Chapter 19
The Circulatory System
Courtesy of Russel Kightley Media: Scientific Illustrator
Your heart is made of cardiac tissue. It is an organ and a muscle. Your heart has four chambers. The two upper chambers are your right and left atriums. The two lower chambers are your right and left ventricles. There are three types of circulation- coronary, pulmonary, and systemic.
Coronary circulation is the circulation of blood to and from the heart tissues. Pulmonary circulation is the circulation of blood from the heart to the lungs and back to the heart. Systemic circulation is the circulation of blood through the whole body besides the heart and lungs.
The steps of all circulation are as follows:
Vena Cava => Right Atrium => Right Ventricle => Pulmonary Artery => Lungs => Pulmonary Vein =>
Left Atrium => Left Ventricle => Aorta => Body => Vena Cava and so on and so forth.
There are three types of blood vessels- arteries, veins, and capillaries.
Arteries have four layers (connective tissue, smooth muscle, elastic connective tissue, and smooth lining) and are the thickest blood vessels. They carry blood away from the heart. All arteries carry oxygen rich blood besides the pulmonary artery.
Veins have the same layers as arteries do. They also have one-way valves to keep blood from flowing backward. Veins are thinner than arteries and carry blood to the heart. All veins carry oxygen poor blood besides the pulmonary vein.
Capillaries have one layer of smooth lining. They are only one cell thick. Capillaries connect arteries and veins. Nutrients and oxygen diffuse through capillary walls into body cells. Carbon dioxide and wastes diffuse through body cell walls into capillaries.
Blood pressure is the force of blood on blood vessel walls. It is measured by two numbers, systolic and diastolic. The first number is called systolic. It is measured when the ventricles push blood into the arteries. The second number is diastolic. It is measured when the ventricles fill with blood again. A normal blood pressure is 120 over 80. To control blood pressure, specialized nerve cells in arterial walls sense when blood pressure is too high or too low and send messages to the brain. The brain will then send messages to raise or lower your blood pressure by speeding up or slowing the heart rate.
Cardiovascular diseases are very dangerous. Some of them are atherosclerosis, hypertension, and heart failure. Atherosclerosis occurs when fatty deposits build up on arterial walls. This can clog arteries so blood flows slower, and a heart attack could occur. Hypertension is also known as high blood pressure. High blood pressure puts strain on the heart because the heart must pump faster to keep blood flowing. Heart failure occurs when the heart cannot pump blood as it should. Not enough oxygen gets to cells because blood is flowing slower.
There are ways to prevent getting serious cardiovascular diseases. Getting regular check ups, eating a diet low in saturated fats, salt, sugar, and chloesterol, exercising, managing stress, and not smoking are all ways to prevent cardiovascular disease.
Coronary circulation is the circulation of blood to and from the heart tissues. Pulmonary circulation is the circulation of blood from the heart to the lungs and back to the heart. Systemic circulation is the circulation of blood through the whole body besides the heart and lungs.
The steps of all circulation are as follows:
Vena Cava => Right Atrium => Right Ventricle => Pulmonary Artery => Lungs => Pulmonary Vein =>
Left Atrium => Left Ventricle => Aorta => Body => Vena Cava and so on and so forth.
There are three types of blood vessels- arteries, veins, and capillaries.
Arteries have four layers (connective tissue, smooth muscle, elastic connective tissue, and smooth lining) and are the thickest blood vessels. They carry blood away from the heart. All arteries carry oxygen rich blood besides the pulmonary artery.
Veins have the same layers as arteries do. They also have one-way valves to keep blood from flowing backward. Veins are thinner than arteries and carry blood to the heart. All veins carry oxygen poor blood besides the pulmonary vein.
Capillaries have one layer of smooth lining. They are only one cell thick. Capillaries connect arteries and veins. Nutrients and oxygen diffuse through capillary walls into body cells. Carbon dioxide and wastes diffuse through body cell walls into capillaries.
Blood pressure is the force of blood on blood vessel walls. It is measured by two numbers, systolic and diastolic. The first number is called systolic. It is measured when the ventricles push blood into the arteries. The second number is diastolic. It is measured when the ventricles fill with blood again. A normal blood pressure is 120 over 80. To control blood pressure, specialized nerve cells in arterial walls sense when blood pressure is too high or too low and send messages to the brain. The brain will then send messages to raise or lower your blood pressure by speeding up or slowing the heart rate.
Cardiovascular diseases are very dangerous. Some of them are atherosclerosis, hypertension, and heart failure. Atherosclerosis occurs when fatty deposits build up on arterial walls. This can clog arteries so blood flows slower, and a heart attack could occur. Hypertension is also known as high blood pressure. High blood pressure puts strain on the heart because the heart must pump faster to keep blood flowing. Heart failure occurs when the heart cannot pump blood as it should. Not enough oxygen gets to cells because blood is flowing slower.
There are ways to prevent getting serious cardiovascular diseases. Getting regular check ups, eating a diet low in saturated fats, salt, sugar, and chloesterol, exercising, managing stress, and not smoking are all ways to prevent cardiovascular disease.
Blood
Courtesy of Penn Medicine
The blood in your body has four functions:
1) Blood carries oxygen to body cells and takes carbon dioxide from the body cells to the lungs to be exhaled.
2) Blood carries wastes to your kidneys to be removed.
3) Blood transports nutrients to your body cells.
4) Cells and molecules in blood fight infection and heal wounds.
There are four components to blood: plasma, red blood cells, white blood cells, and platelets.
Plasma is the liquid part of blood. It is made of 95% water. Nutrients, oxygen, and minerals all dissolve in plasma. Plasma also carries wastes away from cells.
Red blood cells are half the size of white blood cells. There are 5 million red blood cells per cubic millimeter in the body. Red blood cells are disk shaped with an indent in the middle. They contain a chemical called hemoglobin that carries oxygen and carbon dioxide and gives blood its red color. The life span of a red blood cell is about 120 days.
White blood cells are two times the size of red blood cells. There are five thousand to ten thousand white blood cells per cubic millimeter in the body. White blood cells are round or amoeba shaped. They destroy bacteria and viruses and absorb dead cells. The life span of a white blood cell varies from a few days to many months.
Platelets are one third the size of red blood cells and one sixth the size of white blood cells. There are 400,000 platelets per cubic millimeter in the body. Platelets are irregularly shaped since they are cell fragments. They help start the blood clotting process. The life span of a platelet is five to nine days.
There are eight steps to blood clotting:
1) I am cut.
2) Platelets stick to the wound and release chemicals.
3) Clotting factors carry out many chemical reactions that form threadlike fibers called fibrin.
4) Fibrin forms a sticky net around the wound.
5) The sticky net traps escaping plasma and blood cells and forms a clot.
6) The clot keeps even more blood from escaping.
7) After the clot hardens, skin cells begin to repair the wound.
8) Eventually, the scab falls and the skin is healed.
During blood transfusions, people need to have a certain type of blood put into them that is compatible with their body. Otherwise the transfusion will not be successful.
To figure this out, there is the ABO system. People have one of four types of blood: A, B, AB, or O. These blood types have antigens (chemical identification tags). Type A blood has A antigens. Type B blood has B antigens. Type AB blood has A and B antigens. Type O blood has no antigens. Blood also has antibodies that destroy anything they think doesn't belong in the body (ie-a foreign blood type). Type A blood has B antibodies. Type B blood has A antibodies. Type AB blood has no antibodies. Type O blood has A and B antibodies.
People with certain blood types can receive or donate blood to and from people with certain blood types. Type A blood can receive type A and O blood. Type B blood can receive type B and O blood. Type AB blood can receive all blood types. Type O blood can only receive type O blood. Type A blood can be donated to people with type A and AB blood. Type B blood can be donated to people with type B and AB blood. Type AB blood can be donated to people with only type AB blood. Type O blood can be donated to people with all blood types. Type AB blood is called the universal receiver. Type O blood is called the universal donor.
The Rh factor is another chemical identification tag in blood. If the Rh factor is on your blood, you are Rh positive. If no Rh factor is found in your blood, you are Rh negative. People with Rh positive blood can receive blood from Rh positive and negative people. People with Rh negative blood can only receive blood from people with Rh negative blood.
Diseases of the blood are serious because blood moves through the whole body, and the disease could spread quickly. Two blood diseases are anemia and leukemia.
Anemia occurs when not enough red blood cells are made. Body cells are starved for oxygen and nutrients and can't carry out their normal functions. Causes of anemia include heredity, a large loss of blood, a diet lacking iron, or a side-effect to treatment for another disease.
Leukemia is a disease in which white blood cells are made in great numbers. These white blood cells are immature and cannot fight infections correctly. They crowd out normal cells in the bone marrow. Then there are not enough red blood cells, platelets, and normal white blood cells made. Treatments of leukemia include medicines, blood transfusions, and bone marrow transplants. If these treatments are not successful, however, the person will eventually die.
1) Blood carries oxygen to body cells and takes carbon dioxide from the body cells to the lungs to be exhaled.
2) Blood carries wastes to your kidneys to be removed.
3) Blood transports nutrients to your body cells.
4) Cells and molecules in blood fight infection and heal wounds.
There are four components to blood: plasma, red blood cells, white blood cells, and platelets.
Plasma is the liquid part of blood. It is made of 95% water. Nutrients, oxygen, and minerals all dissolve in plasma. Plasma also carries wastes away from cells.
Red blood cells are half the size of white blood cells. There are 5 million red blood cells per cubic millimeter in the body. Red blood cells are disk shaped with an indent in the middle. They contain a chemical called hemoglobin that carries oxygen and carbon dioxide and gives blood its red color. The life span of a red blood cell is about 120 days.
White blood cells are two times the size of red blood cells. There are five thousand to ten thousand white blood cells per cubic millimeter in the body. White blood cells are round or amoeba shaped. They destroy bacteria and viruses and absorb dead cells. The life span of a white blood cell varies from a few days to many months.
Platelets are one third the size of red blood cells and one sixth the size of white blood cells. There are 400,000 platelets per cubic millimeter in the body. Platelets are irregularly shaped since they are cell fragments. They help start the blood clotting process. The life span of a platelet is five to nine days.
There are eight steps to blood clotting:
1) I am cut.
2) Platelets stick to the wound and release chemicals.
3) Clotting factors carry out many chemical reactions that form threadlike fibers called fibrin.
4) Fibrin forms a sticky net around the wound.
5) The sticky net traps escaping plasma and blood cells and forms a clot.
6) The clot keeps even more blood from escaping.
7) After the clot hardens, skin cells begin to repair the wound.
8) Eventually, the scab falls and the skin is healed.
During blood transfusions, people need to have a certain type of blood put into them that is compatible with their body. Otherwise the transfusion will not be successful.
To figure this out, there is the ABO system. People have one of four types of blood: A, B, AB, or O. These blood types have antigens (chemical identification tags). Type A blood has A antigens. Type B blood has B antigens. Type AB blood has A and B antigens. Type O blood has no antigens. Blood also has antibodies that destroy anything they think doesn't belong in the body (ie-a foreign blood type). Type A blood has B antibodies. Type B blood has A antibodies. Type AB blood has no antibodies. Type O blood has A and B antibodies.
People with certain blood types can receive or donate blood to and from people with certain blood types. Type A blood can receive type A and O blood. Type B blood can receive type B and O blood. Type AB blood can receive all blood types. Type O blood can only receive type O blood. Type A blood can be donated to people with type A and AB blood. Type B blood can be donated to people with type B and AB blood. Type AB blood can be donated to people with only type AB blood. Type O blood can be donated to people with all blood types. Type AB blood is called the universal receiver. Type O blood is called the universal donor.
The Rh factor is another chemical identification tag in blood. If the Rh factor is on your blood, you are Rh positive. If no Rh factor is found in your blood, you are Rh negative. People with Rh positive blood can receive blood from Rh positive and negative people. People with Rh negative blood can only receive blood from people with Rh negative blood.
Diseases of the blood are serious because blood moves through the whole body, and the disease could spread quickly. Two blood diseases are anemia and leukemia.
Anemia occurs when not enough red blood cells are made. Body cells are starved for oxygen and nutrients and can't carry out their normal functions. Causes of anemia include heredity, a large loss of blood, a diet lacking iron, or a side-effect to treatment for another disease.
Leukemia is a disease in which white blood cells are made in great numbers. These white blood cells are immature and cannot fight infections correctly. They crowd out normal cells in the bone marrow. Then there are not enough red blood cells, platelets, and normal white blood cells made. Treatments of leukemia include medicines, blood transfusions, and bone marrow transplants. If these treatments are not successful, however, the person will eventually die.
The Lymphatic System
Courtesy of Cancer Research UK
Cells don't use all the nutrients brought to them through the blood. Extra water and other substances exit the cell and become tissue fluid between cells. The lymphatic system collects the tissue fluid and returns it to the blood.
Tissue fluid absorbed into lymphatic capillaries is called lymph. It travels through a series of lymphatic capillaries and larger lymph vessels to be returned to the blood by draining into large veins near the heart. The lymphatic system relies on smooth and skeletal muscle to move lymph through the lymph vessels. There also are valves in the lymph vessels to prevent lymph from traveling backward. Lymph contains lymphocytes. Lymphocytes are white blood cells that defend your body from diseases.
Lymphatic organs include lymph nodes, tonsils, thymus, and spleen.
Lymph nodes are bean-shaped organs. They filter out harmful microorganisms and foreign materials taken up by lymphocytes. Tonsils are organs in the back of your throat. They protect your body from harmful microorganisms entering the body through the mouth or nose. The thymus is an organ located behind the sternum. It makes lymphocytes that fight infections. The largest lymph organ is the spleen. It destroys harmful material and also filters worn out or damaged cells from the blood.
One lymphatic disease is called HIV. This HIV virus destroys lymphocytes in a person's body. This can take away the immunity people have to certain diseases. People do not usually die from HIV. They die from the diseases they are not immune to anymore.
Tissue fluid absorbed into lymphatic capillaries is called lymph. It travels through a series of lymphatic capillaries and larger lymph vessels to be returned to the blood by draining into large veins near the heart. The lymphatic system relies on smooth and skeletal muscle to move lymph through the lymph vessels. There also are valves in the lymph vessels to prevent lymph from traveling backward. Lymph contains lymphocytes. Lymphocytes are white blood cells that defend your body from diseases.
Lymphatic organs include lymph nodes, tonsils, thymus, and spleen.
Lymph nodes are bean-shaped organs. They filter out harmful microorganisms and foreign materials taken up by lymphocytes. Tonsils are organs in the back of your throat. They protect your body from harmful microorganisms entering the body through the mouth or nose. The thymus is an organ located behind the sternum. It makes lymphocytes that fight infections. The largest lymph organ is the spleen. It destroys harmful material and also filters worn out or damaged cells from the blood.
One lymphatic disease is called HIV. This HIV virus destroys lymphocytes in a person's body. This can take away the immunity people have to certain diseases. People do not usually die from HIV. They die from the diseases they are not immune to anymore.
