Cardiovascular

• Cardiovascular System


  An organ system that permits blood to circulate and transport nutrients, oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body
• Functions of the Cardiovascular System

  • Provide nourishment
  • Help in fighting diseases
  • Stabilize temperature and pH
  • Maintain homeostasis
• Heart


  A muscular pump that forces blood through a system of vessels made of arteries, veins and capillaries
• Location of the Heart

  • Positioned obliquely between the lungs in the mediastinum
  • Lies in the pericardial cavity

  
• Functions of the Heart

  • Generate Blood Pressure
  • Route Blood
  • Ensure One-way Blood Flow
  • Regulation of Blood Supply
• Size of the Heart

  • Size of a fist
  • Hollow, cone-shaped heart has a mass of 250 to 350 grams—less than a pound
• Mediastinum


  The central compartment of the thoracic cavity surrounded by loose connective tissue, as region that contains a group of structures within the thorax
• Precordium


  The part of the front of the chest wall that overlays the heart and the epigastrium

  
• Pericardium


  • Surrounds the heart and anchors it within the mediastinum
  • Has 2 layers: Fibrous pericardium and Serous pericardium
• Fibrous Pericardium


  • Layer of connective tissue that provides support and protection for the heart
  • Attachments to the diaphragm, the sternum, and the vertebral column
  • Holds the heart in place

  
• Serous Pericardium


  • Contains the pericardial fluid
  • Has 2 layers: Parietal pericardium and Visceral pericardium (epicardium)
• Layers of the Heart

  • Epicardium (visceral pericardium)
  • Myocardium
  • Endocardium

  
• Chambers and Internal Anatomy of the Heart

  • Humans have a 4 chambered heart: 2 atria and 2 ventricles
  • Left and right sides divided by the septum: Interatrial septum and Inter-ventricular septum

  
• Valves of the Heart

  • Atrioventricular Valve: Tricuspid Valve and Bicuspid (Mitral valve)
  • Semilunar Valves: Pulmonic Semilunar Valves and Aortic Semilunar Valves
• Chordae Tendinae


  Tendon-resembling fibrous cords of connective tissue that connect the papillary muscles to the tricuspid valve and the bicuspid valve in the heart
• Coronary System


  • Circulation of blood that supply oxygen to the myocardium
  • Coronary arteries and Coronary veins
• Sequence of Systemic Blood Circulation

  Not provided
• Mechanism of a Heart Beat

  • The hearts conduction system consists of special electrical cells that generate and coordinate electrical impulses to the myocardial cells
  • Properties of the myocardial cells: Rhythmicity, Automaticity, Conductivity, Contractility, Excitability
• Components of Conduction System of the Heart

  • Sinoatrial Node (SA Node)
  • Atriventricular Node (AV Node)
  • Bundle of His / Atrioventricular Bundle
  • Left and Right Bundle Branches
  • Purkinjie Fibers
• Examples of Arrhythmia


  • Not provided
• Electrocardiogram (ECG / EKG)


  • Procedure that measures electrical signals in the heart
  • Each time the heart beats, an electrical signal travels through the heart
  • An EKG can show if the heart is beating at a normal rate and strength, and help show the size and position of the heart's chambers

  
• Normal Heart Beat

  60-100 beats per minute
• Normal Heart Sounds


  • Lubb (S1): Lower in pitch, occurs at the beginning of ventricular systole, results from closure of AV valves
  • Dubb (S2): Occurs at the beginning of ventricular diastole and results from closure of the semilunar valves
• Cardiac Cycle


  • Refers to the filling and emptying of heart chambers
  • Two phases: Diastole (Filling, Relaxation of Ventricles) and Systole (Emptying, Contraction of Ventricles)
• Phases of Cardiac Cycle

  • Atrial Systole
  • Ventricular Systole
  • Atrial Diastole
  • Ventricular Diastole
• Cardiac Output


  • Volume of blood pumped by either ventricle per minute
  • CO (mL/min) = SV (mL/beat) x HR (beats/min)
• Stroke Volume


  • Volume of blood pumped per ventricle each time the heart contracts
  • Approximately 70mL per beat
• Heart Rate


  • Number of times the heart contracts per minute
  • Approximately 72 beats/min for normal adults
• Points of Auscultation


  • Aortic Area
  • Pulmonic Area
  • Erb's Point
  • Mitral (Apical Area)
  • Tricuspid Area
• How to Auscultate
• Heart Sounds


  • S1 (lubb): Closure of AV valves
  • S2 (dubb): Closure of semilunar valves
  • S3 (ventricular gallop): Passive filling of left ventricle
  • S4 (atrial gallop): Active LV filling when atrial contraction forces blood into a noncompliant LV
• Blood Vessels


  • Tubular structures carrying blood through the tissues and organs
  • Functions: Carry Blood, Exchange Nutrients/Waste/Gases, Transport Substances, Regulate Blood Pressure, Direct Blood Flow
• Layers of Blood Vessels


  Tunica Adventitia/Externa, Tunica Media, Tunica Intima
• Arteries


  • Carry blood away from the heart
  • Carry Oxygenated Blood
  • Classified as: Elastic Artery, Muscular Artery, Arterioles
• Capillaries


  • Extremely small blood vessels located within the body tissues
  • Gasses, nutrients, and fluids are exchanged through capillaries
• Capillary Exchange

  • Most exchange across the capillary wall occur by diffusion
  • Blood pressure, capillary permeability and osmosis affect the movement of fluid form the blood to the tissues
  • Fluid gained by the tissues is removed by the lymphatic system
• Veins


  • Carry deoxygenated blood back to the heart
  • Veins with more than 2mm diameter contains valves which prevents blood from flowing toward the feet in response to the pull of gravity
• Types of Veins


  • Large Veins
  • Small Veins
  • Venules
• Varicose Veins


  • Swollen, twisted veins that can be seen just under the skin
  • Caused by weakened valves in the veins or weakened walls of the veins due to age, or by inflammation in the veins (phlebitis)
  • Treatment: Sclerotherapy
• Neck Vessels


  • Carotid arteries and Jugular Veins
  • Assessment of pulses of these vessels reflect the integrity of the heart muscle