Detailed Notes on Cardiovascular and Lymphatic Systems

Anatomy of the Heart

• Structures on Models and Dissected Heart

  • Major Structures:

    • Superior vena cava: The large vein that carries deoxygenated blood from the upper body to the right atrium of the heart.

    • Apex: The lower tip of the heart where the left ventricle narrows; it is the point of maximal impulse during contraction.

    • Inferior vena cava: The large vein that carries deoxygenated blood from the lower body to the right atrium of the heart.

    • Base: The wide, upper portion of the heart where major blood vessels are connected.

    • Aorta (ascending, arch, descending): The major artery that carries oxygenated blood from the left ventricle to the body; includes:

    • Ascending aorta: The section that rises from the heart.

    • Aortic arch: The curved portion that connects the ascending aorta to the descending aorta.

    • Descending aorta: The section that carries blood downward through the thorax and abdomen.

    • Fossa ovalis: A depression in the right atrium, a remnant of the foramen ovale which allows blood to bypass the lungs in fetal circulation.

    • Right & Left pulmonary arteries: Arteries that carry deoxygenated blood from the right ventricle to the lungs for oxygenation (right) and oxygenated blood from the lungs to the left atrium (left).

    • Pectinate muscles: Ridges found on the inner surface of the atria that help in the contraction of the heart.

    • Right & Left pulmonary veins: Veins that carry oxygenated blood from the lungs to the left atrium of the heart.

    • Trabeculae carneae: Muscular ridges found in the ventricles, contributing to the contraction of the heart.

    • Pulmonary trunk: The large vessel that carries deoxygenated blood from the right ventricle to the lungs; it splits into the right and left pulmonary arteries.

    • Papillary muscles: Muscles located in the ventricles involved in the opening and closing of the heart valves.

    • Ligamentum arteriosum: A small ligament that is a remnant of the ductus arteriosus in fetal circulation, which connected the pulmonary trunk to the aorta.

    • Chordae tendineae: Tendinous cords that connect the valve leaflets to the papillary muscles, ensuring the valves close properly during ventricles contraction.

    • Right & Left auricle: Small pouches on top of the atria that increase the capacity of the atria.

    • Right atrium: The chamber that receives deoxygenated blood from the body via the superior and inferior vena cavae.

    • Tricuspid valve: The valve located between the right atrium and right ventricle that prevents backflow of blood into the atrium.

    • Left atrium: The chamber that receives oxygenated blood from the lungs via the pulmonary veins.

    • Bicuspid (mitral) valve: The valve located between the left atrium and left ventricle that prevents backflow of blood into the atrium.

    • Right ventricle: The chamber that pumps deoxygenated blood to the lungs through the pulmonary valve.

    • Pulmonary semilunar valve: The valve that prevents backflow into the right ventricle from the pulmonary trunk.

    • Left ventricle: The chamber that pumps oxygenated blood to the body via the aortic semilunar valve.

    • Aortic semilunar valve: The valve that prevents backflow into the left ventricle from the aorta.

    • Interventricular septum: The wall separating the right and left ventricles, ensuring proper flow of the blood.

    • Epicardium (visceral pericardium): The outer layer of the heart wall; it also forms part of the pericardium, providing protection.

    • Interventricular sulcus: The external groove that marks the division between the right and left ventricles on the heart's surface.

    • Myocardium: The muscular middle layer of the heart responsible for contraction and pumping.

    • Endocardium: The inner lining of the heart chambers and valves, providing a smooth surface for blood flow.

• Coronary Vessels

  • Major Vessels:

    • Right coronary artery: Supplies blood to the right side of the heart.

    • Circumflex artery: Supplies blood to the left atrium and the side and back of the left ventricle.

    • Marginal artery: Provides collateral circulation to the heart.

    • Great cardiac (anterior interventricular) vein: Drains blood from the anterior heart and empties into the coronary sinus.

    • Posterior interventricular artery: Supplies blood to the posterior part of the heart.

    • Middle cardiac (posterior interventricular) vein: Drains the posterior part of the heart and empties into the coronary sinus.

    • Left coronary artery: Supplies blood to the left side of the heart.

    • Coronary sinus: Collects deoxygenated blood from the myocardial veins and delivers it to the right atrium.

    • Anterior interventricular artery (LAD): Supplies blood to the interventricular septum and anterior wall of the left ventricle.

• Tracing Blood Path:

  • Students should practice tracing the path of blood through the heart.

Blood Vessels Models

• Structures on Human Models - Arteries:

  • Ascending Aorta: The initial section of the aorta arising from the left ventricle.

  • Aortic Arch: The curved segment of the aorta that distributes blood to the upper body.

  • Descending Aorta: The segment that carries blood down through the thorax and into the abdomen.

  • Abdominal Aorta: The continuation of the descending aorta supplying blood to the lower organs.

  • Right Brachiocephalic: Supplies blood to the right arm and the head.

  • Common Carotid: Supplies blood to the neck and head.

  • External Carotid: Supplies blood to the face and neck.

  • Internal Carotid: Supplies blood to the brain.

  • Vertebral: Supplies blood to the posterior parts of the brain.

  • Basilar: Forms from the merging of the vertebral arteries, supplying blood to the brainstem and cerebellum.

  • Posterior Cerebral: Supplies blood to the posterior part of the brain.

  • Posterior Communicating: Connects the posterior and anterior arterial systems of the brain.

  • Middle Cerebral: Supplies blood to the lateral surfaces of the cerebral hemispheres.

  • Anterior Cerebral: Supplies blood to the medial parts of the frontal lobes.

  • Anterior Communicating: Connects the left and right anterior cerebral arteries.

  • Subclavian: Supplies blood to the arms and upper body.

  • Axillary: Continuation of the subclavian artery supplying blood to the armpit and upper limb.

  • Brachial: Supplies blood to the upper arm.

  • Ulnar: Supplies blood to the forearm and hand (medial side).

  • Radial: Supplies blood to the forearm and hand (lateral side).

  • Intercostal: Supplies blood to the ribs and chest muscles.

  • Splenic: Supplies blood to the spleen.

  • Celiac Trunk: Supplies blood to the stomach, liver, and spleen.

  • Superior Mesenteric: Supplies blood to the small intestine and parts of the large intestine.

  • Suprarenal: Supplies blood to the adrenal glands.

  • Renal: Supplies blood to the kidneys.

  • Gonadal: Supplies blood to the gonads (ovaries or testes).

  • Inferior Mesenteric: Supplies blood to the distal parts of the large intestine.

  • Common Iliac: Supplies blood to the pelvic area and legs.

  • External Iliac: Supplies blood to the lower limbs.

  • Internal Iliac: Supplies blood to the pelvic organs.

  • Femoral: Supplies blood to the thigh.

  • Popliteal: Supplies blood to the knee region.

  • Anterior Tibial: Supplies blood to the anterior compartment of the leg.

  • Posterior Tibial: Supplies blood to the posterior compartment of the leg.

  • Fibular: Supplies blood to the lateral compartment of the leg.

• Functions:

  • Arteries: Carry oxygenated blood away from the heart to various parts of the body.

Venous Structures

• Venous Structures - Ascending Aorta

  • Aortic Arch: Similar to arterial structures, important for drainage.

  • Descending Aorta: Returns blood from the body back to the heart.

  • Abdominal Aorta: Carries deoxygenated blood back to the heart from lower organs.

  • Right Brachiocephalic: Drains blood from the right side of the head and neck.

  • Internal Jugular: Drains blood from the brain and superficial parts of the face and neck.

  • External Jugular: Drains blood from the exterior of the cranium and deep parts of the face.

  • Brachiocephalic: The large veins that drain deoxygenated blood from the arms and head.

  • Subclavian: Returns deoxygenated blood from the arms and shoulders to the heart.

  • Axillary: Drains blood from the armpit and upper limb.

  • Brachial: Drains blood from the upper arm.

  • Ulnar: Returns blood from the forearm and hand (medial side).

  • Radial: Returns blood from the forearm and hand (lateral side).

  • Median Cubital: Connects the brachial vein and cephalic vein, commonly used for blood draws.

  • Cephalic: Drains blood from the arm to the shoulder.

  • Basilic: Drains the medial arm and forearm.

  • Hepatic Portal: Drains blood from the gastrointestinal tract to the liver.

  • Superior Mesenteric: Returns blood from the small intestine and parts of large intestine.

  • Inferior Mesenteric: Returns blood from the distal portions of the colon.

  • Splenic: Drains blood from the spleen.

  • Azygos: Drains blood from the thoracic wall and upper lumbar region into the superior vena cava.

  • Hemiazygos: Drains blood from the left side of the thorax into the azygos vein.

  • Intercostal: Drains blood from the ribs and pleura.

  • Renal: Returns blood from the kidneys.

  • Gonadal: Drains blood from the ovaries or testes.

  • Superior Vena Cava: Drains deoxygenated blood from the upper body into the right atrium.

  • Inferior Vena Cava: Drains deoxygenated blood from the lower body into the right atrium.

  • Common Iliac: Drain blood from the pelvis and lower limbs into the inferior vena cava.

  • External Iliac: Drains blood from the lower limbs.

  • Internal Iliac: Drains blood from the pelvic organs.

  • Femoral: Drains blood from the thigh.

  • Popliteal: Drains blood from the knee region.

  • Anterior Tibial: Drains blood from the anterior compartment of the leg.

  • Posterior Tibial: Drains blood from the posterior compartment of the leg.

  • Fibular: Drains blood from the lateral compartment of the leg.

  • Great Saphenous: The longest vein in the body; drains blood from the lower limb to the femoral vein.

  • Small Saphenous: Drains blood from the posterior part of the leg to the popliteal vein.

• Functions:

  • Veins: Return deoxygenated blood back to the heart.

Fetal Circulation

• Fetal Structures:

  • Ductus arteriosus: Connects the pulmonary artery to the aorta, allowing blood to bypass the lungs.

  • Ductus venosus: Allows oxygenated blood from the umbilical vein to bypass the liver.

  • Ligamentum venosum: The remnant of the ductus venosus.

  • Foramen ovale: An opening between the right and left atria, allowing blood to bypass the lungs.

  • Umbilical veins & arteries: Carry oxygenated blood from the placenta to the fetus and deoxygenated blood back to the placenta.

• Functions:

  • Ductus arteriosus: Ensures efficient blood flow during fetal development.

  • Ductus venosus: Maximizes oxygen delivery to the fetus by bypassing the liver.

  • Foramen ovale: Prevents blood from passing into the non-functional fetal lungs.

Vessel Anatomy

• Layers of Blood Vessels:

  • Tunica intima: The innermost layer providing a smooth surface for blood flow.

  • Tunica media: The muscular middle layer responsible for regulating blood vessel diameter.

  • Tunica externa: The outer layer that provides structural support and protection.

  • Valves in Veins: Prevent backflow of blood in veins, ensuring unidirectional blood flow back to the heart.

• Functions:

  • Tunica intima: Reduces friction as blood flows through the vessel.

  • Tunica media: Controls blood pressure and flow by constriction and dilation.

  • Tunica externa: Anchors the vessel to surrounding tissues.

Cardiovascular Physiology

• Auscultation Areas:

  • Aortic semilunar valve: Location for listening to heart sounds from the aorta.

  • Pulmonary semilunar valve: Location for listening to heart sounds from the pulmonary trunk.

  • Bicuspid valve: Location for listening to heart sounds from the left atrium and ventricle.

  • Tricuspid valve: Location for listening to heart sounds from the right atrium and ventricle.

• Functions:

  • Auscultation areas: Essential for assessing heart function through listening techniques.

• Heart Sounds:

  • Understand the causes of heart sounds and their significance.

• Pulse Points:

  • Common carotid artery: Checks pulse in the neck.

  • Femoral artery: Checks pulse in the groin.

  • Temporal artery: Checks pulse at the temple.

  • Popliteal artery: Checks pulse behind the knee.

  • Facial artery: Checks pulse along the jawline.

  • Posterior tibial artery: Checks pulse behind the ankle bone.

  • Brachial artery: Checks pulse at the elbow.

  • Dorsalis pedis artery: Checks pulse on the top of the foot.

  • Radial artery: Checks pulse at the wrist.

• Functions:

  • Pulse points: Used for assessing heart rate and circulation.

• Blood Pressure Measurement:

  • Use a sphygmomanometer to measure blood pressure.

  • Understand Korotkoff sounds, and systolic & diastolic blood pressure.

  • Calculate pulse pressure and mean arterial pressure.

• Functions:

  • Blood pressure measurement: Assess cardiovascular health; high or low readings indicate health status.

Heart Conduction System

• Conduction Structures:

  • Sinoatrial (SA) node: The natural pacemaker of the heart, initiating electrical impulses.

  • Atrioventricular (AV) node: Relays impulses from the atria to the ventricles, providing a delay.

  • AV bundle (bundle of His): Conducts impulses from the AV node to the ventricles.

  • Right and left bundle branches: Conduct impulses along the interventricular septum to the ventricles.

  • Purkinje fibers: Distribute the electrical stimulus throughout the ventricles.

• Functions:

  • Conduction structures: Regulate the heartbeat and ensure the coordinated contraction of heart chambers.

• ECG Components:

  • P wave: Represents atrial depolarization.

  • QRS complex: Represents ventricular depolarization.

  • T wave: Represents ventricular repolarization.

  • P-R segment: Reflects the time delay at the AV node.

  • S-T segment: Represents the time when the ventricles are fully depolarized.

• Functions:

  • ECG: Monitors electrical activity of the heart to identify arrhythmias and other heart conditions.

Blood Composition

• Formed Elements:

  • Erythrocytes: Red blood cells that transport oxygen and carbon dioxide.

  • Neutrophils: White blood cells that fight infection.

  • Eosinophils: White blood cells that combat parasites and play a role in allergic reactions.

  • Basophils: White blood cells that release histamine and other chemicals during inflammatory responses.

  • Lymphocytes: White blood cells that are key to the immune response, including T cells and B cells.

  • Monocytes: White blood cells that differentiate into macrophages and dendritic cells in tissues.

  • Platelets: Cell fragments that play a crucial role in blood clotting.

• Functions:

  • Erythrocytes: Essential for gas exchange; carrying oxygen to tissues and carbon dioxide back to the lungs.

  • Leukocytes: Provide defense against infections and foreign substances.

  • Platelets: Critical for stopping bleeding and wound healing.

• Physical Characteristics:

  • Conduct experiments to determine physical characteristics of plasma and examine formed elements microscopically.

• Hematocrit Determination:

  • Calculate hematocrit and interpret results.

• Blood Typing:

  • Explain blood type results and identify antigens (agglutinogens) and antibodies (agglutinins).

• Blood Disorders:

  • Sickle cell anemia: A genetic disorder leading to abnormally shaped red blood cells and complications.

  • Leukemia: A type of cancer that affects blood and bone marrow.

• Functions:

  • Understanding formed elements helps in diagnosing and treating blood disorders.

Lymphatic System and Immune Response

• Lymphatic Structures:

  • Right lymphatic duct: Drains lymph from the right side of the head, neck, and upper limb.

  • Cisterna chyli: A muscular sac that collects lymph from the lower body.

  • Thoracic duct: Drains lymph from the left side and lower body into the left subclavian vein.

  • Lymph nodes: Filter lymph and house immune cells (cervical, axillary, inguinal, mediastinal, mesenteric).

  • Lymphatic collecting vessels: Transport lymph to nodes and larger ducts.

  • Thymus: An organ where T lymphocytes mature and differentiate.

  • Spleen: Filters blood and plays a role in immune response.

  • Mucosa-associated lymphoid tissues (MALT): Provides immune responses to pathogens entering through mucosal surfaces.

  • Tonsils: Lymphoid tissues that help protect against pathogens entering through the mouth and nose:

    • Pharyngeal (adenoid)

    • Palatine

    • Lingual

  • Peyer’s patches: Aggregated lymphoid nodules in the distal small intestines that protect against pathogens in the gut.

  • Appendix: Contains fused lymphoid nodules involved in immune function.

• Functions:

  • Lymphatic system: Maintains fluid balance, absorbs fats, and plays a crucial role in the immune response.

• Histological Features:

  • Lymph nodes: Capsule, afferent and efferent lymphatic vessels, cortex, medulla.

  • Spleen: Capsule, red pulp, white pulp.

  • Tonsils: Epithelial layer, lymphoid nodules, germinal center, crypts.

  • Thymus: Thymic corpuscle, lobes, cortex, medulla.

  • Peyer’s patches in ileum: Organized lymphoid tissue in the intestinal wall.

  • Activity: Conduct immunoassays and interpretation of results.

• Functions:
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