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Male Reproductive System – Locations and Functions of the Male Reproductive Organs

By | 2018-07-11T06:08:50+00:00 July 24th, 2017|Anatomy, Body Systems, Physiology, Reproductive System|

The primary functions of the male reproductive system are the production of male sex hormones, the formation of sperm, and the placement of sperm in the female reproductive tract, where one sperm can unite with a female sex cell. The organs of the male reproductive system include (1) paired testes, which produce sperm and male [...]

Male Sexual Response

By | 2018-07-11T06:11:03+00:00 July 24th, 2017|Physiology, Reproductive System|

In the absence of sexual stimulation, the vascular sinusoids in the erectile tissue of the penis contain a small amount of blood and the penis is flaccid (flak'-sid), or soft. Sexual stimulation initiates parasympathetic nerve impulses that cause the dilation of the arterioles and constriction of the venules supplying the erectile tissue. These vascular changes [...]

Disorders of the Reproductive Systems

By | 2018-07-11T06:42:29+00:00 July 24th, 2017|Physiology, Reproductive System|

Male Disorders Prostatitis is acute or chronic inflammation of the prostate gland and is often associated with tenderness and enlargement of the prostate. It is usually caused by bacteria in connection with urinary tract infections or sexually transmitted diseases. It also occurs without a known cause. Benign prostatic hyperplasia (BPH) is the enlargement of the [...]

The Processes of Fertilization, Preembryonic Development and Implantation

By | 2018-07-11T06:42:46+00:00 July 24th, 2017|Physiology, Reproductive System|

Each primary oocyte undergoes the first meiotic division while still in the ovarian follicle. This division forms a secondary oocyte and the first polar body, each containing 23 chromosomes. At ovulation, the secondary oocyte and first polar body, still enclosed within a sphere of granulosa cells, are released into a uterine tube. They are slowly [...]

Embryonic Development – Germ Layers, Extraembryonic Membranes and Placenta

By | 2018-07-11T06:42:53+00:00 July 24th, 2017|Physiology, Reproductive System|

The embryonic stage of development begins at the start of the third week of development and is completed at the end of the eighth week. During this time, the embryo undergoes rapid development, forming the rudiments of all body organs, extraembryonic membranes, and the placenta. By the end of the eighth week, it has a [...]

Fetal Development Stages

By | 2018-07-11T06:43:12+00:00 July 24th, 2017|Physiology, Reproductive System|

At the beginning of the ninth week of development, the developing offspring has a distinctively human appearance and is now referred to as a fetus. Weeks of Development Changes 5-8 Weeks Recognizable human shape; head as large as the body; eyes far apart; upper and lower limbs present with digits; heart possesses four chambers; tail [...]

Hormonal Control of Pregnancy

By | 2018-07-11T06:43:20+00:00 July 24th, 2017|Physiology, Reproductive System|

Without the formation of a preembryo, the corpus luteum degenerates about two weeks after ovulation as a result of the decline in luteinizing hormone from the anterior lobe of the pituitary gland. The resulting decline in blood levels of estrogens and progesterone causes the endometrium to break down and to be shed with menstruation. Pregnancy [...]

Lactation – The Control of Lactation and Milk Ejection

By | 2018-07-11T06:40:18+00:00 July 24th, 2017|Endocrine System, Physiology, Reproductive System|

High blood levels of estrogens and progesterone during pregnancy stimulate the development of the mammary glands and enlargement of the breasts in preparation for milk secretion, or lactation (lak-ta'-shun). Although the mammary glands are capable of secreting milk, the high levels of estrogens and progesterone inhibit the hypothalamus so that milk secretion does not occur [...]

Hormonal Control of Reproduction in Females – The Ovarian and Menstrual Cycles

By | 2018-07-11T06:40:30+00:00 July 24th, 2017|Physiology, Reproductive System|

Reproduction in females is controlled by hormones produced by the hypothalamus, anterior lobe of the pituitary gland, and ovaries. Female Sex Hormones The ovaries produce the two major groups of female sex hormones-estrogens and progesterone-plus inhibin, which aids estrogens in exerting an inhibitory effect on the anterior lobe of the pituitary gland via a negative-feedback [...]