Reproductive System Flashcards
(30 cards)
Discuss the advantages of sexual reproduction.
Sexual reproduction involves the fusion of a male gamete (sperm) and a female gamete (egg), forming a genetically unique zygote. Advantages include genetic variation due to meiosis and crossing over, which promotes survival under harsh conditions (natural selection), reduces intraspecific competition, and enables population control.
what are the male primary sex organs and what are their functions?
The male primary sex organs are the testes, which produce sperm (spermatogenesis) and male sex hormones called androgens (testosterone, DHEA, and androstenedione). Accessory structures include 4 ducts (epididymides, vasa deferentia, ejaculatory ducts, urethra) and 3 glands (seminal vesicles, prostate, bulbourethral glands).
What is the function of the scrotum?
The scrotum houses the testes and maintains an optimal temperature (~34’C) for sperm production.
Describe how the cremaster and dartos muscle act in cold weather to maintain the intrascrotal temperature?
In cold weather, the cremaster muscle contracts to pull the scrotum closer to the body and the dartos muscle wrinkles the skin to reduce heat loss. In hot weather, both muscles relax to increase surface area and promote heat loss.
Name the cells in the testes that act as endocrine cells and are stimulated by luteinizing hormone (LH) to produce the 3 types of androgens? Name the major androgen. Discuss the prenatal actions of testosterone in sexual differentiation.
Leydig (interstitial) cells in the testes are stimulated by LH to produce androgens (DHEA, androstenedione, testosterone). Testosterone (converted to DHT) is essential for prenatal development of male genitalia. Deficiency or receptor dysfunction may result in female-like external genitalia in XY individuals.
What structures in the testes are called “sperm factories” and why?
Seminiferous tubules are ‘sperm factories’ where spermatogenesis occurs.
Name and describe the three sequential steps in spermatogenesis.
Spermatogenesis has three phases: (1) Mitosis of spermatogonia to form primary spermatocytes (diploid); (2) Meiosis to form secondary spermatocytes and spermatids (haploid); (3) Spermiogenesis, the maturation of spermatids into spermatozoa.
Which spermatogenic cells are diploid?
Diploid cells: spermatogonia, primary spermatocytes
Which spermatogenic cells are haploid?
Haploid cells: secondary spermatocytes, spermatids, spermatozoa.
What is spermiogenesis?
Spermiogenesis is the final stage of spermatogenesis where spermatids mature into motile spermatozoa (sperm)
Describe a spermatozoon (sperm): what is the acrosome?
A sperm has: a head with a haploid nucleus and an acrosome (containing enzymes to penetrate the ovum), a midpiece with mitochondria for ATP production, and a tail (flagellum) for motility.
List the path taken by ejaculated sperm in the male accessory reproductive ducts.
Ejaculated sperm travels through: epididymis -> vas deferens -> ejaculatory duct -> urethra.
Which ducts are referred to as “storage sites” for sperm?
Sperm is stored in the vas deferens.
What is semen and where does semen form?
Semen is a mixture of sperm and secretions from the seminal vesicles, prostate, and bulbourethral glands.
Is the penis part of the male accessory reproductive ducts?
The penis is not part of the accessory reproductive ducts.
Name the male reproductive glands and indicate chemicals released by each gland.
a. Seminal vesicles secrete fructose, coagulating enzymes, vitamin C, and prostaglandins
b. Bulbourethral glands secrete alkaline pre-ejaculate fluid.
Which gland secretes acid phosphatase and what is the significance of rising levels of acid phosphatase in the blood?
a. the prostate secretes citrate, fibrinolysin, and acid phosphatase.
b. Rising acid phosphatase levels can indicate prostate gland enlargement or cancer.
Name the cells in the testes that act as target cells for FSH? What is the significance of the blood-testis barrier?
Sertoli (sustentacular) cells are the target cells for FSH. They form the blood-testis barrier, protecting developing sperm from immune attack. They also secrete androgen-binding proteins (ABP) to concentrate testosterone and testicular fluid for sperm transport.
what are the female sex organs and what are their functions?
The female sex organs are the ovaries. Their functions are oogenesis (egg production) and secretion of sex hormones (estrogens and progesterone). Accessory ducts include fallopian tubes (site of fertilization), uterus (site of implantation), and vagina (copulatory organ).
Discuss three structural differences between testes and ovaries.
Testes are external, ovaries are internal; testes have lobules separated by tunica albuginea, ovaries do not; testes produce sperm continuously, while ovaries release one egg per cycle.
Describe the process of oogenesis; name and describe the four different
types of ovarian follicles – Primordial follicles; Primary follicles; Secondary follicles; Graafian (Dominant) follicles.
Oogenesis begins with oogonia forming primary oocytes arrested in prophase I. At puberty, follicles mature monthly. Primordial follicles contain primary oocytes with squamous cells. Primary follicles have a primary oocyte with 2+ cuboidal cell layers. Secondary follicles have granulosa cells. Graafian follicles contain a secondary oocyte arrested in metaphase II.
Which types of follicles contain primary oocyte? Which type contains a secondary follicle?
Primary follicles have a primary oocyte with 2+ cuboidal cell layers. Secondary follicles have granulosa cells. Graafian follicles contain a secondary oocyte arrested in metaphase II.
Which type of follicles produce estrogens? In detail describe how the estrogens are synthesized.
Secondary follicles produce estrogens. Theca cells produce androgens (DHEA, androstenedione, testosterone), which granulosa cells convert into estrogens (estriol, estrone, estradiol) using aromatase.
Discuss three differences between spermatogenesis and oogenesis.
- Spermatogenesis yields 4 sperm per meiosis; oogenesis produces 1 viable ovum.
- Spermatogenesis is continuous; oogenesis is cyclical
- All primary oocytes form before birth, while spermatogenesis begins at puberty.
