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Physiology II
Cardiovascular Physiology
Peripheral Circulation Q & A

How do you do with these questions?

Questions Answers
1.  Where is resistance controlled? Smooth muscle arterioles
2. What organs always get blood flow exactly matching metabolic need? Heart & Brain
3. What two issues are involved in regulating blood flow to tissues? Local control & central control of pressure gradient
4. What two cell types are responsible for Local control of MSAP? (sandwich) endothelium & parenchyml (tissue)
5. What constitutes the "sandwich" for central control? SNS and blood plasma
6. Name two general sources of Ca++ Extracellular via Ca++ channels used by vascular smooth muscle to contract. Intracellular (SR & mitochondria)
7. What second messenger system is involved in mobilizing Ca++ from sources? IP3-DAP (IP3 SR/mitochondria, & DAP for Ca++ channels)
8. What does Calcium bind with in smooth muscle? In cardiac muscle? Calmodium, to form Ca-Calmodium Complex Troponin C on Actin filament
9. What does CCC do? Activates Myosin Kinase Light Chain so that crossbridges can form.
10. Stimulation of what receptors produces vascular smooth muscle contraction? Alpha one
11. What second messenger system do most vasoconstrictors use? How does it work? IP3-DAP, to mobilize Ca++
12. What is the basic underlying event in muscle relaxation? Intracellular (cytoplasmic) Ca++ levels drop
13. Stimulation of what receptors produces vascular relaxation? Beta
14. What is the second messenger system involved in muscle relaxation? CAMP turned on
15. Name basic three types of receptors, (for adrenergic system) the second messenger each uses, and what it does to calcium. Alpha one (turn on IP3-DAP to mobilize Ca++). Alpha two (turn off cAMP, allows Ca++ to hang around). Beta (turn on cAMP, which removes Ca++ from cytoplasm
16. What does Beta one receptor stimulation do in the Heart? (in contrast to other muscles) Turning on cAMP both allows calcium in, creating stronger contraction, and removes calcium, shortening systole (as compared to the long systole of smooth muscle). Smooth muscle has B2 effect of removing Ca++ & causing relaxation.
17. Name two primary vasoconstrictors, locally produced & acting. Endothelin & Thromboxane (& serotonin)
18. What secondary messenger system do most vasoconstrictors use? Turn on IP3-DAP to mobilize Ca++
19. What is the stimulus for endothelin? Increased wall pressure in the vessel
20. Is endothelin stored? No
21. What happens to the vessel radius, due to effect of endothelin, in the presence of chronically elevated MSAP? Radius decreases due to remodeling
22. Fill in the Blank with (+) or (-) :
Poor Anastomosis = ____ chronic turbulent flow = ____ velocity = ____ pressure = ____ endothelin = ____ wall thickness = ____ vessel radius
23. What is the "myogenic response"? tissue constricts when stretched
24. What is the stimulus for Thromboxane production? Platelet injury; production dependent on cyclooxygenase which ASA inhibits
25. Name two actions of Thromboxane Vasocontriction & clot formation
26. What second messenger system is most often involved in vasodilators? Turning on cAMP, to remove Ca++
27. List five "links" between metabolism in tissue and local vasodilation. Low pO2, high pCO2, H+, K+, Adenosine
28a. Areas of inflamation produce what local vasodilator? Histamine
28b.  What receptor does this dilator act on? H2 on smooth muscle cells
28c.  What second messenger system? Cyclic AMP
29. What do Adenosine & Histamine have in common? stimulate the endothelium to produce NO (Adenosine on A1, Histamine via H1)
30a. What effect does increased velocity have on the endothelium? Creates shear deformation
30b.  What does this stimulate? NO
31. What (atypical) second messenger system does nitric oxide use? Cyclic GMP, but it does the same thing to Ca++ as turning on cAMP (removes it)
32. What is the "really neat thing" about nitric oxide and vasodilation? Retrograde transmission of the dilation from Pre-capillary sphinters on up to larger vessels.
33. What is a local vasodilator that is cyclo-oxygenase dependent? prostacyclin (PGI2)
34. Name four centrally stimulated vaso-constrictors Epi, Angiotension II, Dopamine, Vasopressin
35. What two ways do Angiotensin II and Vasopressin work to correct low MSAP? Acutely, they cause vasoconstriction & increase TPR. Long term, they cause Na+/H20 retention
36. Does Angiotension II cause remodeling of vessels or heart? Yes, Both.
37. Does Vasopressin cause Na+/H20 retention? Yes (ADH)
38. Does ADH cause increase TPR? Yes (Vasopressin)
True/False
39. Local control of Blood Flow occurs in those tissues where flow=metabolsim, and refers to heart/kidney False, (heart/brain would make it true)
40. Flow depends on special homestatic needs, such as during exercise, for skeletal muscle True
41. The liver will always receive at least itís minimum flow need. False, it falls subject to SNS and flow may fall below requirements.

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