The Male and Female Reproductive Systems: Quick Revision

A brief note on The Male and Female Reproductive Systems. Read it before a test. Try each question at the end before you open its answer.

The male system

• Testes: in the scrotum, 2 to 2.5 °C below the body temperature. About 250 lobules in each, with one to three seminiferous tubules in each lobule.
• Cells: spermatogonia (germ cells) and Sertoli cells (feed the germ cells) in the tubule. Leydig cells (interstitial cells) outside it make androgens.
• Route: seminiferous tubule, rete testis, vasa efferentia, epididymis, vas deferens, ejaculatory duct, urethra, urethral opening.
• Glands: a pair of seminal vesicles, the prostate and a pair of bulbourethral glands. Seminal plasma is rich in fructose, calcium and enzymes.

The female system

• Ovary: 2 to 4 cm, with the cortex (follicles) and the medulla. It makes the ovum and steroid hormones.
• Follicles in order: primary, secondary, tertiary (antrum), Graafian. After ovulation: corpus luteum, then corpus albicans.
• Oviduct: infundibulum (fimbriae), ampulla (fertilisation), isthmus.
• Uterus: perimetrium, myometrium (muscle), endometrium (lining that changes). Cervical canal and vagina form the birth canal.
• Mammary gland: 15 to 20 lobes, alveoli, mammary tubules, mammary duct, mammary ampulla, lactiferous duct.

The gametes

• Sperm: head (haploid nucleus and acrosome), neck, middle piece (mitochondria), tail.
• Semen: 200 to 300 million sperms. NCERT: at least 60 per cent normal and at least 40 per cent vigorously motile.
• Ovum: nucleus, cytoplasm with food, plasma membrane, zona pellucida, corona radiata. A secondary oocyte is released at ovulation.

A worked example

A semen sample of 2.5 mL holds 80 million sperms in each mL. How many sperms is that?

1. Multiply the volume by the count in each mL.
2. $2.5 \times 80 = 200$ million sperms.

Practice with new numbers

A program to try

The program prints the route of a sperm and counts the parts.

Mistakes to avoid

• Saying that Leydig cells make sperms. They make androgens.
• Saying that fertilisation is in the uterus. It is in the ampulla.
• Mixing the layers of the uterus. The muscle layer is the myometrium, and the lining is the endometrium.
• Leaving the acrosome out of the sperm. It is the cap of enzymes on the head.

Check yourself

1. Which cells feed the germ cells in a seminiferous tubule?

2. Which part of the oviduct is the usual site of fertilisation?

3. What does the middle piece of a sperm hold, and why?

4. What is released from the ovary at ovulation?

Sources

• NCERT (2023). Biology, Textbook for Class XII, chapter 2, Human Reproduction.
• Betts J. G. et al. (2022). Anatomy and Physiology 2e, OpenStax, chapter 27, The Reproductive System.
• World Health Organization (2021). WHO laboratory manual for the examination and processing of human semen, 6th edition.