Reproductive System: Histology of Testis & Ovary · Physiology of Male & Female Reproduction · Puberty · Methods of Contraception

Reproductive System

Histology of Testis & Ovary · Physiology of Male & Female Reproduction · Puberty · Methods of Contraception

📘 B.Sc. Zoology 👩‍🏫 Dr. Chandralekha Deka 🏫 PDUAM, Amjonga, Goalpara 📅 Created: 20/06/2023 ♻ UGC Four Quadrant Model

I e-Tutorial

Module Title: Reproductive System — Histology of Testis and Ovary; Physiology of Male and Female Reproduction; Puberty; Methods of Contraception

Course: B.Sc. Zoology (Animal Physiology / Reproductive Biology)

Author: Dr. Chandralekha Deka, Assistant Professor, Department of Zoology, PDUAM, Amjonga, Goalpara

Date of Creation: 20/06/2023

Learning Objectives

• Describe the histological organisation of the testis, including seminiferous tubules, Sertoli cells, and Leydig cells.
• Describe the histological organisation of the ovary, including follicles at various stages and the corpus luteum.
• Explain the hormonal regulation of male reproduction (hypothalamo-pituitary-gonadal axis, spermatogenesis).
• Explain the hormonal regulation of female reproduction (ovarian and menstrual cycles).
• Discuss the physiological changes associated with puberty in males and females.
• Compare and evaluate the major methods of contraception available to males and females.

Structure of this Module

This e-content follows the UGC Four Quadrant Approach:

• Quadrant I: e-Tutorial — objectives, overview and video slot
• Quadrant II: e-Content — detailed text, diagrams and interactive elements
• Quadrant III: Self-Assessment — auto-graded MCQ quiz with instant feedback
• Quadrant IV: Resources — glossary, assignments, references and discussion

🎬

Video Lecture Slot Embed a recorded lecture or YouTube link here on histology of gonads and reproductive physiology. [ Placeholder — insert <iframe> video embed code in this space ]

II Histology of the Testis

The testis is a paired organ enclosed by a dense connective tissue capsule, the tunica albuginea, from which septa divide the organ into lobules, each containing one to four highly coiled seminiferous tubules.

👆 Click on a coloured region to learn about that structure.

Cell Type / Layer	Location	Function
Spermatogonia	Basal compartment, resting on basement membrane	Diploid stem cells; mitotic renewal
Sertoli cells	Extend from basement membrane to lumen	Nutritive support, phagocytosis of residual bodies, secretion of ABP & inhibin, blood-testis barrier
Primary/secondary spermatocytes	Adluminal compartment	Undergo meiosis I and II
Spermatids/Spermatozoa	Near lumen	Spermiogenesis; released as mature sperm
Leydig (interstitial) cells	Connective tissue between tubules	Secrete testosterone (LH-dependent)

II Histology of the Ovary

The ovary is covered by a single layer of cuboidal germinal epithelium beneath which lies the fibrous tunica albuginea. It is differentiated into an outer cortex, housing follicles at various stages, and an inner vascular medulla.

👆 Click each follicle/structure to see its description.

Structure	Key Feature
Primordial follicle	Oocyte + single flattened follicular cell layer
Primary follicle	Cuboidal granulosa cells; zona pellucida appears
Secondary follicle	Multilayered granulosa; antrum begins to form
Graafian follicle	Large antrum; ready for ovulation (LH surge)
Corpus luteum	Secretes progesterone; maintained by LH/hCG
Corpus albicans	Degenerated, fibrosed corpus luteum

II Physiology of Male Reproduction

Male reproductive physiology is regulated by the Hypothalamo-Pituitary-Gonadal (HPG) axis.

Hypothalamus
(GnRH)

→

Anterior Pituitary
(LH, FSH)

→

Testis
(Leydig & Sertoli cells)

→

Testosterone +
Spermatogenesis

Spermatogenesis

Spermatogonia (2n) → Primary spermatocytes (2n) → Meiosis I → Secondary spermatocytes (n) → Meiosis II → Spermatids (n) → Spermiogenesis → Spermatozoa. The entire process in humans takes approximately 64–72 days.

Hormonal Control

• FSH acts on Sertoli cells to support spermatogenesis and stimulate secretion of Androgen Binding Protein (ABP).
• LH acts on Leydig cells to stimulate testosterone secretion.
• Testosterone maintains spermatogenesis, secondary sexual characters, and libido.
• Inhibin, secreted by Sertoli cells, exerts negative feedback on FSH secretion.

II Physiology of Female Reproduction

Female reproductive physiology involves cyclical changes in the ovary (ovarian cycle) and uterus (menstrual/uterine cycle), each of about 28 days, regulated by the HPG axis.

Follicular phase (Day 1–13): FSH stimulates growth of ovarian follicles; granulosa cells secrete oestrogen, which thickens the endometrium.

Ovulation (Day 14): A surge of LH (triggered by peak oestrogen) causes rupture of the Graafian follicle and release of the secondary oocyte.

Luteal phase (Day 15–28): The ruptured follicle transforms into the corpus luteum, secreting progesterone (and some oestrogen) to maintain the endometrium in preparation for implantation.

Menstrual phase (Day 1–5): Fall in progesterone and oestrogen causes shedding of the endometrial lining if fertilisation has not occurred.

Proliferative phase (Day 6–13): Rising oestrogen levels stimulate regeneration and thickening of the endometrium.

Secretory phase (Day 15–28): Progesterone from the corpus luteum makes the endometrium glandular and vascular, ready for implantation.

Hormone	Source	Key Role
GnRH	Hypothalamus	Stimulates FSH and LH release
FSH	Anterior pituitary	Follicular growth
LH	Anterior pituitary	Triggers ovulation; maintains corpus luteum
Oestrogen	Growing follicle/granulosa cells	Endometrial proliferation; secondary sexual characters
Progesterone	Corpus luteum	Secretory changes in endometrium; maintains pregnancy

II Puberty

Puberty is the developmental period during which reproductive organs mature and secondary sexual characteristics appear, triggered by reactivation of the HPG axis after a quiescent childhood period.

• Onset typically between 10–14 years, driven by rising GnRH, LH, FSH and testosterone.
• Enlargement of testes and scrotum; onset of spermatogenesis.
• Growth of facial, axillary and pubic hair; deepening of voice due to laryngeal growth.
• Increase in muscle mass and skeletal growth spurt.

• Onset typically between 8–13 years, generally earlier than in males.
• Thelarche: breast bud development, the earliest visible sign.
• Pubarche: growth of pubic and axillary hair.
• Menarche: onset of first menstruation, marking the establishment of the menstrual cycle.
• Widening of pelvis and fat redistribution under oestrogen influence.

II Methods of Contraception

Contraceptive methods aim to prevent conception through barrier action, hormonal suppression of ovulation, prevention of implantation, or permanent surgical intervention.

Condom (male): Barrier method; sheath worn over the penis to prevent sperm entry into the vagina; also prevents STIs.

Vasectomy: Surgical method involving ligation and cutting of the vas deferens, blocking sperm transport; considered permanent.

Withdrawal (Coitus interruptus): Withdrawal of the penis before ejaculation; relatively unreliable due to pre-ejaculatory fluid.

Oral contraceptive pills: Synthetic oestrogen-progesterone combinations that inhibit ovulation by suppressing FSH/LH surge.

Intrauterine Device (IUD/Copper-T): Device inserted into the uterus that prevents implantation and impairs sperm motility.

Diaphragm/Cervical cap: Barrier device covering the cervix, often used with spermicide.

Tubectomy (Female sterilisation): Surgical ligation and cutting of the fallopian tubes, preventing ovum-sperm meeting; permanent.

Injectables/Implants: Long-acting progestin formulations (e.g., depot injections, subdermal implants) that suppress ovulation for months.

Emergency contraceptive pills: High-dose hormonal pills taken shortly after unprotected intercourse to prevent/delay ovulation.

Rhythm (Fertility awareness) method: Avoiding coitus during the fertile period of the ovarian cycle, estimated from cycle history.

Lactational Amenorrhoea Method (LAM): Suppression of ovulation during intense breastfeeding in the postpartum period, effective for a limited duration.

Spermicides: Chemical agents (foams, jellies) that immobilise or kill sperm, usually used with barrier methods.

Category	Examples	Mechanism
Barrier	Condom, Diaphragm	Physically prevents sperm from reaching the ovum
Hormonal	Pills, Injectables, Implants	Suppresses ovulation via feedback on HPG axis
Intrauterine	Copper-T, hormonal IUD	Prevents implantation/impairs sperm motility
Surgical	Vasectomy, Tubectomy	Permanently blocks gamete transport
Natural	Rhythm method, LAM	Avoids or suppresses fertile window

III Self-Assessment Quiz

Answer all questions below and click Submit Quiz to see your score with instant feedback.

IV Glossary

Spermatogenesis: The process of formation of mature spermatozoa from spermatogonia within seminiferous tubules.

Oogenesis: The process of formation of a mature ovum from an oogonium within the ovary.

Sertoli cells: Non-germinal supporting cells of the seminiferous tubule that nourish developing sperm.

Leydig cells: Interstitial cells of the testis that secrete testosterone.

Graafian follicle: The mature ovarian follicle ready to release a secondary oocyte at ovulation.

Corpus luteum: Endocrine structure formed from the ruptured follicle that secretes progesterone.

Menarche: The first occurrence of menstruation in a female, marking puberty onset.

Contraception: Deliberate prevention of conception or pregnancy by various devices, drugs, or practices.

HPG axis: Hypothalamo-Pituitary-Gonadal axis; the hormonal signalling loop controlling reproduction.

IV Assignments

1. Draw and label a labelled diagram of a cross-section of the seminiferous tubule.
2. Draw and label the stages of follicular development in the ovary.
3. Prepare a flowchart showing hormonal regulation of the menstrual cycle across its three phases.
4. Tabulate the differences between puberty onset in males and females.
5. Prepare a comparative note on the effectiveness and mechanism of any three contraceptive methods, one each from barrier, hormonal, and surgical categories.

IV References & Further Discussion

• Guyton, A.C. & Hall, J.E. — Textbook of Medical Physiology, Elsevier.
• Jayashree Ghosh — Fundamentals of Reproductive Biology, Books & Allied.
• Junqueira's Basic Histology: Text and Atlas, McGraw Hill.
• NCERT — Biology, Class XII, Chapter on Human Reproduction.
• UGC-CBCS Zoology Syllabus, Reproductive Biology unit.

For discussion: How does the negative feedback of inhibin on FSH differ functionally between males and females? Consider this in relation to contraceptive drug design.

IV Module Information

Field	Detail
Subject	Zoology
Course	B.Sc. (Reproductive Biology / Animal Physiology)
Module Title	Reproductive System: Histology of Testis & Ovary; Physiology of Male & Female Reproduction; Puberty; Methods of Contraception
Author	Dr. Chandralekha Deka, Assistant Professor, Department of Zoology, PDUAM, Amjonga, Goalpara
Date of Creation	20/06/2023
Approach	UGC Four Quadrant e-Content Model

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