer. 2. If one zygote splits into two, each can continue development on its own. What do you think would be the result? Explain your answer. 3. Triplets are three babies born at the same time. Describe three ways that triplets could develop.
24 Human fetal development10 weeks