Focused Review Of Cardiovascular System PDF

S.1.3 — Describe the anatomy and physiology of the cardiovascular system The cardiovascular, or circulatory, system is responsible for the movement of blood around the body. This system Objectives allows for nutrient distribution and waste...

S.1.3 — Describe the anatomy and physiology of the cardiovascular system The cardiovascular, or circulatory, system is responsible for the movement of blood around the body. This system Objectives allows for nutrient distribution and waste removal. To This objective includes, but is not limited be successful at meeting the objective, it is important to to, the following examples of knowledge, know not only the structure of these two systems but also skills, and abilities. the functional components of each. Identify structures of the cardiovascular system. PARTS OF THE CARDIOVASCULAR SYSTEM Explain the functions of the cardiovas- The cardiovascular system includes the closed system of cular system. blood pumped around the body by the heart through a Trace blood flow through the cardio- network of arteries, veins, and capillaries. The heart is vascular system. made up of cardiac muscle and is split into four chambers. The upper chambers are called “atria” and the lower chambers are called “ventricles.” Heart Anatomy The atria and ventricles are attached to veins and arteries that are connected to different parts of the body. One-way valves control the flow of blood into and out of the chambers of the heart. The Heart Anatomy diagram shows key parts of the heart. FUNCTIONS OF THE CARDIOVASCULAR SYSTEM The cardiovascular system performs the vital functions of transporting nutrients, hormones, and wastes. There are two well-integrated circulatory systems. The closed circulatory system is a double-loop system consisting of thick-walled arteries that transport blood away from the heart, thinner-walled veins that transport blood to the heart, and capillaries made of a single layer of endothelium that form a network that connect arteries to veins in tissues. The open lymphatic system circulates and filters interstitial fluid between cells and eventually drains into the circulatory system. arteries. Vessels that carry blood away from the heart toward other body parts. veins. Vessels that carry blood toward the heart from other body parts. cardiac muscle. Involuntary muscle found in the heart.cardiovascular system. The system comprised of the heart and blood vessels. 172 Human Anatomy and Physiology ATI TEAS STUDY MANUAL  The closed, double-loop system transports blood and hormones. There are two parts of this loop: the pulmonary and the systemic. The pulmonary loop carries deoxygenated blood from the right ventricle of the heart to the lungs where it is oxygenated and returns oxygenated blood to the left atrium. The systemic loop carries oxygenated blood from the left ventricle to the body, returning deoxygenated blood to the right atrium. The heart undergoes two cycles of contractions: systole and diastole. Systole indicates contraction of heart muscles, and diastole is relaxation of heart muscles. In a simplified overview of the heart cycle, the ventricles contract (i.e., ventricular systole), causing the atrioven- tricular valves (including the mitral and tricuspid valves) to close, making a “lub” sound. Subse- quently, the empty ventricles are filled by blood pushed out during atrial systole. At the same time, the semilunar valves in the aorta and pulmonary trunk close, preventing blood from falling back into the ventricles, making a “dub” sound, and completing the “lub-dub” sound of the heart. These contractions are controlled by a “pacemaker” called the “sinoatrial node,” which sends out electrical signals. Arteries have thick walls to withstand the pressure of blood pumped by the heart, whereas veins have walls with a thinner muscle layer and larger lumen. Blood plasma contains nutrients, hormones, antibodies, and other immune proteins. Red blood cells contain hemoglobin, transport oxygen from the lungs to the rest of the body, and transport some of the carbon dioxide back to the lungs for removal. About 5 to 7% of carbon dioxide is dissolved in plasma, and 85% of carbon dioxide is used to maintain acid-base or pH balance in the blood through the bicarbonate buffer system. White blood cells are divided into two main lineages: granulocytes (basophils, eosinophils, and neutrophils) and agranulocytes (monocytes and lymphocytes). White blood cells defend against pathogens. Blood also contains cells called platelets, which are responsible for blood clotting. The open circulatory system’s capillaries drain interstitial fluid that fills the spaces between the cells and filter it through a system of lymph nodes that are enriched in lymphocytes and macrophages and provide surveillance by the immune system. Lymph (essentially plasma with the red blood cells removed) eventually drains into the large veins leading back to the heart. Large numbers of leukocytes and lymphocytes are enriched in lymph nodes, where they monitor and respond to foreign molecules washed into the system. Typically, lymph nodes are enriched in oral, nasal, and genital regions where foreign entities enter the body. You should have a general understanding of pathologies of the circulatory system, such as heart attacks, stroke, aneurysms, atherosclerosis, arrhythmias, and hypertension. systole. The portion of the cardiac cycle in which the heart expels blood. relaxation. Release of tension in a muscle. plasma. Clear pale yellow component of blood that carries red blood cells, white blood cells, and platelets throughout the body. hemoglobin. Protein in red blood cells that carries oxygen from the lungs to the rest of the body. buffer. A solution of a weak acid and its conjugate base or a weak base and its conjugate acid. Buffers maintain the proper pH of the body. lymphocyte. A category of white blood cells that includes natural killer cells, B cells, helper T cells, and cytotoxic T cells. lymph. Clear fluid that moves throughout the lymphatic system to fight disease. macrophage. A large white blood cell that ingests foreign material. leukocyte. White blood cells, which protect the body against disease. ATI TEAS STUDY MANUAL S.1.3 — Describe the anatomy and physiology of the cardiovascular system 173  BLOOD FLOW THROUGH THE CARDIOVASCULAR SYSTEM Blood flows throughout the cardiovascular system in Blood Cycle a cyclic pattern as shown in the following diagram. Starting in the left ventricle, oxygenated blood is pumped to the body. As it flows through arteries to capillaries, it transports oxygen to tissues and picks up carbon dioxide. Then, the deoxygenated blood returns to the heart through veins. This blood is now deoxy- genated and concentrated with carbon dioxide. It enters the heart through the right atrium and then flows into the right ventricle. The right ventricle pumps the blood toward the lungs through arteries, where it picks up oxygen and loses carbon dioxide. Then, it returns to the heart through the left atrium using veins and starts the cycle again. Practice Problems 1. Which of the following lists the primary parts of the 3. Which of the following chambers pumps blood toward heart? the lungs? A. Blood cells A. Left atrium B. Muscle tissue split into two chambers B. Right atrium C. Muscle tissue split into four chambers C. Left ventricle D. Four ventricles D. Right ventricle 2. Which of the following blood components is responsible 4. Which of the following statements best describes the for transporting oxygen? function of veins? A. Red blood cells A. Veins carry deoxygenated blood. B. Plasma B. Veins carry oxygenated blood. C. Dissolved gases C. Veins carry blood back to the heart. D. Leukocytes D. Veins carry blood away from the heart. 5. In two to three sentences, describe two chambers of the heart that have thicker walls. Why would these chambers be thicker? peristalsis. A series of muscle contractions that move food through the digestive tract. 174 Human Anatomy and Physiology ATI TEAS STUDY MANUAL