About the NDA/CDS 1 2026 Exam
The NDA (National Defence Academy) and CDS (Combined Defence Services) Examinations are conducted by the Union Public Service Commission (UPSC) to select candidates for the Indian Armed Forces – Army, Navy, and Air Force.
In the General Science section, Biology plays a key role, testing your understanding of basic human physiology, anatomy, and life processes.
A clear grasp of the Reproductive and Circulatory systems helps not just in scoring well but also in understanding essential life mechanisms relevant to physical fitness and defense life sciences.
Topic: Reproduction in Humans
Introduction
Reproduction is the biological process by which living organisms produce offspring to ensure the continuity of their species. In humans, it is a sexual process involving the fusion of male and female gametes.
Subtopics
- Human Reproductive System
- Male Reproductive System: Testes, vas deferens, seminal vesicles, prostate gland, penis.
- Female Reproductive System: Ovaries, fallopian tubes, uterus, cervix, vagina.
- Gamete Formation
- Spermatogenesis – formation of sperm in testes.
- Oogenesis – formation of ovum in ovaries.
- Fertilization and Development
- Process of fusion of sperm and ovum in the fallopian tube.
- Zygote formation, implantation, and embryonic development.
- Menstrual Cycle
- Phases: Menstrual, Follicular, Ovulatory, and Luteal phases.
- Hormonal regulation by FSH, LH, estrogen, and progesterone.
- Pregnancy and Birth
- Gestation period, development of placenta, and parturition (childbirth).
- Reproductive Health
- Importance of family planning, contraceptive methods, and awareness about STDs (AIDS, Syphilis, Gonorrhea).
Topic: Circulatory System in Humans
Introduction
The circulatory system is responsible for the transportation of oxygen, nutrients, hormones, and waste products throughout the body. It plays a vital role in maintaining homeostasis and overall body function.
Subtopics
- Human Heart
- Structure and function of four chambers (two atria, two ventricles).
- Flow of blood through the systemic and pulmonary circuits.
- Blood and Its Components
- Plasma, Red Blood Cells (RBCs), White Blood Cells (WBCs), and Platelets.
- Functions: transport, defense, and clotting.
- Blood Vessels
- Arteries, Veins, and Capillaries – structure and functions.
- Double Circulation
- Distinction between systemic and pulmonary circulation ensuring efficient oxygenation.
- Heartbeat and Pulse
- Cardiac cycle, heart rate, and blood pressure regulation.
- Lymphatic System
- Composition and role of lymph, lymph nodes, and immune defense.
Conclusion
The Human Reproductive and Circulatory Systems are vital for sustaining life and species. Understanding these systems helps in appreciating the complex coordination of organs that maintain health, growth, and survival. For NDA/CDS aspirants, mastering these topics enhances both academic performance and awareness of body functions crucial for a fit and disciplined military life.
