Your Body: A Peek Inside
Anatomists are people who study the human body.
Everyone is unique. We have different skin colors, hair colors, body shapes and sizes — but we all look alike inside. If you could peek inside your own body, what would you see? Hundreds of bones, miles of blood vessels, and trillions of cells, all of which are constantly working together, doing all kinds of different things.
Main job: To protect your internal (inside) organs from drying up and to prevent harmful bacteria from getting inside.
How much: The average person has a total of six pounds of skin.
Skin facts: Your skin …
… is flexible so that you can bend and stretch.
… feels heat, cold, pain, pressure, moisture, irritation, and tickles because it has nerves.
… heals itself when wounded.
… keeps heat in on cold days and releases it as perspiration on hot days.
… is a watertight container for your body.
The largest bone in the body is the femur, or thigh bone; it is 20 inches long in a 6-foot-tall person.
Main job: To give shape to your body.
How many: At birth you had more than 300 bones in your body. As an adult you'll have 206, because some fuse together.
The smallest bone is the stirrup bone, in the ear; it is .1 inch long.
Kinds of Bones
Bones don't bend. It is the joint that allows two bones next to each other to move.
Main job: To allow bones to move in different directions.
Main job: These bands of tough tissue hold joints together. They are strong and flexible.
Every day, the average person's muscles work as hard as if they were placing 2,400 pounds on a 4-foot-high shelf.
Main job: To make involuntary or voluntary body movement possible.
How many: Your body has more than 650 muscles. Each muscle does only two things: contract when being used and expand when resting.
Kinds of Muscles
Your fingers are mostly powered by muscles in your palm and wrist.
Main job: To hold your muscles to your bones.
Tendon fact: Tendons look like rubber bands.
This term refers to the organs, including the trachea or windpipe, lungs, liver, gallbladder, spleen, stomach, large intestine, small intestine, and bladder, that fill your body's chest and abdominal cavity. They belong to many different systems: respiratory, digestive, and urinary.
Main job: To provide your body with food and oxygen and to remove waste.
How many: The viscera are made up of 10 organs.
Main job: To manufacture substances that help your body to function in various ways.
Kinds of Glands
There are 26 billion cells in a newborn baby and 50 trillion cells in an adult.
Main job: To perform the many jobs necessary to stay alive, such as moving oxygen around your body, taking care of the fuel supply, communications, and waste removal.
Some Different Cells
Fact Monster/Information Please® Database, © 2007 Pearson Education, Inc. All rights reserved.