Overview
This lecture introduces the human reproductive system, highlighting key structures, sex hormones, and the process of reproduction, including pregnancy and birth.
Functions of the Reproductive System
- The reproductive system enables humans to produce offspring by combining genetic material from egg and sperm.
- It involves sex organs and certain brain areas that control reproductive processes.
Major Male Reproductive Organs
- Testes produce sperm, the male genetic contribution to a baby.
- The penis delivers sperm into the female reproductive tract.
Major Female Reproductive Organs
- Ovaries produce eggs, the female genetic contribution; each ovary typically releases one egg per month.
- The uterus is a thick muscular organ where the baby develops during pregnancy.
- Breasts produce milk after childbirth through lactation, which nourishes and supports the infant's immune system.
Reproductive Hormones
- Hormones from the reproductive system have broad effects on the body and secondary sexual traits.
- Testosterone (from testes) promotes male traits such as body hair, deep voice, muscle development, and may affect aggression.
- Estrogen and progesterone (from ovaries) regulate female traits and egg release, including breast development.
Brain Control of Reproductive System
- The hypothalamus in the brain releases GnRH (gonadotropin-releasing hormone).
- GnRH stimulates the anterior pituitary to release LH (luteinizing hormone) and FSH (follicle stimulating hormone), which control the testes and ovaries.
Fertilization, Pregnancy, and Birth
- Fertilization occurs when sperm meets and fuses with an egg, forming a zygote.
- The zygote implants in the uterus and develops during gestation (about nine months).
- Birth (labor or parturition) is triggered by hormonal changes signaling the mother's body to deliver the baby.
Key Terms & Definitions
- Testes — male organs producing sperm and testosterone
- Ovary — female organ producing eggs, estrogen, and progesterone
- Sperm — male reproductive cell carrying genetic information
- Egg — female reproductive cell carrying genetic information
- Uterus — muscular female organ where pregnancy develops
- Lactation — production of breast milk
- Hormone — chemical messenger affecting body processes
- Testosterone — main male sex hormone
- Estrogen — main female sex hormone
- Progesterone — female hormone involved in menstrual cycle and pregnancy
- Hypothalamus — brain region controlling endocrine functions
- GnRH — hormone from hypothalamus that triggers LH and FSH release
- LH/FSH — hormones regulating sex organ function
- Zygote — first cell formed by fertilization
- Gestation — development of fetus from conception to birth
- Parturition — process of giving birth
Action Items / Next Steps
- Review and memorize structures and functions of male and female reproductive organs.
- Understand the hormonal control of reproduction.
- Prepare for a quiz on key terms and definitions.