Control of Blood Volume handout 1 per page

• To describe the hormonal mechanisms involved in long-term regulation of blood pressure (i.e. vasopressin, the renin-angiotensin-aldosterone system and atrial-natriuretic peptide) and how their involvement is regulated.

• To predict the short-term, intermediate and long-term physiological changes in the cardiovascular system in response to increased/decreased plasma volume, or changes in plasma osmolarity.

Plasma osmolarity = a measure of the different solutes in plasma

short term changes …

there are 5 main things that will change when blood volume loss occurs

immediately after Haemorrhage

= decrease in Stroke volume (volume pushed out from Left ventricle)

= no change in HR

= decrease in CO (litres of blood/p/min leaving the heart)

= no change in TPR

= decrease in MABP

after a short period of time after haemorrhage (still very much preliminary NOT long term)

SV = inc slightly (due to contraction of vasculature PUSHING blood towards the heart coupled with an increase in contractility of the heart)