Florida Biology 1 End-Of-Course Assessment Book + Online by Allen John;

Author:Allen, John;
Language: eng
Format: epub
Publisher: Research & Education Association
Published: 2013-08-15T00:00:00+00:00

Human Sexual Reproduction

Sexual reproduction includes the making of two kinds of sex cells, or gametes, and the processes that result in fertilization. Since the overall goal of reproduction is to pass on genes to the next generation, sexual reproduction has many drawbacks compared to asexual reproduction. We will review these a bit later. However, sexual reproduction does have the advantage of variation. With random mating and recombination of parents’ chromosomes, new traits can emerge that strengthen the overall population.

The basic anatomy of the human male reproductive system includes the following.

The testis is the male gonad, where the male gametes, called sperm, are produced. Each male has two testes. The testes are contained in the scrotum, a sac located outside the abdominal cavity, where cooler temperatures enable sperm to survive.

The seminiferous tubules are where sperm is produced in the testes. Interstitial cells in the testes produce male sex hormones including testosterone.

The epididymis is the coiled tube in each testis where sperm mature and are stored.

The vas deferens is one of two muscular ducts that carry sperm from one epididymis to the urethra, a tube running through the penis. During ejaculation, the penis emits sperm through the urethra.

Also during ejaculation, the seminal vesicles secrete mucus (a liquid medium for sperm), fructose sugar (energy source for the sperm), and prostaglandin (a hormone that stimulates uterine contractions) into the vas deferens.

The prostate gland is a large gland that secretes semen directly into the urethra. The milky fluid helps neutralize the acidity of any urine left in the urethra.

The basic anatomy of the human female reproductive system includes the following.

The ovary is the organ where the female gamete, or egg, is produced. Eggs are also called ova (singular: ovum). Each female has two ovaries.

The oviduct is where fertilization occurs. The egg moves through the oviduct to the uterus after ovulation. The oviduct is also called the fallopian tube. Each female has two oviducts, one for each ovary.

Inside the uterus, the fertilized egg, or blastocyst, is implanted on the inside wall. There the embryo develops for a nine-month gestation period until birth.

The endometrium is the lining, or inside wall, of the uterus. It thickens monthly in preparation for a fertilized egg being implanted.

The vagina is the birth canal. During labor and delivery, the baby passes through the cervix, or opening in the uterus, and into the vagina.

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