Biomedical Core

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Biomedical Core
2013-03-12 23:33:20

Objective 18-21
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  1. Heart Sounds:

    Lower pitched "lub"

    -this is the AV valves closing plus the semilunar valves opening
  2. Heart Sounds:

    Higher pitched "dup"

    - this is the semilunar valves closing plus the AV valves opening
  3. Listening to the sounds the heart makes is called
  4. Define heart rate
    -beats per minute (bpm)

    - number of cardiac cycles per minute
  5. Define End-diastolic volume
    - at diastole, ventricles fill to about 120 ml

    - ventricular volume at diastole is the EDV
  6. Define End-systolic volume
    - amount remaining in ventricles after contraction

    - about 50 ml
  7. Define Stroke volume output
    - at systole, volume of ventricles decreases by amount pumped out

    - end-diastolic volume -- end-systolic volume = about 70 ml

    - this is stroke volume output

    SV = EDV - ESV
  8. Define Ejection fraction
    - stroke volume output divided by end-diastolic volume

    - i.e. percentage of ventricle emptied at systole

    - usually ~60 %  (70 ml/120 ml)

    - lower ejection fraction means blood is pooling in heart and may clot.

    - also, heart not effectively pumping

    • SV (edv - esv)
    • _____________    =  %

  9. Define cardiac output
    - quantity of blood pumped into aorta each minute

    SV x HR = Cardiac Output
  10. Frank-Starling mechanism: the more the ventricles fill,
    the more forcefully they contract.

    The more blood that returns to the heart, the greater force it can use to pump blood out.
  11. Structure of Blood Vessel:

    The opening of the vessel is the
  12. Structure of Blood Vessel:

    Tunica interna (endothelium) forms the
    innermost layer and consists of a simple layer of squamous epithelium connected to a basement membrane.
  13. Structure of Blood Vessel:

    Tunica media (smooth muscle) is a
    muscular and connective tissue layer that displays the greatest variation among the different vessels.
  14. Structure of Blood Vessel:

    Tunica externa (connective tissue) is the
    outer covering of blood vessels made up of elastic and collagen fibers.
  15. Tunica externa contains numerous sympathetic nerves which control the diameter of the vessel, and tiny blood vessels called the
    vasa vasorum; which are especially present in large vessels like the aorta.
  16. Blood vessels (from center out):
    • lumen
    • endothelium
    • elastic tissue
    • smooth muscle
    • elastic connective tissue
  17. Describe artery
    - smooth muscle layer thickened

    - lumen diameter can change depending on muscle tone
  18. Describe Veins
    - thin or absent smooth muscle layer

    - lumen diameter does not change

    - valves prevent backflow
  19. Sizes of Blood Vessels:

    Elastic arteries
    - Large diameter and thin walls. Able to withstand high pressure.
  20. Sizes of Blood Vessels:

    Muscular or distributing arteries
    - Medium size. Contain more smooth muscle and fewer elastic fibers
  21. Sizes of Blood Vessels:

    - tiny arteries. Adjust rate of blood flow to the capillaries
  22. Sizes of Blood Vessels:

    Site of nutrient and gas exchange
  23. Sizes of Blood Vessels:

    Small veins
  24. Describe Varicose veins
    - valves become incompetent and "floppy"

    - backflow of blood results

    - pooling occurs: venous stasis

    - increased risk of clots forming
  25. Capillaries join
    - arterioles (smallest arteries) and venules (smallest veins)

    - occur as capillary beds of interconnected vessels

    - small enough that RBCs must fold to pass through
  26. Precapillary sphincters are
    smooth muscle cuffs that regulate flow of blood through capillary bed
  27. There are approximately 20 billion ________ in the body that form ______ around the individual cells. It is through the walls of the capillaries that the exchange of _______, _______, and ________ products occurs.
    capillaries; beds; nutrients, oxygen, and waste
  28. Describe Continuous capillaries
    Endothelial cells form a continuous tube, interrupted only by small intercellular clefs.

    form tile floor

    passage of substances by pinocytosis
  29. Describe Fenestrated capillaries
    much more porous. They are found in the kidneys, villi of the small intestine, and endocrine glands.
  30. Describe Sinusoids
    have open spaces between cells and the basement membrane to facilitate easy passage of substances. Sinusoids are found in the liver and the spleen.