Key Differences Between Male and Female Gonads
During puberty, both the male and the female bodies go through numerous changes, and the most obvious ones are an increase in height, change in voice tone, and body shape. Also, there is an increase in the activity of sebaceous and sweat glands and the development of sex organs and secondary sexual traits which are prevalent during adolescence.
Importantly, these hormones play a significant role in the overall growth and development of the human body and the functioning of its organs. In this article, you will be introduced to one of the vital hormone-secreting organs called gonads, the meaning of gonads, and their function.
Gonads
The Gonads are a part of the endocrine system, and gonads are known as the male and female reproductive organs. Ovaries are the female gonad while testes are the male gonad, and they are responsible for producing sex hormones in our bodies.
Functions of Gonads
The Gonads are the most vital hormone-secreting organ in the human body, the functions of the gonads are given below:
Secretion of sex hormones.
Production of gametes.
It facilitates cell division, especially meiosis.
They are indirectly responsible for controlling the maturation of reproductive organs.
They are responsible for the development of secondary sex characteristics in both males and females.
Male Gonad Hormones
Androgens, also known as the ‘male hormone’ is responsible for the maturation of the male reproductive system.
The Primary Male Gonads Hormones are –
Testosterone: These hormones are essential for the growth of bone, muscle and body hair and are produced by testes. It is also responsible for the growth of the penis, deepening voice and appearance of facial hair.
Inhibin: Essentially, inhibin obstructs the release of follicle-stimulating hormone or FSH. It also regulates the development and regulation of sperm cells.
Androstenedione: They are forerunners of oestrogen and testosterone and promote and regulate their production within the body.
Female Gonadal Hormones
Androgens are also present in females and are produced in their ovaries, fat cells and adrenal glands. They are responsible for stimulating hair growth in the underarms and pubic area in females.
These are the Primary Female Gonads –
Oestrogens: They aid in the development of the female reproductive system and facilitate reproduction. For instance, oestrogens promote the growth of a uterus, maturation of vagina, widening of breasts and pelvis.
Progesterone: They help to prepare a uterus for conception and are also responsible for regulating it during the menstrual cycle. Progesterone also plays a key role in milk production during pregnancy and even for stimulating glands.
Notably, both over and underproduction of gonadal hormones is often responsible for several disorders in males and females. Typically, factors like long-term illness, inherited disease, poor lifestyle choices, etc. are responsible for hypo or hyperproduction of gonadal hormones.
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FAQs on Gonads: Structure, Function and Importance
1. What is the biological definition of gonads?
Gonads are the primary reproductive organs responsible for producing gametes (sex cells). In males, the gonads are the testes, which produce sperm. In females, the gonads are the ovaries, which produce eggs or ova. They are a crucial part of both the reproductive and endocrine systems.
2. What are the two main functions of gonads in the human body?
The gonads have two critical functions, known as their dual function:
Gamete Production (Gametogenesis): This is their primary reproductive or exocrine function. The testes produce sperm, and the ovaries produce eggs.
Hormone Secretion: This is their endocrine function. Gonads secrete sex hormones that regulate the reproductive cycle and the development of secondary sexual characteristics. For example, testes secrete testosterone, and ovaries secrete estrogen and progesterone.
3. What are the main hormones secreted by the male gonads (testes) and what is their importance?
The testes produce a group of hormones called androgens. The most important ones are:
Testosterone: This is the principal male sex hormone. It is essential for the development of male reproductive tissues (testes, prostate), stimulating the development of secondary sexual characteristics like muscle mass, bone density, deepening of the voice, and growth of body hair.
Inhibin: This hormone is involved in regulating sperm production (spermatogenesis) by providing negative feedback to the pituitary gland, specifically inhibiting the secretion of Follicle-Stimulating Hormone (FSH).
4. What are the primary hormones produced by the female gonads (ovaries) and what are their functions?
The ovaries produce two main types of hormones:
Estrogen: This hormone is responsible for the development and regulation of the female reproductive system and secondary sexual characteristics. This includes the growth of the uterus and vagina, widening of the pelvis, and breast development.
Progesterone: This hormone plays a vital role in the menstrual cycle and in maintaining the early stages of pregnancy. It prepares the uterus for the implantation of a fertilized egg and helps in the development of mammary glands.
5. What is the difference between primary and secondary sexual characteristics, and how are gonads involved?
Primary sexual characteristics are the gonads themselves (testes and ovaries) and the reproductive passages, which are present at birth. Secondary sexual characteristics are features that emerge during puberty and are not directly part of the reproductive system. The gonads are directly involved by producing hormones (testosterone and estrogen) that trigger the development of these secondary traits. Examples in males include facial hair and a deeper voice, while in females they include breast development and wider hips.
6. What are the key physical changes initiated by gonadal hormones during puberty?
During puberty, hormones from the gonads cause significant physical changes. Common changes for both sexes include a rapid growth spurt and the growth of pubic and underarm hair. Specific changes include:
In Males: Deepening of the voice, growth of facial hair, increased muscle mass, and enlargement of the penis and testes.
In Females: Onset of menstruation (menarche), development of breasts, and widening of the hips and pelvis.
7. How do gonads function as both endocrine and exocrine glands?
Gonads exhibit a dual function. Their endocrine function involves secreting hormones like testosterone and estrogen directly into the bloodstream to act on various parts of the body. Their exocrine function involves releasing products—gametes (sperm and eggs)—through a duct system. For example, sperm travels through the vas deferens, and an egg travels through the fallopian tube. This dual capability makes them unique organs known as heterocrine glands.
8. How do the undifferentiated gonads in an embryo develop into either testes or ovaries?
In the early stages of embryonic development, all individuals have 'indifferent' or bipotential gonads. The path of differentiation is determined by genetics. If the embryo has a Y chromosome, a gene on it called the SRY gene (Sex-determining Region Y) is activated. This gene triggers a cascade of events that causes the indifferent gonads to develop into testes. In the absence of the SRY gene (in an XX embryo), the gonads follow a default pathway and develop into ovaries.
9. Why are the male gonads (testes) located outside the main abdominal cavity?
The testes are located in the scrotum, outside the abdominal cavity, because the process of sperm production, or spermatogenesis, is highly sensitive to temperature. It requires a temperature that is approximately 2–2.5°C lower than the core body temperature. The location in the scrotum provides this cooler environment, which is optimal for the development and maturation of viable sperm.
10. Do females have androgens (male hormones) and do males have estrogens (female hormones)?
Yes, both sexes have both types of hormones, but in different amounts and with different effects. Females produce small amounts of androgens in their ovaries and adrenal glands, which are important for libido and bone health. Similarly, males produce small amounts of estrogen, which is converted from testosterone and is necessary for sperm maturation and maintaining bone density. The balance of these hormones is what determines sex-specific development.
