What is angiotensin?; Angiotensin is a substance that constricts blood vessels. What is atherosclerosis?; Atherosclerosis is the condition characterized by deposits of plaque in arteries. What is bradycardia?; Bradycardia is an abnormally slow heartbeat. What is diastolic pressure?; Diastolic pressure is the blood pressure when the ventricle of the heart is relaxed. What is edema?; Edema is the accumulation of fluids in the tissues that causes them to swell. What is an electrocardiogram?; An electrocardiogram is a recording of the electrical changes in the myocardium during a cardiac cycle. What is a semilunar valve?; A semilunar valve is a valve with crescent-shaped flaps. What is the myocardium?; The myocardium is the muscle tissue within the wall of the heart. What is a papillary muscle?; A papillary muscle is a small mound of muscle projecting into a ventricle of the heart. What is phlebitis?; Phlebitis is the inflammation of a vein. What is arteriosclerosis?; Arteriosclerosis is the loss of elasticity and hardening of a blood vessel wall. What is a syncytium?; A syncytium is a mass of merging cells that act together. What is systolic pressure?; Systolic pressure is the blood pressure resulting from a single ventricular contraction. What is tachycardia?; Tachycardia is an abnormally fast heartbeat. What is the total amount of blood the heart pumps through the body each day?; The heart pumps 7,000 liters of blood through the body each day. How many times does the heart contract in an average lifetime?; The heart contracts 2.5 billion times in an average lifetime. What is the sequence of blood flow through the blood vessels?; The heart pumps blood through the blood vessels in this order: arteries → arterioles → capillaries → venules → veins → back to heart. What components make up the cardiovascular system?; The heart and all blood vessels make up the cardiovascular system. What does the term 'cardiovascular' refer to?; 'Cardiovascular' refers to both the heart and blood vessels. What is the function of the pumping action of the heart?; The pumping action of the heart transports blood through blood vessels. What are the two circuits formed by blood vessels?; The two circuits formed by blood vessels are the Pulmonary Circuit and the Systemic Circuit. What is the function of the Pulmonary Circuit?; The Pulmonary Circuit transports oxygen-poor blood from the heart to the lungs, and back to the heart. In the lungs, blood picks up O2 and drops off CO2. What is the function of the Systemic Circuit?; The Systemic Circuit transports oxygen-rich blood from the heart to all body cells, and back to the heart. Blood delivers nutrients to cells and removes wastes. What type of blood does the left side of the heart contain?; The left side of the heart contains oxygen-rich blood. What type of blood does the right side of the heart contain?; The right side of the heart contains oxygen-poor blood. What are the two circuits through which blood runs in the body?; Blood runs through the pulmonary circuit to the lungs and the systemic circuit to body cells. What is the shape and function of the heart?; The heart is a hollow, cone-shaped, muscular pump. Where is the heart located?; The heart is located in the mediastinum of the thoracic cavity, superior to the diaphragm. How many chambers does the heart contain and what are they?; The heart contains 4 chambers: 2 atria (upper chambers) and 2 ventricles (lower chambers, responsible for pumping action). What is the average size of the heart?; The average size of the heart is 14 cm long and 9 cm wide. Where is the heart located in the body?; The heart is located in the thoracic cavity, posterior to the sternum, medial to the lungs, and anterior to the vertebral column. Where does the base of the heart lie?; The base of the heart lies beneath the 2nd rib. Where does the apex of the heart lie?; The apex of the heart lies at the 5th intercostal space. What is the location of the heart within the body?; The heart is located in the thoracic cavity, between the lungs, and slightly to the left of the midline. What is the mediastinum?; The mediastinum is the central compartment of the thoracic cavity that houses the heart, trachea, esophagus, and other structures. What is the pericardium?; The pericardium is a double-walled sac that encloses the heart, providing protection and reducing friction as the heart beats. What is the function of the pericardial fluid?; Pericardial fluid reduces friction between the heart and the pericardial sac as the heart beats. What is the Pericardium?; The Pericardium is the covering over the heart and large blood vessels. What is the Fibrous pericardium?; The Fibrous pericardium is the outer layer that surrounds the double-layered serous membrane. What is the Parietal pericardium?; The Parietal pericardium is deep to the fibrous pericardium; it is the outer layer of the serous membrane. What is the Visceral pericardium?; The Visceral pericardium is the inner layer of the serous membrane; it is attached to the surface of the heart and is also called the epicardium. What is the outer layer of the heart wall called?; Epicardium: Outer layer; also called visceral pericardium; thin layer. What is the middle layer of the heart wall composed of?; Myocardium: Middle layer; composed of cardiac muscle tissue; thickest layer. What is the inner layer of the heart wall that forms the inner lining of all heart chambers?; Endocardium: Inner layer; forms inner lining of all heart chambers; thin layer. What is the Epicardium?; The Epicardium, also known as the visceral pericardium, is the outer layer of the heart composed of a serous membrane of connective tissue covered with epithelium, including blood capillaries, lymph capillaries, and nerve fibers. It forms a protective outer covering and secretes serous fluid. What is the function of the Myocardium?; The Myocardium is the middle layer of the heart, composed of cardiac muscle tissue separated by connective tissue and including blood capillaries, lymph capillaries, and nerve fibers. Its primary function is to contract and pump blood from the heart chambers. What is the Endocardium?; The Endocardium is the inner layer of the heart, consisting of a membrane of epithelium and underlying connective tissue, including blood vessels. It forms a protective inner lining of the heart chambers and valves. What are the atria in the heart?; The atria are thin-walled upper chambers of the heart that receive blood returning to the heart. What are auricles in the context of the heart?; Auricles are flap-like projections from the atria, which allow for atrial expansion. What are ventricles in the heart?; Ventricles are thick-walled lower chambers of the heart that pump blood into arteries. What is the function of the right atrium?; The right atrium receives blood returning from the systemic circuit (from the superior and inferior vena cavae and coronary sinus) and pumps blood to the right ventricle. What is the function of the right ventricle?; The right ventricle receives blood from the right atrium and pumps it to the lungs. What is the function of the left atrium?; The left atrium receives blood from the pulmonary veins and pumps it to the left ventricle. What is the function of the left ventricle?; The left ventricle receives blood from the left atrium and pumps it to the systemic circuit. What is the function of the Tricuspid valve?; Prevents blood from moving from the right ventricle into the right atrium during ventricular contraction. Where is the Pulmonary valve located?; Entrance to pulmonary trunk. What is the function of the Pulmonary valve?; Prevents blood from moving from the pulmonary trunk into the right ventricle during ventricular relaxation. What is the function of the Mitral valve?; Prevents blood from moving from the left ventricle into the left atrium during ventricular contraction. Where is the Aortic valve located?; Entrance to aorta. What is the function of the Aortic valve?; Prevents blood from moving from the aorta into the left ventricle during ventricular relaxation. What is the tricuspid valve?; The tricuspid valve is a valve in the heart situated between the right atrium and the right ventricle. What is the mitral (bicuspid) valve?; The mitral (bicuspid) valve is a valve in the heart located between the left atrium and the left ventricle. What is the aortic valve?; The aortic valve is a valve in the heart that lies between the left ventricle and the aorta. What is the pulmonary valve?; The pulmonary valve is a valve in the heart situated between the right ventricle and the pulmonary artery. What is the skeleton of the heart?; The skeleton of the heart is made up of rings of dense connective tissue that surround the origins of the pulmonary trunk and aorta, and orifices between atria and ventricles. These rings provide attachments for heart valves and muscle fibers and prevent excess dilation of heart chambers during contraction. What is the function of the right atrium?; The right atrium receives deoxygenated blood from the body through the superior and inferior vena cava. What role does the tricuspid valve play in the heart?; The tricuspid valve prevents backflow of blood from the right ventricle to the right atrium. What is the purpose of the right ventricle?; The right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery. What is the function of the pulmonary valve?; The pulmonary valve prevents backflow of blood from the pulmonary artery into the right ventricle. What is the role of the left atrium?; The left atrium receives oxygenated blood from the lungs through the pulmonary veins. What is the function of the mitral valve?; The mitral valve prevents backflow of blood from the left ventricle to the left atrium. What is the purpose of the left ventricle?; The left ventricle pumps oxygenated blood to the body through the aorta. What role does the aortic valve play in the heart?; The aortic valve prevents backflow of blood from the aorta into the left ventricle. What is the function of the superior vena cava?; The superior vena cava returns deoxygenated blood from the upper body to the right atrium. What is the role of the inferior vena cava?; The inferior vena cava returns deoxygenated blood from the lower body to the right atrium. What is the purpose of the pulmonary arteries?; The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs. What is the function of the pulmonary veins?; The pulmonary veins carry oxygenated blood from the lungs to the left atrium. What is the role of the aorta?; The aorta distributes oxygenated blood from the left ventricle to the rest of the body. What do the left and right coronary arteries supply blood to?; The left and right coronary arteries supply blood to tissues of the heart. What are the first 2 branches of the aorta?; The coronary arteries are the first 2 branches of the aorta. What is the function of the coronary arteries?; The coronary arteries supply blood to the heart muscle, providing it with the oxygen and nutrients needed for it to function properly. What role do the coronary veins play in the cardiovascular system?; The coronary veins collect deoxygenated blood from the heart muscle and transport it back to the right atrium of the heart. What is the significance of the coronary sinus?; The coronary sinus is a large vein that collects blood from the coronary veins and empties it into the right atrium of the heart. What is myocardial infarction?; Myocardial infarction, commonly known as a heart attack, occurs when a part of the heart muscle is deprived of oxygen due to blockage of a coronary artery, leading to tissue damage or death. What is the role of the left anterior descending artery?; The left anterior descending artery supplies blood to the front and bottom of the left ventricle and the front of the septum between the ventricles. What is angina pectoris?; Angina pectoris is chest pain or discomfort that occurs when the heart muscle does not get enough oxygen-rich blood, often due to narrowed coronary arteries. What is the function of the right coronary artery?; The right coronary artery supplies blood to the right atrium, right ventricle, and parts of the heart's electrical conduction system. What is the cardiac cycle?; The events of a heartbeat, involving the coordinated function of heart chambers where atria contract (atrial systole) while ventricles relax (ventricular diastole), and then ventricles contract (ventricular systole) while atria relax (atrial diastole). What occurs during atrial systole?; During atrial systole, the atria contract while the ventricles relax. What occurs during ventricular systole?; During ventricular systole, the ventricles contract while the atria relax. What occurs during atrial diastole?; During atrial diastole, the atria relax while the ventricles contract. What occurs during ventricular diastole?; During ventricular diastole, the ventricles relax while the atria contract. What is a Heart Transplant?; Replacement of most of a failing heart with a donor heart. What is a Left Ventricular Assist Device (LVAD)?; A mechanical half-heart, used in some cases temporarily, until a donor heart is available. What is an Implantable Replacement Heart?; A titanium and plastic artificial heart, used in people that cannot have a heart transplant and do not have long to live. What is Stem Cell Technology in the context of cardiac care?; Cardiac muscle tissue can now be cultured from altered somatic cells or from stem cells, potentially allowing for 'stem cell heart patches' in the future. What happens to the ventricles during atrial systole and ventricular diastole?; The ventricles are relaxed. What happens to the A-V and semilunar valves during atrial systole and ventricular diastole?; The A-V valves open and the semilunar valves close. What percentage of blood flows passively from atria into ventricles during atrial systole and ventricular diastole?; About 70% of blood flows passively from atria into ventricles. What causes ventricular pressure to increase during atrial systole?; Atrial systole pushes the remaining 30% of blood into the ventricles, causing ventricular pressure to increase. What happens to the A-V valves during ventricular systole and atrial diastole?; The A-V valves close. What prevents the cusps of the A-V valves from bulging too far backward into the atria during ventricular systole?; The chordae tendineae prevent the cusps of the valves from bulging too far backward into the atria. What happens to the atria during ventricular systole and atrial diastole?; The atria relax. Where does blood flow into the atria from during ventricular systole and atrial diastole?; Blood flows into atria from venae cavae and pulmonary veins. What causes the semilunar valves to open during ventricular systole?; The ventricular pressure increases and opens the semilunar valves. Where does blood flow into during ventricular systole?; Blood flows into the pulmonary trunk and aorta. What is the sound 'lubb' in a heartbeat?; 'Lubb' is the first heart sound, occurring during ventricular systole and associated with the closing of the A-V valves. What is the sound 'dupp' in a heartbeat?; 'Dupp' is the second heart sound, occurring during ventricular diastole and associated with the closing of the pulmonary and aortic semilunar valves. What is a heart murmur?; A heart murmur is an abnormal heart sound derived from the incomplete closure of cusps of a valve. What are the regions at which sounds of heart valves can be heard?; The regions at which sounds of heart valves can be heard are specific areas on the chest where the sounds of the heart valves closing can be auscultated. These regions include the aortic area, pulmonic area, tricuspid area, and mitral area. What are intercalated discs in cardiac muscle cells?; Intercalated discs between cells contain gap junctions, so action potentials can be spread through a network of cells. What is a functional syncytium in the context of cardiac muscle fibers?; A functional syncytium is a mass of merging cells that function as a unit. What are the two types of functional syncytia in the heart?; The two types of functional syncytia in the heart are the atrial syncytium in the atrial walls and the ventricular syncytium in the ventricular walls. What is the Cardiac Conduction System?; A group of clumps and strands of specialized cardiac muscle tissue, which initiates and distributes impulses throughout the myocardium, coordinating the events of the cardiac cycle. What is the function of the SA (Sinoatrial) Node in the cardiac conduction system?; Pacemaker; initiates rhythmic contractions of the heart. What is the role of the Internodal Atrial Muscle in the cardiac conduction system?; Conducts impulses from SA node to atria. What is the function of Junctional Fibers in the cardiac conduction system?; Conduct impulses from SA node to AV node. What is the role of the AV (Atrioventricular) Node in the cardiac conduction system?; Conducts impulses to AV Bundle; delays impulse, so that atria finish contracting before ventricles contract. What is the function of the AV (Atrioventricular) Bundle (of His) in the cardiac conduction system?; Conducts impulses rapidly between SA node and bundle branches. What is the role of the Left and Right Bundle Branches in the cardiac conduction system?; Split off from AV bundle, conduct impulses to Purkinje fibers on both sides of the heart. What is the function of Purkinje Fibers in the cardiac conduction system?; Large fibers that conduct impulses to ventricular myocardium. What are the major components of the cardiac conduction system?; The major components of the cardiac conduction system include the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, bundle branches, and Purkinje fibers. What is the function of Purkinje fibers in the cardiac conduction system?; Purkinje fibers stimulate muscle cells in the ventricles, causing them to contract with a twisting motion. How do ventricles contract when stimulated by Purkinje fibers?; Ventricles contract with a twisting motion when stimulated by Purkinje fibers. What is an Electrocardiogram (ECG or EKG)?; A recording of electrical changes that occur in the myocardium during the cardiac cycle, used to assess the heart’s ability to conduct impulses. What does the P wave in an ECG represent?; Atrial depolarization, occurring just prior to atrial contraction. What does the QRS complex in an ECG represent?; Ventricular depolarization, occurring just prior to ventricular contraction. What does the T wave in an ECG represent?; Ventricular repolarization, occurring just prior to ventricular relaxation. Why is the record of atrial repolarization not visible in an ECG?; It is 'hidden' in the large QRS complex because ventricular depolarization is a much larger event. What is the cardiovascular system?; The cardiovascular system is a complex network of the heart and blood vessels that circulates blood throughout the body, supplying oxygen and nutrients, and removing waste products. What are arteries?; Arteries are blood vessels that carry oxygen-rich blood away from the heart to the tissues of the body. What are veins?; Veins are blood vessels that carry oxygen-depleted blood back to the heart from the tissues of the body. What is the function of the heart?; The heart functions as a pump to circulate blood throughout the body, maintaining the flow of oxygen, nutrients, and removal of waste products. What is an electrocardiogram (ECG)?; An electrocardiogram (ECG) is a test that records the electrical activity of the heart, helping to diagnose various heart conditions. What is blood pressure?; Blood pressure is the force exerted by circulating blood on the walls of blood vessels, typically measured in millimeters of mercury (mmHg). What is hypertension?; Hypertension is a condition characterized by consistently elevated blood pressure, which can lead to cardiovascular diseases if left untreated. What are capillaries?; Capillaries are the smallest blood vessels in the body, where the exchange of oxygen, nutrients, and waste products occurs between blood and tissues. What is venous return?; Venous return is the flow of blood back to the heart from the body's tissues, primarily through the veins. What are varicose veins?; Varicose veins are swollen, twisted veins that have filled with an abnormal collection of blood, often resulting from faulty valves within the veins. What is the cardiac cycle?; The cardiac cycle is the sequence of events in a single heartbeat, including the contraction (systole) and relaxation (diastole) of the heart chambers. What is central venous pressure?; Central venous pressure is the pressure within the thoracic vena cava, near the right atrium of the heart, reflecting the amount of blood returning to the heart. What is the role of the aorta?; The aorta is the largest artery in the body, carrying oxygen-rich blood from the left ventricle of the heart to the rest of the body. What is atherosclerosis?; Atherosclerosis is a condition characterized by the buildup of fatty deposits (plaques) inside the arteries, leading to reduced blood flow and increased risk of cardiovascular diseases. What changes occur in the cardiovascular system with aging?; With aging, the cardiovascular system undergoes changes such as stiffening of blood vessels, reduced cardiac output, and increased risk of hypertension and other cardiovascular diseases. What is hypertension?; Hypertension is a condition in which the force of the blood against the artery walls is too high, often defined as blood pressure above 140/90 mmHg. What are the primary functions of the cardiovascular system?; The primary functions of the cardiovascular system are to transport nutrients, oxygen, and hormones to cells throughout the body and to remove metabolic wastes such as carbon dioxide and nitrogenous wastes. What is the cardiac cycle?; The cardiac cycle is the sequence of events that occur when the heart beats, including systole (contraction) and diastole (relaxation) phases. What role do veins play in circulation?; Veins carry deoxygenated blood back to the heart except for the pulmonary veins, which carry oxygenated blood from the lungs to the heart. What is the function of the aorta?; The aorta is the main artery that carries oxygen-rich blood from the left ventricle of the heart to the rest of the body. What is an electrocardiogram (ECG or EKG)?; An electrocardiogram (ECG or EKG) is a test that measures the electrical activity of the heart to show whether or not it is working normally. What is the significance of systolic blood pressure?; Systolic blood pressure measures the pressure in your blood vessels when your heart beats. What is atherosclerosis?; Atherosclerosis is a condition in which fatty deposits called plaques build up inside the arteries, leading to reduced blood flow. What is central venous pressure (CVP)?; Central venous pressure (CVP) is the pressure within the thoracic vena cava, near the right atrium of the heart, reflecting the amount of blood returning to the heart. What changes occur in the cardiovascular system with aging?; With aging, the cardiovascular system undergoes changes such as stiffening of the arteries and heart valves, and a decrease in maximum heart rate and cardiac output. What node normally controls the heart rate?; The SA node normally controls the heart rate. How do sympathetic fibers affect the heart rate?; Sympathetic fibers increase the heart rate by influencing the SA and AV nodes, and the ventricular myocardium. How do parasympathetic fibers affect the heart rate?; Parasympathetic fibers decrease the heart rate via vagus nerves by influencing the SA and AV nodes. What factors can modify the heart rate?; Physical exercise, body temperature, fight-or-flight response, and the concentration of various ions such as K+ and Ca2+ can modify the heart rate. What role do baroreceptor reflexes play in the regulation of the cardiac cycle?; Baroreceptor reflexes arise from the cardiac control center in the medulla oblongata and balance the inhibitory and excitatory effects of parasympathetic and sympathetic fibers. What is the function of the cardiac control center?; The cardiac control center regulates autonomic impulses to the heart. What is the Baroreceptor Reflex?; The Baroreceptor Reflex is a mechanism by which autonomic impulses alter heart action in response to changes in blood pressure. What is the function of autonomic impulses in the cardiovascular system?; Autonomic impulses alter heart action, such as heart rate and strength of contraction, in response to signals from the body, helping to regulate blood pressure and circulation. What is an arrhythmia?; Altered heart rhythms; several types include fibrillation, tachycardia, bradycardia, flutter, and premature beats. What is fibrillation?; Uncoordinated, chaotic contraction of small areas of myocardium. Atrial fibrillation is not life-threatening, while ventricular fibrillation is often fatal. What is tachycardia?; Abnormally fast heartbeat, greater than 100 beats per minute at rest. What is bradycardia?; Abnormally slow heartbeat, less than 60 beats per minute at rest. What is a flutter in cardiac terms?; Rapid, regular contraction of a heart chamber, typically 250-350 beats per minute. What is a premature beat?; A beat that occurs before expected in the normal cardiac cycle; often originates from ectopic regions of the heart (other than the SA node). What is an ectopic pacemaker?; Damage to the SA node may lead to the AV node taking over and acting as a secondary pacemaker, with a rate of 40-60 beats per minute, instead of 70-80. What is an artificial pacemaker?; A device used to treat disorders of the cardiac conduction system; it is implantable and battery-powered. What are blood vessels?; Blood vessels are organs of the cardiovascular system that form a closed circuit, transporting blood from the heart to body cells (or lungs) and back to the heart. What is the function of arteries?; Arteries carry blood away from the ventricles of the heart. What is the role of arterioles?; Arterioles receive blood from the arteries and carry it to the capillaries. What occurs at the capillaries?; Capillaries are the sites of exchange of substances between the blood and the body cells. What is the function of venules?; Venules receive blood from the capillaries and conduct it to veins. What is the role of veins?; Veins receive blood from venules and carry it back to the atria of the heart. What is an arteriole?; An arteriole is a small diameter blood vessel that extends and branches out from an artery and leads to capillaries. What is a venule?; A venule is a small blood vessel that allows deoxygenated blood to return from the capillary beds to larger blood vessels called veins. What is angiogenesis?; Formation of new blood vessels. What factor primarily controls angiogenesis?; Vascular Endothelial Growth Factor (VEGF). How does the body respond to a blocked coronary artery in terms of angiogenesis?; The body secretes VEGF in response to a blocked coronary artery. What method can be used if natural secretion of VEGF is not sufficient to promote angiogenesis?; VEGF may be delivered in time-release capsules. Why do tumors secrete VEGF?; Tumors secrete VEGF to nourish themselves. What type of drugs are used to prevent angiogenesis in cancer treatment?; Antiangiogenesis drugs. In addition to cancer, what other condition is treated with antiangiogenesis drugs?; Age-related macular degeneration. What are the main characteristics of arteries?; Arteries have thick, strong walls that are thicker than the walls of veins. They consist of three layers or tunics: the tunica interna (intima), the tunica media, and the tunica externa (adventitia). They transport blood under high pressure and give rise to smaller arterioles. What is the tunica interna (intima) in arteries?; The tunica interna (intima) is the innermost layer of an artery. What is the tunica media in arteries?; The tunica media is the middle layer of an artery, composed of smooth muscle and elastic tissue. What is the tunica externa (adventitia) in arteries?; The tunica externa (adventitia) is the outer layer of an artery, made up of connective tissue. What do arteries give rise to?; Arteries give rise to smaller arterioles. What are arterioles?; Arterioles are small blood vessels with thinner walls than arteries, consisting of the same three layers or tunics. The walls of the middle and outer layers become thinner as arterioles get smaller. What common functions do arteries and arterioles share?; Both arteries and arterioles can undergo vasoconstriction and vasodilation. What do small arterioles contain in their walls?; Small arterioles only contain a few muscle fibers in their walls. What are capillaries?; Capillaries are the smallest-diameter blood vessels that connect the smallest arterioles and the smallest venules. They are extensions of the inner lining of arterioles and consist of endothelium (simple squamous epithelium) only. Capillaries are semi-permeable. What regulates capillary blood flow?; Capillary blood flow is regulated mainly by precapillary sphincters, which are smooth muscle surrounding the capillary when it branches off an arteriole or metarteriole. What process allows substances to be exchanged in capillaries?; Substances are exchanged by diffusion. Where are the openings in the walls of capillaries found?; Openings in the walls of capillaries are thin slits found where endothelial cells overlap. How does the size of openings in capillary walls vary?; The sizes of openings in capillary walls vary among tissues. How does permeability of capillaries vary?; Permeability of capillaries varies with the size of the slits. What determines the density of capillary networks in a tissue?; The metabolic rate of a tissue determines the density of its capillary networks; higher metabolic rates result in denser capillary networks. Why do muscle and nerve tissues have a rich capillary supply?; Muscle and nerve tissues have a rich capillary supply because they use a large amount of O2 and nutrients. What is the capillary density like in tissues with a lower metabolic rate, such as cartilage?; Tissues with a lower metabolic rate, such as cartilage, have fewer capillaries. What is the most important method of transfer in capillary exchange?; Diffusion is the most important method of transfer in capillary exchange. How do lipid-soluble substances transfer through capillary walls?; Lipid-soluble substances diffuse through the cell membrane. How do water-soluble substances transfer through capillary walls?; Water-soluble substances diffuse through membrane channels and slits. What forces molecules through the capillary membrane during filtration?; Hydrostatic pressure forces molecules through the capillary membrane during filtration. Where does the pressure for filtration in capillaries come from?; The pressure for filtration in capillaries is derived from ventricular contraction. What creates osmotic pressure inside capillaries?; The presence of impermeant solutes, such as plasma proteins, creates osmotic pressure inside capillaries. What effect does osmotic pressure have on water in capillaries?; Osmotic pressure draws water into capillaries, opposing filtration. What happens at the arteriolar end of a capillary?; At the arteriolar end of a capillary, H2O and other substances leave the capillary because hydrostatic pressure is greater than osmotic pressure. What occurs at the venular end of a capillary?; At the venular end of a capillary, H2O enters the capillary because osmotic pressure is greater than hydrostatic pressure. What are venules?; Microscopic vessels that transport blood from the capillaries to veins. They have thinner walls and less smooth muscle than arterioles. What are the characteristics of veins?; Veins have thinner walls than arteries (3 layers or tunics), a less developed tunica media, carry blood under relatively low pressure, function as blood reservoirs, and many have flap-like valves. What proportion of blood is in veins and venules at any time?; About two-thirds of blood is in veins and venules at any time. What is the function of an artery?; Carries blood under relatively high pressure from the heart to arterioles. What are the characteristics of an artery's wall?; Thick, strong wall with three layers — an endothelial lining, a middle layer of smooth muscle and elastic connective tissue, and an outer layer of connective tissue. How does an arteriole contribute to blood flow?; Connects an artery to a capillary, helps control the blood flow into a capillary by vasoconstricting or vasodilating. What is the structure of an arteriole's wall?; Thinner wall than an artery but with three layers; smaller arterioles have an endothelial lining, some smooth muscle tissue, and a small amount of connective tissue. What is the primary function of capillaries?; Allows nutrients, gases, and wastes to be exchanged between the blood and tissue fluid. Describe the structure of capillary walls.; Single layer of squamous epithelium. What role do venules play in the circulatory system?; Connects a capillary to a vein. What are the characteristics of a venule's wall?; Thinner wall than an arteriole, less smooth muscle and elastic connective tissue. What is the function of veins in the circulatory system?; Carries blood under relatively low pressure from a venule to the heart; valves prevent a backflow of blood; serves as a blood reservoir. Describe the structure of vein walls.; Thinner wall than an artery but with similar layers; the middle layer is more poorly developed; some have flap-like valves. What is Atherosclerosis?; Deposits of cholesterol plaque form in inner lining of walls of arteries. What is an Aneurysm?; A bulge in the wall of an artery, formed when blood pressure dilates a weakened area of the vessel; can burst wall of artery. What is Phlebitis?; Inflammation of a vein; common disorder. What are Varicose Veins?; Abnormal and irregular dilations in superficial veins; most common in legs. What is blood pressure?; The force the blood exerts against the inner walls of the blood vessels. What does the term 'blood pressure' most commonly refer to?; Pressure in systemic arteries. How does blood move throughout the vascular system?; Blood moves from higher to lower pressure throughout the system. What is arterial blood pressure?; Arterial blood pressure rises when the ventricles contract and falls when the ventricles relax. What is systolic pressure (SP)?; Systolic pressure (SP) is the maximum pressure reached during ventricular contraction. What is diastolic pressure (DP)?; Diastolic pressure (DP) is the minimum pressure remaining before the next ventricular contraction. What is pulse pressure (PP)?; Pulse pressure (PP) is the difference between systolic and diastolic blood pressures (SP - DP). What is mean arterial pressure (MAP)?; Mean arterial pressure (MAP) is the average pressure in the arterial system and represents the average force driving blood to the tissues. It can be calculated using the formula: MAP = DP + 1/3(PP). How is blood pressure typically stated?; Blood pressure is typically stated as a fraction, such as 120/80, and is measured in units of mm Hg. What is typically used to measure Arterial Blood Pressure?; Arterial Blood Pressure is typically measured with a sphygmomanometer. What happens to blood pressure as the distance from the left ventricle increases?; Blood pressure decreases as distance from the left ventricle increases. What is the term for the sites at which the pulse is most easily detected?; Sites for Measuring Arterial Pulse What is arterial blood pressure?; Arterial blood pressure is the force that blood exerts on the walls of the arteries as it circulates through the body. What factors influence arterial blood pressure?; Factors influencing arterial blood pressure include cardiac output, blood volume, resistance to flow, and the elasticity of arterial walls. How does cardiac output affect arterial blood pressure?; Cardiac output affects arterial blood pressure by determining the amount of blood pumped by the heart per minute; higher cardiac output increases blood pressure. What role does blood volume play in arterial blood pressure?; Blood volume influences arterial blood pressure by affecting the amount of blood available to circulate through the arteries; higher blood volume increases blood pressure. How does resistance to flow impact arterial blood pressure?; Resistance to flow impacts arterial blood pressure by determining how hard the heart must work to pump blood through the vessels; increased resistance leads to higher blood pressure. What is the significance of the elasticity of arterial walls in blood pressure?; The elasticity of arterial walls is significant in blood pressure regulation because more elastic arteries can expand and contract more easily, helping to maintain stable blood pressure. What is stroke volume (SV)?; Stroke volume (SV) is the volume of blood that enters the arteries with each ventricular contraction (~70 mL/beat). What is cardiac output (CO)?; Cardiac output (CO) is the volume of blood discharged from a ventricle each minute, calculated as CO = SV × HR. How does blood pressure vary with cardiac output?; Blood pressure varies with cardiac output; an increase in stroke volume (SV) or heart rate (HR) causes an increase in cardiac output (CO), which in turn increases blood pressure (BP). What is Blood Volume?; The sum of volumes of plasma and formed elements in the blood. How does blood volume vary?; Blood volume varies with age, body size, and gender. What is the typical blood volume for adults?; Usually about 5 liters for adults, with 4 to 5 liters in females and 5 to 6 liters in males. What percentage of body weight is blood volume?; Blood volume is 8% of body weight. How is blood pressure related to blood volume?; Blood pressure is directly proportional to blood volume. What can happen to blood pressure if blood volume decreases?; Any factor that decreases blood volume, such as hemorrhage, can decrease blood pressure. What is Peripheral Resistance (PR)?; Force of friction between blood and walls of blood vessels. What must blood pressure overcome in order to flow?; Blood pressure must overcome Peripheral Resistance (PR) in order to flow. How do factors that change Peripheral Resistance (PR) affect blood pressure?; Factors that change Peripheral Resistance (PR) also change blood pressure. What effect does vasoconstriction of arterioles have on Peripheral Resistance (PR) and blood pressure?; Vasoconstriction of arterioles increases Peripheral Resistance (PR), which increases blood pressure. What happens when blood is pumped out of the ventricles?; When blood is pumped out of ventricles, arteries swell; rapid elastic recoil sends the blood through the arteries, against Peripheral Resistance (PR) in arterioles and capillaries. What is viscosity?; Difficulty with which molecules of fluid flow past each other. Greater the viscosity, the greater the resistance to blood flow. How do blood cells and plasma proteins affect blood viscosity?; Blood cells and plasma proteins increase the viscosity of the blood. What is the relationship between viscosity and blood pressure?; Greater the resistance to flow due to higher viscosity, the greater the force necessary to transport the blood, which increases blood pressure. How does anemia affect blood viscosity and blood pressure?; Anemia lowers the concentration of blood cells, which lowers blood viscosity and subsequently lowers blood pressure. What factors can alter blood viscosity?; Any factor that alters the concentration of blood cells or plasma proteins also alters blood viscosity. What is Blood Pressure (BP) determined by?; Blood Pressure (BP) is determined by cardiac output (CO) and peripheral resistance (PR): BP = CO × PR. What are the two factors that need to be regulated to maintain blood pressure?; The two factors that need to be regulated to maintain blood pressure are cardiac output (CO) and peripheral resistance (PR). What is hypertension?; Hypertension is long-lasting elevated arterial blood pressure. What are some causes of hypertension?; Causes of hypertension include unknown cause, increased sodium intake, psychological stress that activates the sympathetic nervous system, obesity (by increasing peripheral resistance), and kidney disease (via renin-angiotensin response). Why is hypertension referred to as the 'silent killer'?; Hypertension is referred to as the 'silent killer' because it may not cause any direct symptoms. How does hypertension contribute to atherosclerosis?; Hypertension contributes to the formation of atherosclerosis by causing damage to the arterial walls, which can lead to plaque formation. What are some possible complications of hypertension?; Possible complications of hypertension include coronary thrombosis or embolism, cerebral thrombosis, embolism, or hemorrhage, which may result in a transient ischemic attack (TIA, ministroke) or a cerebral vascular accident (CVA, stroke). How can hypertension be prevented?; Hypertension can be prevented through a healthy diet and weight, regular exercise, and limiting sodium intake. What are some treatments for hypertension?; Treatments for hypertension include diuretics and sympathetic inhibitors. What happens to blood pressure as it moves through the arterial system into the capillary network?; Blood pressure decreases as it moves through the arterial system into the capillary network, leaving little pressure at the venous ends of the capillaries. What is venous blood flow partly a result of?; Venous blood flow is only partly a direct result of heart action. What are the factors that venous blood flow is dependent on?; Venous blood flow is dependent on skeletal muscle contraction, breathing movements, and vasoconstriction of veins. What is central venous pressure?; Pressure in the right atrium is called central venous pressure. Where do all veins, except those returning from the lungs, drain into?; All veins, except those returning to the heart from the lungs, drain into the right atrium. What factors influence central venous pressure?; Factors that influence central venous pressure alter the flow of blood into the right atrium. How does a weakly beating heart affect central venous pressure?; A weakly beating heart increases central venous pressure. What effect does increased central venous pressure have on peripheral veins?; An increase in central venous pressure causes blood to back up into the peripheral veins. What condition can be caused by increased central venous pressure?; Increased central venous pressure can lead to peripheral edema. What happens when there is an increase in blood volume or venoconstriction?; An increase in blood volume or venoconstriction increases blood flow to the right atrium, which increases central venous pressure. What is the effect of regular aerobic exercise on the cardiovascular system?; Regular aerobic exercise increases pumping efficiency, blood volume, hemoglobin concentration, and the number of mitochondria. The heart may enlarge by 40% or more, stroke volume increases, and heart rate and blood pressure decrease. What changes occur in the heart due to regular aerobic exercise?; The heart may enlarge by 40% or more, and stroke volume increases. How does regular aerobic exercise affect heart rate and blood pressure?; Regular aerobic exercise decreases both heart rate and blood pressure. What are the requirements for exercise to benefit the cardiovascular system?; The heart rate must increase to 70 to 85% of maximum (220 minus your age), the exercise must last 30 to 60 minutes, and it should be performed at least 3 to 4 times per week. What are the two pathways formed by blood vessels?; The pulmonary circuit and the systemic circuit. What is the pathway of blood in the pulmonary circuit?; Right ventricle → pulmonary trunk → right and left pulmonary arteries → lobar branches, repeated divisions → pulmonary arterioles → pulmonary capillaries → pulmonary venules and veins → left atrium. What are the characteristics of blood in pulmonary arteries and arterioles?; Blood in pulmonary arteries and arterioles is low in O2 and high in CO2. Where does gas exchange occur in the pulmonary circuit?; Gas exchange occurs in pulmonary (alveolar) capillaries. What are the characteristics of blood in pulmonary venules and veins?; Blood in pulmonary venules and veins is rich in O2 and low in CO2. What is the pathway of oxygen-rich blood in the systemic circuit?; Oxygen-rich blood moves from left atrium to left ventricle, and then contraction of the left ventricle sends blood into the systemic circuit: Left ventricle → aorta → all arteries and arterioles leading to body tissues → systemic capillaries → systemic venules and veins → right atrium. What effect does high osmotic pressure in interstitial fluid have on alveoli?; High osmotic pressure in interstitial fluid draws water out of alveoli. What is the largest artery in the body?; The aorta is the largest artery in the body. What does the aorta supply blood to?; The aorta supplies blood to all of the systemic arteries. What are the branches of the ascending aorta?; Right and left coronary arteries. Which organs are supplied by the celiac artery?; Organs of the upper digestive tract. What regions are supplied by the brachiocephalic trunk?; Right upper limb and right side of the head. Which artery supplies the diaphragm?; Phrenic artery. What is the role of the left common carotid artery?; Supplies the left side of the head. Which artery supplies portions of the small and large intestines?; Superior mesenteric artery. Which artery supplies the left upper limb?; Left subclavian artery. Which organ is supplied by the suprarenal artery?; Adrenal gland. Which artery supplies the kidneys?; Renal artery. Which artery supplies the bronchi?; Bronchial artery. Which artery supplies the ovaries or testes?; Gonadal artery. What is the function of the pericardial artery?; Supplies the pericardium. Which artery supplies the lower portions of the large intestine?; Inferior mesenteric artery. Which artery supplies the esophagus?; Esophageal artery. Which artery supplies the posterior abdominal wall?; Lumbar artery. What is the role of the mediastinal artery?; Supplies the mediastinum. Which artery supplies the sacrum and coccyx?; Middle sacral artery. Which artery supplies the thoracic wall?; Posterior intercostal artery. What regions are supplied by the common iliac artery?; Lower abdominal wall, pelvic organs, and lower limb. What is the function of the aorta?; The aorta is the main artery that carries oxygenated blood from the left ventricle of the heart to the rest of the body. What is the role of the superior vena cava?; The superior vena cava is a large vein that carries deoxygenated blood from the upper half of the body to the right atrium of the heart. What does the inferior vena cava do?; The inferior vena cava is a large vein that carries deoxygenated blood from the lower half of the body to the right atrium of the heart. What is the function of the pulmonary arteries?; The pulmonary arteries carry deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation. What is the role of the pulmonary veins?; The pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart. What is the function of the coronary arteries?; The coronary arteries supply oxygenated blood to the heart muscle (myocardium). What is the purpose of the coronary veins?; The coronary veins remove deoxygenated blood from the heart muscle and return it to the right atrium. What are the major branches of the abdominal aorta?; The major branches of the abdominal aorta include the celiac trunk, superior mesenteric artery, renal arteries, gonadal arteries, inferior mesenteric artery, and the common iliac arteries. What arteries supply blood to the brain, head, and neck?; Branches of the subclavian and common carotid arteries supply blood to the brain, head, and neck. What is the cerebral arterial circle (circle of Willis)?; The cerebral arterial circle (circle of Willis) joins the carotid and vertebral artery systems and provides alternate pathways for blood to reach the brain. What is the function of the cerebral arteries that emerge from the circle of Willis?; The cerebral arteries that emerge from the circle of Willis supply blood to brain tissues. What artery gives off branches in the neck and then continues into the arm?; The subclavian artery gives off branches in the neck and then continues into the arm. What arteries supply blood to the thoracic wall?; Blood reaches the thoracic wall via branches of several vessels, including the subclavian artery and the thoracic aorta. What does the abdominal aorta divide into?; The abdominal aorta divides into the common iliac arteries. What regions do the common iliac arteries supply blood to?; The common iliac arteries supply blood to the pelvic organs, gluteal region, and lower limbs. Into which arteries does the common iliac artery divide?; The common iliac artery divides into the internal iliac artery and external iliac artery. What does the internal iliac artery supply blood to?; The internal iliac artery supplies blood to the pelvic and gluteal areas. What is the major blood supply to the lower limbs?; The external iliac arteries provide the major blood supply to the lower limbs. What is the venous system?; The venous system is a network of veins that carry deoxygenated blood from the body back to the heart. What are veins?; Veins are blood vessels that carry blood towards the heart, typically deoxygenated blood from the tissues. What is the function of the superior vena cava?; The superior vena cava is a large vein that carries deoxygenated blood from the upper half of the body to the heart. What is the function of the inferior vena cava?; The inferior vena cava is a large vein that carries deoxygenated blood from the lower half of the body to the heart. What are venules?; Venules are small blood vessels that collect blood from capillaries and join to form veins. What role do valves in veins play?; Valves in veins prevent the backflow of blood, ensuring it moves in one direction towards the heart. What is central venous pressure?; Central venous pressure is the pressure within the thoracic vena cava near the right atrium, reflecting the amount of blood returning to the heart. What is the significance of the venous system in circulation?; The venous system is significant in circulation as it returns deoxygenated blood back to the heart, completing the systemic circulation loop. What is systemic venous circulation?; Systemic venous circulation returns blood to the heart after the exchange of gases, nutrients, and wastes between blood and cells. How do vessels of the venous system originate?; Vessels of the venous system originate from the merging of capillaries into venules, venules into small veins, and small veins into larger ones. Why are venous pathways difficult to follow?; Venous pathways are difficult to follow due to irregular networks and unnamed tributaries. How do the pathways of larger veins relate to arteries?; Pathways of larger veins usually parallel arteries of the same name. Into which veins do all systemic veins converge?; All systemic veins converge into the superior and inferior venae cavae and return to the heart through the right atrium. What do the external jugular veins drain blood from?; The external jugular veins drain blood from the face, scalp, and superficial neck. What do the internal jugular veins drain blood from?; The internal jugular veins drain blood from the brain, and deep portions of the face and neck. What are the two systems of veins that drain the upper limb and shoulder?; The two systems of veins that drain the upper limb and shoulder are the deep set of veins and the superficial set of veins. What is the pathway of the deep set of veins in the upper limb?; The pathway of the deep set of veins in the upper limb is: Digital veins → Radial and ulnar veins → Brachial veins. What is the pathway of the superficial set of veins in the upper limb?; The pathway of the superficial set of veins in the upper limb is: Anastomoses in the palm and wrist → Basilic and cephalic veins. Which veins do the basilic and cephalic veins join?; The basilic vein joins the brachial vein, and the cephalic vein joins the axillary vein. What veins drain the abdominal and thoracic walls?; The abdominal and thoracic walls are drained by tributaries of the brachiocephalic and azygos veins. Into which vein does the azygos vein drain?; The azygos vein drains directly into the superior vena cava. What are portal veins?; Portal veins are unusual in that they do not transport blood directly to the heart. What is the hepatic portal system?; The hepatic portal system is a unique venous pathway that drains blood from the abdominal viscera and transports it to the liver for processing before delivering it to the inferior vena cava. Which organs' capillaries drain into the hepatic portal vein?; Capillaries in the stomach, intestines, pancreas, and spleen drain into the hepatic portal vein. What is a portal system?; A portal system is a network that filters blood through two sets of capillaries, instead of the usual one set. What is the Hepatic Portal System?; The Hepatic Portal System is a portal system that filters blood through two sets of capillaries, involving the liver. What is the Renal Portal System?; The Renal Portal System is a portal system that filters blood through two sets of capillaries, involving the kidneys. What is the longest vein in the body?; The great saphenous vein is the longest vein in the body. Into which vein do the anterior and posterior tibial veins drain?; The anterior and posterior tibial veins drain into the popliteal vein. What are the two groups of veins in the lower limb?; The two groups of veins in the lower limb are the deep set of veins and the superficial set of veins. Into which vein does the popliteal vein drain?; The popliteal vein drains into the femoral vein. What is the drainage pathway of the superficial set of veins in the lower limb?; The superficial set of veins in the lower limb drains from the veins in the foot into the small and great saphenous veins. Into which vein does the femoral vein drain?; The femoral vein drains into the external iliac vein. What is the effect of cholesterol deposition in the blood vessels?; Cholesterol deposition in the blood vessels leads to the buildup of plaque, which can narrow and harden the arteries, restricting blood flow. What happens to coronary arteries as a person ages?; Coronary arteries may narrow, which can restrict blood flow to the heart muscle and increase the risk of heart disease. How can the size of the heart change due to disease?; The heart may shrink slightly or enlarge due to disease. What happens to the proportion of cardiac muscle in the heart with aging?; The proportion of the heart consisting of cardiac muscle declines. What type of tissue increases in the heart as a person ages?; There is an increase in fibrous connective tissue in the heart. What happens to the amount of adipose tissue in the heart with aging?; The amount of adipose tissue in the heart increases. What changes occur in the heart valves and left ventricular wall with aging?; The heart valves and left ventricular wall may thicken. How does systolic blood pressure change with age?; Systolic blood pressure increases with age. What happens to the resting heart rate as a person ages?; The resting heart rate decreases with age. How do the lumens of large arteries change with aging?; The lumens of large arteries narrow as arterial walls thicken. What happens to arterial elasticity with age?; Arterial elasticity decreases with age. What is Marfan syndrome?; Marfan syndrome is a connective tissue defect involving an abnormal type of the protein fibrillin, which can weaken the wall of the aorta and result in bursting of the aorta and sudden death. What is Familial hypertrophic cardiomyopathy?; Familial hypertrophic cardiomyopathy is an inherited overgrowth of myocardium caused by an abnormal myosin chain in cardiac muscle, which can result in sudden death. What results from an inherited deficiency of a mitochondrial enzyme that breaks down fatty acids?; Heart failure results from the inability to break down long-chain fatty acids and use them for energy, as cardiac muscle uses them as a primary energy source. What is Familial hypercholesterolemia?; Familial hypercholesterolemia is a condition where abnormal LDL (low-density lipoprotein) receptors on liver cells do not take up cholesterol from the blood, resulting in high cholesterol and coronary artery disease. What is Coronary Artery Disease (CAD)?; Disease involving deposition of cholesterol plaque on inner walls of coronary arteries, leading to obstruction of coronary arteries and oxygen deficiency in cardiac muscle. What often accompanies Coronary Artery Disease (CAD)?; High serum cholesterol and hypertension. What symptom is often caused by Coronary Artery Disease (CAD) upon exertion?; Pain in the chest called angina pectoris. What major medical event can Coronary Artery Disease (CAD) contribute to?; Myocardial infarction (heart attack). What is Percutaneous Transluminal Coronary Angioplasty (PTCA)?; A treatment for Coronary Artery Disease (CAD) involving the widening of narrowed or obstructed coronary arteries. What is Coronary Bypass Surgery?; A treatment for Coronary Artery Disease (CAD) where a blood vessel from another part of the body is grafted to bypass a blocked coronary artery. What is the best location to hear the aortic valve?; The aortic valve is best heard in the second intercostal space right of the sternum. Where can the pulmonary valve be best heard?; The pulmonary valve is best heard in the second intercostal space left of the sternum. At which location can the tricuspid valve be best heard?; The tricuspid valve is best heard at the fifth intercostal space left of the sternum. Where is the best place to listen to the mitral valve?; The mitral valve is best heard in the fifth intercostal space on the left at the nipple line. What is the site for measuring the pulse of the temporal artery?; The pulse of the temporal artery can be taken anterior to the ear. Where can the pulse of the carotid artery be measured?; The pulse of the carotid artery can be measured in the inferior medial portion of the neck. Where is the brachial artery pulse located?; The brachial artery pulse is located in the distal brachial region on the anterior side. Where can the pulse of the radial artery be taken?; The pulse of the radial artery can be taken on the lateral side of the wrist on the anterior side. Where is the site for measuring the femoral artery pulse?; The femoral artery pulse can be measured in the inguinal region. Where can the pulse of the popliteal artery be measured?; The pulse of the popliteal artery can be measured in the popliteal region. Where is the dorsalis pedis artery pulse located?; The dorsalis pedis artery pulse is located in the anterior ankle. Where can the pulse of the posterior tibia artery be taken?; The pulse of the posterior tibia artery can be taken in the posterior ankle. What are the functions of the organs of the cardiovascular system?; The organs of the cardiovascular system function to transport nutrients, oxygen, and hormones to cells throughout the body and removal of metabolic wastes (carbon dioxide, nitrogenous wastes). What is the pericardium?; The pericardium is the covering of the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane. What are the layers that compose the wall of the heart?; The heart wall is composed of three layers: the epicardium (outer layer), myocardium (middle muscular layer), and endocardium (inner layer). What is the function of the atria in the heart?; The atria are the upper chambers of the heart that receive blood returning to the heart from the body and lungs. What is the function of the ventricles in the heart?; The ventricles are the lower chambers of the heart that pump blood out of the heart to the lungs and the rest of the body. What is the pathway of blood through the heart?; Blood flows through the heart in the following sequence: right atrium -> right ventricle -> pulmonary arteries -> lungs -> pulmonary veins -> left atrium -> left ventricle -> aorta -> body. What is coronary circulation?; Coronary circulation is the circulation of blood in the blood vessels of the heart muscle (myocardium). What is the cardiac cycle?; The cardiac cycle is the sequence of events in one complete heartbeat, including systole (contraction) and diastole (relaxation) of both atria and ventricles. How are heart sounds produced?; Heart sounds are produced by the closing of the heart valves. The 'lub' sound is caused by the closure of the atrioventricular valves, and the 'dub' sound is caused by the closure of the semilunar valves. What are the parts of a normal ECG pattern?; The parts of a normal ECG pattern include the P wave, QRS complex, and T wave. These components represent the depolarization and repolarization of the atria and ventricles. What is the significance of a normal ECG pattern?; A normal ECG pattern is significant as it reflects the electrical activity of the heart, indicating the normal functioning of the heart's conduction system. How is the cardiac cycle controlled?; The cardiac cycle is controlled by the sinoatrial node (SA node), which acts as the pacemaker of the heart, and the atrioventricular node (AV node), which regulates the timing of ventricular contraction. What are the major types of blood vessels and their functions?; The major types of blood vessels are arteries, veins, and capillaries. Arteries carry blood away from the heart, veins return blood to the heart, and capillaries facilitate the exchange of substances between blood and tissue fluid. How are substances exchanged between blood in capillaries and tissue fluid?; Substances are exchanged between blood in capillaries and tissue fluid through mechanisms such as diffusion, osmosis, and filtration, allowing for nutrient delivery and waste removal. How is blood pressure produced?; Blood pressure is produced by the force exerted by circulating blood on the walls of blood vessels, primarily driven by the contraction of the heart and the resistance of the blood vessels. How is blood pressure controlled?; Blood pressure is controlled through mechanisms involving the autonomic nervous system, hormones like adrenaline and angiotensin, and the kidneys, which regulate blood volume. What mechanisms aid in returning venous blood to the heart?; Mechanisms that aid in returning venous blood to the heart include the skeletal muscle pump, respiratory pump, and the presence of valves in veins that prevent backflow. What is the pulmonary circuit?; The pulmonary circuit is the part of the cardiovascular system that carries deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium. What is the systemic circuit?; The systemic circuit is the part of the cardiovascular system that carries oxygenated blood from the left ventricle to the body and returns deoxygenated blood to the right atrium. What are the major arteries in the human body?; Major arteries include the aorta, carotid arteries, subclavian arteries, renal arteries, and iliac arteries, among others. What are the major veins in the human body?; Major veins include the superior and inferior vena cava, jugular veins, subclavian veins, renal veins, and iliac veins, among others. What are some lifespan changes in the cardiovascular system?; Lifespan changes in the cardiovascular system include thickening of the arterial walls, decreased elasticity of blood vessels, and reduced efficiency of the heart.