Testes: Structure, Hormones, Function, Practice Problems and FAQs

Adolescence comes with a lot of changes in both boys and girls. What changes do boys experience during adolescence? Growth of beard, pubic hair, growth of hair in the armpits, broader shoulder and chest, change in their voice and so on. Have you wondered what brings about this change? What is the driving force behind these changes that one experiences during puberty? All these changes are driven by hormones secreted by the reproductive organs present in males- Testes. So, not only do the testes produce the gametes for human males, they also play a major role in regulating the balance of sex hormone in males. But aren’t you curious to know about the hormones which are capable of bringing about such drastic changes in our body?? Come let’s try to understand the role of testes as a hormone producing gland in our body.

Table of Contents

• Introduction to Testes
• Internal Structure of Testes
• Hormones of Testes
• Practice Problems of Testes
• FAQs of Testes

Introduction to Testes

Testes are present in the scrotal sac of the males in pairs. Testes serve dual function in human males. They serves as sex organs as well as endocrine glands. They are the primary reproductive organ in males which produces the male gametes, i.e, sperms and as endocrine glands they secrete androgens which are primary sex hormones in males.

Internal Structure of Testes

Testes are further divided into approximately 250 compartments known as testicular lobules. Each lobule consists of one to three highly coiled seminiferous tubules. Seminiferous tubules are the highly coiled structure which are 70 cm long. These are the sites for sperm production.

Each tubule is lined internally by two types of cells -male germ cells (Spermatogonia) which divide meiotically in order to produce sperm and sertoli cells which provide nourishment to the germ cells. Sertoli cells also release hormones- inhibin and activin. The region surrounding the seminiferous tubules is filled with stromal or interstitial tissue which consist of blood vessels, immunogenic cells and Leydig cells or interstitial cells. Leydig cells produce and secrete androgens or testicular hormones.

Hormones of Testes

Androgens

Androgens are the major stimulatory hormones secreted by the testes which are involved in the process of spermatogenesis. Release of androgens influences the central nervous system and hence, influences the male sexual behaviour (libido). These hormones also influence anabolism of proteins and carbohydrates. These are also involved in development, maturation and functioning of the male accessory organs such as vas deferens, epididymis, prostate gland etc. 

These are also responsible for secondary sexual characteristics observed in males during puberty. Androgens also contribute to the growth of body tissues like bones and muscles.

Inhibin and Activin

These are the hormones secreted by sertoli cells. Inhibin is involved in the inhibition of FSH (Follicle Stimulating Hormone) production from the anterior lobe of the pituitary gland while activin is involved in activating the production of FSH.

Practice Problems of Testes

Question 1. Below mentioned are the hormones released by testes and their respective functions. Find the correct match.

a. Androgens - Increases growth of bones and muscles
b. Activin- Development of secondary sexual characteristics
c. Inhibin- Maturation of accessory sex organs
d. None of the above

Solution: Androgens are the major stimulatory hormones secreted by the testes. These hormones have several functions like helps in spermatogenesis, development of secondary sexual characteristics in males, increases growth of bones and muscles, influences male sexual behaviour and affects the metabolism of protein and carbohydrates.

Hence, the correct option is a.

Question 2. Find the odd one out from the options given below in context with the parts of male reproductive system.

a. Sertoli cells
b. Leydig cells
c. Fallopian tube
d. Seminiferous tubules

Solution: Sertoli cells, leydig cells and seminiferous tubules are the parts of testes- the primary male sex organ while fallopian tubes are part of female reproductive system.

Hence, the correct option is c.

FAQs of Testes

 Question 1. Name the hormones released by testes.

Answer: Testes are the primary male sex organ in males. It function both as sex organ and endocrine gland. Testes are involved in production of three hormones:

• Androgens
• Activin
• Inhibin

Question 2. What is the function of activin and inhibin?

Answer: Activin and inhibin are the hormones secreted by sertoli cells. Inhibin is involved in the inhibition of FSH (Follicle Stimulating Hormone) production from the anterior lobe of the pituitary gland while activin is involved in activating the production of FSH.

Question 3. What are testes? Mention different parts of testes.

Answer: Testes are present in the scrotal sac of the males in pairs. Testes serve dual function in human males. They serve as sex organs as well as endocrine glands. They are the primary reproductive organs in males and secrete androgens which are primary sex hormones in males.

Testes are composed of the following components: 

• Seminiferous tubules
• Leydig cells or interstitial cells
• Sertoli cells 
• Stromal or interstitial tissues

Question 4. What are androgens?

Answer: Group of sex hormones involved in growth, development and maintenance of reproductive system are known as androgens.

Question 5. What are the functions of androgens?

Answer: Androgens are the major stimulatory hormones secreted by the testes which are involved in the process of spermatogenesis. Release of androgens influences the central nervous system and hence, influences the male sexual behaviour (libido). These hormones also enhance anabolism of proteins and carbohydrates. These are also involved in development, maturation and functioning of the male accessory organs such as vas deferens, epididymis, prostate gland etc. These are also responsible for secondary sexual characteristics observed in males during puberty. Androgens also contribute to the growth of body tissues like bones and muscles.

Question 6. What changes are observed in males during puberty?

Answer: Androgens are the major driving force for the following changes observed in males during puberty:

• Appearance of acne
• Growth of facial hair
• Growth of larynx as it gets bigger and voice deepens
• Growth of hair in the armpits
• Growth of penis, seminal vesicle and prostate gland
• Development of bones and muscles

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