2.4 Circulatory system

  1. What are the 3 organs of the circulatory system


  2. Circulatory system are dynamic structures that can...(3)


  3. What do the organs of circulatory system transport? (3)


    -waste products
  4. Systematic circulation ) what is the route of blood flow?
    Arteries to capillaries to veins
  5. What are capillary beds?
    Site of product interchange where O2, CO2, and nutrients/waste exchanged
  6. Where does the interstitial fluid returned by lymphatic system drained into?
    Large veins close to the heart
  7. Blood vessel structure) what are the 3 walls called?
  8. Blood vessel structure) how many layers are there?
  9. Blood vessel structure) inner layer
    Tunica intima
  10. Blood vessel structure) middle layer
    Tunica media
  11. Blood vessel structure) outer layer
    Tunica adventitia
  12. Blood vessel structure) Inner layer: description
    • Intimate contact with blood in the lumen
    • *its the innermost layer that's why
  13. Blood vessel structure) Inner layer: what does it contain?
    endolethium cells (smooth epithelial cells lining) that nourishes the Luminal lining through blood
  14. Blood vessel structure) Inner layer: in vessels greater than 1 mm, a
    subendothelial layer containing a basement is present
  15. Blood vessel structure) Tunica media : what does it contain
    It contains smooth muscle for vasoconstriction & vasodilator which controls blood pressure
  16. Blood vessel structure) Adventitia : composed of
    Mainly loosely woven collagen fibers that protect and reinforce vessel
  17. Blood vessel structure) Adventitia : in larger veins, a network of elastic fibers is also present which
    Allows for stretch & rebound of venous walls
  18. Located in outer layers: nervi vascular
    Vasomotor nerves of ANS located in outer layers for innervation of smooth muscle in tunica media
  19. Located in outer layers: vasa vasorum
    • It is a blood supply network that nourishes outer layer of larger blood vessels of the body
    • *red and blue small dots in schematic
  20. Arteries ) main function
    Convey blood away from the heart
  21. Arteries ) characteristics (5)
    -smaller lumen than veins of same name

    -thicker walls than veins of same name

    -resist collapse due to thick walls

    -tunics are more distinct than in veins

    -tunica media is the thickest of the 3
  22. Arteries ) can be classified as 3 things


  23. Arteries ) Classified: large or elastic
    They conduct blood away from the heart
  24. Arteries ) Classified: medium or muscular
    distribute blood to different body regions
  25. Arteries ) Classified: small or arterioles
    Small diameter creates resistance slowing down the flow of the blood for exchange of products within capillaries
  26. Arteries ) Large or Elastic Arteries : 3 characteristics
    -large lumen

    -3 distinct tunics

    -very elastic walls
  27. Arteries ) Large or Elastic Arteries : what does its elastic walls allow it to do
    To stretch with ventrical contraction & then recoil which allows it to maintain blood pressure between contractions
  28. Arteries ) Large or Elastic Arteries : major function
    conduct blood away from heart to conducting arteries
  29. Arteries ) Large or Elastic Arteries : where can they be found (3)

    -pulmonary trunk

    -major arteries from aorta
  30. Arteries ) medium or muscular arteries : characteristics (3)
    -smaller lumen

    -3 tunics with media being the largest

    • -lots of smooth muscle
    • *bc media is the largest
  31. Arteries ) medium or muscular arteries : major function
    • distirubte blood to organs or working muscles
    • *thus AKA distributing arteries
  32. Arteries ) medium or muscular arteries : regulates blood supply by
    Contracting and relaxing of smooth muscle (vasoconstriction/dilation) under the influenced of nervi vasculari
  33. Arteries ) medium or muscular arteries : what is significant about how thick its media is?
    media is thicker than elastic arteries also thus contains more smooth muscle
  34. Arteries ) small arteries and Arterioles : where can 3 tunics be found in?
    Only in the largest of small arteries
  35. Arteries ) small arteries and Arterioles : what can only be found in smallest of small arteries?
    Only endothelium and smooth muscle
  36. Arteries ) small arteries and Arterials: small arteries contain...
    3-8 layers of smooth muscle
  37. Arteries ) small arteries and Arterioles : arterioles have
    1-2 layers of smooth muscle
  38. Arteries ) small arteries and Arterioles : AKA
    Resistance vessels
  39. Arteries ) small arteries and Arterioles : major function
    • Regulate the distribution of blood to tissues by vasoconstriction and vasodilation
    • *ANS control
  40. Arteries ) small arteries and Arterioles : which tissue do they have the most of?
    Smooth muscle makes the bulk of wall
  41. Capillaries ) characteristics (3)
    -smaller blood vessels

    -single layer of endothelial cells

    -3 types of of capillaries
  42. What are the 3 types of capillaries ?


  43. Continuous Capillaries : Characteristics (3)
    -located in most tissues

    -endothelial cells linked by tight junctions which provides an uninterrupted lining of the vessel

    -least permeable most common
  44. Continuous Capillaries : how are products exchanged?
    Thru cleft between junctions & cytoplasm of endothelial cells
  45. Which of the 3 capillaries is the most common?
    Continuous capillaries
  46. Where are continuous capillaries found in?
    Skin, muscle, lung
  47. Fenestrated capillaries: what does fenestra mean?
    Little window
  48. Fenestra capillaries ) Porous
    endothelial cells contain little oval pores in cell membrane that allow for easy formation of filtrate or absorption of fluids from intercellular environment
  49. Fenestra capillaries ) what do they deliver? (3)
    Hormones, collect nutrients, and form urine
  50. Fenestra capillaries ) where are these located?
    • In places where products must be easily emptied into the blood
    • *endocrine delivering hormones
  51. Discontinuous capillaries) leaky capillaries
    allow large molecules and blood cells to pass through
  52. Discontinuous capillaries ) basement membrane
    It has an incomplete membrane
  53. Discontinuous capillaries ) what does it large irregular lumens do?
    Slows the speed of flow
  54. Discontinuous capillaries ) where are these found?
    In areas requiring filtration of large products & cells across the capillaries
  55. What is capillary bed?
    Network of capillaries formed by precapillary arterioles & post capillary venue
  56. Capillary bed: sequence (2)
    Each individual capillary branching from metaarterioles contains a cuff of smooth muscle, precapillary sphincter. When precapillary sphincter opened, they allow rich O2 blood to flow into true capillaries bed for product exchange between microcirculation & interstitial environment.

    -low O2 blood received by post capillary venue by way of thoroughfare channel
  57. Ateriovenous shunt) process
    Capillary beds are bypassed altogether by atriovenous shunt. Arterial blood will shunt directly into venous system for delivery elsewhere in body

    Ex) exercise under sympathetic control opens capillary bed in working muscle. At the same time, this shunt is active in gut b/c they only work under parasympathetic
  58. Veins) main function
    Return blood towards the heart
  59. Veins) characteristics (6)
    -larger lumens than arteries of same name

    -thinner walls than same arteries

    -tunics are less distinct

    -easily collapsed

    -tunica adventitia is the thickest layer

    • -contain valves
    • *one way process
  60. Veins) 3 ways they are classified
    -small veins

    -medium veins

    -large veins
  61. Veins) small veins: (4) composed
    -composed of leaky endothelium

    • -thin tunica media
    • *little smooth muscle

    -thin adventitia

    -do not contain valves
  62. Veins) small veins: which are the smallest?
    Post capillary venules
  63. Veins) small veins: without elastic tissue,
    They convey blood to veins
  64. Veins) medium veins: composition (3)
    -thickest layer is the adventitia

    -contain valves to facilitate correct flow of blood back to heart

    -named veins of the viscera and distal extremities often accompany artery of same name
  65. Veins) medium veins: where can these be found?
  66. Veins) larger veins: (2) composition
    -thickest layer is the adventitia

    -central body veins do not contain valves
  67. Calf Pump)
    Pumps blood from the lower extremity upwards
  68. Calf Pump) What's another organthat does this also
    • Diaphragm
    • *that's why when people who suffer from venous insufficiency are often told to take walks & breathing techniques
  69. Veins are
    Capacitance vessels
  70. Veins are capacitance vessels AKA
    Blood reservoirs
  71. What percent of blood volume is in veins
  72. How can veins hold so much blood?
    Possible bc they ae able to stretch & hold under low pressure situations
  73. What are varicose veins
    Veins that have become diluted due to incompetent valves so it allows back flow of blood, pooling.
  74. Factors that contribute to varicose veins (4)


    -prolonged standing

  75. What are venous sinuses?
    Large vessels that collect blood
  76. What are the 2 venous sinuses
    -coronary sinus

    -dural sinus
  77. Anastomoses)
    Coming together
  78. Anastomoses) arterial: (2)
    -alternate channels to insure blood flow for vital organs

    -more than one supply
  79. Anastomoses) veins: (3)
    Have numerous anastomoses to facilitate blood return

    -numerous between superficial and deep veins

    -blood can easily be recruited around damage areas
  80. 2 things systematic circulation does
    -distributes O2

    -retrieves waste products CO2
Card Set
2.4 Circulatory system
Circulatory system