Your heart, blood and blood vessels are called your circulatory system because they deliver everything your body needs as it operates continuously in a circle starting with your heart. The power of your heart pushes your blood through vessels called arteries. Arteries have thick muscular walls which help squeeze blood to your cells. Your arteries get smaller and smaller forming capillaries as they branch out to reach every cell in your body. Some capillaries are 10 times finer than a human hair and so narrow that red blood cells squeeze through them in single file. Food, energy and oxygen slip through the thin walls of the capillaries to the cells and waste products from the cell squeeze into the capillaries. The capillaries join back together to make larger vessels called veins, which carry the blood back to the heart to complete the circle. What an amazing system!
During our lives, the heart performs a staggering amount of work. Your heart beats 100,000 times each day. That's over 42 million times a year! Your heart pumps over 40 tons of blood a day, which is more than the weight of 6 full-grown elephants. A child weighing 50 pounds has about 1 and 1/2 quarts of blood in its body. As you grow into an adult, your body will hold 5 - 6 quarts of blood. The heart muscle is unlike any other muscle in the body, working by itself, contracting and relaxing in rhythm without any prompting. Take a few minutes and press a hand against the middle of your chest and you should feel your heart pounding away inside.
Bone is living material and is said to be as strong as concrete. However, a lot of force or pressure can cause a bone to break or fracture. Broken bones heal best if they are kept still and in the correct position with a splint or cast for 6 - 8 weeks.
When a bone breaks, blood from the damaged blood vessels form a clot around the fracture. New cartilage forms and holds the two parts of bone together. Bone cells gradually take over and new bone grows, knitting the break together.
We can keep our bones strong by eating a healthy diet including foods with rich sources of calcium, phosphorous, and vitamin D. Some food sources with these nutrients are milk, eggs, cheese, nuts, fish, and meat.
Your bones are like the framework of a building. Without a skeleton, you would look like a blob of jelly unable to move. Bones not only support your body and enable movement but they also protect important organs in your body. The bones in your skull protect your brain, eyes and inner ears, while those in your spine protect the nerves in your spinal cord. Your ribs protect your heart, lungs, liver and stomach. Bone is four times as strong, in relation to its weight, as concrete.
Nurse Ray and Nurse Shirrel would like to continue the weekly wondrous body facts and for the next several months the focus will be on the skeletal system or bones.
Did you know that babies are born with over 300 bones and yet adults only have 206 bones. What happens to the other bonees? As you grow, some smaller bones join to make one bone.
Everyone has a unique pattern of wrinkles on the outer surface of the brain. This part of the brain is called the grey matter. This is where all the messages from the senses are received and signals for body movement are sent to the muscles. All this activity uses lots of energy and oxygen which is suppied by the bloodstream. Your brain utilizes about 9 gallons of blood every hour.
Scientists think people are born with a range of possible intelligence. How smart you become depends on how much you exercise your brain. You can't add brain cells but you can add connections between the cells which makes your brain faster and more powerful.
There are 10 to 100 billion nerve cells in your brain. Millions fo nerve signals enter your brain every second of your life at speeds of 180 miles per hour.
The brain consumes 1/5th of all the energy used by the body. This means the brain is 10 times more energy-hungry than any other body part. That's why it is so important to eat a good breakfast each day before you come to school.
Nurse Ray and Nurse Shirrell think the human body is fascinating and plan to share a weekly, wondrous body fact each Monday. Our hope is to increase awareness, respect, and knowledge about our bodies. We will start with the brain and nervous system and then cover a new body system every one - two months.
So, here"s an interesting fact about your brain: the human brain is about 1/50th of the total body weight, weighing about three pounds and consisting of 85% water. Dolphins, one of the most intelligent animals have a brain 1/120th of its total body weight. Humans have the largest brain in comparison to any other animal that has ever lived.