Tadepalli_ Overview of CVS & Lymphatic System Notes 2024 PDF

August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] Overview of Cardiovascul...

August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] Overview of Cardiovascular and Lymphatic system Recommended Reading Moore, Dalley & Agur. Clinically Oriented Anatomy, 9th ed. “COA” Chapter 1: Nervous System section, pgs. 37-45, Cardiovascular & Lymphatic Systems. Chapter 4: Thorax, pg.355, 363 Practice Questions Lippincott’s Q&A: Chapter 1 pg.11. #s 22-26 Learning Objectives: After attending or viewing the lecture, text / atlases / notes, students should be able to: By the end of the session student should be able to: 1. Describe the functions of the cardiovascular and lymphatic system 2. Understand the structures of the cardiovascular and lymphatic systems, particularly their vessels and integrate its clinical relevance 3. Compare and contrast the fluids transported by the cardiovascular and lymphatic systems and its applied aspects 4. Diagram and label the major arteries, veins, and lymph vessels as presented and its significance 5. Define the special terms and their functional significance 6. Describe and analyze the pathologic conditions and its clinical significance 7. Describe the best location to auscultate heart valves and its clinical significance Follow the following steps: Engage in the lecture-Learn & Deepen thinking with notes provided- Practice sample questions and reflect in exam The Circulatory system: Cardiovascular System- Transports blood and Lymphatic systems- Transports lymph in the body. Cardiovascular system: It consists of Heart and Blood Vessels Functions: The heart and blood vessels make up the blood transportation network. The heart pumps blood through the body’s vast system of blood vessels. The blood carries nutrients, oxygen, and waste products to and from the cells. Helps maintain body temperature. It helps the body meet the demands of activity, exercise, and stress. I. The Heart A. Pericardium: Has Two layers a. Fibrous pericardium: 1) Tough fibrous tissue surrounding the heart 2) Does not stretch easily (inelastic)  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] b. Serous pericardium: 1) Further divided into two layers a) Parietal – fused with the internal surface of the fibrous pericardium b) Visceral – reflected onto the outer surface of the heart to form the epicardium Pause and Learn: What is the inelastic layer of pericardium? What are 2 layers of serous pericardium? The wall of the heart has three layers: Outer Epicardium (epi = upon; cardia = heart) Middle Myocardium (myo = muscle) and the Inner Endocardium (endo = within ) The epicardium is the visceral layer of the pericardium Pause and Learn: What is the muscle layer of heart called? 2) Pericardial cavity: a) Small space between the parietal and visceral layers of the serous pericardium b) It consists of pericardial fluid which acts as lubricant for the pumping heart (15ml-50ml) Clinical Correlations: a. Pericarditis (itis=inflammation): Inflammation of Pericardium b. Pericardial effusion: Collection of excess fluid in pericardial cavity c. Cardiac tamponade: Compression of the heart due to fluid accumulation within the pericardial cavity and reduces ventricular filling Pause and Learn: What is the space between 2 layers of serous pericardium called?  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] What is the purpose of Pericardial fluid? What is pericarditis? What happens if fluid collection increases in pericardial cavity? A. Heart External Anatomy a. Chamber locations: 1) Right atrium (RA) – right most 2) Right ventricle (RV) – anterior most 3) Left ventricle (LV) – left most 4) Left atrium (LA) – posterior most b. Great vessels: 1) Superior vena cava (SVC) 2) Inferior vena cava (IVC) 3) Pulmonary trunk (PT) 4) Pulmonary veins (PV) 5) Ascending aorta (aortic arch) (AA): 3 branches a) Brachiocephalic trunk (BCT) b) Left common carotid artery (Lt CCA) c) Left subclavian artery (Lt SCA) Pause and Learn: What are chambers and great vessels of heart? B. Heart Chambers a. Right atrium: 1) Openings: a) Superior vena cava b) Inferior vena cava c) Coronary sinus 2) Tricuspid valve (right atrioventricular valve) b. Right ventricle: 1) Three papillary muscles – Anterior, Posterior and Septal 2) Pulmonary valve c. Left atrium 1) Openings: a) Four pulmonary veins (two superior, two inferior) 2) Mitral valve (bicuspid or left atrioventricular valve) d. Left ventricle 1) Two papillary muscles – Anterior and Posterior 2) Aortic valve – Posterior, left, and right cusps (thicker cusps) Pause and Learn: What are valves of heart and its location?  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] C. Heart Sounds – consists of two major sounds, lubb – dupp 1. lubb – closure of mitral and tricuspid valves, representing the beginning of ventricular systole (contraction) - S1 2. dupp – closure of aortic and pulmonary valves, representing the beginning of ventricular diastole (relaxation) – S2 D. Best location to auscultate specific valves a. Aortic – right 2nd intercostal space, adjacent to sternum b. Pulmonary – left 2nd intercostal space, adjacent to sternum c. Tricuspid – left (or right) 4th intercostal space, adjacent to sternum d. Mitral – left 5th intercostal space in midclavicular line Clinical correlations: Murmurs: Turbulence of blood flow near the valves occurs due to damaged valve cusps. Pause and Learn: Learn the location of the 4 heart valves and their clinical significance? Pulmonary and Systemic circulations. Pulmonary Circuit: The right ventricle of the heart propels low-oxygen blood returning from the systemic circulation into the lungs via the pulmonary arteries. Carbon dioxide is exchanged for oxygen in the capillaries of the lungs, and then the oxygen-rich blood is returned via the pulmonary veins of the lungs to the heart’s left atrium. This circuit, from the right ventricle through the lungs to the left atrium, is the pulmonary circulation. Systemic Circuit: The left ventricle propels the oxygen-rich blood returned to the heart from the pulmonary circulation through systemic arteries (the aorta and its branches), exchanging oxygen and nutrients for carbon dioxide in the remainder of the body’s capillaries. Low-oxygen blood returns to the heart’s right atrium via systemic  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] veins (tributaries of the superior and inferior vena cava). This circuit, from left ventricle to right atrium, is the systemic circulation. Pause and Learn: How does the blood flow during Pulmonary circulation? How does the blood flow during Systemic circulation? Summary of Blood circulation: Deoxygenated blood from entire body---→ SVC &IVC-→ Rt atrium -→ Rt Ventricle -→ Rt and Lt Pulmonary arteries -→ Lungs-→ Via 2Rt and 2Lt Pulmonary Veins -→ Lt atrium- → Lt Ventricle -→ Aorta -→ Oxygenated blood to the entire body Clinical aspects: When oxygenated and deoxygenated blood mix in the heart, it can have several negative effects: 1. Decreased oxygen supply: The blood's ability to carry oxygen is reduced, making it harder for the heart to deliver oxygen to the body's organs. 2. Cyanosis: When the mixed blood flows through the arteries, it can cause a blue-red-violet hue, like the color of deoxygenated blood in veins. 3. Mixing can occur when the heart's chambers aren't fully formed or when there's a congenital heart defect. For example, Tetralogy of Fallot is a congenital heart condition that causes deoxygenated blood to mix with oxygenated blood. Symptoms include bluish skin, difficulty breathing, poor growth, and a heart murmur. Treatments include surgery and medication. Pause and Learn: What are the first arteries affected if blood clot is in Superior Vena Cava? Where does the blood clot dislodge first if it is in pulmonary veins? 2.Blood Vessels There are three types of blood vessels: arteries, veins, and capillaries. Arteries: Blood under high pressure leaves the heart and is distributed to the body by a branching system of thick-walled arteries. Arterioles: Final distributing vessels deliver oxygen-rich blood to capillaries. Capillaries: Where interchange of oxygen, nutrients, waste products, and other substances with the extracellular fluid occurs. Venules: Blood from the capillary bed passes into thin-walled venules (resemble capillaries) Venules drain into small veins that open into larger veins. Largest veins: Return low-oxygen blood to the heart. (Examples: superior and inferior venae cava FIGURE 1.23.  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] View OriginalDownload Slide (.ppt) Pause and Learn: What are high pressure vessels? In which vessel does gaseous and nutrient exchange take place? Which vessels do venules finally drain into? Most vessels of the circulatory system have three coats, or tunics: 1. Tunica intima, 2. Tunica media, 3. Tunica adventitia/externa Arteries are blood vessels that carry blood under relatively high pressure (compared to the corresponding veins) from the heart and distribute it to the body. The blood passes through arteries of decreasing caliber. Direction of flow: Heart -→ Large elastic arteries-→ Medium sized muscular arteries-→ small arteries -→ arterioles -→ blood capillary There are three types of arteries: 1) Large elastic arteries (conducting arteries): Large arteries are larger in size, They are called elastic due to presence of elastic fibers so that they stretch and relax when blood flow occurs. If damaged fluid loss is extensive. Examples of large elastic arteries are the aorta, the arteries that originate from the arch of the aorta (brachiocephalic trunk, subclavian and carotid arteries), and the Pulmonary trunk and Pulmonary arteries. 2) Medium muscular arteries (distributing arteries). They have muscle fibers, so they are inelastic. Used for monitoring Blood pressure. Their function is to distribute blood to other parts of the body. Most of the named arteries, including those observed in the body wall and limbs during dissection such as the brachial or femoral arteries, are medium muscular arteries.  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] 3) Small arteries and arterioles have relatively narrow lumina and thick muscular walls. Examples: Vasa recta of small intestine. Arterioles can be observed only under magnification. Pause and Learn: Why are large elastic arteries called elastic arteries? What happens if they are stabbed/ruptured? Special Features 1) Vasa Vasorum: A network of small blood vessels that supply oxygen and nutrients to the walls of larger blood vessels, such as arteries and veins. 2) Nervi Vascularis: Small postganglionic sympathetic nerve bundles which innervate blood vessels- controls vasoconstriction and vasodilatation. 3) Anastomoses (communications) between multiple branches of an artery which provides numerous detours for blood flow in case the usual pathway is obstructed by compression due to the position of a joint, pathology, or surgical ligation. If a main channel is occluded, the smaller alternate channels can usually increase in size over a period of time, providing collateral circulation. 4) Collateral circulation or alternate pathway that ensures the blood supply to structures 5) Terminal arteries: Arteries that do not anastomose with adjacent arteries are true (anatomical) terminal arteries (end arteries). Occlusion of an end artery interrupts the blood supply to the structure or segment of an organ it supplies. True terminal arteries supply the retina, for example, where occlusion will result in blindness. While not true terminal arteries, functional terminal arteries (arteries with ineffectual anastomoses) supply segments of the brain, liver, kidneys, spleen, and intestines; they may also exist in the heart. Pause and Learn: What are the communications between arteries termed as? What are the advantages of anastomosis among arteries? What are the disadvantages of terminal arteries? Clinical correlations: 1) Stenosis: Narrowing of Blood Vessel 2) Arteriosclerosis: Hardening of the arteries, characterized by thickening and loss of elasticity of the arterial walls. Common as age advances 3) Atherosclerosis: Buildup of fat (mainly cholesterol) + calcium deposition in the arterial walls forms an atheromatous plaque (atheroma)- well-demarcated, hardened yellow areas or swellings on the intimal surfaces of arteries. 4) Thrombosis: Formation of a local intravascular blood clot, which occlude the artery. 5) Emboli: Dislodged blood clot 6) The consequence of atherosclerosis includes: A. Ischemia: Reduction of blood supply to an organ or region and  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] B. Infarction: Local death, or necrosis, of an area of tissue or an organ resulting from reduced blood supply. These consequences are particularly significant in regard to the heart (ischemic heart disease and myocardial infarction [MI] or heart attack), brain (stroke), and distal parts of limbs (gangrene/necrosis). Pause and Learn: What is dislodged blood clot called? What is death of a tissue due to decreased blood supply called? What is infarction of distal limbs called as? Major arteries to know. Note: the aorta resides a little left of midline, and the sup. & inf. vena cava are a little to the right of midline. In most cases, the major branches of the aorta reside anterior to the major branches.  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] Blood capillaries: They are simple endothelial tubes connecting the arterial and venous sides of the circulation. It allows the exchange of materials with interstitial or extracellular fluid (ECF). Capillaries are arranged in capillary beds, networks that connect the arterioles and venules. Special Features: 1) Arteriolovenular (arteriovenous) anastomoses (AVAs): Permits blood to pass directly from the arterial to the venous side of the circulation without passing through capillaries. Arteriovenous (AV) shunts are numerous in the skin, where they have an important role in conserving body heat. 2) Portal venous system: When blood passes through two capillary beds before returning to the heart it is a portal venous system. The venous system by which nutrient-rich blood passes from the capillary beds of the alimentary tract to the capillary beds or sinusoids of the liver—the hepatic portal system—is the major example. Pause and Learn: What is portal venous system? Veins: Return low-oxygen blood from the capillary beds to the heart, which gives the veins a dark blue appearance except large pulmonary veins carries oxygen-rich blood from the lungs to the heart. Because of the lower blood pressure in the venous system, the walls of veins are thinner than those of their companion arteries. Normally, veins do not pulsate and do not squirt or spurt blood when severed. Because of the veins’ larger diameter and ability to expand only 20% of the blood occupies arteries, whereas 80% is in the veins. There are three sizes of veins: 1) Venules are the smallest unnamed veins. Small veins are the tributaries of larger veins that unite to form venous plexuses as dorsal venous plexus. 2) Medium veins accompany medium arteries, the medium veins have valves, making flow of blood unidirectional (toward the heart but not in the reverse direction. Examples of medium veins include the named superficial veins (cephalic and basilic veins of the upper limbs and great and small saphenous veins of the lower limbs) and the accompanying veins that are named according to the artery they accompany. 3) Large veins: Examples are the superior vena cava, Inferior vena cava. Special Features: 1) Venae comitantes: Those veins that accompany deep arteries and surround them in an irregular branching network. It is enclosed by fascia. This arrangement serves as a countercurrent heat exchanger as well as arteriovenous pump because, they are stretched and flattened when artery expands during contraction of the heart, which aids in driving venous blood toward the heart. View OriginalDownload Slide (.ppt)  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] 2) Musculo venous pump. The outward expansion of the bellies of contracting skeletal muscles in the limbs surrounded by deep fascia, compresses the deep veins within and around the skeletal muscle inside the deep fascia, “milking” the blood superiorly toward the heart. The venous congestion that hot and tired feet experience at the end of a busy day is relieved by resting the feet on a footstool that is higher than the trunk (of the body). This position of the feet also helps the veins return blood to the heart. Superficial veins of the limbs are external to the deep fascia and so are not affected by muscle contraction. Multiple perforating veins along their course penetrate the deep fascia, continuously shunting blood to the deep veins to assist the return of blood to the heart. Clinical Correlations: 1) Varicose Veins: Abnormally swollen, dilated veins—most often seen in the legs. When the walls of veins lose their elasticity, they become weak. A weakened vein dilates under the pressure of supporting a column of blood against gravity. Varicose veins have incompetent valves; thus, placing increased pressure on the weakened walls. Complication: When blood clots from deep veins (deep vein thrombosis-DVT), break free and may dislodge to pulmonary veins and result in pulmonary emboli. Blood clot from deep veins of leg-→ femoral vein-→ External iliac vein→ Common iliac -→ inferior vena cava-→ Rt atrium-→ Rt ventricle-→ Pulmonary artery emboli View OriginalDownload Slide (.ppt) View OriginalDownload Slide (.ppt) Based on Willis MC. Medical Terminology: The Language of Health Care, 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2006 Pause and Learn: How does a blood clot in deep veins dislodge and result in pulmonary emboli?  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] FIGURE 1.24. View OriginalDownload Slide (.ppt) Pause and Learn The names of Systemic arteries and veins to apply knowledge on emboli pathway questions. The lymphatic system Functions: 1. To maintain tissue homeostasis, it absorbs surplus extracellular fluid (ECF), leaked proteins, and cell/tissue debris (lymph), draining it into the venous system (up to 3L/d) 2. Immune defense: foreign material/proteins draining from an infected area are detected in lymph nodes. Antibodies are produced by various immune cells & dispatched to the infected area. 3.Chyle: In the GI system, special lymphatic vessels (lacteals) absorb dietary lipids and lipid- soluble vitamins August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] The Starling hypothesis explains how most of the fluid and electrolytes entering the extracellular spaces from the blood capillaries is also reabsorbed by them. The important components of the lymphoid system are as follows: Lymphatic capillaries: Originate blindly in the extracellular (intercellular) spaces of most tissues. Lymphatic vessels: Thin-walled vessels with abundant lymphatic valves. In living individuals, the vessels bulge where each of the closely spaced valves occur, giving lymphatics a beaded appearance. Superficial lymphatic vessels, more numerous and accompany the veins in the subcutaneous tissue and anastomosing freely. These vessels eventually drain into deep lymphatic vessels that accompany the arteries and also receive the drainage of internal organs. Both superficial and deep lymphatic vessels traverse lymph nodes becoming larger as they merge with vessels draining adjacent regions. Large lymphatic vessels enter large collecting vessels, called lymphatic trunks, which unite to form either the right lymphatic duct or the thoracic duct. Lymphatic trunks are large collecting vessels that receive lymph from multiple lymphatic vessels. Lymphatic capillaries and vessels occur almost everywhere blood capillaries are found, except, for example, teeth, bone, bone marrow, and the entire central nervous system. (Excess tissue fluid of the CNS drains into the cerebrospinal fluid). The right lymphatic duct drains lymph from the body’s right upper quadrant (right side of the head, neck, and thorax plus the right upper limb). At the root of the neck, it enters the junction of the right internal jugular and right subclavian veins, the right venous angle. The thoracic duct drains lymph from the remainder of the body. The lymphatic trunks draining the lower half of the body merge in the abdomen, sometimes forming a dilated collecting sac, the cisterna chyli. From this sac (if present), or from the merger of the trunks, the thoracic duct ascends into and then through the thorax to enter the left venous angle (junction of left internal jugular and left subclavian veins). August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] Lymph (L. lympha, clear water), the tissue fluid that enters lymph capillaries and is conveyed by lymphatic vessels. Usually clear, watery, and slightly yellow, lymph is similar in composition to blood plasma. Lymph nodes, small masses of lymphatic tissue located along the course of lymphatic vessels through which lymph is filtered on its way to the venous system. Lymphocytes, circulating cells of the immune system that react against foreign materials. Lymphoid organs, parts of the body that produce lymphocytes, such as the thymus, red bone marrow, spleen, tonsils, and the solitary and aggregated lymphoid nodules in the walls of the alimentary tract and appendix. Lymphatic vessels communicate with veins freely in many parts of the body. Consequently, ligation of a lymphatic trunk or even the thoracic duct itself may have only a transient effect as a new pattern of drainage is established through more peripheral lymphaticovenous & interlymphatic anastomoses. Clinical aspects: 1) Lymphangitis and lymphadenitis are secondary inflammations of lymphatic vessels and lymph nodes. These conditions occur when the lymphoid system is involved in bacterial transport. The lymphatic vessels, not normally evident, may become apparent as red streaks in the skin, and the nodes become painfully enlarged. 2) Lymphedema: a localized edema, occurs when lymph does not drain from an area of the body. For instance, if cancerous lymph nodes are surgically removed from the axilla lymphedema of the limb may occur. Solid cell growths may permeate lymphatic vessels and form minute cellular emboli (plugs), which break free and pass to regional lymph nodes. 3) Chylothorax: If thoracic duct is lacerated or damage to any lymphatic channels, lymph and chyle drain into the pleural cavity. 4) Lymphadenopathy: Swollen lymph nodes secondary to nearby infection 5) Spread of Cancer: Cancer invades the body by contiguous spread (direct growth into adjacent tissue) or by metastasis (the dissemination of tumor cells to sites distant from the original or primary tumor). Metastasis occurs three ways: a. Direct seeding of serous membranes of body cavities b. Lymphogenous spread (via lymphatic vessels): Lymphogenous spread of cancer is the most common route for the initial dissemination of cancer. Cells loosened from the primary cancer site enter and travel via lymphatics. The lymph- borne cells are filtered through and trapped by lymph nodes, which thus become  August 5th,2024 Dr. Krupa Sailaja Tadepalli, MBBS; MD; FFM MREB-2102 [email protected] secondary (metastatic) cancer sites. The pattern of cancerous lymph node involvement follows the natural routes of lymph drainage. Thus, when removing a potentially metastatic tumor, surgeons stage the metastasis (determine the degree to which cancer has spread) by removing and examining lymph nodes that receive lymph from the organ. Therefore, it is important for physicians to literally know the lymphatic drainage “backward and forward. c. Hematogenous spread (via blood vessels): Hematogenous spread of cancer is the most common route for the metastasis of the less common (but more aggressively malignant) sarcomas (connective tissue cancers). Because veins are more abundant and have thinner walls that offer less resistance, metastasis occurs more often by venous than arterial routes. Since the blood-borne cells follow venous flow, the liver and lungs are the most common sites of secondary sarcomas. Typically, the treatment or removal of a primary tumor is not difficult, but the treatment or removal of all the affected lymph nodes or other secondary (metastatic) tumors may be impossible. Pause and Learn: What is rupture of lymph into thoracic cavity is called? Which lymphatic trunk drain Rt Hemidiaphragm? Which terminal lymph duct the cancer cells from left breast drain into?