A&P Chapter 18

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  1. What is a detector?
    sensor or receptor
  2. The afferent neural pathway travels from _____ to ______
    detector to CNS
  3. What is the coordinating center?
    Receives and processes signal from detector then generates an appropriate response
  4. The efferent neural pathway travels from ______ to _______
    coordinating center to effectors
  5. What are effectors
    carry out the response
  6. What are two types of detectors/receptors for controlling MAP? What do they sense?
    • Baroreceptors - stretch, vascular wall distention
    • Chemoreceptors - changes in blood o2, co2, pH
  7. What 3 places are control centers for controlling MAP located?
    • 1) Medulla
    • 2) Cerebral Cortex
    • 3) Hypothalamus
  8. What are 3 types of effector cells for controlling MAP?
    • 1) Pacemaker cells of the heart
    • 2) Vascular smooth muscle cells
    • 3) Adrenal Medulla
  9. What are the 3 components of the vasomotor center?
    • 1) vasoconstrictor
    • 2) vasodilator
    • 3) sensory
  10. What is a major function of the vasoconstrictor portion of the vmc? how does it accomplish this?
    vasomotor tone - through continuous signaling to sympathetic vasoconstrictor nerve fibers
  11. What is the primary neurotransmitter involved in vasomotor tone?
  12. How does the vasodilator area in the VMC work? What area controls this?
    it inhibits vasoconstrictor activity to cause vasodilation. Controlled by the anterior hypothalamus.
  13. What does the cardioaccelerator area of the VMC control?
    heart rate and contractility
  14. The lateral and medial area of the vmc have different functions. What are these? How is this accomplished?
    Lateral - transmits excitatory signals via sympathetic fibers to the heart to increase rate and contractility (NE -->beta 1 on SA node)

    Medial - transmits inhibitory signals via vagus nerve to decrease heart rate and contractility (ach --> m2)
  15. Where is the sensory portion of the vmc? What nerves does it receive input from? What are its effectors?
    • 1) Tractus Solitarus in the posterior lateral portions of the medulla and lower pons
    • 2) vagus and glossopharyngeal
    • 3) vasoconstrictor and vasodilator areas
  16. Where are baroreceptors located?
    the carotid sinus and the walls of the aortic arch
  17. Describe the path of the baroreceptors from the carotid sinus to the medulla.
    carotid sinus --> Hering's nerve --> glossopharyngeal nerve --> nucleus tractus solitarius of the medulla
  18. Describe the path from the aortic arch to the medulla.
    aortic arch --> vagus nerve --> nucleus tractus solitarius of the medulla
  19. What range of mean arterial pressure do the baroreceptors work? Where is it the strongest?
    • 80-160 
    • 100
  20. What happens when signals arrive in the Nucleus tractus solitarius?
    • 1) vasoconstrictor area in the medulla is inhibited
    • 2) vagal parasympathetic center is excited
  21. Where are chemoreceptors located?
    • 1) carotid bodies near the carotid bifurcation
    • 2) aortic arch
  22. When are the chemoreceptors activated? what do they do?
    • 1) in response to decreased o2, pH or increased co2 when the MAP is < 80
    • 2) they increase SNS activity
  23. Describe the CNS ischemic response
    cerebral ischemia --> increased CO2 --> vasomotor center --> increased sympathetic activity --> incrusted arterial pressure
  24. At what blood pressure in the CNS ischemic Response active?
    < 60
  25. What is Cushing reaction?
    A type of CNS ischemic response when the pressure in the CSF = SBP which causes arteries in brain to compress so that blood supply is cut off --> CNS ischemic response to increase SBP above CSF pressure
  26. What happens in the atrial and pulmonary artery reflexes?
    low pressure receptors sense an increase in pressure/blood volume --> lowering arterial pressure

    Also, decreased release of ADH, increased GFR, decreased Na reabsorption --> lowering of ECFV
  27. What is the bainbridge reflex?
    increase in atrial pressure --> vagus nerve --> VMC --> increased HR/contractility
  28. What is a normal respiratory wave? What does it mean if it increases?
    4-6 mmHg, if increased, it indicates hypovolemia
Card Set
A&P Chapter 18
Acute Regulation of Arterial Pressure
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