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18 Cards in this Set
- Front
- Back
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blood
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the body's internal transportation system.
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circulatory system
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connects the various muscles and organs of the body with one another. It consists of the heart, blood, and blood vessels. The circulatory system has four functions:
Transports nutrients and wastes Transports oxygen and carbon dioxide Transports hormones Distributes heat |
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heart
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a hollow, muscular organ that contracts at regular intervals, forcing blood through the circulatory system. The walls are made of three layers of tissue. The outer and inner layers are epithelial tissue. The middle layer is cardiac muscle tissue. The pattern of circulation in the human body includes two separate circulatory loops. The right side of the heart pumps blood from the body into the lungs, where deoxygenated blood gives up carbon dioxide and picks up oxygen. This is the pulmonary circulation loop. The left side of the heart pumps oxygenated blood from the lungs to the rest of the body. This is the systemic circulation loop.
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pericardium
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protective sac of tissue that encloses the heart
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septum
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divides the two sides of the heart, preventing the mixing of the blood
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left atrium
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Oxygen-rich blood flows from the lungs into the left side of the heart through the pulmonary veins and empties into the heart's collection chamber. From here, Oxygen-rich blood flows from the lungs into the left side of the heart through the pulmonary veins and empties into the heart's collection chamber. After delivering oxygen to the body's cells, blood returns to the heart through veins. Two large veins collect all the oxygen-poor blood. The superior vena cava drains blood from the upper body, while the inferior vena cava drains blood from the lower body. These veins empty into the bena cava which then delivers the blood to the right atrium of the heart. The blood will then flow into the right ventricle through the tricuspid valve. As the right ventricle contracts, the blood is sent through the pulmonary valve and into the pulmonary arteries. These arteries carry the blood to the lungs. The blood will then return to the left atrium, full of oxygen.
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Blood circulation to and from the lungs is
A lymphatic. B systemic. C pulmonary. D coronary. |
The correct choice is C. Pulmonary circulation involves blood entering and exiting the lungs to give up carbon dioxide and pick up oxygen. The lymphatic system collects fluid and returns it to the circulatory system. Systemic circulation moves blood from the lungs to the rest of the body. Coronary refers to the health of the circulatory system, generally the status of the coronary arteries.
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heartbeat
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The heart does not contract in a single motion. Instead, the contraction spreads out over the heart like a wave. A smaller cluster of cells, the sinoatrial node, (SA node) embedded in the right atrium, initiates this wave. These cells act as a pacemaker, setting the pace for the heart rate. The impulse travels to the left and right atria, causing both of them to contract almost simultaneously. The right and left ventricles will also contract simultaneously when the impulse reaches them. A tenth of a second usually passes before the lower part of the heart starts to contract.
These contractions cause the chambers to squeeze the blood, pushing it in the proper direction along its path. In most people at rest, the heart rate is between 60 and 80 beats per minute. The heart rate will increase during exercise in order to pump oxygen-rich blood through the body more quickly. |
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blood vessels
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Arteries carry blood from the heart to the body tissues. The walls of arteries are thicker than that of veins. Except for pulmonary arteries, all arteries carry oxygen-rich blood. The wall of an artery is made up of three layers of tissue. This allows the artery to retain a semi-rigid structure while expanding as blood is pumped through them. The smallest arteries are called arterioles. Arterioles branch into networks of capillaries, which are small blood vessels. It is in the capillaries that the real work of circulation is done. They often exist as a network of bed of capillaries to accommodate the flow of blood rather than as a single capillary The walls of capillaries consist of only one layer of cells. This makes it easy for oxygen and nutrients to diffuse from the blood into tissues and waste products to diffuse out of the cell to be removed by the circulatory system. Capillaries are extremely narrow—blood cells must move along them in single file.
The flow of blood moves from capillaries into veins. Veins collect blood from the body and carry it back to the heart. The smallest veins are venules. Veins are lined with smooth muscle; however, the walls are thinner and less elastic than arteries. The walls of veins are able to stretch out, thus reducing the resistance the flow of blood encounters on its way back to the heart. Large veins contain one-way valves that keep blood from flowing backward. The largest vein in the body is the vena cava, which leads into the heart. The cardiovascular system is very leaky. Fluids are forced out of the capillaries by the pressure generated when the heart pumps. A network of vessels, known as the lymphatic system collects the fluid and returns it to the circulatory system. The fluid, called lymph, collects in lymph capillaries and nodes. The fluid is returned to the circulatory system at openings in veins such as the one located under the left clavicle, just below the shoulder. |
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The smallest blood vessels are
A veins. B capillaries. C lymph vessels. D arteries. |
Hope you chose B, because the capillaries are so small and narrow, the blood cells have to move in a single file pattern. Veins are the next size and arteries are the largest. Lymph vessels are not blood vessels.
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blood
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a type of liquid connective tissue that has many functions:
Transports nutrients, dissolved gases, enzymes, hormones, and waste products Regulates body temperature, pH, and electrolytes Protects the body from invaders Restricts the loss of fluid The human body contains four to six liters of blood. Fifty-five percent of blood is made up of a fluid portion called plasma. The remaining forty-five percent consists of formed elements. Plasma is a straw-colored fluid that is 90 percent water and 10 percent dissolved fats, salts, sugars, and proteins. The plasma proteins are divided into three types: albumins, globulins, and fibrinogen. Albumins regulate osmotic pressure. Globulins include antibodies that help fight off infection. Fibrinogen helps the blood to clot. Plasma also carries nutrients, hormones, and waste products. |
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red blood cells
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also called erythrocytes, are the most numerous of the blood cells. They are bi-concave shaped so that they exhibit increased surface area: they are narrower in the center than along the edges. Erythrocytes are produced from cells in bone marrow that gradually fill with hemoglobin. Upon maturity, they lack nuclei and organelles. Red blood cells normally stay in circulation for 120 days before they are destroyed by specialized white blood cells in the liver and spleen. They are constantly being remade by the bone marrow.
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white blood cells
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also called leukocytes, are outnumbered by red blood cells almost 500 to 1. They are produced in the bone marrow, are larger than red blood cells, are colorless, and do not contain hemoglobin. The main function of leukocytes is to protect the body against invasion by foreign cells or substances. White blood cells respond quickly to infection.
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platelets
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cell fragments. They are formed when pieces of cytoplasm are pinched off megakaryocytic cells in the bone marrow. The life span of a platelet is 5 to 9 days. Platelets play a key role in blood clotting. They clump together and form a plug at the site of a wound. Then, they release proteins called clotting factors. The proteins, fibrin, form a netlike covering over the damaged site.
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hemoglobin
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iron-containing protein that carries oxygen from the lungs to the tissues of the body. It also gives the erythrocytes their characteristic red color.
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About 90 percent of plasma is composed of
A salts. B sugars. C proteins. D water. |
About 90 percent of plasma is composed of
A salts. B sugars. C proteins. D water. |
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blood pressure
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moves through the vessels because it is under pressure. This pressure is produced by the contraction of the heart and by the muscles surrounding blood vessels. Blood pressure is a measure of the force that blood exerts against a vessel wall. The low pressure that occurs during relaxation of the heart is diastolic pressure. The higher pressure that results when a pulse of blood is forced into the arterial system is systolic pressure.
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What is one of the main functions of lymphatic vessels?
A Blood transport B Fluid return to the blood C Antibody production D Blood clotting control |
B is the correct choice. The lymphatic system collects the fluid that has leaked out of the circulatory system and returns it to the blood. Blood is transported by the circulatory system. The immune system produces antibodies. Blood clotting is controlled by platelets in the circulatory system.
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