cardiovascular control mechanisms

Question 1

feedback for small amount of blood loss (haemorrhage)

Answer 1

haemmorrhage → decrease blood volume → decrease venous pressure → decrease venous return → decrease atrial pressure → decrease end diastolic volume and stroke volume → decrease cardiac output and blood pressure → BARORECEPTOR feedback → increase SNS discharge to veins → increase venous constriction → increase venous pressure

Question 2

cardiac feedback for large amount of blood loss to increase cardiac output to increase arterial blood pressure

Answer 2

haemorrhage → less stroke volume → less baroreceptor firing → reflexes: decrease in PNS discharge to heart, increase in SNS discharge to heart → increase contractility → increase stroke volume → increase cardiac output

Question 3

venous feedback for large amount of blood loss to increase cardiac output and contractility to increase arterial blood pressure

Answer 3

haemorrhage → less stroke volume → less baroreceptor firing → reflexes: increase SNS discharge to veins → increase in venous tone → increase in venous pressure → increase venous return → increase end-diastolic volume → increase cardiac output and contractility

Question 4

arterial feedback for large amount of blood loss to increase total peripheral resistance to increase arterial blood pressure

Answer 4

haemorrhage → less stroke volume → less baroreceptor firing → reflexes: increase SNS discharge to arterioles → increase arteriolar vasoconstriction → increase total peripheral resistance