The Human Body From Head To Toe

Astounding facts about the human body you never knew

Published on July 22, 2012 by Alex Lickerman, M.D. in Happiness in this World

Photo: adrigu

One of the reasons I was drawn to medicine is that I've always been fascinated by the workings of the human body on all its levels. Truly, nothing in nature stands as its equal—flaws and all (and there are a few). So I thought today I'd share just a few of the fascinating facts about the way the human body works that many people don't know. From the bottom up:

• Feet: The average person walks about 10,000 steps a day. Twenty-five percent of bones in the human body are located in the feet, which are made up of 52 bones. The plantar fascia, or connective tissue, on the bottom of the feet is about the toughest soft tissue in the body and carries approximately 14 percent of the total load of the body with each step. Experiments on cadavers suggest that this fascia can withstand a force of up to 12 g, or 12 times the force of gravity, before it ruptures.
• Knees: All bone comes from the ossification (hardening) of cartilage, but this happens at different rates. Babies, in fact, don't have kneecaps at all. They have a small piece of cartilage in each knee that eventually turns into their kneecap by about the age of three.
• Liver: The liver has many jobs, most of which are essential for life. If your liver stopped working entirely, you'd die within about 24 hours. (And one thing that can destroy it, after a few day's delay, is a massive overdose of Tylenol.) It's the second largest organ in the body, second only to the skin. The liver is the only internal organ that can regenerate itself (as little as 25 percent of the liver can regenerate into a whole new organ). Further, only 10 percent of the liver needs to be functioning in order for blood to clot normally.
• Pancreas: The pancreas both makes insulin and digestive enzymes. It's a brittle organ in that even ginger handling of it during surgery can cause potentially life-threatening inflammation. You can't live without a pancreas—not because of the work it does digesting food but because no other organ in the body makes insulin.
• Intestine: More bacteria live in our intestines than there are cells in our bodies. We're just beginning to understand the benefits of our intestinal flora and what may happen when it's disturbed. You can't feel pain in your intestine when it's cut. You only feel pain when the intestine is distended. The intestine also has its own nervous system ("the enteric nervous system") whose functions we are only beginning to figure out.
• Stomach: You don't need your stomach to digest food, but people who've had theirs removed must eat frequent small meals or risk regurgitation. Despite the fact that stomach acid is similar in strength to battery acid, the inner lining of the stomach tolerates it with ease.
• Heart: When athletes train, their hearts enlarge to about 500 grams and no larger. Any increase in fitness thereafter comes from an increase in their exercising muscles' ability to extract oxygen from blood. Hearts that enlarge past 500 grams do so pathologically as a result of heart failure. Your heart beats about 35 million times each year and with each beat contracts with enough strength to shoot blood a distance of up to 30 feet (I have, unfortunately, seen this). Amazingly, all the muscle in the heart together could lift 3,000 pounds! The total length of blood vessels into which the heart pumps blood is approximately 60,000 miles (this figure includes blood vessels all the way down to capillaries). Within in 24 hours of quitting smoking, your risk of dying from a heart attack drops by 50 percent.
• Lungs: The lungs have two circulatory systems, one from which it absorbs carbon dioxide and to which it imparts oxygen to be delivered to the tissues of the body by the heart, and another from which it pulls oxygen for its own tissues. We lose half a liter of water every day through breathing. The reason premature babies can't survive well outside of their mothers' wombs is because their lungs are often deficient in pulmonary surfactant, which reduces the surface tension in their alveoli (air sacs) and allows the lungs to inflate at the pressures that babies are able to produce.
• Brain: The brain is the pinnacle of evolution, a control center that runs the body above which it sits and which is simultaneously aware of itself doing so. It weighs only three pounds but contains 100 billion neurons, each of which makes about 10,000 connections to it neighbors, which means, according to author and neuroscientist David Eagleman, "there are as many connections in a single cubic centimeter of brain tissue as there are stars in the Milky Way galaxy." And as many neurons as their are in the brain, there are even more glial cells (1-5 trillion), whose function seems to be to support the functioning of neurons. Among all the facts I know about the brain, this one currently fascinates me the most: according to the work of one of my colleagues, Richard Kraig, thinking represents an aversive stimulus (it creates actual inflammation in the brain) that, if followed by a period of rest, actually strengthens neurons. That is, it makes them more resistant to migraines, seizures, and even dementia.

Obviously, this list barely scratches the surface of this most enigmatic of life forms, ourselves. When I think about how intricate the human body's systems are and how harmoniously they work together (in health), I find it amazing that we evolved from single-celled organisms. Yet evolve we clearly did. And as often as I see things go wrong, I often find myself marveling, when I think about the incredible complexity of the human body, how often things go right.

When Your Spouse Is Out of Work, What's a Good Way to Talk About It?

Many years ago while my wife was pregnant with our first child, I took a workshop based on Parent Effectiveness Training by Dr. Thomas Gordon. The book emphasizes active listening, a communication technique, which requires the listener to feed back to the speaker what she/he hears by re-stating or paraphrasing. The feedback also can consist of labeling the emotion that the listener thinks underlies the speaker’s message. Dr. Gordon’s approach to communication has been central to improving my parenting skills as well as my work as a psychologist. Not surprisingly, I have used his methods to help clients improve communication skills with their children, bosses, employees and spouses. Inevitably, the vast majority reports improvement in their ability to communicate and resolve conflicts.

Unemployment impacts significantly on the entire family. Men and women sometimes find themselves unsure of how to respond to their spouse. Should they make suggestions, act as a cheerleader or just stay out of the way? I strongly suggest one strategy: be a good listener. A good listener can be as helpful as a good advisor. Think back, have you ever called a friend to talk about a problem you faced and come to a solution even though your friend said very little? Sometimes just having someone listen to you is the best help you can get.

When someone is under emotional strain—like a person who is unemployed—what he or she says is often distorted by the strong feelings driving the message. An active listener sometimes restates a speaker’s statement; thereby, giving the other person a chance to hear and reconsider what they are saying. This can enable the speaker to clarify the message and sometimes identify their feelings. Talking through what someone is thinking and feeling can help them stay motivated and on task.

Let’s assume the husband is the unemployed member of the family. For instance he comes into the kitchen and says angrily: “Isn’t dinner ready yet!” You might be tempted to respond angrily yourself, but try restating his message: “You’re really hungry, aren’t you?” Responding by restating helps the speaker hear what they are saying and gives them a chance to restate their message more clearly. He answers: “I worked all day on the computer looking for a job. I really don’t think I got anywhere.” His wife responds by identifying the emotion underlying his second message: “Sounds like searching for a job has you really frustrated and angry.” He realizes he is not really angry that dinner isn’t ready but frustrated at the process of looking for work. Labeling the emotion that underlies a message facilitates the release of emotions. He responds: “I need to take a break. When will dinner be ready?”

The first step for the listener is to maintain good eye contact and focus on the message. It is important to pick a time and place where there are no distractions so that you can stay focused on what your husband is saying. While listening, try to repeat in your own words what your spouse says. Avoid trying to provide solutions or advice. The goal is to convey you are there for him/her. It isn’t necessary to respond verbally to everything they say. Sometimes silence is enough. Use body language like nodding your head to indicate your interest and attention.

In summary, active listening is a great way to help your spouse through the emotional storm of unemployment. Do not jump in with solutions, judge or criticize. Listen intently, sometimes just restating what you heard and, at other times, labeling the emotion underlying his message. The unemployed often withdraw and feel socially isolated. Active listening will communicate your acceptance and your willingness to help.