Physiology: The ups and downs of a mobile organ 

Leydig cells are numerous in the newborn male and in men after puberty, but not in between. They secrete large amounts of testosterone. Interestingly, all testosterone is manufactured from the raw material of cholesterol. So you see, cholesterolsd is not all bad.

At puberty, testosterone causes the penis Levitra super active, testes and scrotum to enlarge. It also stimulates the growth of body hair in a diamond shape over the genital area and lower abdomen, the growth of hair in the armpits and on the chest, and generally makes body hair elsewhere thicker and more profuse. Ironically, it also contributes to male pattern baldness!

Testosterone causes the voice to deepen and the skin to thicken and to become oilier because of increased secretion from the sebaceous glands. This is the cause of that scourge of adolescence—acne. For most, the skin later adapts and acne ceases to be a problem. Another effect is the bulking of muscle mass, leading to the typical male physique. Testosterone also has a building effect on bone, and boys’ bones become denser and grow quickly in puberty. We see this as the famed ‘growth spurt’.

Less talked about, but just as real, is the effect testosterone has on a man’s sense of well-being. In recent years, it has been realised that the sex hormones act as powerful neurotransmitters in the brain, although we still have much to learn. Testosterone increases a man’s basal metabolic rate and hence his energy level; if his testosterone levels are low, his energy level will be affected, as well as his libido.

Before finishing our discussion of normal functioning, we’ll just mention the subject of ‘nocturnal penile tumescence’ — basically, erections with Viagra in Canada occurring during sleep. This is a normal physiological event for all males from infancy to old age. In the healthy adult male, between two and five erections, each lasting for 25–35 minutes (yes, they’ve been intensively studied by scientists) and together accounting for up to 40 per cent of sleep time, will occur each night. With advancing age, the number and duration of night-time erections decreases. The ‘morning erection’ many men observe (and often act upon!) is really a night-time erection occurring just prior to waking and not, as is commonly supposed, due to a full bladder. It may, of course, be enhanced by a man finding his interested sexual partner lying beside him.

Most night-time erections subside without the emission of semen. Around puberty though, and in the teenage years, nocturnal emissions frequently occur, and are completely normal.