Unit Two Circulatory System Lisa Michelek

Transport After digestion is completed, nutrients go into the blood stream and are transported to the cells of the body. In the cells, nutrients are chemically combined with oxygen and energy is released. Transport is the process of absorption and circulation of materials throughout the body.

Transport Absorption involves the passage of materials into and out of the bloodstream. Circulation is the distribution of materials to all parts of the body. The transport system is also called the circulatory system. The circulatory system is made up of the heart, blood vessels, blood, lymph and lymph vessels.

Circulation Blood flows in a circle throughout the body and is used over and over. Blood moves in a continuous pathway of blood vessels. This system provides the body cells with needed substances and carries away cellular excretions.

The Heart The heart is a muscular, four-chambered organ. The heart pumps blood through blood vessels adjusting the rate and flow and pressure to changing body requirements. watch?v=BEWjOCVEN7Mhttps:// watch?v=BEWjOCVEN7M

Blood Vessels Blood vessels are tubes that transport blood to and away from body parts. The three major types of blood vessels are: –arteries, –veins, –capillaries.

Arteries Arteries are blood vessels that carry blood away from the heart. Because they are very muscular and elastic, they help pump blood through the body. To do this, they expand and then snap back to normal size. –This expansion and snapping back of the arterial walls is called the pulse. Blood in the arteries is under pressure from the pumping action of the heart. –This pressure is called blood pressure.

Capillaries The capillaries are the smallest blood vessels. They are one-celled, microscopic blood vessels that connect arteries to veins. Exchanges of oxygen and carbon dioxide, between the blood and body parts takes place through the capillary walls. This exchange takes place by diffusion.

Veins Veins are blood vessels that transport blood under low pressure from the capillaries back to the heart. Veins have valves that prevent the backflow of blood.

Composition of Blood Blood is the liquid that transports materials throughout the body within the blood vessels. Plasma, red blood cells, white blood cells, and platelets make up the blood. Plasma is the straw colored, non-living part of blood. –Plasma is 90% water. –Plasma transports blood cells, end products of digestion, hormones, cellular excretions, and antibodies throughout the body. –Plasma also helps to regulate body temperature.

Red Blood Cells Red Blood Cells are shaped like round plates that are indented in the center. –Mature Red Blood Cells do not have a nucleus. Blood appears to be red because red blood cells contain the iron-rich pigment hemoglobin. –Hemoglobin carries oxygen from the lungs to the body cells.

Platelets Platelets are smaller than either red or white blood cells and do not contain a nucleus. They live only 2 to 4 days and are very numerous. Platelets are involved in the clotting of blood.

White Blood Cells White blood cells fight infections and are part of the body’s defense or immune system. They are irregular in shape and have no color. White blood cells are larger than red blood cells and have a nucleus. There are fewer white cells than red cells unless they are fighting infection, when they increase in number.

White Blood Cells There are several different types of white blood cells. Some, called phagocytes, aid in fighting disease by engulfing (ingesting) bacteria, viruses, and other foreign organisms. –Phagocytes engulf bacteria the same way amoebas engulf food. Other white blood cells (lymphocytes) produce proteins known as antibodies. –Antibodies are produced when foreign particles, antigens enter the body. –Some common antigens are bacteria and foreign tissue.

Lymph and Lymph Vessels Lymph comes from the portion of the blood plasma that diffuses out of the capillaries. This fluid is also called intercellular fluid or tissue fluid. This intercellular fluid helps transport dissolved materials between capillaries and cells. Excess intercellular fluid enters lymph vessels and is circulated through these vessels as lymph. Lymph vessels transport the lymph to veins where it enters the blood and becomes part of the plasma again.

Lymph and Lymph Vessels The lymph system also helps protect the body against infection. The armpits, neck, and groin contain groups of tiny bean-shaped organs called lymph nodes. –Lymph tissue is also located in the tonsils, adenoids, spleen, thymus gland, digestive tract, and bone marrow. These structures filter out bacteria and viruses from lymph. Lymph tissue also produces a type of white blood cell that helps the body fight disease.

Immunity The ability of the body to resist certain disease-causing organisms (pathogens) is known as immunity. To resist disease the body has certain body defenses. –One body defense is the presence of barriers such as skin, nose hairs, and mucus coated linings in the digestive and respiratory tracts. –Another defense is hydrochloric acid in the stomach. –A third defense is the ability of white blood cells to engulf bacteria. –The body’s final defense is the production of antibodies to fight foreign substances that enter the body. These antibodies are carried by the blood.

Immunity Immune reactions occur between antibodies and antigens when the body defends itself against invading organisms. Along with antibody production, there are other types of immune responses such as skin graft rejection and organ transplant rejection. Antibodies (defender) Antigen (invader)

Active Immunity Active immunity occurs when the body makes its own antibodies to a particular antigen. This can occur as a result of having a particular disease and recovering from it or by having a vaccination to a particular disease. If you had chicken pox, you now have active immunity against this disease.

Vaccinations A vaccination consists of an injection of a dead or weakened form of a disease-causing microorganism. This organism can no longer cause the disease, but can still stimulate antibody production by white blood cells. This type of immunity lasts a long time. Diphtheria-Tetanus (DPT), Oral Polio, Measles Mumps and Rubella (MMR) are immunizations required for public school attendance.

Passive Immunity Passive immunity is a temporary immunity to a disease produced by the injection of antibodies into the body. The antibodies can be produced by another person or by an animal. Passive immunity lasts for only a short time. It is used to increase the body’s defense temporarily against a particular disease. For example, people who have been exposed to hepatitis are given injections of antibodies to hepatitis.

Blood Typing and Transfusions There are three blood types known as A, B, and O. The typing of blood in the ABO blood group system is based on the presence or absence of antigens on the surface of the red blood cells. Blood type is important when giving transfusions. If the blood types of the donor and receiver are not agreeable, an antigen-antibody reaction occurs. This reaction results in the clumping of blood. When this happens, the blood cells clog the capillaries and cause death.

Transport System Disorders High Blood Pressure occurs when the blood pressure in the arteries is increased. –This can be caused by stress, diet, heredity, cigarette smoking, and aging. –High blood pressure can damage the lining of the arteries and weaken the heart muscle. –Some ways of controlling high blood pressure are by decreasing stress, loosing weight, and taking medication.

Transport System Disorders Arthrosclerosis is the buildup of plaque on artery walls. The buildup of plaque will cause a decrease in blood flow through the artery to vital organs. In some cases, this plaque buildup will occur in coronary arteries. The blockage stops the flow of blood to some of the heart muscle. The heart muscle is then usually damaged from lack of oxygen. This is called a heart attack.

Transport System Disorders Leukemia is a form of cancer in which the bone marrow makes too many non-working white blood cells. –The large numbers of white cells crowd out developing red blood cells and platelets. Sickle Cell Anemia is red blood cell disorder, where instead of being like normal round cells, affected blood becomes hard, sticky and shaped like sickles, which clog blood flow and break apart. –All forms of sickle cell disease are inherited and present in African Americans, Arabs, Greeks, Italians, Latin Americans and Native Americans.

Sickle Cell Anemia

Transport System Disorders AIDS –The acquired immune deficiency syndrome is a disease caused by a virus that scientists call HIV (human immunodeficiency virus). –The virus destroys the body’s immune system, making it unable to fight off even small infections. –The disease is transmitted by body secretions during sexual contact or by direct exposure to blood.