Lecture on the Reproductive System: Sexual Intercourse

Overview

• Discussion on sexual intercourse, its mechanisms, and differences between males and females.
• Introduction of semen into the female reproductive tract.

Male Reproductive Mechanism

Neural Reflexes

• Coordinated complex neural reflex using:
  • Sympathetic nervous system
  • Parasympathetic nervous system

Process of Sexual Arousal

• Occurs under parasympathetic control.
• Engorgement of penis with blood leads to erection.

Emission and Ejaculation

• Emission:

  • Switch from parasympathetic to sympathetic stimulation.
  • Sympathetic stimulation leads to peristaltic contractions pushing sperm and fluids into the prostatic urethra.
  • Contracted urinary bladder prevents semen backflow into the bladder.

• Ejaculation:

  • Rhythmic contractions of muscles push semen towards external urethral opening.
  • Results in orgasm and subsequent reduction of erectile tissue.

Male Sexual Dysfunction

• Known as impotency.
• May involve physical and psychological factors.

Female Reproductive Mechanism

Sexual Arousal

• Parasympathetic activation leads to engorgement and increased secretion in cervical mucus.
• Blood vessels in vaginal wall dilate aiding lubrication.

Female Orgasm

• Not necessary for reproduction but occurs with peristaltic contractions.
• Thought to aid in sperm movement.

Sexually Transmitted Diseases (STDs)

• Includes bacterial, viral, and fungal infections: PID, AIDS, gonorrhea, syphilis, herpes, genital warts.
• Statistics and trends observed in populations.

Aging and the Reproductive System

Female Changes

• Menopause occurs between ages 45-55.
• Decline in estrogen levels, cessation of ovarian and uterine cycles.
• Reduction in breast size, bone density leading to osteoporosis.

Male Changes

• Andropause occurs typically between ages 50-60.
• Decline in testosterone levels.

Effects of Sex Hormones

• Impact on brain, behavior, muscle mass, bone density, and body proportions.
• Hormones influence appearance, strength, and physiological functions.

Connections with Other Systems

• Reproductive system interacts with multiple other systems: skin, skeleton, muscles, nervous system, endocrine, urinary, digestive, respiratory, lymphatic, cardiovascular.

Successful Reproductive System Function

Male Requirements

• Adequate sperm count and semen composition.
• Proper functioning of erection and ejaculation.

Female Requirements

• Communication and coordination between ovaries and uterus.
• Transport of oocytes and environment conducive to sperm survival.
• Prevention of STD-induced blockages in fallopian tubes.

Conclusion

• Successful reproduction requires the proper functioning of both male and female reproductive systems and coordination with other bodily systems.