Hormonal Regulation in Male Reproduction

Cells that are found in the space between the seminiferous tubules of the testes and secrete the male hormone testosterone.

Large cells located in the seminiferous tubules of the testes, responsible for nourishing developing sperm cells, forming a barrier between the blood and sperm, and responding to hormones like FSH and testosterone.

A hormone produced by the hypothalamus that triggers the release of LH and FSH from the pituitary gland.

A hormone produced by the pituitary gland that stimulates sperm production in the testes.

A hormone produced by the pituitary gland that stimulates the Leydig cells to produce testosterone.

The primary male sex hormone, responsible for developing and maintaining male characteristics and reproductive function.

A hormone produced by the Sertoli cells in the testes that regulates FSH production, ultimately controlling the rate of sperm production.

An enzyme that converts testosterone into dihydrotestosterone (DHT), which is more potent and plays a crucial role in male sexual development.

Puberty marks the start of the process of sperm production, initiated by increased secretion of GnRH from the hypothalamus.

GnRH acts on the anterior pituitary gland, stimulating the release of two crucial hormones: FSH and LH, which orchestrate sperm production and testosterone.

LH, or luteinizing hormone, acts directly on Leydig cells, located within the testes, to initiate testosterone production.

Testosterone, a vital male hormone, is synthesized from cholesterol within the testes. Its production involves a series of enzymatic steps.

Testosterone production is tightly regulated by a negative feedback loop. High levels of testosterone signal the hypothalamus and pituitary to reduce GnRH and LH secretion, thereby reducing testosterone synthesis.

FSH, or follicle-stimulating hormone, specifically targets spermatogenesis - the process of sperm production within seminiferous tubules. FSH stimulates the development of sperm precursor cells.

Both FSH and testosterone stimulate Sertoli cells located in the seminiferous tubules to produce androgen-binding protein (ABP). ABP binds to testosterone, keeping its concentration high in the vicinity of developing sperm.

Testosterone, at sufficiently high concentrations, is essential for the final stages of sperm maturation. This ensures the production of functional, motile sperm.

Sertoli cells, once sufficient sperm have been produced, release inhibin. Inhibin acts on the pituitary to suppress further release of FSH, thus regulating sperm production.

Male hypogonadism refers to disorders characterized by insufficient testosterone production, resulting in impaired development of male sexual characteristics and function.

A condition caused by a deficiency in gonadotropin-releasing hormone (GnRH), leading to incomplete sexual development and infertility. It is characterized by a lack of puberty and the absence of secondary sex characteristics.

A condition where the prostate gland becomes enlarged, often affecting men over 60. It can cause frequent urination, weak urine stream, and difficulty emptying the bladder.

A type of cancer that affects the prostate gland, a common cancer among men. It is often detected by a blood test for prostate-specific antigen (PSA).

A medication like Viagra (Sildenafil citrate) that works by inhibiting the enzyme PDE5, leading to increased blood flow and erection.

The natural process through which a female's body prepares itself for potential pregnancy, involving changes in the ovaries and uterus, as well as the release of hormones like estrogen and progesterone.

Hormone produced by the hypothalamus that regulates the release of FSH and LH from the pituitary gland, playing a key role in the female reproductive cycle.

A hormone that stimulates the growth of ovarian follicles and the production of estrogen.

A hormone that stimulates ovulation and the formation of the corpus luteum, which produces estrogen and progesterone.

A hormone produced primarily by the corpus luteum, important for preparing the uterus lining for pregnancy, and for breast development during pregnancy.

A hormone produced by the corpus luteum, which relaxes the uterus and makes the cervix wider for childbirth. It also relaxes pelvic ligaments.

A synthetic form of the female sex hormone progesterone used in hormonal contraceptives. It prevents ovulation, thickens cervical mucus, and changes the lining of the uterus.

Substances that can cause birth defects in a developing embryo or fetus. They can be chemicals, drugs, radiation, or infections.

A type of teratogen that can cause developmental defects in a fetus.

A type of teratogen that can cause a range of developmental and health problems in a fetus, including facial abnormalities, heart defects, and learning disabilities.

This phase of the menstrual cycle starts after menstruation and lasts until ovulation. During this phase, the lining of the uterus (endometrium) starts to thicken and grow, preparing for a potential pregnancy.

The release of a mature egg from the ovary, typically occurring around day 14 of a 28-day cycle.

The period after ovulation, lasting until menstruation. During this phase, the empty follicle transforms into the corpus luteum, which produces progesterone, helping to maintain the uterine lining.

The level of estrogen during the pre-ovulatory phase, promotes the release of GnRH (Gonadotropin-Releasing Hormone), LH (Luteinizing Hormone), and FSH (Follicle-Stimulating Hormone) from the pituitary gland.

Moderate estrogen levels secreted by secondary follicles during the pre-ovulatory phase inhibit the release of GnRH, LH, and FSH, preventing the development of new follicles.

When estrogen and progesterone levels are low after the formation of the corpus albicans, it triggers the release of GnRH, LH, and FSH, leading to menstruation and a new cycle.

Combined oral contraceptives contain synthetic estrogen and progesterone. The estrogen inhibits FSH, preventing follicle development, and the progesterone inhibits LH, preventing ovulation. They also make the cervical mucus inhospitable to sperm and the endometrium unsuitable for implantation.

Progesterone-only pills contain synthetic progesterone, which inhibits LH, preventing ovulation. They also thicken cervical mucus, making it difficult for sperm to reach the egg, and can also affect the endometrium, making it unsuitable for implantation.

Hormonal birth control works by altering the normal levels of estrogen and progesterone in the body, preventing the development and release of eggs and making it difficult for sperm to reach the egg and for a fertilized egg to implant in the uterus.

These are the key hormones involved in the regulation of the menstrual cycle. They work together, often through feedback mechanisms (positive and negative), to ensure the proper development and release of eggs and the regulation of the uterine lining.

A condition caused by deficiency in gonadotropin-releasing hormone (GnRH), leading to incomplete sexual development and infertility. It is characterized by a lack of puberty and the absence of secondary sex characteristics.

Enlargement of the prostate gland, often affecting men over 60. It can cause frequent urination, weak urine stream, and difficulty emptying the bladder.

A type of cancer that affects the prostate gland. It is often detected by a blood test for prostate-specific antigen (PSA).

A medication like Viagra that works by inhibiting the enzyme PDE5, leading to increased blood flow and achieving an erection.

Changes that take place in the ovaries during and after the maturation of an oocyte, including the development of follicles and ovulation.

A series of changes in the uterine endometrium preparing it for the arrival of a fertilized ovum. If implantation does not occur, the stratum functionalis is shed during menstruation.

A hormone secreted by the hypothalamus that controls the ovarian and uterine cycles. It stimulates the release of FSH and LH from the anterior pituitary gland.

A hormone secreted by ovarian follicles (mainly β-estradiol). It plays various roles in maintaining female reproductive structures, secondary sex characteristics, protein anabolism, and regulating hormone levels.

A hormone mainly secreted by the corpus luteum. It works with estrogen to prepare and maintain the endometrium for implantation and mammary glands for milk production and also inhibits the secretion of GnRH and LH.

A hormone produced by the corpus luteum that relaxes the uterus by inhibiting contraction of its muscles, increases flexibility of the pubic symphysis, and dilates the uterine cervix.

The first phase of the menstrual cycle, lasting from day 1 to 5. It begins with menstruation, the shedding of the uterine lining. During this phase, the ovaries start to develop follicles, which may take several cycles to mature.

The event that signals the end of a menstrual cycle, where the uterine lining is shed as blood and tissue. It occurs when progesterone and estrogen levels decrease, which happens if the egg isn't fertilized.