Reproduction Flashcards

Flashcards about Reproduction

Asexual reproduction is common in which organisms?

Many invertebrates, including sponges, cnidarians, rotifers, flatworms, and annelids. Some vertebrates reproduce asexually under certain conditions.

What are the advantages of asexual reproduction?

Single parent, sessile animals have difficulty finding a mate.

What are the disadvantages of asexual reproduction?

Genetically identical to the parent, difficult to evolve.

Define fission in the context of asexual reproduction.

Division along the entire longitudinal or transverse plane.

Give an example of an organism that reproduces by fission.

Protists.

Define budding.

Viable offspring bud off from the adult.

Give an example of organisms that reproduce by budding.

Sponges and cnidarians.

Define fragmentation.

The body breaks into several pieces, each piece regenerates missing parts to develop a whole animal.

Give an example of organisms that reproduce by fragmentation.

Some flatworms and annelids.

Define parthenogenesis.

Unfertilized egg develops into an adult which is typically haploid; most species alternate with sexual reproduction.

Give an example of organisms that reproduce by parthenogenesis.

Insects, crustaceans, some nematodes, grotopods, and fishes.

What are the advantages of sexual reproduction?

Promotes genetic variety; favorable for evolution in changing environments.

What are the requirements for sexual reproduction?

Production and fusion of two haploid gametes (sperm and ovum).

What happens during external fertilization?

often simultaneous release of eggs and sperm into water.

What happens during internal fertilization?

Sperm deposited into or enter female’s reproductive track.

Define hermaphroditism.

Single individual produces both eggs and sperm (monoecious).

Describe self-fertilization.

Some species (flatworm) can self-fertilize; prevented by development of sperm and eggs at different times.

What determines sex in humans?

Presence or absence of masculizing factors.

What is genotypic sex?

XX or XY.

What does genotypic sex result in?

Results in gonadal sex.

Which chromosome codes for Anti-Mullerian Hormone (AMH)?

Chromosome 19 codes for secretion of AMH.

What is the function of Sertoli cells?

Secretes AMH.

What is the function of Interstitial cells of Leydig?

Secrete testosterone and dihydrotestosterone; stimulate differentiation of Wolffian ducts into non-testes structures in males.

What triggers testicular development?

A single gene on the Y chromosome, SRY (sex-determining region).

What is the function of the male duct system?

Carries sperm in semen secreted by accessory organs and involved in expelling sperm from reproductive system.

What structures are located in the spermatic cord?

Vas deferens, blood and lymphatic vessels, nerves.

What is an inguinal hernia?

Protrusion of abdominal visceral tissues into inguinal canal.

List the main structures of the male reproductive system.

Scrotum, testis, seminiferous tubules, epididymis, vas deferens, seminal vesicles, prostate, urethra, bulbourethral gland, penis.

What do the seminal vesicles secrete?

Secretes fructose (energy source), ascorbic acid, prostaglandins, fibrinogen.

What does the prostate secrete?

Secretes alkaline fluid, enzymes, prostaglandins, clotting enzymes, prostate-specific antigens (PSA).

What do the bulbourethral glands secrete?

Secretes mucus to neutralize acid.

What is the function of the epididymis?

Sperm storage and maturation.

What structure makes up the vas deferens?

Sperm storage and maturation; smooth muscles expel sperm.

What is the function of the testis?

Site of sperm synthesis.

Describe the structure of the Testes.

Testes are ovoid structures located outside the abdominopelvic cavity.

Describe the structure of the scrotum.

Sac-like structure; smooth muscle for temperature regulation.

What are seminiferous tubules?

Tightly coiled branches in lobules; actual site of sperm production in wall of tubule.

What are spermatogenetic cells?

Sperm-forming cells.

What is the function of sustentacular (Sertoli, nurse) cells?

Support sperm production.

What is the function of interstitial (Leydig) cells?

Produce and secrete androgens (mainly testosterone).

What is the function of myoid cells?

Muscle-like cells surrounding seminiferous tubules; contract to push sperm and testicular fluid through tubules.

What are the functions of the sustentacular Cells (Sertoli cells, nurse cells)?

Produces Androgen-binding protein and Inhibin.

What does the interstitial cells of Leydig produce?

Testosterone.

Where is spermatogenesis located?

In wall of seminiferous tubules.

What are spermatogonia?

Stem cells that initiate spermatogenesis.