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• Cardiopulmonary or cardiorespiratory system


  Works with the pulmonary system
• Purposes of the cardiorespiratory system


  • Transport O2 and nutrients to tissues
  • Removal of CO2 wastes from tissues
  • Regulation of body temperature
• Two major adjustments of blood flow during exercise


  • Increased cardiac output
  • Redistribution of blood flow from inactive organs to active muscle
• Heart


  Creates pressure to pump blood
• Arteries and arterioles


  Carry blood away from the heart
• Capillaries


  Exchange of O2, CO2, and nutrients with tissues
• Veins and venules


  Carry blood toward the heart
• Pulmonary circuit


  • Right side of the heart
  • Pumps deoxygenated blood to the lungs via pulmonary arteries
  • Returns oxygenated blood to the left side of the heart via pulmonary veins
• Systemic circuit


  • Left side of the heart
  • Pumps oxygenated blood to the whole body via arteries
  • Returns deoxygenated blood to the right side of the heart via veins
• The purposes of the cardiovascular system are the following: (1) the transport of O2 to tissues and removal of wastes, (2) the transport of nutrients to tissues, and (3) the regulation of body temperature.
• The heart is two pumps in one. The right side of the heart pumps blood through the pulmonary circulation, while the left side of the heart delivers blood to the systemic circulation.
• Myocardium


  • The heart wall
  • Epicardium
  • Myocardium
  • Endocardium
  • Receives blood supply via coronary arteries
  • High demand for oxygen and nutrients
  • Myocardial infarction (MI)
  • Blockage in coronary blood flow results in cell damage
  • Exercise training protects against heart damage during MI
• Regular exercise is cardioprotective
• Exercise reduces the amount of myocardial damage from heart attack
• Improvements in heart's antioxidant capacity
• Improved function of ATP-sensitive potassium channels
• Systole


  • Contraction phase
  • Ejection of blood
  • ~2/3 blood is ejected from ventricles per beat
• Diastole


  • Relaxation phase
  • Filling with blood
  • At rest, diastole longer than systole
  • During exercise, both systole and diastole are shorter
• Diastole


  • Pressure in ventricles is low
  • Filling with blood from atria
  • AV valves open when ventricular P < atrial P
• Systole


  • Pressure in ventricles rises
  • Blood ejected in pulmonary and systemic circulation
  • Semilunar valves open when ventricular P > aortic P
• Heart sounds


  • First: closing of AV valves
  • Second: closing of aortic and pulmonary valves
• Hypertension


  • Blood pressure above 140/90 mmHg
  • Primary (essential) hypertension
  • Cause unknown
  • 90% cases of hypertension
  • Secondary hypertension
  • Result of some other disease process
  • Risk factor for:
  • Left ventricular hypertrophy
  • Atherosclerosis and heart attack
  • Kidney damage
  • Stroke
• Determinants of mean arterial pressure (MAP)


  • Cardiac output
  • Total vascular resistance
• Short-term regulation


  • Sympathetic nervous system
  • Baroreceptors in aorta and carotid arteries
  • Increase in BP = decreased SNS activity
  • Decrease in BP = increased SNS activity
• Long-term regulation


  • Kidneys
  • Via control of blood volume
• MAP = cardiac output x total vascular resistance
• Conduction system


  • Sinoatrial node (SA node)
  • Pacemaker, initiates depolarization
  • Atrioventricular node (AV node)
  • Passes depolarization to ventricles
  • Brief delay to allow for ventricular filling
  • Bundle Branches
  • To left and right ventricle
  • Purkinje fibers
  • Throughout ventricles
• Electrocardiogram (ECG)


  • Records the electrical activity of the heart
  • P wave
  • Atrial depolarization
  • QRS complex
  • Ventricular depolarization and atrial repolarization
  • T wave
  • Ventricular repolarization
  • ECG abnormalities may indicate coronary heart disease
  • ST-segment depression can indicate myocardial ischemia
• Graded exercise test to evaluate cardiac function
• Observe ECG during exercise
• Also observe changes in blood pressure
• Atherosclerosis


  • Fatty plaque that narrows coronary arteries
  • Reduces blood flow to myocardium
  • Myocardial ischemia
• 1. T segment depression


  Suggests myocardial ischemia
• The myocardium is composed of three layers: (1) epicardium (outer layer); (2) Myocardium (middle layer composed of cardiac muscle fibers); and endocardium (inner layer).
• The contraction phase of the cardiac cycle is called systole and the relaxation period is called diastole.
• The average blood pressure during a cardiac cycle is called mean arterial pressure.
• Blood pressure can be increased by one or all of the following factors: a. Increase in blood volume, b. Increase in heart rate, c. Increased blood viscosity, d. Increase in stroke volume, e. Increased peripheral resistance
• The pacemaker of the heart is the SA node.
• A recording of the electrical activity of the heart during the cardiac cycle is called the electrocardiogram (ECG).
• Cardiac Output


  • The amount of blood pumped by the heart each minute
  • Product of heart rate and stroke volume