Two students, Vineet and Kamlesh were asked to demonstrate in dogs the role of sinus nerve in hypo-volemic shock. Vineet severed the sinus nerve when the mean blood pressure (MBP) was 85 mm Hg and Kamlesh cut the sinus nerve when the mean blood pressure was 60 mm Hg. On cutting the sinus nerve
Correct Answer: Both recorded an increase in MBP
Description: C i.e. Both recorded an increase in MBPWhen carotid sinus nerve is sectionedLoss of inhibitory impulse from carotid sinus nerve --> Medullary vasomotor center activated -* 1' sympathetic discharge -> Vasoconstriction ( TBP), IHR & T CO.The baroreceptors do not fire when mean BP is below 30 mm Hg (fire maximally at mean BP of 150 mm Hg) Carotid sinus nerve and vagal fibres from aoic arch commonly called Buffer nerves.* Severing only carotid sinus nerve will not lead to decrease in BP because aoic arch baroreceptors are still functional. If both are severed the BP rise to more than 200-300 mm Hg.
Category:
Physiology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now