CVS homeostasis

Question 1

what are both CO & VR dependent on

Answer 1

MAP

- overtime, CO must = VR

Question 2

various distribution of CO

Answer 2

• function of circulation = distribute blood to peripheral tissues
• Q to organs altered by modulating vessel resistance
• Q to liver, kidneys, brain stays constant w/ change in CO; Q to skin, muscle increases

Question 3

RAAS (leading to increased BP)

Answer 3

renin released from JG cells in response to:

• sympathetic stimulation
• decreased P in afferent arterioles
• reduced Na at macula densa

angiotensinogen -> angiotensin 1 (by renin) -> angiotensin 2 (by ACE)

effects of angiotensin 2:

• increased sympathetic
• increased aldosterone
• increased ADH
• vasoconstriction

Question 4

natriuretic peptides (leading to decreased BP)

Answer 4

• synthesised by heart, brain, other organs
• cardiac distention -> ANP release (atria) & BNP release (ventricles)
• effects: vasodilation, decreased renin (antagonist RAAS)

Question 5

what causes an increase in CO

Answer 5

increases w/ MRAP -> increased filling of ventricle (preload) -> increase CO

inotropic state increased gives higher gradient & higher plateau = give increased VR & CO