Cardiovascular System Quiz

The Cardiovascular System - Heart and Vessels

• This is a lecture about the cardiovascular system, specifically the heart and vessels.
• The lecture is part 1 of a two-part series.

Chapter 10

• The Cardiovascular System - Heart and Vessels Part 1
• Anatomy, Physiology, & Disease
• Foundations for the Health Professions - Third Edition
• Authors: Deborah Roiger and Nia Bullock

Outline

• 10.1: Use medical terminology related to the cardiovascular system
• 10.2: Identify the chambers, valves, and features of the heart.
• 10.3: Relate the structure of cardiac muscle to its function.
• 10.4: Explain why the heart does not fatigue.
• 10.5: Trace blood flow through the heart.
• 10.6: Describe the heart's electrical conduction system.
• 10.7: Describe the events that produce the heart’s cycle of contraction and relaxation.
• 10.8: Interpret a normal EKG, explaining what is happening electrically in the heart.
• 10.9: Calculate cardiac output given heart rate and stroke volume.
• 10.10: Explain the factors that govern cardiac output.
• 10.11: Summarize nervous and chemical factors that alter heart rate, stroke volume, and cardiac output.
• 10.12: Locate and identify the major arteries and veins of the body.
• 10.13: Compare the anatomy of the three types of blood vessels
• 10.14: Describe coronary and systemic circulatory routes.
• 10.15: Explain how blood in veins is returned to the heart.
• 10.16: Explain the relationship between blood pressure, resistance, and flow.
• 10.17: Describe how blood pressure is expressed and how mean arterial pressure and pulse pressure are calculated.
• 10.18: Explain how blood pressure and flow are regulated
• 10.19: Explain the effect of exercise on cardiac output
• 10.20: Summarize the effects of aging on the cardiovascular system.
• 10.21: Describe common diagnostic tests used to diagnose heart and vessel disorders.
• 10.22: Describe heart and vessel disorders and relate abnormal function to pathology

Overview

• The heart is a pump that circulates blood through a system of vessels.
• Combining forms & roots:
  • arter/o: artery
  • arteri/o: artery
  • ather/o: fatty substance
  • atri/o: atrium
  • brady: slow
  • cardi/o: heart
  • coron/o: heart
  • pericardi/o: pericardium
  • rhythm/o: rhythm
  • sphygm/o: pulse
  • steth/o: chest
  • tachy/: rapid
  • vas/o: vessel
  • vascul/o: vessel
  • ven/i: vein
  • ven/o: vein
  • ventricul/o: ventricle

Heart Anatomy

• The heart is located in the mediastinum, tilted with two-thirds resting left of the midsagittal plane.
• It is approximately the size of an adult fist (about 300g or 10oz).

Pericardium

• The heart is surrounded by the pericardium.
• Outer Fibrous Pericardium: attached to diaphragm, sternum, vertebral column, connective tissues
• Inner Serous Pericardium:
  • Parietal pericardium–lines the fibrous pericardium
  • Visceral pericardium–synonymous with epicardium
• The pericardial cavity (between parietal & visceral layers) is filled with pericardial fluid.

Heart Wall

• Epicardium (visceral pericardium): outermost layer, contains blood vessels nourishing the heart.
• Myocardium: layer of cardiac muscle providing contraction force.
• Endocardium: simple squamous epithelium lining vessels attached to the heart.

Heart Chambers

• Two atria (atria receive blood from veins).
• Atrial septum (interatrial): separates atria.
• Two ventricles (ventricles pump blood to arteries).
• Interventricular septum: separates ventricles.

Heart Valves

• Atrioventricular valves (AV): allow blood flow from atria to ventricles, and prevent backflow:
  • Tricuspid valve: between R atrium and ventricle
  • Bicuspid valve (Mitral valve): between L atrium and ventricle
• Chordae tendineae extend from valve cusps to papillary muscles in ventricle walls.
• Semilunar valves: located at base of blood vessels attached to ventricles:
  • Pulmonary semilunar valve: between R ventricle and pulmonary trunk.
  • Aortic semilunar valve: between L ventricle and aorta.

Cardiac Muscle Tissue

• Cardiac muscle is striated, branched, has one nucleus per cell, and has intercalated discs.
• Cardiac muscle tissue is specially adapted to stay aerobic.
• It has a rich supply of mitochondria for aerobic respiration, myoglobin, and glycogen as fuel sources (glucose, fatty acids, amino acids, and ketones).

Heart Physiology

• Blood flow through the heart (pulmonary and systemic circuits)
• Cardiac conduction system: The sinoatrial (SA) node, the atrioventricular (AV) node, AV bundle, bundle branches, and Purkinje fibers.
• Cardiac cycle: one complete contraction and relaxation of the heart.
• Systole (contraction) and diastole (relaxation).
• Phases of the Cardiac Cycle:
  • Atrial Systole: SA node fires, atria depolarize, atria contract together, atrial volume decreases, ventricular volume increases.
  • Atrial Diastole: Atria repolarize together, atria relax, atria refill.
  • Ventricular Systole: impulses pass to Purkinje fibers, ventricular depolarization, ventricles contract together, papillary muscles contract (ensuring AV valves stay closed), ventricular pressure increases, semilunar valves push open, ventricles empty, ventricular volume decreases.
  • Ventricular Diastole: ventricles repolarize, ventricles relax, ventricular pressure decreases, ventricular volume increases, ventricles fill.
• Heart Sounds: Lubb-dupp (heart sounds occur due to turbulence of blood when valves close).
  • Lubb: closing of AV valves during ventricular diastole.
  • Dupp: closing of semilunar valves during ventricular systole.

Cardiac Rhythm

• Normal pace: sinus rhythm (70-80 beat per minute).
• Ectopic focus: when tissues other than the SA node set the pace.
• Nodal rhythm: AV node is the ectopic focus.
• Arrhythmia: abnormal heart rhythm (e.g., heart block, hypoxia, caffeine, nicotine, electrolyte imbalance).
• Electrocardiogram (ECG or EKG): shows electrical activity of the heart during a cardiac cycle, includes P, Q, R, S, and T waves, waves show atrial/ventricular depolarization/repolarization.

Cardiac Output

• The amount of blood ejected by each ventricle of the heart each minute (CO = HR x SV).
• Heart rate (HR): measured by feeling the pulse.
• Stroke volume (SV).
• Cardiac Reserve: difference between resting and maximum cardiac output.
• Factors affecting stroke volume (preload, contractility, afterload).

Heart Regulation

• Autonomic nervous system;
  • Cardiac accelerator and inhibitory centers in medulla oblongata
  • Factors being monitored by proprioceptors, baroreceptors, chemoreceptors.
  • Chronotropic factor influences heart rate
• Medulla oblongata:
  • Cardiac accelerator center–sympathetic neurons to stimulate SA and AV nodes.
  • Cardiac inhibitory centre–parasympathetic neurons of the vagus nerve keep the SA node at 70-80 beats/min (vagal tone).

Blood Pressure Regulation

• Factors determining blood flow (resistance, blood pressure, blood flow).
  • Local control: opening/closing of precapillary sphincters (controlled by rate of nutrients). inflammation, basophils (vasodilators), reactive hyperemia, angiogenesis
  • Hormonal control: ADH (vasopressin), aldosterone, angiotensin II, and Epinephrine.
  • Neural control: Baroreflex, high blood pressure stretches carotid arteries triggering a reflex to lower blood pressure, Chemoreflex, high carbon dioxide/acid levels trigger vasoconstriction, Medullary ischemic reflex–direct monitor of cerebral blood pressure.
• Effects of Exercise on Cardiac Output
• Effects of Aging on the Cardiovascular System
  • Blood pressure generally remains normal throughout life.
  • For hypertensive individuals, age-related changes may include increased vascular resistance, decrease in stroke volume, and thickening/loss of elasticity in blood vessels.

Diagnostic tests

• Echocardiography: sound waves create picture of the heart; Electrocardiography: measures electrical activity of the heart; Heart CT Scan: computerized tomography of the heart; Nuclear Heart scan: uses radioactive dye to view the heart.
• Assess cardiac function during activity: Holter Monitor; Stress Test.
• Visualize coronary vessels, arteries, veins: Cardiac catheterization; CT angiography; Ultrasound; Venography.

Vessel Disorders

• Atherosclerosis: buildup of fatty deposits (plaque) within arterial walls. Obstructs blood flow. If fatty deposits become calcified, it is called arteriosclerosis. Coronary artery disease (CAD): Atherosclerosis or arteriosclerosis in coronary arteries which supply blood to the heart.
• Thrombophlebitis: inflammation of vein caused by thrombosis (blood clot in blood vessel).
  • Deep venous thrombosis (DVT): Affects deep veins, can lead to pulmonary embolism (blood clot).
  • Superficial thrombophlebitis: affects veins close to the skin.
• Varicose veins: veins in which valves preventing backflow of blood are not working properly. Blood is allowed to pool and causes vein to enlarge.

Test your knowledge on the cardiovascular system with this comprehensive quiz. It covers key concepts such as echocardiography, cardiac output, and the functions of various heart structures. Perfect for students or anyone interested in understanding heart health and diagnostics.