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• What is an electrocardiogram (ECG or EKG)?

  A test to record heart's electrical signals
• Why is an electrocardiogram performed?

  To check the heartbeat's speed and rhythm
• What conditions can an ECG help diagnose?

  • Irregular heartbeats (arrhythmias)
  • Previous heart attack
  • Causes of chest pain (e.g., blocked arteries)
• What symptoms may indicate the need for an ECG?

  Chest pain, dizziness, and shortness of breath
• What is the Frank-Starling mechanism?

  • Explains heart response to venous return
  • Increased venous return leads to stronger contractions

  
• What is the cardiac cycle?

  The performance of the heart between beats

  
• What are the two periods of the cardiac cycle?

  • Diastole: heart relaxes and fills with blood
  • Systole: heart contracts and pumps blood

  
• What is cardiac output (CO)?

  Amount of blood pumped by left ventricle per minute
• What is stroke volume (SV)?

  Volume of blood pumped by each ventricle per beat

  
• How is stroke volume calculated?

  SV = EDV - ESV

  
• What does end-diastolic volume (EDV) represent?

  Blood volume in ventricles before contraction

  
• What is the typical value of end-diastolic volume?

  120 ml
• What is end-systolic volume (ESV)?

  Blood volume in ventricles at the end of systole

  
• What is the typical value of end-systolic volume?

  50 ml
• How is cardiac output calculated if heart rate is 70 bpm and stroke volume is 70 ml?

  CO = 70 x 70 = 4900 ml/min

  
• What does ejection fraction measure?

  Percentage of blood leaving the heart per contraction
• What is preload in cardiac physiology?

  • Initial stretching of cardiac myocytes before contraction
  • Increased preload raises stroke volume
  • Decreased preload lowers stroke volume

  
• What are positive inotropics?

  • Increase cardiac contractility
  • Examples: caffeine, glucagon, digitalis
• What are negative inotropics?

  • Decrease cardiac contractility
  • Examples: calcium antagonists, barbiturates
• What is laminar blood flow?

  • Blood flow in parallel lines
  • No sound produced
• What is turbulent blood flow?

  • Disturbed blood flow due to narrow vessels
  • Produces sound
• What is arterial blood pressure (ABP)?

  Pressure exerted by blood on vascular walls

  
• What is systolic blood pressure?

  Arterial blood pressure during cardiac systole

  
• What is diastolic blood pressure?

  Arterial blood pressure during cardiac diastole

  
• How is pulse pressure calculated?

  Pulse pressure = Systolic - Diastolic

  
• What is the mean arterial blood pressure formula?

  Mean ABP = Diastolic + 1/3 pulse pressure

  
• What are vasoconstrictors?

  • Angiotensin II
  • Epinephrine
  • Norepinephrine

  
• What are vasodilators?

  • Nitric oxide
  • Prostaglandins
  • Histamine
  • Bradykinin
• What factors affect blood flow resistance?

  • Diameter of blood vessels
  • Vascular tone
  • Total peripheral resistance

  
• How do sympathetic nerves affect blood vessels?

  • Cause contraction of vascular smooth muscle
  • Mediated by alpha-adrenoceptors
• What is the role of parasympathetic fibers in blood vessels?

  • Found in certain organs
  • Release acetylcholine for vasodilation
• What is the role of baroreceptors?

  • Detect changes in blood pressure
  • Send signals to the medulla

  
• What centers are involved in autonomic control of blood pressure?

  • Cardiac accelerator center
  • Vasomotor center
  • Cardiac inhibitory center

  
• How does the medulla regulate blood pressure?

  • Receives sensory input from receptors
  • Modulates autonomic nerve outflow
• What is the effect of increased arterial blood pressure on baroreceptors?

  • Stimulates baroreceptors
  • Increases sympathetic discharge

  
• How does the hypothalamus influence cardiovascular responses?

  • Modifies medullary activity
  • Stimulates responses to stress and emotion
• What is the role of chemoreceptors in blood pressure regulation?

  • Detect changes in CO2 and O2 levels
  • Influence sympathetic and parasympathetic activity