Sperm are produced in the male testicle (testis). The testis is filled with tiny coiled tubes (seminiferous tubules) through which sperm move as they are produced. Each seminiferous tubule is lined with sperm nurse cells (Sertoli cells) and sperm stem cells (Spermatagonia).

Instant face-lift tape sounds too good to be true. In a nutshell, you apply it to your forehead to pull the skin up for a smoother appearance. While reviews are fairly mixed for the results, knowing how to use the product properly can increase your chances of a good result.

The peripheral, sympathetic and parasympathetic nervous systems in your body are responsible for calming the nervous system.

According to the National Institute of Mental Health, 6.7 percent of American adults suffer from major depressive disorder, or severe depression. For many of these patients, physicians will prescribe the selective serotonin reuptake inhibitor sertraline, or Zoloft, to treat their symptoms of depression.

Radiation exposure originates from many sources, not just the fallout from nuclear weapons or power plants. Other sources of radiation include X-rays, microwaves, power lines, cell phones and computer monitors.

Pregnancy requires many body systems -- including your cardiovascular system -- to make major changes, including elevation of your heart rate. However, elevated heart rate can also indicate an underlying problem.

As a person's heart beats, it pumps blood through their vascular system. For blood to flow from the heart to the tissues, the arteries must be pressurized. High blood pressure can cause organ and tissue damage, while overly-low blood pressure can mean that tissues aren't getting enough oxygen.

Swollen glands in the neck can have a variety of causes ranging from flu, mononucleosis, a tooth abscess or an infection of a salivary gland. Regardless of the cause, swollen glands are usually painful. Using home remedies to help reduce swelling and pain may be helpful in certain conditions.

Calcium bentonite clay contains calcium, magnesium, sodium and trace amounts of a number of other minerals. The clay is made from volcanic ash deposits that have settled on the earth. The ash has settled over the course of hundreds to thousands of years, which allows a variety of the earth's nutrients to be absorbed.

Toddlers learning to explore their world often take tumbles that result in nasty bumps to the head. It is important to be able to determine if your child may have sustained a concussion.

Whenever you have a tooth pulled, especially a molar, there is a risk of developing a dry socket. This is a painful and sometimes long-lasing result in about 3 percent to 5 percent of all tooth extractions, according to the Columbia University College of Dental Medicine's website, Simple Steps.

If you've ever tried to move your ears, you'll notice that it's not the ears themselves that move but the muscles surrounding them. Muscles in the scalp and in the face, jaw and the neck may facilitate movement of the ears, according to Jocelyn Selim in the June 2004 issue of Biology and Medicine.