Human Anatomy: Heart Structure and Function

Anterior cardiac vein = Drains the right ventricle and opens into the right atrium Myocytes = Muscle cells responsible for heart contraction Sulcus = Drains the right atrium and right ventricle Sinoatrial (SA) node = Pacemaker of the heart located in the right atrium

Excitability = Ability of a cell to respond to external stimulus by depolarization Depolarization = State where the inside of the cell becomes less negatively charged Intrinsic conduction system = Nodal system where cardiac cells are self-excitable AP (Action Potential) = Electrical impulse initiated by depolarization in cardiac cells

Cardiac cells = Contract in a regular, continuous way SA node = Initiates action potentials in the heart Right atrium = Receives deoxygenated blood from the body Right ventricle = Pumps deoxygenated blood to the lungs

<p>1% of cardiac cells = Self-excitable cells in the heart Regular, continuous contraction = Characteristic of cardiac muscle Synchronized by SA node = Ensures coordinated heartbeats Nerve impulses required = Not necessary for heart muscle contraction</p> Signup and view all the answers

<p>SA node = Located in the wall of the right atrium Anterior cardiac vein = Opens directly into the right atrium Sulcus = Associated with drainage of the right atrium and right ventricle Myocytes = Found throughout the heart muscle</p> Signup and view all the answers

<p>Venules = Small veins formed by a group of capillaries Arteries = Blood vessels with thick muscular-elastic walls Arterioles = Microscopic vessels regulating blood flow to capillaries Veins = Larger blood vessels that convey deoxygenated blood back to the heart</p> Signup and view all the answers

<p>Femoral artery = Distributing artery Brachial artery = Distributing artery Radial artery = Distributing artery Axillary artery = Distributing artery</p> Signup and view all the answers

<p>Precapillary sphincter = Monitors blood flow into the capillary Metarteriole = Tapering terminal end of an arteriole Capillaries = Sites of nutrient and gas exchange Arterial compliance = Ability to stretch without tearing</p> Signup and view all the answers

<p>Apex = Directed anteriorly, inferiorly, and to the left Base = Opposite the apex and forms the posterior aspect Atrium = Upper chamber of the heart Ventricle = Lower chamber of the heart responsible for pumping blood</p> Signup and view all the answers

<p>Homeostasis = Maintaining stable internal conditions Pericardial Fluid = Reduces friction between heart layers Pericardial Cavity = Contains lubricating serous fluid Heart Rate = Number of beats per minute</p> Signup and view all the answers

<p>Veins = Do not have the ability to recoil like arteries Arteries = Contain abundant elastic fibers Arterioles = Regulate flow to capillary networks Venules = Merge to form veins</p> Signup and view all the answers

<p>Daily Heartbeats = 100,000 times Yearly Heartbeats = 35 million times Lifetime Heartbeats = 2.5 billion times Daily Blood Pumped = 14,000 liters</p> Signup and view all the answers

<p>Tunica media = Thick muscular-elastic layer Tunica interna = Inner layer of blood vessels Tunica externa = Outer layer providing structural support Endothelium = Lining of the blood vessel</p> Signup and view all the answers

<p>Arterioles = Regulate resistance to blood flow Precapillary sphincters = Control blood entering capillaries Venules = Collect blood from capillaries Arteries = Propel blood under high pressure</p> Signup and view all the answers

<p>Parietal Layer = Outermost layer lining the fibrous pericardium Visceral Layer = Innermost layer adhering to the heart surface Pericardium = Membrane surrounding and protecting the heart Pericardial Space = Contains a few milliliters of fluid</p> Signup and view all the answers

<p>Axillary artery = Branches into the arm Femoral artery = Supplies blood to the thigh Brachial artery = Supplies blood to the arm Radial artery = Supplies blood to the forearm and hand</p> Signup and view all the answers

<p>Pumped weight per minute = 30 times its own weight Amount pumped to lungs = 5 liters Annual blood volume = 5 million liters Daily blood volume = 14,000 liters</p> Signup and view all the answers

<p>Fibrous Pericardium = Protective outer layer Serous Pericardium = Inner layer secreting lubricating fluid Pericardial Fluid = Slippery secretion reducing friction Mediastinum = Cavity containing the heart</p> Signup and view all the answers

<p>Arteries = High compliance due to elastic fibers Veins = Larger vessels conveying deoxygenated blood Venules = Smallest veins formed by merging capillaries Arterioles = Small arteries regulating capillary flow</p> Signup and view all the answers

<p>Arteries = Blood vessels carrying blood away from the heart Veins = Blood vessels carrying blood to the heart Capillaries = Vessels where gas exchange occurs Endocardium = Inner lining of the heart chambers</p> Signup and view all the answers

<p>Atria = Receive blood returning to the heart ventricles = Eject blood into circulation Septum = Divides left and right sides of the heart Valves = Prevent backflow of blood</p> Signup and view all the answers

<p>Fibrous Pericardium = Superficial layer preventing overstretching of the heart Serous Pericardium = Deeper, thinner, protective membrane around the heart Visceral Layer = Thin, transparent outer layer of the heart wall Adipose Tissue = Thickest over ventricular surfaces, houses major vessels</p> Signup and view all the answers

<p>Epicardium = Imparts a smooth, slippery texture to the heart surface Myocardium = Responsible for the pumping action of the heart Endocardium = Lines the interior of the heart chambers Adipose Tissue = Provides cushioning and insulation for the cardiac muscle</p> Signup and view all the answers

<p>Auricle = Increases the capacity of an atrium Sulci = Grooves that contain coronary blood vessels Coronary Sulcus = Encircles the heart, marking the boundary between chambers Interventricular Septum = Wall dividing the right and left ventricles</p> Signup and view all the answers

<p>Coronary Vessels = Major blood vessels supplying the heart Myocardium = Composed of cardiac muscle tissue Visceral Pericardium = Part of the serous pericardium closely attached to the heart Fibrous Pericardium = Anchors the heart in the mediastinum</p> Signup and view all the answers

<p>Epicardium = Outermost layer with blood vessels and nerves Myocardium = Middle layer facilitating contraction Endocardium = Innermost layer providing smooth lining Visceral Layer = A layer of the serous pericardium covering the heart</p> Signup and view all the answers

<p>Auricle = Pouch-like structure on the anterior surface of atrium Sulci = Grooves on the surface of the heart Right Atrium = Receives deoxygenated blood from the body Left Ventricle = Pumps oxygenated blood to the body</p> Signup and view all the answers

<p>Fibrous Pericardium = Tough, inelastic tissue Serous Pericardium = Composed of mesothelial membranes Visceral Layer = Inner layer of the serous pericardium Parietal Layer = Outer layer of the serous pericardium</p> Signup and view all the answers

<p>Epicardial Fat = Fat located on the surface of the heart Pericardial Fat = Fat between the heart and inner wall of the pericardium Subendocardial Fat = Fat located under the endocardium Intramyocardial Fat = Fat found within the myocardium</p> Signup and view all the answers

<p>Elastic Artery = Pressure reservoir that helps propel blood Capillaries = Exchange of substances between blood and interstitial fluid Muscular Venules = Receive blood from capillaries Veins = Return blood to the heart with valve assistance</p> Signup and view all the answers

<p>Aorta = Largest elastic artery in the body Postcapillary Venules = Initially receive blood from capillaries Superior Vena Cava = Large vein entering the heart Capillaries = Smallest blood vessels with thin walls</p> Signup and view all the answers

<p>Elastic Arteries = Opposition to blood flow Veins = Contain valves to prevent backflow Capillaries = Very thin walls for substance exchange Muscular Venules = Thicker walls for fluid exchange</p> Signup and view all the answers

<p>Pressure Reservoir = Role of elastic arteries during ventricular relaxation Resistance Vessel = Function in regulating blood flow Valve Cusps = Prevent backflow of blood in veins Micturition = Exchange of substances in capillaries</p> Signup and view all the answers

<p>Capillaries = 5-10 μm in diameter Muscular Venules = 50 μm to 200 μm Small veins = 0.5 mm in diameter Superior Vena Cava = Up to 3 cm in diameter</p> Signup and view all the answers

<p>Aorta = Main artery conducting blood from heart Postcapillary Venules = First to receive blood post-capillary Muscular Venules = Regulate fluid exchange with interstitial fluid Veins = Transport deoxygenated blood back to the heart</p> Signup and view all the answers

<p>Veins = Contain valves made of tunica intima Capillaries = Form U-turns connecting arterial and venous flow Elastic Arteries = Have thick walls to withstand pressure Muscular Venules = Involved in fluid exchange with interstitial fluid</p> Signup and view all the answers

<p>Elastic Arteries = Help propel blood while ventricles relax Capillaries = Facilitate exchange between blood and tissues Postcapillary Venules = Receive blood from capillary beds Veins = Help prevent blood backflow via valves</p> Signup and view all the answers