Androgen is a term embracing any of the male sex hormones, substances that induce and maintain secondary sex characteristics in males. The principal androgens are testosterone and androsterone. They are found in the male testes and adrenal glands, in which they are produced; in the blood, in which they circulate; and in the urine, in which they are excreted. Androgens function principally, beginning at puberty, in the stimulation of such secondary sex characteristics as development of the genital organs and maturation of sperm, growth of body hair, and changes in the larynx that lower the voice. They also account for the growth of muscle mass and bonetissue in the developing male. Research Androgen
The epiphysis is the end of a developing bone. It is distinguished from the non-developing segment of the bone by the epiphyseal line. When bones form, calciumsalts are first deposited within the diaphysis, and this calcification spreads outward to the ends of the bone (epiphyses). As this progresses, the periosteal membrane produces a network of fibrils (osteoblasts) in front of this advancing line of calcification, which provides a mesh framework for the ensuing calcification. Once this calcified cartilage has developed, the periosteal membrane sends blood vessels into the bone which carry nutrients as well as regulatory cells known as osteoclasts. The osteoblasts and osteoclasts work together to replace the calcified cartilage with true, osseous material. This process is carried out on the ends of the bones as well, though a layer of uncalcified cartilage demarcates the epiphyses from the diaphysis until later in the life of the bone. Once the true bone has developed, the center becomes hollowed out, which allows for the development
of the marrow and the spongy tissue layer (trabeculae). The growth and development of the bone is regulated by a hormone secreted by the pituitary gland, with new growth taking place at the epiphyseal line. At some stage, however, hormones, secreted by the testes in the male and ovaries in the female, cause this bonegrowth to cease, whereupon the epiphysis fuses to the diaphysis. Beyond this point, which usually occurs earlier in females, the bone undergoes simultanous resorption (where it breaks down and re-absorbs osseous material) and reconstruction. Healthy bone is constantly undergoing resorption and reconstruction, though, in the elderly, the reconstruction of bone is somewhat diminished, making healing of fractures slower. Research Epiphysis
Hydrocele is a collection of serous fluid in some of the coverings of the testicle or spermatic cord, or in the areolar texture of the scrotum. It is generally the result of a strain or an inflammation of the testes. A large tumour is formed, filled with fluid, which has often to be drawn off three or four times a year. A radical cure may be effected by setting up an inflammation which brings the opposite surfaces of the sac into adhesion, and thus obliterates the cavity. Research Hydrocele
The male reproductive system is responsible for generating, storing, and transporting the genetic material contained in the sperm cells, or spermatozoa. The chief organs include the testicles (or testes), the epididymides, the vas deferens, the ejaculatory duct, the urethra, and the penis. Auxiliary organs include the bulbourethral (Cowper's) glands, the prostate gland, and the seminal vesicles. Spermatozoa (sperm cells) contain the chromosomes which will combine with those of the ovum, or egg (produced by the female reproductive system), to form the embryo of a new human. These spermatozoa are generated within the testicles and stored within the epididymides. During sexual arousal, a fluid created by the seminal vesicles and the prostate gland combines with the sperm cells to create semen, which is carried through the urethra and out of the opening, or meatus, in the end of the erect penis. When the semen is deposited in the female vagina, the spermatozoa swim through the uterus to the fallopian tube, where one, or more, may fertilize an egg, or ovum. Research Male Reproductive System
The ovaries are lobe-like structures which are responsible for generating the mature ova, or eggs, in the female reproductive system. They are about the same size as the testes in the male, being about 2.5 cm wide and 3.8 cm long. The ovaries are located on either side of the pelvic cavity and are attached to the fallopian tubes and the upper margin of the uterus by the ovarian ligaments. Within the ovaries are a number of small sacs, called graafian follicles, which contain the maturing ova. The ovaries produce a mature ovum about once every month. When this occurs, called ovulation, the follicle containing the mature ovum erupts from the surface of the ovary and the ovum passes into a fallopian tube. If the ovum is fertilized, the graafian follicle then develops into a corpus luteum. If the ovum is not fertilized, the follicle disintegrates into a small scartissue, called a corpus albicans. In addition to generating the mature ova, the ovaries also produce female sex hormones, such as estrone and estradiol, which regulate mammary growth, placental development, and menstruation. Research Ovaries
The scrotum is the protective skin pouch which contains the testes (testicles). It is located in the groin, on the outside of the abdominal cavity. This positioning allows the testicles to remain at a temperature slightly below body temperature, a critical condition in the development of viable spermatozoa. After puberty, the hair begins to grow on the scrotum and nearby skin. This pubic hair remains for the rest of the adult life. Research Scrotum
The testes consist of two oval-shaped glands about three centimeters long and two centimeters wide. The testes are suspended in a sac called the scrotum outside the body to maintain the lower temperature necessary for efficient sperm production. Each of the testes consists of several lobules, and each lobule consists of a narrow, but long, coiled seminiferous tubule. From the age of puberty, the cells of the seminiferous tubules are almost continuously producing spermatozoa (sperm), the male reproductive cells. Other cells, referred to as interstitial cells, secrete the male hormonetestosterone into the blood. These cells are located in numerous clusters in the connective tissue between the seminiferous tubules. Testosterone performs several functions: it is important to the development of masculine characteristics, it promotes and maintains the development of the male accessory organs (the prostate gland, seminal vesicles, etc.), and it has a stimulating effect on protein anabolism. Research Testes
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Research Testes
