Cardio - Lec 14: The Baroreflex

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Across
  1. 3. true or false? There are more alpha receptors than beta receptors in cardiac and skeletal muscle vascular beds.
  2. 6. If pressure remains elevated, firing rate of high pressure receptors decreases to a new ‘____ ______’.
  3. 7. high pressure receptors in the aortic arch and carotid sinuses respond ________ to changes in blood pressure.
  4. 10. the medullary cardiovascular centre has both a ______ region (normal tonic symp stmulation to blood vessels and heart) and a DEPRESSOR region (stimulated by baroreceptor firing – inhibits sympathetic discharge from _______ region).
  5. 11. cardiopulmonary low pressure stretch receptors respond to absolute pressure, not pressure _________. Respond to changes in blood volume in heart and great veins (affects venous return).
  6. 14. the baroreflex is a ___________ feedback loop.
  7. 15. increased sympathetic drive in cases of low blood volume  sympathetic stimulation of the _____________ apparatus in the kidney  activation of the RAAS system  conservation of water and salt. Also increases ADH release.
  8. 19. ________ arch high pressure baroreceptors respond to pulsatile flow, whereas carotid sinuses baroreceptors respond to non pulsatile stretch.
  9. 20. the receptors for parasympathetic stimulation at effector organs are __________ receptors (bind to acetylcholine)
  10. 22. the sympathetic NS not only increases stroke volume directly by increasing contractility, but also indirectly by increasing EDV (preload) due to increased ________ ________ (by venoconstriction of veins) .
  11. 23. sympathetic nerves arise from the _______ and lumbar regions of the spinal column, whereas parasympathetic arise from cervical and sacral regions.
  12. 25. the pressor region of the medullary cardiovascular centre provides normal sympathetic stimulation to blood vessels and heart. Baseline ____ of blood vessels.
  13. 26. decreased stretch of cardiopulmonary baroreceptors (low pressure receptors) indicates decreased venous return. Nerve conveys this to medullary cardiovascular centre  increases __________ drive to heart and blood vessels, decreases PS drive to heart.
  14. 28. when these adrenoceptors are stimulated  relaxation of vessels due to adenylate cyclase activation and cAMP production. High propotion of these receptors in cardiac and skeletal muscle vasculature.
Down
  1. 1. the ____________________ tract has a high proportion of alpha receptors cf beta. Means that when sympathetic stimulation increases, these vessels constrict. Divert blood away. This is because of activation of phospholipase C and IP3 production  calcium release from SR  contraction.
  2. 2. the ratio of _____ to beta receptors varies in different vascular beds.
  3. 4. sympathetic supply to the blood vessels includes : arterioles (increases TPR at alpha receptors), and at ______ increases venous return.
  4. 5. ______________ receptors aka low pressure receptors. Stretch receptors in atria, great veins/artial junction, ventricles and pulmonary veins.
  5. 8. cardiopulmonary receptors are found in the heart and pulmonary veins, also known as ____ pressure receptors. They respond to ABSOLUTE pressure, not changes in pressure.
  6. 9. sympathetic stimulation of the myocardium increases ________________ (force generated for a given length of muscle fibre) by increasing intracellular Ca during contraction. (increases stroke volume). Also increases heart rate at SA node (therefore increases CO = SV x HR)
  7. 12. afferent pathways for the baroreceptor reflex (heading TO the brain) are via cranial nerve 9 (glossophayngeal) and CN 10 (_____ nerve)
  8. 13. parasympathetic supply to the heart contacts only the _____ ______ node. (decreases heart rate). Sympathetic contacts this node, as well as the myocardium.
  9. 16. sympathetic supply to the heart contacts the sino artial node (increase rate of contraction, but also contacts the ___________ (increased force of contraction).
  10. 17. noradrenaline is the neurotransmitter of the sympathetic nervous system (at the effector organ), it binds to alpha and beta ________________.
  11. 18. this region of the medullary cardiovascular centre is stimulated by baroreceptor firing (when there is increased stretch)  suppresses the sympathetic drive coming from the pressor region.
  12. 21. control of the systemic _______ pressure is the most important aspect of controlling cardiovascular function. Heart rate is NOT monitored. This control is the baroreflex.
  13. 24. ____ pressure receptors (arterial receptors) are stretch receptors located in the carotid sinuses and aortic arch. Respond RAPIDLY (within one heart beat).
  14. 27. there is sympathetic supply to the ______ and blood vessels, but parasympathetic only to ______ (not blood vessels).