Heart Anatomy Quiz

ANA 2 Anatomy and Physiology 2

• This course covers the human anatomy and physiology.
• The course facilitator is Mark Joseph V. Liwanag, MSN, RN.

Module 2 - Unit IV: Cardiovascular System: Heart

• The heart is a muscular organ, pumping blood throughout the body.
• It pumps approximately 5 liters of blood per minute.
• It's roughly the size of a closed fist.

Cardiovascular System

• The cardiovascular system includes the heart, blood vessels, and blood.
• Pulmonary circulation involves the heart's right side pumping blood to the lungs and then back to the left side.
• Systemic circulation has the heart's left side pumping blood to the entire body, returning to the right side.

Heart Functions

• Generating blood pressure: Heart contractions produce blood pressure.
• Routing blood: Separates pulmonary and systemic blood flow.
• Ensuring one-way blood flow: Valves in the heart direct blood flow.
• Regulating blood supply: Heart rate and force change to support tissue needs.

Heart Size, Shape, and Location

• Apex: The blunt, rounded end of the heart.
• Base: The broader, flatter portion opposite the apex.
• Mediastinum: The midline partition in the chest cavity.
• Pericardial cavity: The surrounding cavity of the heart.
• Importance: Accurate stethoscope placement, ECG lead positioning, and CPR procedures depend on the heart's location.

Heart Location

• Apex: Located to the left of the fifth intercostal space, near the midclavicular line, approximately 7-9 cm from the sternum.
• Base: Under the sternum, around the second intercostal space

Anatomy of the Heart: Pericardium

• Pericardial cavity: The space where the heart lies.
• Pericardium/Pericardial sac: Surrounds and anchors the heart within the mediastinum.
• Fibrous pericardium: Tough, outer protective layer of connective tissue.
• Serous pericardium: Inner layer with epithelial and connective tissues.
  • Parietal pericardium: Lines the fibrous pericardium.
  • Visceral pericardium (epicardium): Covers the heart's surface.
• Pericardial fluid: Reduces friction as the heart moves.

Anatomy of the Heart: External Anatomy

• Atria: The entrance chambers at the heart's base.
• Ventricles: The heart's pumping chambers that extend from the base to the apex
• Sulci/Grooves: Contain blood vessels and fats on the heart's surface.
  • Coronary sulcus: Separates atria and ventricles.
  • Anterior interventricular sulcus: Extends inferiorly from the coronary sulcus on the anterior surface of the heart
  • Posterior interventricular sulcus: Extends inferiorly from the coronary sulcus on the posterior surface of the heart

Anatomy of the Heart: External Anatomy (cont.)

• Veins: Large blood vessels carrying blood to the atria
  • Superior and inferior vena cava: Bring blood to the right atrium.
  • Pulmonary veins: Carry blood from the lungs to the left atrium.
• Arteries: Large vessels taking blood away from the ventricles
  • Pulmonary arteries: Deliver blood to the lungs.
  • Aorta: Transports blood to the rest of the body.

Anatomy of the Heart: Internal Anatomy (Atria)

• Atria: Blood collection areas.
  • Right atrium receives blood from superior vena cava, inferior vena cava, and coronary sinus.
  • Left atrium receives blood from pulmonary veins.

Anatomy of the Heart: Internal Anatomy (ventricles)

• Ventricles: The major pumping chambers, ejecting blood into arteries.
  • Right ventricle: Pumps blood into the pulmonary trunk.
  • Left ventricle: Pumps blood into the aorta. The left ventricle wall is thicker than the right.

Heart Valves

• Atrioventricular (AV) valves: Control blood flow between atria and ventricles

  • Tricuspid valve (right side): Between right atrium and right ventricle.
  • Bicuspid/Mitral valve (left side): Between left atrium and left ventricle.

• Semilunar valves: Regulate blood flow from ventricles to pulmonary trunk/aorta

  • Pulmonary: Between right ventricle and pulmonary trunk
  • Aortic: Between left ventricle and aorta.

Heart Valves (cont.)

• Papillary muscles and chordae tendineae: Prevent valve inversion during ventricular contraction.

Cardiac Skeleton

• A fibrous supportive structure.
• Isolates electrical activity between atria and ventricles.
• Provides a rigid attachment site for cardiac muscles.

Blood Flow Through the Heart

• Describes routes of blood flow through the heart, from veins to the right atrium, through the ventricles and into the arteries.

Blood Supply to the Heart

• Coronary arteries: Supply blood to the heart wall.
  • Left coronary artery: Divides into Anterior interventricular artery, Circumflex artery, and Left marginal artery.
  • Right coronary artery: Supplies blood to the right side of the heart, with branches including Posterior interventricular artery, and Right marginal artery.

Coronary Circulation (Veins)

• Coronary veins: Return blood from the heart wall.
• Great and small cardiac vein blood drains into the coronary sinus, then into the right atrium.

Histology of the Heart: Heart Wall

• Epicardium/Visceral Pericardium: Outermost layer, smooth surface, consists of simple squamous epithelium with connective tissue and adipose tissue.
• Myocardium: Middle layer, thickest, cardiac muscles, responsible for heart contraction.
• Endocardium: Innermost layer, simple squamous epithelium over connective tissue, forms the heart valves.
  • Trabeculae carneae: Ridges and columns of cardiac muscle.

Histology of the Heart: Cardiac Muscle Cells

• Elongated, branching cells with centrally located nuclei.
• Myofilaments (actin and myosin) form sarcomeres.
• Rich in mitochondria for ATP production.
• Relies on Ca2+ and ATP for contraction.

Histology of the Heart: Cardiac Muscle (cont.)

• Intercalated disks: specialized cell-to-cell contacts which greatly increase contact, and prevent cells from pulling apart
• Gap junctions: specialized cell membrane structures allow cytoplasm to flow freely between cells.

Electrical Activity of the Heart

• Depolarization, Plateau and Repolarization phases in heart muscle cells.
• Different action potentials to skeletal muscle action potentials, due to the plateau phase.
• Refractory period (which is much longer than in skeletal muscle): Allows for the heart to complete contractions and relax.

Conduction System of the Heart

• Sinoatrial (SA) node: The heart's pacemaker.
• Atrioventricular (AV) node: Slows the action potential.
• Atrioventricular bundle: carries impulse to ventricles.
• Bundle branches: Carry impulse to ventricles.
• Purkinje fibers: Conduct rapid action potentials to ventricles.
  • Action potentials travel through the conduction system, starting at the SA node, through the bundle, bundle branches, then to the Purkinje fibers.

Electrocardiogram (ECG)

• A record of the heart's electrical activity.
• P wave: Atrial depolarization.
• QRS complex: Ventricular depolarization.
• T wave: Ventricular repolarization.
  • Intervals (e.g., PQ, PR, QT): Time between events.

Abnormal Heart Rhythms

• Tachycardia: Heart rate exceeding 100 beats/minute.
• Bradycardia: Heart rate below 60 beats/minute.

Cardiac Cycle

• A repetitive pumping process with several phases including:
  • Atrial systole: Atria contract to fill ventricles.
  • Ventricular systole (first phase): Ventricles contract to pump blood.
  • Ventricular systole (second phase): Blood is ejected into large arteries.
  • Ventricular diastole: Relaxation of ventricles allowing blood to actively refill the ventricles.

Heart Sounds

• Lubb: Closure of AV valves.
• Dub: Closure of semilunar valves.
• Murmurs: Abnormal heart sounds, caused by faulty valves.
• Stenosed valves: Valves with narrowed openings.

Regulation of Heart Function

• Cardiac output (CO): Volume of blood pumped per minute (CO = SV x HR).
• Stroke volume (SV): Volume of blood pumped per ventricle contraction.
• Heart rate (HR): Number of times the heart contracts per minute.
  • Factors that regulate heart function: Nerves and Hormones.

Intrinsic Regulation of the Heart

• Venous Return: Amount of blood returning to the heart
• Preload: Degree ventricular walls are stretched at the end of diastole
• Starling's law of the Heart: Relationships between preload and stroke volume
• Afterload: Pressure against which ventricles pump blood

Extrinsic Regulation of the Heart

• Baroreceptor Reflex: Mechanism of the nervous system in regulating heart function.
  • Baroreceptors: Stretch receptors monitoring blood pressure
  • Cardioregulatory center: Receives and integrates action potentials.

Extrinsic Regulation of the Heart (cont.)

• Chemical Regulation: Chemoreceptor Reflex
  • Epinephrine and Norepinephrine: Cause increased heart rate and stroke volume.
  • Increased CO2: Increases sympathetic stimulation, thus heart rate and force of contraction.

Representative Diseases and Disorders of the Heart

• Coronary heart disease: Reduces blood supply to the heart muscle.
• Coronary thrombosis: Blood clots in coronary arteries.
• Myocardial infarction (heart attack): Damaged heart muscle due to lack of blood flow.
• Endocarditis: Inflammation of the endocardium, affects valves more severely.
• Pericarditis: Inflammation of the pericardium.
• Rheumatic heart disease: Infection in young people can cause inflammation and damage to the heart valves.
• Septal defect: Hole in the septum between the heart's chambers.
• Cyanosis: Insufficient heart function.

Test your knowledge on the anatomy and functions of the heart with this engaging quiz. From blood flow to heart valves and coronary arteries, assess your understanding of cardiovascular structures. Perfect for students studying anatomy or medicine.