Chapter 10: Cardiovascular Responses to Physiological Stress

Question 1

How does inspiration affect the cardiovascular system (3 receptor systems to list)?

Answer 1

(1) increaed venous return and decreased pulmonary vascular resistance –> increased CO and BP –> increaes inhibitory firing of baroreceptors –> drop in HR

(2) stretch of intrathoracic low-pressure cardiopulmonary baroreceptors –> drop in HR

(3) stretched lung mechanoreceptors –> opposite effect –> inhibits vagal tone –> increasing HR

Question 2

Describe how positive pressure ventilation affects the cardiovascular system.

Answer 2

decreased venous return
increased RV afterload

Question 3

How does the cardiovascular system change after birth?

Answer 3

during gestation –> pulmonary vascular system high resistance low compliance; systemic circulation due to placenta is low resistance, high compliance

taking first breath –> abruptly decreases pulmonary vascular resistance
removal from placenta –> increases systemic resistance

instead of venous blood flowing through the foramen ovale (from RA to LA) and ductus arteriosus (PA to aorta), blood flows into the pulmonary vasculature and these openings will continue to close