Bio 209 Ch 20A

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Bio 209 Ch 20A
2010-07-20 12:50:22

The Heart
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  1. How much blood does the heart pump each minute throughout the body?
    5 liters/min and our body has approx. 5-6 liters of blood
  2. Describe the heart and its location
    • Cone shaped about the size of a first
    • - Base is formed by atria and has broad posterior surface
    • - Apex is formed by left ventricle and has a pointed tip

    Located in mediastinum
  3. Where are the Base and Apex located?
    Base: (?)

    Apex: left side, resting on diaphragm
  4. Describe the Pericardium and its function
    Membrane that surrounds & protects the heart

    It confines heart to its location in mediastinum
  5. Describe the Fibrous Pericardium & its function
    Superficial layer of Pericardium

    It prevents overstretching of the heart by attaching to diaphragm & BV
  6. Describe the Serous Pericardium & its function
    • 2 Layers:
    • - Parietal: fused to fibrous pericardium
    • - Visceral/Epicardium: adheres to surface of heart

    • Pericardial Cavity: space between parietal & visceral
    • Pericardial Fluid: slippy fluid that reduces friction during contraction
  7. What are the three layers of the heart?
    • Epicardium
    • Myocardium
    • Endocardium
  8. What layer of the heart is the outermost layer?
  9. What layer is the thickest layer and describe its function?
    Myocardium: middle layer of the heart that is responsible for contraction of the heart
  10. What layer does the Endocardium sit and what is its function?
    Innermost layer, and it provides slippery surface that prevents friction as blood passes through within the chambers and valves
  11. Name the heart chamers (2)
    Atria & Ventricles
  12. Which part of the heart chamber receives blood and describe its structure?
    Atria: these are the upper heart chambers that contain auricles (pouch-like structures on anterior surface and slightly increases amount of blood it can hold)
  13. Which part of the heart chambers distribute blood & describe its structure?
    Ventricles: these are the lower heart chambers
  14. What three veins carry blood to the Right Atrium?
    • Superior Vena Cava
    • Inferior Vena Cava
    • Coronary Sinus
  15. What artery (from the Right Ventricle) is blood pumped?
    Pulmonary Trunk
  16. Which veins carry blood from the lungs to the Left Atrium?
    Pulmonary Veins
  17. Where does blood pass through from the Left Ventricle?
  18. Describe the Sulci on the surface of the heart
    • Sulci are grooves that contain BV & fat:
    • - Coronary Sulcus: deep groove encircling heart, separating atria & ventricles
    • - Anterior Interventricular Sulcus: shallow groove on anterior surface of heart separating R & L ventricles
    • - Posterior Interventricular Sulcus: continues AIS on posterior surface and separates R & L ventricles
  19. What are the two heart valves?
    Atrioventricular Valves & Semilunar Valves
  20. Describe the structure and function of the Atrioventricular Valves
    Tricuspid Valve (R Atrioventricular): three cusps, located between R Atrium & R Ventricle

    Bicuspid Valve (L Atrioventricular): two cusps, located between L Atrium & L Ventricle

    Chordae Tendinae attaches cusps to papillary muscles
  21. Describe the structure & function of the Semilunar Valves
    Pulmonary Semilunar Valve: between R Ventricle & Pulmonary Trunk

    Aortic Semilunar Valve: between L Ventricle & Aorta

    Semilunar Valves eject blood into Aorta
  22. Describe the blood pathway thru R heart
    1. Inferior Vena Cava to Superior Vena Cava to Coronary Sinus into R atrium

    • 2. Right Atrioventricular Valve into R Ventricle
    • 3. Pulmonary Valve into Pulmonary Trunk

    4. Enters Pulmonary Arteries
  23. Describe the blood pathway thru L heart
    1. Pulmonary Veins into L Atrium

    2. Left Atriventricular into L Ventricle

    3. Aoric Valve into Aorta to body tissues
  24. Compare the thickness of the myocardium of each chamber
    Thicker - L Ventricle

    Thinner - R Ventricle
  25. How does thickness of myocardium relate to function of each chamber?
    Thickness indicates amount of force it contracts - the thicker the muscle, the stronger the contraction

    R Ventricle pumps blood into lungs, therefore its walls are thinner

    L Ventricle pumps to the rest of the body, therefore its walls are thicker
  26. Define Stenosis
    Narrowing of heart valve opening that decreases flow of blood
  27. Define Insufficiency
    Failure of valve to close completely allowing backflow of blood
  28. How does Rheumatic Fever affect the heart?
    It damages/destroys heart valves
  29. Describe the pathway of blood thru Pulmonary Circulation (Right Side of heart)
    1. Oxygen-poor blood pumped from R Ventricle into Pulmonary Trunk

    • 2. Pulmonary Arteries to lung
    • 3. Oxygen is added, Carbon Dioxide is removed

    4. Pulmonary Veins to Left Atrium
  30. Describe the pathway of blood thru Systemic Circulation (Left Side of the heart)
    1. Oxygen-rich blood pumped from Left Ventricle into Aorta

    2. Systemic Arteries to different body areas

    3. Enters Capillaries, loses Oxygen & gains Carbon Dioxide

    4. Returns to Systemic Veins to Right Atrium
  31. What is the function of Coronary Circulation?
    Supply blood to the heart wall
  32. What are some of the effects of blockage of coronary arteries?
    • Myocardial Ischemia
    • Hypoxia
    • Myocardial Infarction
    • Reperfusion
  33. What's the function of Autorhythmic Cells?
    1. Spontaneously generates Action Potentials

    2. Pacemakers

    3. Form conduction system
  34. What are the components of the Conduction System?
    1. Sinoatrial Node

    2. Atrioventricular Node

    3. Atrioventricular Bundle

    4. Bundle Branches

    5. Purkinje Fibers
  35. Describe the Sinoatrial (SA) Node of the Conduction System
    • - Right atrial wall near superior vena cava
    • - Unstable resting membrane potential
    • - Action Potentials initiated by SA node spread to both atria via gap junctions
    • - Spreads to AV Node
  36. Describe the Atrioventricular (AV) Node of the Conduction System
    • - Interatrial Septum
    • - Spreads to AV Bundle (bundle of His)
  37. Describe the Atrioventricular (AV) Bundle of the Conduction System
    • - Conducts Action Potential from Atria to Ventricles
    • - AV Bundles allow Action Potential to spread from atria to ventricles (because atria is electrically insulated from ventricles)
    • - Spreads to Right & Left Bundle Branches
  38. Describe the Right & Left Bundle Branches of the Conduction System
    • - Interventricular Septum
    • - Propogated along bundle branches towards Apex
    • - Enters Perkinje Fibers at Apex
  39. Describe the Perkinje Fibers of the Conduction System
    • - Conduct Action Potential upwards to remainder of Ventricular Myocardium
    • - Ventricles contract and blood is ejected to Semilunar Valves
  40. What is the pacemaker of the heart?
    Sinoatrial Node (SA Node)
  41. Define Ectopic Pacemaker
    Site other than SA Node is pacemaker due to damaged SA Node (Slow HR)
  42. What effect does the ANS have on the heart?
    • Modifies Action Potentials the SA Node generates by:
    • - Sympathetic: increases HR by increased Action Potential
    • - Parasympathetic: decreases HR by decreased Action Potential
  43. Describe the stages of the Cardiac Muscle Cell Action Potential
    1. Depolarization: opening of Voltage-Gated fast Na channels and Na enters cell

    2. Plateau (Sustained Depolarization): opening of Voltage-Gated Ca channels and Ca enters cell

    3. Repolarization: opening of Voltage-Gated K channels and K leaves cell
  44. Why is the Refractory Period length important in the cardiac muscle?
    Tetanus can't occur in cardiac muscle fibers because Refractory Period lasts longer than the contraction itself
  45. What is ECG?
    Electrocardiogram - a record currents generated by Action Potentials in the heart
  46. What are the components of a ECG?
    • P Wave: atrial depolarization
    • QRS Complex: ventricular depolarization (atrial repolarization)

    T Wave: ventricular repolarization

    P-Q Interval: time between atrial action potential to ventricular action potential (elongated in heart block)

    Q-T Interval: time between ventricular depolarization to ventricular repolarization (elongated in myocardial damage)
  47. Correlation of ECG and Atrial Systole
    • - Follows P Wave
    • - Precedes ventricular systole, adding amount of blood to ventricles
  48. Correlation of ECG and Ventricular Systole
    • - Follows QRS Complex (atrial diastole)
    • - Dystole follows T Wave