Circulatory System

• Circulatory System


  • Carries oxygen and food to the cells of the body and carries carbon dioxide and other wastes away from the cells
  • Coagulation process
  • Defends body against disease
  • Regulation of body’s temperature
• Components of the Circulatory System

  • Cardiovascular System
  • Lymphatic System
• Heart Structure


  • Four chambered, hollow, muscular organ
  • Surrounded by PERICARDIUM
  • LAYERS of the heart: Epicardium, Myocardium, Endocardium
• Chambers of the Heart

  • Atria - upper chambers; receiving
  • Ventricles - lower chambers; delivering
• Valves of the Heart

  • Atrioventricular valves - entrance to the ventricles
  • Semilunar valves - exit the ventricles
• Septa of the Heart

  • Interatrial septum - partition that separates the right and left atria
  • Interventricular septum - partition that separates the right and left ventricles
• The heart receives its blood supply via the right and left coronary (also called cardiac arteries). Coronary (cardiac) veins return oxygen poor blood from the heart muscle back to the heart
• Heart Function


  • CARDIAC CYCLE: One complete contraction and subsequent relaxation of the heart. The contracting phase is systole, and the relaxing phase is diastole
  • ELECTRICAL CONDUCTION SYSTEM: Specialized muscle cells synchronize heart contractions, initiated by the Sinoatrial Node/SA node
  • ELECTROCARDIOGRAM: Graphic record of the heart’s electrical activity during the cardiac cycle
  • HEART RATE AND CARDIAC OUTPUT: Heart rate is the number of heart beats per minute, cardiac output is the volume of blood pumped by the heart in 1 minute
• Heart Rate and Cardiac Output Components

  • Arrhythmia
  • Bradycardia
  • Tachycardia
  • Extrasystole
• PULSE: Palpable rhythmic throbbing caused by the alternating expansion and contraction of an artery as a wave of blood passes through it
• BLOOD PRESSURE: Force exerted by the blood on the walls of blood vessels, measured using a sphygmomanometer, expressed in millimeters of mercury (mm Hg). Components include Systolic pressure and Diastolic pressure
• Heart Disorders: Angina pectoris, Aortic stenosis, Bacterial endocarditis, Congestive heart failure (CHF)
• Heart conditions


  • Coronary artery disease
  • Aortic stenosis
  • Bacterial endocarditis
  • Congestive heart failure (CHF)
  • Myocardial infarction (MI)
  • Myocardial ischemia
  • Pericarditis
• Heart diagnostic tests


  • Arterial blood gases (ABGs)
  • Aspartate aminotransferase (AST) or serum glutamic–oxaloacetic transaminase (SGOT)
  • Cholesterol
  • Creatine kinase (CK)
  • Creatine kinase (CK)-MB
  • Digoxin
  • Electrocardiogram (ECG or EKG)
  • Lactate dehydrogenase (LD) isoenzymes
  • Microbial cultures
  • Myoglobin
  • Potassium (K)
  • Triglycerides
  • Troponin T (TnT)
• Vascular system divisions


  • Pulmonary circulation carries blood from the heart to the lungs to remove carbon dioxide and pick up oxygen
  • Systemic circulation carries blood and nutrients from heart to the body cells
• Arteries


  • Blood vessels that carry blood away from the heart
  • Carry oxygenated (oxygen-rich) blood
  • Normal systemic arterial blood is bright red
• The pulmonary artery is the only artery that carries deoxygenated, or oxygen-poor blood. It carries deoxygenated blood from the heart to the lungs
• Veins


  • Blood vessels that return blood to the heart
  • Carry blood that is low in oxygen (deoxygenated or oxygen-poor)
  • Venous blood is dark red
• The pulmonary vein is the only vein that carries oxygenated, or oxygen-rich blood. It carries deoxygenated blood from the lungs back to the heart
• Arterioles


  • Smallest branches of arteries that join with the capillaries
• Aorta


  • Largest artery in the body
• Venules


  • Smallest veins at the junction of the capillaries
• Venae Cavae


  • Largest veins in the body
• Great Saphenous Vein


  • Longest veins in the body
• Capillaries


  • Microscopic, one-cell-thick vessels that connect the arterioles and venules, allowing the exchange of oxygen for carbon dioxide and nutrients for wastes between the cells and the blood
• Blood vessel structure layers

  • Tunica adventitia - outer layer
  • Tunica media - middle layer
  • Tunica intima - inner layer or lining of a blood vessel
• Valves help keep blood flowing toward the heart by allowing blood to flow in only one direction
• Antecubital fossa is a shallow depression in the arm where antecubital veins are found
• Antecubital veins


  • “H” Shape: Median cubital vein (1st choice), Cephalic vein (2nd choice), Basilic vein (3rd choice)
  • “M” Shape: Median vein, Median cephalic vein, Median basilic vein
• Other sites for venipuncture include other arm and hand veins, leg, ankle, and foot veins. Arteries are not used for routine blood collection
• Other sites for Venipuncture

  • Other arm and hand veins
  • Leg, Ankle, and Foot Veins
  • Arteries - not used for routine blood collection
• Aneurysm: a localized dilation or bulging in the wall of a blood vessel, usually an artery
• Arteriosclerosis: thickening, hardening, and loss of elasticity of artery walls
• Atherosclerosis: a form of arteriosclerosis involving thickening of the intima of the artery due to the buildup of plaque (lipid–calcium deposits)
• Disseminated intravascular coagulation (DIC): pathological widespread clotting and fibrinolysis in which coagulation factors are consumed to such an extent that bleeding occurs
• Embolism: obstruction of a blood vessel by an embolus
• Embolus: a blood clot, part of a blood clot, or other mass of undissolved matter
• Hemorrhoids: varicose veins in the rectal area
• Phlebitis: inflammation of a vein
• Thrombophlebitis: inflammation of a vein along with thrombus (blood clot) formation