The Human Body - Systems Working Together (1980)

[Music] um the human body is composed of trillions of separate cells in their needs cells are not much different from the people in any large community the people have to depend on each other from any specialized services that provide them with food and clothing information and transportation and fill other vital needs and it's very much the same with your cells all cells carry on the same basic life functions but cells also specialize there are bone cells and skin cells and muscle cells by coordinating their specialized functions cells form tissues and tissues form organs and then the organs themselves work together in various combinations to help your body carry out its vital functions we call these combinations the systems of the human body an organ may be part of more than one system helping to carry on the functions of each of the systems it's part of in fact the idea of a system is simply a human invention helping us organize our understanding of the incredible things going on inside our bodies to understand how the systems of the human body work together we need to see how they maintain the life of the cells and how tissues and organs that are formed of specialized cells interact during a cell's life it uses nutrients for its building materials and its energy it uses oxygen to release that energy and as a result of all this chemical activity the cell produces wastes nutrients oxygen and waste products are all carried by your blood is part of your circulatory system blood flowing through the vessels of that system is the link between the various systems of your body it's both a line of communication and Supply helping your cells perform the necessary and complicated work of keeping themselves and you alive since blood is involved in the functioning and sustaining of all your body's systems we can see how the systems work together by simply following the flow of blood through your body we'll start in the capillaries a network of microscopic thin walled tubular blood vessels that extend into every part of your body through the walls of these capillaries the exchanges of nutrients oxygen and waste products take place between your blood and your cells the blood flows from the capillaries into larger and larger vessels veins and then reaches the main part of the circulatory system the muscle that pumps the blood through your entire body your heart your heart moves your blood through two separate circuits at the same time to your lungs and back and then through your body to all its cells and back blood returning from its circuit through your body is carrying carbon dioxide and other wastes from the cells that blood enters one of the heart's two upper chambers the right one that chamber contracts squeezing the blood into the lower right chamber then that chamber contracts and the blood is squeezed out of your heart and pumped through arteries to your lungs where it picks up oxygen then the blood returns to the other upper chamber of the heart the left one and one circuit is complete the upper left chamber contracts and blood is squeezed into the lower left chamber and when that one contracts the blood is pumped out of your heart and into your arteries now the second circuit begins but remember both upper chambers and both lower Chambers contract at the same time and both circuits take place together allowing your blood to absorb oxygen from the air and then deliver it to the cells of your body The Blood also carries nutrients to your cells your cells use these nutrients both for energy and for raw materials that new cells are built from the nutrients come from the food you eat turning a mouthful of food into something useful that the circulatory system can carry to the cells is the job of your digestive system digestion starts in your mouth your tongue and teeth work together to help you break down the food into small pieces that you can swallow this is mainly a physical breakdown but the food has to be broken down chemically too your saliva starts this chemical breakdown but most of the changes take place further along in your digestive system slow removes the food from your mouth into your esophagus wave-like squeezes of the esophagus muscles push the food along into your stomach the stomach is a muscular Sac that continues the mechanical breakdown of the food by its turning action and continues the chemical breakdown of the food by mixing it with gastric juices that it secretes enzymes that are part of these gastric juices secreted from glands in the lining of your stomach start to break down the complex proteins in your food into simpler parts while some nutrients are absorbed through the stomach wall into the blood vessels that surround it most of the soupy liquid that the food has become is squeezed into the small intestine glands in the upper part of your small intestine secrete more enzymes these along with enzymes from your pancreas and bile from the liver continue the digestion of your food most of the nutrients your body can make use of pass into your bloodstream through walls of capillaries that line your small intestine and what's left substances your body can't use eventually passes into your large intestine and out of your body the nutrients that have passed into the circulatory system are carried first to the liver here some of them are stored or processed further and then carried to your body's cells now the oxygen your cells use to get energy from these nutrients is in the air around you the job of bringing in the oxygen is the responsibility of your respiratory system when you inhale the air humidified and to some extent cleaned as it continues its Journey down your windpipe the windpipe divides into smaller tubes that divide again and again into still smaller branches that extend into your lungs there are air sacs at the ends of these branches oxygen passes through the thin walls of the air sacs and into the capillaries that weave around them uniting chemically with the hemoglobin of the red blood cells that give your blood its color at the same time waste carbon dioxide passes out of your blood through the air sacs joining the Air that brought the oxygen in then when you exhale the carbon dioxide travels with the air it's now part of back up the trachea and out of your body in order to move the oxygen into your body and the carbon dioxide out the respiratory system needs the assistance of other systems besides the circulatory system among them are the muscular system and the skeletal system your lungs are surrounded supported and protected by your ribs part of your skeletal system and by a thick sheet of muscle under them your diaphragm part of your muscular system there are also muscles attached to your ribs when these muscles contract they lift the ribs at the same time the diaphragm contracts and flattens out both of these actions increase the space inside your chest expanding your elastic lungs air pressure inside your lungs drops and the higher outside pressure pushes air into your lungs through your nose and mouth [Music] when the muscles pulling on your ribs and your diaphragm relax the stretched elastic lungs return to their original smaller size squeezing out the air the whole process repeats itself or Every Breath You Take there are many other ways in which the muscular and skeletal systems work together for instance the skeletal system provides the framework for your body or the muscular system holds that framework together and makes it move your arm is a good example of this partnership a muscle is anchored with a tendon to one end of your lower arm bone when the muscle contracts it moves the lower arm bone since a Muscle Works only by Contracting you need another muscle to move your arm in the opposite direction when the muscle on one side pulls the muscle on the other side relaxes but not all muscles in your body are skeletal a second type of muscle cell forms the tissues of your heart the muscle that powers your circulatory system and the third type is especially important in your digestive system these muscles create the waves in various organs that move your food along muscle cells like all the other living cells of your body need nutrients and oxygen to survive the digestive system provides the food the respiratory system the oxygen and the circulatory system delivers both to your cells but this process of converting food into energy produces wastes that have to be removed these wastes are mainly water heat carbon dioxide and various poisonous chemicals their removal is mostly the responsibility of the excretory system after your blood picks up the wastes from the cells it carries them to the various organs of the expiratory system that will dispose of them most of the water and various other unneeded or poisonous substances are eliminated by your kidneys two large arteries carry your blood to that pair of organs in the kidneys excess water and poisonous waste materials are filtered out of the blood then pass out of the kidneys and into the bladder for removal from the body carbon dioxide of course is eliminated through the lungs but the lungs also help your body get rid of waste heat and water heat and water as well as some mineral salts are also eliminated through the skin your skin is an important organ of your excretory system but the skin is also involved in another of your body systems woven through your skin is a fine network of nerves that help you sense heat and cold pressure and pain these nerves are part of your nervous system your nervous system extends its Network to all parts of your body it's formed of billions of very specialized nerve cells called neurons when they're stimulated neurons generate and pass on electrochemical impulses from one nerve cell to another in this way impulses can move along the length of the nerves the neurons form nerve cells like all the other cells of your body depend upon food and oxygen obtained by the digestive and respiratory systems and delivered by the circulatory system and the waste products are disposed of by the excretory system your nervous system helps you keep in touch with the world outside your body as well as keeping you aware of some of the things going on inside it nerves all over your body are linked to your spinal cord and your spinal cord is linked to your brain the complexly interconnected nerve cells of your brain allow you to think and feel talk and dream see and understand your brain and the rest of your nervous system exercise most of the control over your other systems your nervous system controls your circulatory system by regulating the rate of your heartbeat it controls your respiratory system monitoring the level of carbon dioxide in your blood and activating the muscles that make you breathe it also controls all your other muscles sending them signals that cause them to contract to relax and it keeps track of the way they move you your nervous system also affects the behavior of a tiny group of Highly specialized cells hanging by a stalk from your brain this is the pituitary gland that controls the activities of most of the other glands of the system it's part of the endocrine system endocrine glands secrete powerful chemical Messengers called hormones these hormones pass directly into your bloodstream and are distributed by your blood to certain target cells whose activities they affect and coordinate hormones from the endocrine system control the way you grow how rapidly your body uses the food you eat the balance of all sorts of substances in your blood the endocrine system also secretes hormones that affect the development of your reproductive system through the activity of your endocrine system your reproductive system matures only the mature male and female reproductive systems can reproduce the human body two kinds of cells are needed for human reproduction and exhale from a woman and a sperm cell from a man when these two cells unite a fertilized egg is produced inside the woman's body the egg begins to divide and grow dependent on the systems of its mother's body eventually it will develop systems of its own that will help to support its existence as an independent new human being the people of a community depend on each other for the necessities of their lives like the trillions of cells that form your body organized into tissues and organs that coordinate their activities the cells are able to feed protect and support each other one system intimately coordinated with another systems working together interrelated and interdependent keeping alive and healthy an incredibly complex living organism the human body [Music] [Applause]