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?; Blood runs through two circuits: 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?; The heart contains 4 chambers: 2 atria (upper chambers) and 2 ventricles (lower chambers, 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 relation to the sternum?; The heart is located posterior to the sternum. Where is the heart located in relation to the lungs?; The heart is located medial to the lungs. Where is the heart located in relation to the vertebral column?; The heart is located 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 sternum?; The sternum is a long, flat bone located in the center of the chest, to which the ribs are attached. What is the base of the heart?; The base of the heart is the broader, upper part of the heart where major blood vessels are attached. What is the apex of the heart?; The apex of the heart is the pointed, lower tip of the heart that points downwards and to the left. Where is the heart located in relation to the diaphragm?; The heart is located above the diaphragm, which is the muscle that separates the chest cavity from the abdominal cavity. What is the pericardium?; A covering over the heart and large blood vessels. What is the fibrous pericardium?; The outer layer that surrounds the double-layered serous membrane. What is the parietal pericardium?; The layer deep to the fibrous pericardium; it is the outer layer of the serous membrane. What is the visceral pericardium?; 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 forms the inner lining of all heart chambers?; Endocardium: Inner layer; forms inner lining of all heart chambers; thin layer. What is the epicardium (visceral pericardium)?; The epicardium is a serous membrane of connective tissue covered with epithelium and includes blood capillaries, lymph capillaries, and nerve fibers. It forms a protective outer covering and secretes serous fluid. What is the myocardium?; The myocardium is composed of cardiac muscle tissue separated by connective tissue and includes blood capillaries, lymph capillaries, and nerve fibers. It contracts to pump blood from the heart chambers. What is the endocardium?; The endocardium is a membrane of epithelium and underlying connective tissue, including blood vessels. It forms a protective inner lining of the chambers and valves. What are the atria?; The atria are thin-walled upper chambers of the heart that receive blood returning to the heart. What are auricles?; Auricles are flap-like projections from the atria that allow atrial expansion. What are the ventricles?; The 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 blood to the lungs. What is the function of the left atrium?; The left atrium receives blood from the pulmonary veins and pumps blood to the left ventricle. What is the function of the left ventricle?; The left ventricle receives blood from the left atrium and pumps blood 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. Where is the mitral valve located?; Left atrioventricular orifice. 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 function of the aorta?; The aorta is the main artery that carries oxygenated blood from the left ventricle to the rest of the body. What is the role of the right pulmonary artery?; The right pulmonary artery carries deoxygenated blood from the right ventricle to the right lung. What is the function of the left atrium?; The left atrium receives oxygenated blood from the lungs via the pulmonary veins and pumps it into the left ventricle. What is the purpose of the tricuspid valve?; The tricuspid valve prevents backflow of blood from the right ventricle into the right atrium during ventricular contraction. What is the role of the pulmonary valve?; The pulmonary valve prevents backflow of blood from the pulmonary artery into the right ventricle. What is the function of the interventricular septum?; The interventricular septum is the wall that separates the left and right ventricles of the heart. What is the function of the superior vena cava?; The superior vena cava carries deoxygenated blood from the upper body to the right atrium. What is the function of the left pulmonary veins?; The left pulmonary veins carry oxygenated blood from the left lung to the left atrium. What is the role of the papillary muscles?; Papillary muscles attach to the cusps of the atrioventricular valves via the chordae tendineae and prevent valve inversion during ventricular contraction. What is the function of the chordae tendineae?; The chordae tendineae are tendinous cords that connect the papillary muscles to the atrioventricular valves, preventing valve prolapse during ventricular contraction. What is the tricuspid valve?; The tricuspid valve is a valve in the heart located between the right atrium and the right ventricle. It has three cusps and prevents backflow of blood into the right atrium. 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. It has two cusps and prevents backflow of blood into the left atrium. What is the aortic valve?; The aortic valve is a valve in the heart located between the left ventricle and the aorta. It prevents backflow of blood into the left ventricle. What is the pulmonary valve?; The pulmonary valve is a valve in the heart located between the right ventricle and the pulmonary artery. It prevents backflow of blood into the right ventricle. What is the skeleton of the heart?; The skeleton of the heart consists of rings of dense connective tissue that surround the origins of the pulmonary trunk and aorta, and the orifices between the atria and ventricles. These structures provide attachments for heart valves and muscle fibers and prevent excess dilation of heart chambers during contraction. What is the function of the rings in the heart's skeleton?; The rings in the heart's skeleton provide attachments for heart valves and muscle fibers, and prevent excess dilation of heart chambers during contraction. What is the function of the tricuspid valve?; The tricuspid valve prevents backflow of blood from the right ventricle to the right atrium. What is the role of the pulmonary veins?; The pulmonary veins carry oxygenated blood from the lungs to the left atrium. What occurs at the alveolar capillaries?; At the alveolar capillaries, gas exchange occurs where oxygen is absorbed into the blood and carbon dioxide is released from the blood. What is the function of the mitral (bicuspid) valve?; The mitral (bicuspid) valve prevents backflow of blood from the left ventricle to the left atrium. What is the purpose of the aortic valve?; The aortic valve prevents backflow of blood from the aorta into the left ventricle. What is the significance of the pulmonary trunk?; The pulmonary trunk carries deoxygenated blood from the right ventricle to the pulmonary arteries, which lead to the lungs. What is the role of the superior vena cava?; The superior vena cava carries deoxygenated blood from the upper body to the right atrium. What is the function of the inferior vena cava?; The inferior vena cava carries deoxygenated blood from the lower body to the right atrium. What is the role of the left ventricle?; The left ventricle pumps oxygenated blood into the aorta for systemic circulation. 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 are the left and right coronary arteries?; The left and right coronary arteries supply blood to tissues of the heart. What are the first two branches of the aorta?; The coronary arteries are the first two branches of the aorta. What is the function of the right coronary artery?; The right coronary artery supplies blood to the right atrium, right ventricle, and portions of the left ventricle. What does the left coronary artery supply?; The left coronary artery supplies blood to the left atrium, left ventricle, and interventricular septum. What is the role of the posterior interventricular artery?; The posterior interventricular artery supplies blood to the posterior walls of the ventricles and the posterior portion of the interventricular septum. What does the marginal artery supply?; The marginal artery supplies blood to the right atrium and right ventricle. What is the function of the circumflex artery?; The circumflex artery supplies blood to the left atrium and the posterior walls of the left ventricle. What is the role of the anterior interventricular artery?; The anterior interventricular artery supplies blood to the anterior walls of the ventricles and the anterior portion of the interventricular septum. What is the function of cardiac veins?; Cardiac veins collect deoxygenated blood from the myocardial capillaries and return it to the coronary sinus. What is the coronary sinus?; The coronary sinus is a large vein that collects blood from the cardiac veins and empties into the right atrium. 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 are the pulmonary veins?; The pulmonary veins are the veins that carry oxygenated blood from the lungs to the left atrium of the heart. What is the role of the right atrium?; The right atrium receives deoxygenated blood from the body through the superior and inferior vena cava and pumps it into the right ventricle. What does the left coronary artery supply?; The left coronary artery supplies oxygenated blood to the heart muscle (myocardium). 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 right atrium of the heart. What is the pulmonary trunk?; The pulmonary trunk is a major vessel that carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation. What is the role of the right ventricle?; The right ventricle pumps deoxygenated blood into the pulmonary arteries, which carry it to the lungs for oxygenation. What is the apex of the heart?; The apex of the heart is the pointed end of the heart, located at the bottom, which points downward and to the left. What is the function of the coronary sinus?; The coronary sinus is a large vein that collects deoxygenated blood from the heart muscle and delivers it to the right atrium. What is the cardiac cycle?; The cardiac cycle refers to the events of a heartbeat, where the heart chambers function in a coordinated manner. Heart actions are regulated so that atria contract (atrial systole) while ventricles relax (ventricular diastole); then ventricles contract (ventricular systole) while atria relax (atrial diastole). What happens during atrial systole?; During atrial systole, the atria contract while the ventricles relax (ventricular diastole). What occurs during ventricular systole?; During ventricular systole, the ventricles contract while the atria relax (atrial diastole). What is a Heart Transplant?; Replacement of most of a failing heart with a donor heart. What is a Left Ventricular Assist Device (LVAD)?; Mechanical half-heart, used in some cases temporarily, until donor heart is available. What is an Implantable Replacement Heart?; Titanium and plastic artificial heart, used in people that cannot have heart transplant, and do not have long to live. What is Stem Cell Technology in the context of cardiac treatment?; Cardiac muscle tissue can now be cultured from altered somatic cells or from stem cells. This may allow “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 valves 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 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. From where does blood flow into the atria during ventricular systole and atrial diastole?; Blood flows into the atria from the 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 during ventricular systole?; Blood flows into the pulmonary trunk and aorta. What causes the 'lubb' sound in a heartbeat?; The 'lubb' sound is the first heart sound, occurring during ventricular systole and is associated with the closing of the A-V valves. What causes the 'dupp' sound in a heartbeat?; The 'dupp' sound is the second heart sound, occurring during ventricular diastole and is 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 the cusps of a valve. What is the aortic area?; The aortic area is the region on the chest where the sounds of the aortic valve can be heard most clearly. What is the pulmonary area?; The pulmonary area is the region on the chest where the sounds of the pulmonary valve can be heard most clearly. What is the tricuspid area?; The tricuspid area is the region on the chest where the sounds of the tricuspid valve can be heard most clearly. What is the mitral area?; The mitral area is the region on the chest where the sounds of the mitral valve can be heard most clearly. What is a functional syncytium?; A functional syncytium is a mass of merging cells that function as a unit. What are intercalated discs?; Intercalated discs are structures between cardiac muscle cells that contain gap junctions, allowing action potentials to spread through a network of cells. What is the atrial syncytium?; The atrial syncytium is a mass of merging cells in the atrial walls that function as a unit. What is the ventricular syncytium?; The ventricular syncytium is a mass of merging cells in the ventricular walls that function as a unit. 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. It coordinates the events of the cardiac cycle. What is the function of the SA node in the cardiac conduction system?; The SA node, or sinoatrial node, is responsible for initiating the electrical impulses that set the pace for the heart rate, often referred to as the heart's natural pacemaker. What role do the Purkinje fibers play in the cardiac conduction system?; Purkinje fibers conduct the electrical impulses rapidly throughout the ventricles, ensuring coordinated contraction of the ventricular myocardium. What is the AV node and its function in the cardiac conduction system?; The AV node, or atrioventricular node, receives the electrical impulse from the atria and delays it slightly before passing it to the ventricles, allowing the atria to contract and complete ventricular filling before the ventricles contract. What is the role of the Bundle branches in the cardiac conduction system?; The bundle branches carry the electrical impulses from the AV bundle down through the interventricular septum to the Purkinje fibers, ensuring the impulses reach the ventricles. What is the function of the SA (Sinoatrial) Node?; Pacemaker; initiates rhythmic contractions of the heart. What is the role of the Internodal Atrial Muscle?; Conducts impulses from SA node to atria. What do Junctional Fibers do?; Conduct impulses from SA node to AV node. What is the function of the AV (Atrioventricular) Node?; Conducts impulses to AV Bundle; delays impulse, so that atria finish contracting before ventricles contract. What is the purpose of the AV (Atrioventricular) Bundle (of His)?; Conducts impulses rapidly between SA node and bundle branches. What is the function of the Left and Right Bundle Branches?; Split off from AV bundle, conduct impulses to Purkinje fibers on both sides of heart. What do Purkinje Fibers do?; Large fibers that conduct impulses to ventricular myocardium. What are the Purkinje fibers?; Purkinje fibers are specialized muscle fibers in the heart that conduct electrical impulses, causing the ventricles to contract with a twisting motion. What is the function of the cardiac conduction system?; The cardiac conduction system is responsible for generating and transmitting electrical impulses that coordinate the contraction of the heart muscles. What is an Electrocardiogram (ECG, 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; occurs just prior to atrial contraction. What does the QRS complex in an ECG represent?; Ventricular depolarization; occurs just prior to ventricular contraction. What does the T wave in an ECG represent?; Ventricular repolarization; occurs 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, since ventricular depolarization is a much larger event. What is an electrocardiogram (ECG)?; An electrocardiogram (ECG) is a test that measures the electrical activity of the heart and is used to detect heart abnormalities. What does the P wave in an ECG represent?; The P wave represents atrial depolarization, which is the electrical activity associated with the contraction of the atria. What does the QRS complex in an ECG indicate?; The QRS complex indicates ventricular depolarization, which is the electrical activity associated with the contraction of the ventricles. What does the T wave in an ECG signify?; The T wave signifies ventricular repolarization, which is the process of the ventricles returning to their resting state. What is the significance of the PR interval in an ECG?; The PR interval represents the time taken for the electrical impulse to travel from the atria to the ventricles. What does the ST segment in an ECG represent?; The ST segment represents the period between ventricular depolarization and repolarization, usually indicating the time when the ventricles are contracting and emptying. What is the term for the graphical representation of the heart's electrical activity?; Electrocardiogram (ECG) What phase of the cardiac cycle involves the contraction of the atria?; Atrial systole What is the term for the phase when the ventricles contract?; Ventricular systole Which valve opens when ventricular pressure exceeds aortic pressure?; Aortic valve What is the term for the phase when the ventricles relax?; Ventricular diastole What heart sound is associated with the closure of the atrioventricular (AV) valves?; The first heart sound (S1) What heart sound is associated with the closure of the semilunar valves?; The second heart sound (S2) What is the term for the maximum volume of blood in the ventricles at the end of ventricular filling?; End-diastolic volume (EDV) What is the term for the minimum volume of blood in the ventricles at the end of ventricular contraction?; End-systolic volume (ESV) What node normally controls the heart rate?; The SA node normally controls the heart rate. How do sympathetic fibers modify the heart rate?; Sympathetic impulses via accelerator nerves increase heart rate by influencing the SA and AV nodes, and ventricular myocardium. How do parasympathetic fibers modify the heart rate?; Parasympathetic impulses via vagus nerves decrease heart rate by influencing the SA and AV nodes. What factors can modify the heart rate?; Factors such as physical exercise, body temperature, fight-or-flight response, and concentration of ions like 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 does the cardiac control center regulate?; The cardiac control center regulates autonomic impulses to the heart. What is the Baroreceptor Reflex?; The Baroreceptor Reflex is a mechanism by which the body maintains blood pressure at nearly constant levels. It involves sensors (baroreceptors) that detect changes in blood pressure and send signals to the central nervous system, which then adjusts heart rate and blood vessel diameter through autonomic impulses. What role do baroreceptors play in the Baroreceptor Reflex?; Baroreceptors are sensors located in the walls of certain blood vessels, such as the carotid arteries and aorta, that detect changes in blood pressure and send signals to the central nervous system to help regulate heart rate and blood vessel diameter. How do autonomic impulses alter heart action in the Baroreceptor Reflex?; Autonomic impulses, which are part of the autonomic nervous system, can either increase or decrease heart rate and force of contraction. These impulses are sent from the central nervous system to the heart in response to signals from baroreceptors detecting changes in blood pressure. What are arrhythmias?; Altered heart rhythms; several types. What is fibrillation?; Uncoordinated, chaotic contraction of small areas of myocardium. Atrial fibrillation is not life-threatening; ventricular fibrillation is often fatal. What is tachycardia?; Abnormally fast heartbeat, >100 beats/min at rest. What is bradycardia?; Abnormally slow heartbeat, < 60 beats/min at rest. What is flutter?; Rapid, regular contraction of a heart chamber, 250-350 beats/min. 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 SA node). What is an ectopic pacemaker?; Damage to SA node may lead to AV node taking over and acting as a secondary pacemaker; 40-60 beats/min, instead of 70-80. What is an artificial pacemaker?; A device used to treat disorders of the cardiac conduction system; implantable and battery-powered. What are arteries?; Arteries carry blood away from the ventricles of the heart. What are arterioles?; Arterioles receive blood from the arteries, and carry it to the capillaries. What are capillaries?; Capillaries are sites of exchange of substances between the blood and the body cells. What are venules?; Venules receive blood from the capillaries, and conduct it to veins. What are 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. It plays a key role in regulating blood flow and pressure. What is a venule?; A venule is a small blood vessel that allows deoxygenated blood to return from the capillary beds to the larger blood vessels called veins. What is the function of the tunica intima?; The tunica intima is the innermost layer of a blood vessel, composed of a thin layer of endothelial cells that reduce friction between the blood and the vessel wall, allowing for smooth blood flow. What is the tunica media?; The tunica media is the middle layer of the walls of blood vessels, consisting primarily of smooth muscle cells and elastic tissue, which allow the vessel to expand and contract in response to changes in blood pressure and volume. What is the tunica externa?; The tunica externa, also known as the tunica adventitia, is the outermost layer of a blood vessel, composed mainly of connective tissue that provides structural support and protection. What is angiogenesis?; Formation of new blood vessels. What mainly controls angiogenesis?; Vascular Endothelial Growth Factor (VEGF). Why is angiogenesis regulated in the body?; Excess, deficient, or inappropriate blood vessel formation can cause common diseases. How does the body promote angiogenesis in response to a blocked coronary artery?; The body secretes VEGF in response to a blocked coronary artery. What can be done if the body's secretion of VEGF is not sufficient?; VEGF may be able to be delivered in time-release capsules. Why do tumors secrete VEGF?; Tumors secrete VEGF to nourish themselves. What are antiangiogenesis drugs used to treat?; Antiangiogenesis drugs are used to treat cancer and age-related macular degeneration. What are the three layers or tunics of arteries?; The three layers or tunics of arteries are: 1. Tunica interna (intima): innermost layer. 2. Tunica media: smooth muscle & elastic tissue. 3. Tunica externa (adventitia): outer layer, connective tissue. What is the primary function of arteries?; Arteries transport blood under high blood pressure and give rise to smaller arterioles. How do the walls of arteries compare to the walls of veins?; The walls of arteries are thick and strong, thicker than the walls of veins. What is the structural difference between arterioles and arteries?; Arterioles have thinner walls than arteries, although they have the same three layers or tunics. The walls of the middle and outer layers become thinner as arterioles become smaller. What functions can both arteries and arterioles perform?; Both arteries and arterioles can undergo vasoconstriction and vasodilation. What are arterioles?; Arterioles are small blood vessels that extend and branch out from an artery and lead to capillaries. They contain a few muscle fibers in their walls. What is the function of smooth muscle cells in arterioles?; Smooth muscle cells in arterioles help regulate blood flow and pressure by contracting and relaxing, which changes the diameter of the arterioles. What is the role of the endothelium in arterioles?; The endothelium in arterioles provides a smooth lining for blood flow and plays a role in regulating vascular tone and blood pressure. What is a precapillary sphincter?; A precapillary sphincter is a ring of smooth muscle fibers located at the entrance of capillaries that regulates blood flow into the capillary beds. 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 their walls consist of endothelium (simple squamous epithelium) only. They 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 is the primary method of substance exchange 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 vary among tissues; permeability varies with the size of slits. What determines the density of capillary networks in a tissue?; The metabolic rate of the tissue determines the density of its capillary networks. Higher metabolic rate tissues have 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 oxygen (O2) and nutrients. Which type of tissues have fewer capillaries?; Tissues with lower metabolic rates, such as cartilage, have fewer capillaries. What is the most important method of transfer in capillary exchange?; Diffusion How do lipid-soluble substances diffuse in capillary exchange?; Lipid-soluble substances diffuse through cell membrane. How do water-soluble substances diffuse in capillary exchange?; Water-soluble substances diffuse through membrane channels and slits. What forces molecules through the membrane in filtration?; Hydrostatic pressure forces molecules through membrane. What is the source of the pressure used in filtration during capillary exchange?; Pressure is derived from ventricular contraction. What creates osmotic pressure in capillaries?; The presence of impermeant solute, such as plasma proteins, inside capillaries creates osmotic pressure. What role does osmotic pressure play in capillary exchange?; 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 happens 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. Why do substances leave the capillary at the arteriolar end?; Substances leave the capillary at the arteriolar end because hydrostatic pressure is greater than osmotic pressure. Why does H2O enter the capillary at the venular end?; H2O enters the capillary at the venular end because osmotic pressure is greater than hydrostatic pressure.