The heart - Lecture

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  1. Where is the heart located?
    In the Mediastrinum

    The Mediastrinum is is the area from the sternum to the vertebral column and between the lungs
  2. Describe the orientation of the heart
    Apex (means top part)- directed downwards and to the left

    Base - directed upward and to the right

    Anterior surface - under the sternum and ribs

    Inferior surface - rests on the diaphragm

    Left and Right border - faces the left and right lung
  3. What is the Pericardium?
    The heart sack
  4. Describe Fibrous pericardium
    Dense irregular connective tissue membrane

    Protects, anchors and prevents overstretching of the heart
  5. Describe Serous Pericardium
    Thin delicate membrane

    • Made of 2 layers:
    • Parietal layer - attached to the fibrous
    • Visceral layer (epicardium) - attached to the wall of the heart

    Pericardial Cavity with Pericardal Fluid between the Parietal and Visceral layers  - it is used for lubrication
  6. Describe the Right and Left Atrium
    Thin walled receivers of blood from the body and lungs that empty into the ventricles
  7. Describe the Right and Left Ventricle
    Thick walled pumps of blood to lungs and body
  8. Describe the heart wall
    Parietal layer of serous pericardium

    1- Epicardium- visceral layer of serous pericardium

    2- Myocardium - cardiac muscle layer is the bulk of the heart

    3- Endocardium - chambers lining and valves cover
  9. how many cardiac muscles are in the heart?
  10. Name the cardiac muscles and what they do
    • 1- Contractile Cardiac Muscle
    • It makes up of 99% of the muscle
    • Make all the Myocardium muscle
    • Produce contractions of the heart chambers

    • 2- Auto-rhythmic Cardiac Muscles
    • It makes up of 1% of the muscle cells
    • Specialized muscle cells that are self-excitable like nerves
    • Form the heart pacemaker
    • Form the Conduction System through the heart muscles
  11. What is the structure of the Cardiac Muscle?
    • Striated
    • Branched
    • Intercalated Discs
    • Involuntary
    • Aerobic
  12. Describe Autorhythmicity
    Heartbeat is Intrinsic (internal) because it has its own pacemaker that starts each beat
  13. Describe the SA node
    It is the pacemaker that starts each heartbeat by spontaneously depolarizing at the speed of the heart rate producing the normal sinus rhythm.

    Resulting action potential (cardiac impulse or signal) spreads through the conduction system into the contractile cardiac muscle cells
  14. Describe the Conduction System
    • 1- Sinoatrial (SA) Node - Pacemaker
    • Automatically depolarizes and produce the cardiac impulse

    • 2- Atrioventricular (AV) Node
    • Receives electrical impulse from SA node, delays it for a very short time then sends it into the atrioventicular bundle.

    3- AV Bundle (of His) receives signal from AV node

    • 4- Right and left Bundle Branches
    • Formed by division of AV bundle
    • Send signal to each ventricle

    5- Purkinje Fibers spread signal throughout ventricles
  15. Where is the impulse delayed?
    In the Atrioventricular (AV) Node
  16. Describe the Electrocardiogram
    P wave - atrial deploarization

    • QRS complex - ventricular depolarization
    • (the bigger the heart the bigger the QRS wave)
    • T wave - ventricular re-polarization

    P-Q interval - time for the signal to travel from SA node to AV bundle

    • Q-T interval - time for both ventricular depolarization and re-polarization
    • (problems with the purkinje fibers or muscle fibers)
  17. What is the Cardiac Cycle?
    Each impulse produces one cycle by depolarization and repolarization of the heart muscle producing

    Systole - Heart muscles contraction phase

    Diastole - Heart muscles relaxation phase
  18. What is Cardiac Output?
    Is the amount of blood ejected by the heart in one minute
  19. Cardiac output - What is Stroke Volume?
    The amount of blood ejected by the heart in each beat. (S.V.)
  20. Cardiac output - What is Heart Rate?
    Number of heart beats in one minute (H.R.)

    Cardiac output = (S.V.) x (H.R.)
  21. Factors Affecting the Stroke Volume

    Describe Preload
    End Diastolic Volume

    Amount of blood in the Ventricles at the end of the Diastole phase

    Preload increases, stroke volume increases
  22. Factors Affecting the Stroke Volume

    Describe Afterload
    Diastolic Blood Pressure in the Aorta and the Pulmonary Trunk

    Afterload decreases, stroke volume decreases
  23. Factors Affecting the Stroke Volume

    Where is the Contraction Force?
    Contraction force of the cardiac contractile muscles
  24. What are some factors that affect the Heart Rate?
    Neutral control is done by the Cardiac Centers in the Brain

    Acceleratory - Sympathetic Impulss

    Nor-epinephrine - increases heart rate

    Acetylcholine  - decreases heart rate
  25. What does Tachycardia mean?
    A heart rate above 100 beats/min.
  26. What does Bradycardia mean?
    A heart rate below 60 beats/min.
  27. What does Asystole mean?
    A means none

    Cardiac standstill, no contraction
  28. What does Coronary Artery Disease (CAD) mean?
    Narrowing of the coronary arteries
  29. What does Ischemia mean?
    Decreased blood flow to the tissues
  30. What does Pericarditis mean?
    Inflammation of the pericardium
  31. What does Angina pectoris mean?
    Chest pain due to heart problem
  32. What does Myocardial infraction mean?
    Loss of living heart muscle cells
  33. What does Arteriosclerosis mean?
    Thickening of the arterial walls
  34. What does Atherosclerosis mean?
    hardening of arteries
  35. What does Arrhythmias mean?
    Irregularity of heart rhythm
  36. What does heart failure mean?
    Reduced ability of the heart to pump blood
Card Set:
The heart - Lecture
2013-01-23 02:14:09

The heart - Lecture
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