Tag: zoology

Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle. They produce testosterone in the presence of luteinizing hormone (LH). 

In men, testosterone plays a key role in the development of male reproductive tissues, such as the testis and prostate as well as promoting secondary sexual characteristics, such as increased muscle, bone mass, and the growth of body hair.

The male sex hormone testosterone is produced by Leydig cells. These cells are located in the connective (interstitial) tissue, that holds the tubules together within each lobule. The tissue becomes markedly active at puberty under the influence of the interstitial-cell-stimulating hormone of the anterior lobe of the pituitary gland.

In men, testosterone plays a key role in the development of male reproductive tissues, such as the testis and prostate as well as promoting secondary sexual characteristics, such as increased muscle, bone mass, and the growth of body hair.

In women, relaxin is secreted into the circulation by the corpus luteum in the ovary. During pregnancy it is also released from the placenta, the membranes, which surround the foetus, and the lining of the uterus. During pregnancy, relaxin levels are at their highest in the first trimester. At this time it is believed to promote implantation of the developing foetus into the wall of the uterus and the growth of the placenta. Towards the end of pregnancy, relaxin promotes rupture of the membranes surrounding the foetus and the growth, opening and softening of the cervix and vagina to aid the process of childbirth. Relaxin can relax the ligaments at the front of the cervix to ease delivery of the baby. 

Androgens include the male hormones testosterone and androsterone and promote development of male sex characteristics. The androgens promote the secondary sex characteristics of muscle growth, lowered voice range, the Adam's apple, and increased body hair.

Glucagon's role in the body is to prevent blood glucose levels dropping too low. It acts on the liver and stimulates the conversion of stored glycogen (stored in the liver) to glucose, which can be released into the bloodstream. This process is called as glycogenolysis.

Gynaecomastia is enlargement of the male breast tissue. Oestrogen stimulates breast tissue growth, while androgens inhibit it. The important factor is the ratio of active androgens to oestrogens. The ratio can be altered as a result of reduced testosterone production/action or enhanced oestrogen production/action or both. 

The major sex hormone in men is testosterone, which is produced mainly in the testes. They are crucial for male sexual and reproductive function. They are also responsible for the development of secondary sexual characteristics in men, including facial and body hair growth, and bone and muscle development.