Important cardiac reflexes frequently asked in PGMEE

MCQs NEET PG MCQ
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Important cardiac reflexes frequently asked in PGMEE

  1. Bainbridge reflex or atrial reflex
     This reflex is activated whenever there is increase in venous return to the heart
     The receptors for this reflex are located in both right and left atria
     Afferent of this reflex travel through vagus nerve and the efferent mainly travel through
    sympathetic nerves that increase heart rate (Tachycardia) and strength of cardiac
    contraction
  2. Bezold-Jarisch reflex
     Intracardiac injections of chemicals like serotonin, veratridine, capsaicin,
    phenyldiguanide activates this reflex
     Afferents for this reflex travel through unmyelinated vagal C fiber endings
     The reflex responses are,
     Apnea followed by rapid breathing
     Hypotension
     Bradycardia
     Clinical importance of Bezold-Jarisch reflex
     This reflex is responsible for sinus bradycardia seen during myocardial infarction
     This reflex is one of the cause for profound bradycardia and circulatory collapse
    after spinal anesthesia
  3. Cushing reflex
     Is a type of CNS Ischemic Response
     Cushing reflex is characterized by increase in BP and reflex decrease in heart rate
    (bradycardia)
     It is mainly seen in conditions causing increase in intracranial pressure
  4. The Oculocardiac reflex
     Also called as Aschner phenomenon or Aschner-Dagnini reflex
     This reflex is activated during traction applied to extraocular muscles and/or
    compression of the eyeball
     Afferents for this reflex travel through long and short ciliary nerves to the trigeminal
    nucleus
     Efferent travel through vagus nerve to the heart
     Oculocardiac reflex is characterized by profound bradycardia
  5. Brewer-Luckhardt reflex
     Stimulation of anal canal or cervix leads to vagal stimulation that causes,
     Bradycardia
     Laryngospasm
     Bronchospasm
  6. Marey’s Law
     This law states that heart rate and BP are inversely related
     This law explains reflex bradycardia associated with increase in BP