Male Reproduction Flashcards
What are the organs and tubules of the male reproductive system?
The male reproductive system includes the testes, epididymis, vas deferens, seminal vesicles, prostate gland, and penis. The tubules involved in sperm production and transport include the seminiferous tubules within the testes and the vas deferens.
What is the structure and function of the scrotum?
The scrotum is a pouch of skin that contains the testes. It hangs outside the body cavity to maintain a slightly lower temperature than the rest of the body, which is necessary for optimal sperm production and function.
What are the major compartments and cells of the testis, and what are their functions?
The testis is composed of compartments called seminiferous tubules, which are responsible for sperm production. The cells within the seminiferous tubules include Sertoli cells (supporting cells that nourish and protect developing sperm) and Leydig cells (interstitial cells that produce testosterone).
What is spermatogenesis and spermiogenesis?
Spermatogenesis is the process of sperm cell production. It involves the division and differentiation of spermatogonia into spermatocytes, spermatids, and finally, spermatozoa. Spermiogenesis is the final stage of sperm development, during which spermatids undergo structural and functional changes to become mature, motile spermatozoa.
What is the Hypothalamic-Pituitary-Gonadal (HPG) axis in males?
The HPG axis in males is a hormonal pathway involving interactions between the hypothalamus, pituitary gland, and testes. The hypothalamus releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH and FSH act on the testes, regulating the production of testosterone and sperm.
How does testosterone levels change throughout the life-course?
Testosterone levels are low during childhood and increase during puberty, leading to the development of secondary sexual characteristics and sperm production. Testosterone levels typically peak in young adulthood and gradually decline with age.
What are the major functions of male hormones in the body?
Male hormones, primarily testosterone, have several major functions, including the development of male reproductive organs, regulation of sperm production, maintenance of secondary sexual characteristics (such as facial hair and deep voice), stimulation of muscle growth and bone density, and involvement in sexual desire and function.
Compare and contrast the male and female reproductive systems.
Both male and female reproductive systems have the primary function of producing and delivering gametes (sperm and eggs) for reproduction. However, there are several key differences between the two systems. In males, the testes produce sperm, while in females, the ovaries produce eggs. Males have a system of ducts (epididymis, vas deferens) to transport sperm, whereas females have fallopian tubes to transport eggs. The male reproductive system includes accessory glands (seminal vesicles, prostate gland) that contribute to semen production, while females have a uterus and a vagina for fertilization and childbirth. The external genitalia also differ, with males having a penis and scrotum, while females have a clitoris and labia.
Describe the major compartments and cells of the testis and their functions.
The testis is composed of compartments called seminiferous tubules, which are responsible for sperm production. Within the seminiferous tubules, there are two main cell types: Sertoli cells and Leydig cells. Sertoli cells provide support and nutrition to developing sperm cells and contribute to the blood-testis barrier. Leydig cells, located in the interstitial tissue, produce testosterone, which is essential for the development and maintenance of male reproductive structures and functions.
Describe the different stages of sperm production (spermatogenesis) and understand the role of spermiogenesis. What are the major differences between spermatogenesis and oogenesis?
Spermatogenesis involves several stages: spermatogonia (germ cells) undergo mitosis and differentiate into primary spermatocytes, which undergo meiosis I to produce secondary spermatocytes. Secondary spermatocytes then undergo meiosis II to form spermatids. Finally, spermatids undergo spermiogenesis, during which they differentiate and mature into spermatozoa. Spermiogenesis involves the formation of the acrosome, flagellum, and reduction of cytoplasmic content. The major differences between spermatogenesis and oogenesis include the number of functional gametes produced (spermatogenesis produces four sperm, while oogenesis produces one egg) and the timing (spermatogenesis occurs continuously throughout a male’s life, while oogenesis starts before birth and completes during reproductive years).
Describe the feedback loops that regulate testosterone production.
Testosterone production is regulated by a negative feedback loop. When testosterone levels rise, it inhibits the release of luteinizing hormone (LH) from the pituitary gland. This, in turn, decreases the production of testosterone. Conversely, when testosterone levels are low, it leads to increased release of LH, stimulating the production of testosterone.
Describe the levels of testosterone throughout the life-course.
Testosterone levels are low during childhood. During puberty, testosterone production increases, leading to the development of secondary sexual characteristics and sexual maturation. Testosterone levels typically peak in young adulthood and gradually decline with age. However, there can be individual variation in testosterone levels.
List the major functions of male hormones (androgens) a) in the reproductive tract and b) elsewhere in the body.
a) In the reproductive tract: Male hormones, particularly testosterone, are involved in the development and maintenance of male reproductive organs, sperm production (spermatogenesis), and the regulation of reproductive functions.
b) Elsewhere in the body: Male hormones have broader functions, including the development and maintenance of secondary sexual characteristics (such as facial and body hair, deep voice), muscle growth and strength, bone density, regulation of metabolism, mood, and libido.
