Chapter 21 Blood Vessels

  1. The walls of all blood vessels except the smallest consist of three layers
    • Tunica interna
    • Tunica media
    • Tunica externa
  2. The ____________ reduces friction between the vessel walls and blood
    tunica interna
  3. The __________ controls vasoconstriction and vvasodilation of the vessel
    tunica media
  4. THe __________ protects, reinforces, and anchors the vessel to surrounding structures
    tunica externa
  5. Elastic, or ________, arteries contain large amounts of elastin which enables these vessels to withstand and smooth out pressure fluctuations due to heart action
  6. Muscular, or __________, arteries deliver blood to specific body organs, and have the greatest proportion of tunica media of all vessels, making them more active in vasoconstriction
  7. ____________ are the smallest arteries and regulate blood flow into capillary beds through vasoconstriction and vasodilation
  8. ___________ are the smallest vessels and allow for exchange between the blood and interstitial fluid
  9. _____________ capillaries are most common and allow passage of fluids and small solutes
  10. ___________ capillaries are leaky capillaries that allow large molecules to pass between the blood and surrounding tissues
  11. ________________ capillaries are more permeable to fluids and solutes than continuous capillaries
  12. ___________ are microcirculatory networks consisting of a vascular shunt and true capillaries, which function as the exchange vessels
    capillary beds
  13. A cuff of smooth muscles, called a _________________, surrounds each capillary at the ____________ and acts as a valve to regulate blood flow into the capillary
    • precapillary sphincter
    • metarteriole
  14. __________ are formed where capillaries converge and allow fluid and white blood cells to move easily between the blood and tissues
  15. Venules join to form
  16. _____________ are relatively thin-walled vessels with large lumens containing about 65% of the total blood volume
  17. ______________ form where vascular channels unite, allowing blood to be supplied to and drained from an area even in one channel is blocked
    vascular anastomoses
  18. ___________ is the volume of blood flowing through a vessel, organ, or the entire circulation in a given period, and may be expressed as ml/min
    blood flow
  19. ___________ is the force per unit area exerted by the blood against a vessel wall, and is expressed in millimeters of mercury (mm Hg).
    Blood pressure
  20. ____________ is a measure of the friction between blood and the vessel wall, and arises from three sources:

    • Blood viscosity
    • Blood vessel length
    • Blood vessel diameter
  21. If blood pressure increases, blood flow _________; if peripheral resistance increases, blood flow ________
    • increases
    • decreases
  22. Peripheral resistance is the most important factor influencing local blood flow, because...
    Vasoconstriction or vasodilation can dramatically alter local blood flow, while systemic blood pressure remains unchanged
  23. pressure results when blood flow is
    opposed by resistance
  24. Systemic blood pressure is highest in the ______, and declines throughout the pathway until it reaches 0 mmHg in the _______

    right atrium
  25. ___________ reflects how much the arteries close to the heart can be stretched (compliance, or distensibility), and the volume forced into them at a given time
    Arterial blood pressure
  26. When the __________ contracts, blood if forced into the aorta, producing a peak in pressure called _____________ (120 mm Hg)
    left ventricle 

    systolic pressure
  27. ___________ occurs when blood is prevented from flowing back into the ventricles by the closed semilunar valve, and the aorta recoils (70-80 mm Hg)
    Diastolic pressure
  28. THe difference between diastolic and systolic pressure is called the
    pulse pressure
  29. The mean atrial pressure (MAP) represents the
    pressure that propels blood to the tissues
  30. Capillary blood pressure is low, ranging from _______ mm Hg, which protest the capillaries from rupture, but is still adequate to ensure exchange between blood and tissues
  31. Venous blood pressure changes very little during the _________, and is low, reflection cumulative effects of peripheral resistance
    cardiac cycle
  32. Blood pressure varies directly with changes in blood volume and cardiac output, which are dertmined primarily by
    venous return and neural and hormonal controls
  33. __________________________ alter blood distribution to meet specific tissue demands, and maintain adequate MAP by altering blood vessels diameter
    short-term neural controls of peripheral resistance
  34. ___________________ is a cluster of sympathetic neurons in the medulla that controls changes in the diameter of blood vessels
    the vasomotor center
  35. ____________ detect stretch and send impulse to the vasomotor center, inhibiting its activity and promoting vasodilation of arterioles and veins
  36. ______________ detect a rise in carbon dioxide levels of the body, and stimulate the cardioacceletory and vasomotor centers, which increase cardiac output and vasoconstriction
  37. The _______ and __________ can modify arterial pressure by signaling the medullary centers
    • cortex
    • hypothalamus
  38. Chemical controls influence blood pressure by
    acting on vascular smooth muscle or the vasomotor center
  39. ___________ and ___________ promote an increase in cardiac output and generalized vasoconstriction
    Norepinephrine and epinephrine
  40. ________________ acts as a vasodilator and an antagonist to aldosterone, resulting in a drop in blood volume
    Atrial natriuretic peptide
  41. ______________ promotes vasoconstriction and water conservation by the kidneys, resulting in an increase in blood volume
    Antidiuretic hormone
  42. _____________ acts as a vasoconstrictor, as well as promoting the release of aldosterone and antidiuretic hormone
    Angiotensin II
  43. _______________ promote vasoconstrictions, and are released in response to low blood flow
    Endothelium-derived factors
  44. _____________________ counteracts an increase in blood pressure by altering blood volume, which increase the rate of kidney filtration
    The direct renal mechanism
  45. The __________________ is the renin-angiotensin mechanism, which counteracts a decline in arterial blood pressure by causing systemic vasoconstriction
    indirect renal mechanism
  46. Monitoring circulatory efficiency is accomplished by measuring _______________; these values together with respiratory rate and body temperature are called
    pulse and blood pressure

    vital signs
  47. A ________ is generated by the alternating stretch and recoil of elastic arteries during each cardiac cycle
  48. Systemic blood pressure is measured indirectly using the ____________ method, which relies on the uses of a blood pressure cuff to alternately stop and reopen blood flow into the brachial artery of the arm
    ascultatory method
  49. ________ = low bp

    _________ = high bp

    transient or persistent hypertension
  50. ___________ is the slow intermittent flow of blood throughout he capillaries. It reflects the action of the ______________ in response to local _______________
    • Vasomotion
    • precapillary sphincters
    • autoregulatory controles
  51. Capillary exchange of nutrients, gases, and metabolic wastes occurs between the blood and interstitial space through ________
  52. ________________ is the force of a fluid against a membrane
    hydrostatic pressure (HP)
  53. ________________, the force opposing hydrostatic pressure, is created by the presence of large, nondiffusible molecules that are prevented from moving through the capillary membrane
    Colloid osmotic pressure (OP)
  54. Fluids will ________ the capillaries if net HP exceeds net OP, but fluids will ____________ the capillaries if net OP exceeds net HP
    • leave
    • enter
Card Set
Chapter 21 Blood Vessels