Reproductive Systems and Gametes Quiz

Reproductive Systems and Gametes

• Sexual reproduction involves the union of germ cells called gametes.
• Gametogenesis is the process of producing gametes (spermatogenesis and oogenesis).
• Gametes are germ cells with a haploid number of chromosomes.
• Reproductive organs include gonads (producing gametes and hormones), ducts (transporting and storing gametes), accessory sex glands and organs (producing materials supporting gametes), and external genitalia.
• Gonads are the testes in males and ovaries in females. They secrete hormones and produce gametes.

Male Reproductive System

• In adult males, testes secrete androgens (primarily testosterone) and mature spermatozoa (~300 million/day).
• Sperm travel through ducts, mixing with secretions of accessory glands to form semen.
• Semen is expelled from the body during ejaculation.
• Testes produce sperm and secrete hormones.
• Ductal system components include epididymis, ductus deferens, ejaculatory duct, and urethra.
• Accessory sex glands include seminal vesicles, prostate gland, and bulbourethral glands; these contribute secretions to semen.
• Supporting structures include penis and scrotum, which support testes and sperm delivery.
• Sperm maturation, storage, and transport are occurring in the ductal system.
• The pathway of sperm is: testes, epididymis, vas deferens, ejaculatory duct, urethra.

Female Reproductive System

• In adult females, ovaries secrete sex hormones (primarily estrogen and progestins) and release an immature oocyte (~1/month).
• The oocyte travels through uterine tubes to the uterus.
• If fertilization occurs, the oocyte matures into an ovum, and the uterus supports the developing embryo.
• The vagina connects the uterus to the exterior, allowing for sexual intercourse and childbirth.
• Ovaries produce hormones (estrogens, progesterone, inhibin, relaxin), involved in sexual characteristics, reproductive cycle, pregnancy, lactation, and normal reproductive functions.

Ovarian Cycle

• A series of events in ovaries occurring during and after oocyte maturation.
• It's divided into preovulatory (follicular) and postovulatory (luteal) phases.
• The ovarian cycle is coordinated with the uterine cycle.

Oogenesis

• Oogenesis occurs in the ovaries, resulting in single haploid secondary oocytes.
• It begins before birth and only completes with fertilization.
• Primary oocytes complete meiosis I, producing a secondary oocyte and a first polar body.
• The secondary oocyte begins meiosis II but pauses.
• If fertilization occurs; meiosis II resumes.
• The secondary oocyte and first polar body are ovulated.
• After fertilization, meiosis II of the oocyte produces an ovum and a second polar body, with the nuclei uniting to form a diploid zygote.
• Oogenesis involves the production of egg cells in the ovaries.

Uterus

• The uterus is an organ for sperm transport, menstruation, implantation of fertilized ova, development of a fetus, and labor,
• It has three layers: perimetrium, myometrium, and endometrium
• Cervical mucus is produced by secretory cells of cervix mucosa.

Spermatogenesis

• Spermatogenesis is the process by which sperm are produced in the seminiferous tubules of the testes and involves three stages: mitosis, meiosis, and spermiogenesis.

Spermiogenesis

• Spermatids are small, unspecialized cells
• Spermiogenesis is the process by which spermatids mature into spermatozoa (sperm).
• A sperm cell consists of a head (containing chromosomes and acrosome cap), midpiece (with mitochondria for ATP production), and tail (for motility).
• Sertoli cells provide support to spermatogenic cells.

Accessory Glands

• Seminal vesicles secrete fructose for ATP production and prostaglandins for sperm motility.
• Prostate gland secretes milky, slightly acidic fluid containing citric acid for ATP production; proteolytic enzymes.
• Bulbourethral glands secrete sticky mucus for lubrication.

Semen

• Semen is a mixture of spermatozoa and accessory sex gland secretions (fluid for transport, nutrients, neutralizing vagina acidity).
• Normal semen volume is 2.5 - 5 ml per ejaculation containing 50-150 million sperm/mL, as well as fluids from seminal vesicles, prostate, and bulbourethral glands.

Urethra

• Shared terminal duct of the reproductive and urinary systems.

Vulva

• External genitalia of the female reproductive system, including mons pubis, labia majora, labia minora, clitoris, vaginal and urethral orifices, hymen, paraurethral and greater vestibular glands.

Hormonal Control

• Hormones regulate the reproductive systems.
• Follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone.
• Inhibin inhibits FSH secretion.

Test your knowledge on reproductive systems and gametogenesis. This quiz covers the male and female reproductive organs, the processes of sperm and egg production, and hormone secretion. Understand the roles of gametes and their significance in sexual reproduction.