Ear pain can come from a long list of conditions, but if your ears only hurt when you eat, the list of causes narrows considerably. If you go about your day or sleep at night without feeling pain in your ears, two scenarios are likely to be the cause.

Your arm and shoulder contain many different muscles that allow you to perform daily activities. Showering, getting dressed, driving, lifting, carrying and sports activities all require these muscles to function together to coordinate movement of your shoulder, elbow and wrist.

The reproductive system is the key to the procreation and survival of the human race. Human reproduction is the effort of a male and female that involves four functions of the reproductive systems. According to Librarythinkquest.

Hotness of the ears might cause discomfort and interfere with typical daily activities such as listening to music, talking on the phone or even participating in face-to-face conversations. Hotness that persists, worsens or is accompanied by other symptoms such as ear or facial pain might require medical evaluation.

Serotonin and melatonin are both hormones that regulate various human functions such as sleep, appetite and mood. Serotonin, which is produced in the body, is known as a neurotransmitter; this means it is responsible for sending messages between nerve cells.

An understanding of how the respiratory and cardiovascular systems interact requires knowledge of how each of the systems function independently. The cardiovascular system in the human body is made up of the heart and blood vessels, which are divided into arteries, veins and capillaries.

Regular physical activity is crucial when it comes to maintaining -- and building -- muscle mass and bone density. Despite its many benefits, though, exercise is also associated with the development of some side effects, such as leg weakness.

The body has two lines of natural defense to protect against infection. The first are physical barriers, such as the skin, body secretions and mucous membranes. The second line of defense is the immune system.

There are 206 bones in the human body. They come in many shapes in sizes, molded generation after generation to articulate with one another providing support for the body. Bone is composed of hard dense tissue, blood vessels, and nerves. Bones anchor muscles and oppose muscle contractions allowing a limb to move.

Ear plugs can be used for protection from noise or water. These small, ear-canal shaped devices can be made of foam, plastic or wax and fit into the ear canal, according to Occupational Health & Safety, a health resource site dedicated to workplace safety.

Emotions, like fear and love, are carried out by the limbic system, which is located in the temporal lobe. While the limbic system is made up of multiple parts of the brain, the center of emotional processing is the amygdala, which receives input from other brain functions, like memory and attention.

Enterococcus faecalis is a strain of bacteria that is known as a commensal organism in the intestines. This means that it is normally found in the intestine, particularly the large intestine, of most human beings.