Cardiovascular System PDF

THE CARDIOVASCULAR SYSTEM  FUNCTIONS OF THE CARDIOVASCULAR SYSTEM The cardiovascular system consists of the heart, blood vessels, and blood. Cardiovascular means pertaining to the heart and blood vessels (cardi/o means heart, vascul/o means blood vessels, and -ar means pertaining to). The...

THE CARDIOVASCULAR SYSTEM  FUNCTIONS OF THE CARDIOVASCULAR SYSTEM The cardiovascular system consists of the heart, blood vessels, and blood. Cardiovascular means pertaining to the heart and blood vessels (cardi/o means heart, vascul/o means blood vessels, and -ar means pertaining to). These structures work together to efficiently pump blood to all body tissues. FUNCTIONS OF THE CARDIOVASCULAR SYSTEM Blood is a fluid tissue that transports oxygen and nutrients to the body tissues. Blood returns some waste products from these tissues to the kidneys and carries carbon dioxide back to the lungs.  The Heart The heart is a hollow, muscular organ located in the thoracic cavity, between the lungs It is a very effective pump that furnishes the power to maintain the blood flow needed throughout the entire body The apex is the lower tip of the heart. The Walls of the Heart The walls of the heart are made up of these three layers: the epicardium, myocardium, and endocardium The epicardium: is the external layer of the heart’ The myocardium: is the middle and thickest of the heart’s three layers. Also known as myocardial muscle, this consists of specialized cardiac muscle tissue that is capable of the constant contraction and relaxation of this muscle that creates the pumping movement that is necessary to maintain the flow of blood throughout the body. The Walls of the Heart The endocardium , which consists of epithelial tissue, is the inner lining of the heart. This is the surface that comes into direct contact with the blood as it is being pumped through the heart. Blood Supply to the Myocardium The myocardium, which beats constantly, must have a continuous supply of oxygen and nutrients plus prompt waste removal to survive. If for any reason this blood supply is disrupted, the myocardium of the affected area dies. The coronary arteries, which supply oxygen- rich blood to the myocardium, are shown in red in The veins, which are shown in blue, remove waste products from the myocardium.  The Heartbeat The heartbeat is the ability to pump blood effectively throughout the body; the contraction and relaxation (beating) of the heart must occur in exactly the correct sequence. The rate and regularity of the heartbeat is determined by electrical impulses from nerves that stimulate the myocardium of the chambers of the-heart. Pulse and Blood Pressure Heart rate — sometimes called pulse — is the number of times your heart beats every minute. Changes in your heart rate can be influenced by factors like physical activity, emotions and medications. Pulse and Blood Pressure Blood pressure is the force of blood flowing against the walls of your arteries. Your blood pressure values indicate the health of your cardiovascular system and can give insight into conditions like hypertension(high blood pressure) or hypotension (low blood pressure). Pulse and Blood Pressure Systolic pressure, which occurs when the ventricles contract, is the highest pressure against the walls of an artery. The term systole means contraction of the heart. Diastolic pressure, which occurs when the ventricles are relaxed, is the lowest pressure against the walls of an artery. The term diastole means relaxation of the heart.  BLOOD Blood is the fluid tissue in the body. It is composed of 55% liquid plasma and 45% formed elements. Plasma is a straw-colored fluid that contains nutrients, hormones, and waste products. Plasma is 91% water. The remaining 9% consists mainly of proteins, including the clotting proteins.  BLOOD Fibrinogen and prothrombin are the clotting proteins found in plasma. They have an important role in clot formation to control bleeding.  Formed Elements of the Blood The formed elements of blood include erythrocytes, leukocytes, and thrombocytes. Erythrocytes Erythrocytes also known as red blood cells (RBC), are mature red blood cells produced by the red bone marrow (erythr/o means red, and -cytes means cells). The primary role of these cells is to transport oxygen to the tissues. This oxygen is transported by hemoglobin which is the oxygen-carrying blood protein pigment of the erythrocytes (hem/o means blood, and -globin means protein). Leukocytes Leukocytes also known as white blood cells (WBC), are the blood cells involved in defending the body against infective organisms and foreign substances (leuk/o means white, and -cytes means cells). The following are five major groups of leukocytes:  Leukocytes 1- Neutrophils: which are formed in red bone marrow. are the most common type of WBC. Through phagocytosis, neutrophils play a major role in the immune system’s defense against pathogens, including bacteria, viruses, and fungi. Phagocytosis is the process of destroying pathogens by surrounding and swallowing them.  Leukocytes 2- Basophils: which are also formed in red bone marrow. are the least common type of WBC. Basophils are responsible for causing the symptoms of allergies. 3- Eosinophils: are formed in red bone marrow and then migrate to tissues throughout the body. these cells destroy parasitic organisms and play a major role in allergic reactions. Leukocytes 4- Lymphocytes: are formed in red bone marrow, in lymph nodes, and in the spleen. Lymphocytes identify foreign substances and germs (bacteria or viruses) in the body and produce antibodies that specifically target them. 5- Monocytes: are formed in red bone marrow, lymph nodes, and the spleen. Through phagocytosis, monocytes provide immunological defenses against many infectious organisms.  Thrombocytes Thrombocytes which are also known as platelets, are the smallest formed elements of the blood. They play an important role in the clotting of blood (thromb/o means clot, and -cytes means cells). When a blood vessel is damaged, the thrombocytes are activated and become sticky. This action causes the thrombocytes to clump together to form a clot to stop the bleeding. Medical specialties related to the cardiovascular system A Cardiologist is a physician who specializes in diagnosing and treating abnormalities, diseases, and disorders of the heart (cardi means heart, and - ologist means specialist). A Hematologist is a physician who specializes in diagnosing and treating abnormalities, diseases, and disorders of the blood and blood-forming tissues (hemat means blood, and -ologist means specialist). A Vascular surgeon is a physician who specializes in the diagnosis, medical management, and surgical treatment of disorders of the blood vessels.  Pathology of the cardiovascular system Congenital Heart Defects Congenital heart defects are structural abnormalities caused by the failure of the heart to develop normally before birth. Congenital means present at birth. Some congenital heart defects are apparent at birth, whereas others may not be detected until later in life.  Coronary Artery Disease (CAD) Coronary artery disease (CAD) is atherosclerosis of the coronary arteries that reduces the blood supply to the heart muscle. This creates an insufficient supply of oxygen that can cause angina (pain), a myocardial infarction (heart attack), or death.  Atherosclerosis Atherosclerosis is hardening and narrowing of the arteries caused by a buildup of cholesterol plaque on the interior walls of the arteries. This type of plaque (PLACK), which is found within the lumen of an artery, is a fatty deposit that is similar to the buildup of rust inside a pipe.  Atherosclerosis The lumen is the opening within these vessels through which the blood flows. The plaque can protrude outward into the lumen from the wall of the blood vessel or protrude inward into the wall of the vessel. Embolism An embolism is the sudden blockage of a blood vessel by an embolus (embol means something inserted, and -ism means condition). The embolism is often named for the causative factor, such as an air embolism or a fat embolism or its location, such as pulmonary embolism. Embolism An embolus is a foreign object, such as a blood clot, a quantity of air or gas, or a bit of tissue or tumor that is circulating in the blood (embol means something inserted, and -us is a singular noun ending) (plural, emboli) Blood dyscrasia Blood dyscrasia is any pathologic condition of the cellular elements of the blood (dys- means bad, and -crasia means a mixture or blending). Septicemia Septicemia is often associated with severe infections caused by the presence of bacteria in the blood. Also known as bacteremia (bacter means bacteria, and -emia means a blood condition), this condition can begin with a sudden onset of symptoms that include a fever, chills, rapid breathing, and rapid heart rate. Septicemia can lead to sepsis, which is a systemic bacterial infection in the bloodstream. Megaloblastic anemia Megaloblastic anemia is a blood disorder characterized by anemia in which the red blood cells are larger than normal (mega- means large, blast means immature, and -tic means pertaining to). This condition usually results from a deficiency of folic acid or of vitamin B12. Thank you