The expression “frog in your throat” doesn’t come from sounding like a frog because you have a cold or sore throat. It originates from an actual Middle Ages medical treatment for a throat infection.
Doctors believed that if a live frog was placed head-first into a patient’s mouth the animal would inhale the cause of the hoarseness into its own body. Thankfully, the practice is long gone, but the expression “frog in your throat” lives on.
Walking is a great way to exercise. Walking burns calories, strengthens back muscles, strengthens bones, reduces stress, helps improve your mood, helps you sleep better, and requires no equipment. Best of all, it is free and can be done almost anywhere! Walking also helps build community. A simple wave as you walk by your neighbors’ yard helps strengthen community connections. Walking, instead of driving, also reduces traffic congestion and pollution. It is important to be careful when you walk. During the day, wear bright, light clothing; at dusk, dawn, or nighttime, wear reflective clothing, with strips of material or tape attached that bounce back light. Be careful.
Always look both ways before crossing the street, obey traffic signals, and use the crosswalk. Be aware of all traffic, and make sure that drivers see you by making eye contact with them before you cross the street. Walk against the direction of traffic whenever possible. And remember, too, that walking with a friend is always safer than walking on your own. Encourage a friend or family member to join you! Be thoroughly familiar with your route. Know the location of phones, police or fire stations, and businesses, and always bring along some form of identification, like a school ID card.
As people age, their bodies change in many ways that affect the ways their cells and organ systems function. These changes occur little by little, progress over time, and are different for every man and woman. We all lose height as we age, and by the time we reach 80 years old, our height may have decreased by two inches (five centimeters). Changes in posture, in the growth of our spine’s vertebrae, and joint changes all contribute to our loss of height. With aging, the hair follicles produce less melanin, the pigment that gives hair its color.
Hair becomes lighter, gray, and eventually turns white. The nails also change with aging: they grow slower, may become dull and brittle, and may become yellowed and opaque. With aging, the outer skin layer (epidermis) thins and the number of pigment-containing cells (called melanocytes) decreases, but the remaining melanocytes increase in size. Aging skin thus appears thinner, more pale, and translucent. Changes in the connective tissue reduce the skin’s strength and elasticity, resulting in a wrinkly, leathery skin.
The immune system protects the human body against germs, which are microorganisms that cause sickness and disease. There are four major types of germs— harmful bacteria (pathogens), viruses, fungi, and protozoa. This defense system begins with the skin, which stops germs from getting into your blood or tissues. If germs get into your body, for example through your nose or mouth, white blood cells called phagocytes and lymphocytes attack them. Phagocytes scout out and destroy invaders, and long-living lymphocytes remember the invaders and release chemicals called antibodies to make the body resistant, or immune, to them.
White blood cells live in the bloodstream, lymphatic system, and spleen. The lymphatic system (or lymph system, for short) is a far-reaching network that extends throughout your entire body. A clear liquid called lymph runs throughout the system, washing the body’s cells with nutrients and water and detecting and removing pathogens. Lymph is filtered through the lymph nodes, and then passes into the body’s bloodstream.
Your spine, also called the backbone, runs down the length of your back from the base of your neck to your pelvis. The spine has 25 joints connecting 33 individual bones. (The bottom four bones of the spine are fused together to form the terminal vertebrae called the coccyx, or tailbone—and the five bones above that are fused together to form the sacrum. They are caged within the bones of the pelvis.) Each bone in the spine is called a vertebra and they are grouped together to perform specific tasks.
The spine supports your head, lets you twist and bend, and holds your body upright. It also protects the spinal cord, a large bundle of nerves that sends information from your brain to the rest of your body.
As the young red blood cell grows and takes on an adult form in the marrow of the bone, it loses its nucleus, and it increases its production of hemoglobin. Hemoglobin is the red pigment, or color of blood, and contains iron, combined with protein. (Oxygen combined with iron is red; the more oxygen iron has bound to it, the redder it is.)
When blood passes through the lungs, oxygen attaches itself to the hemoglobin of the red cells. From there, the red cells carry the oxygen through the arteries and the capillaries to all other cells of the body. The arteries appear reddish because the iron in the blood gives up its oxygen to the cells that need it as the red blood cells travel throughout the body. By the time the blood is back on its way to the heart and then to the lungs it has less than half as much oxygen as it did before. The veins, therefore, do not get as much oxygen as the other tissues and they appear bluish.
Muscles are attached to bones by tendons, the longest and strongest of which is called the Achilles tendon in your heel. This thick band of tissue attaches the muscles of the calf to the heel bone and is the key to the foot’s ability to flex.
The Achilles tendon allows you to push off of your foot when walking or running. In ancient Greek myth, the hero Achilles died from a wound to his heel, so the popular expression “Achilles heel” often refers to a physical weakness or limitation.
Human beings communicate through language, a complicated system of vocal symbols that our complex brains allow us to learn after we are born. But we also communicate through our bodies and senses. Our organ of touch is our skin, covering the outside of our bodies. (Nerve endings under the surface of skin give us our sense of touch.) Hugging and kissing are ways to share love and caring through touch. When you were born, well before you knew language and could understand caring words, you were learning about love through your sense of touch. As a newborn, when everything was frighteningly new, you immediately experienced the comfort of touch when you were held in your mother’s arms, feeling the warmth of her body and the beat of her heart, sensations familiar to you when you were inside her womb. You were held close when you first learned about food and about how good it felt to have milk in your empty stomach.
Your parents’ caring hands kept you clean and dressed in dry clothes when you could not yet do those things for yourself. So, from your earliest days, you learned that someone’s touch usually made you feel comfortable and safe. Loving and caring about special people in our lives is a feeling inside that is hard to describe in words. But hugs and kisses make it easy to show that love—and their message is clear. Giving hugs and kisses feels as good as getting them. (Because the lips have an extra supply of nerve endings, kissing is an especially intense way to touch.) The human need to share affection through touch is something we all experience throughout our lives.
All living things need water to survive. Without water, the human body stops working properly. Water makes up more than 50 percent of your body weight and a person cannot survive for more than a few days without it. Water flushes toxins out of your organs, carries nutrients to your cells, and provides a moist environment for ear, nose, and throat tissues.
Water is also in lymph, a fluid that is part of your immune system, which helps you fight off illness. You need water to digest your food, to get rid of waste, and to sweat. Too little water in your body leads to dehydration, and it can make you tired and unable to function. Your body gets water from drinking it, but lots of foods, such as fruits and vegetables, contain water too.
The fastest growing hairs on the human body are men’s beard hairs. If the average male never trimmed his beard, it would grow to almost 30 feet (9 meters) long in his lifetime.