Co-ordinated CV Responses 2 Flashcards
What is a normal volume of blood for a 70kg man?
It is around 77ml/Kg
= 5.4L
What is stress relaxation?
When a blood vessel is stretched it passively over time adjusts to decrease its pressure.
What happens in haemorrhage linked to stretch relaxation?
What happens in this process?
How long does this process take to occur?
Reverse stretch relaxation
Veins contract around the reduced blood volume, maintaining pressure and preserving BP as best they can
Begins at 10 minutes, takes a hour to fully develop
What other effects happen in response to haemorrhage?
Increased HR, Inotropy, vasoconstriction, activation of RAAS
What do cardiopulmonary stretch receptors do to reverse blood volume loss in haemorrhage?
They increase ADH and adrenaline to cause thirst and increases in BP respectively.
What happens in internal transfusion following haemorrhage?
Hydrostatic pressure decreases but oncotic pressure remains, therefore the capillary filtration process is reversed and fluid is taken into the blood vessels.
What condition comes with ageing and effects the systemic and diastolic blood pressures?
What are the effects of this condition called?
Why does this occur?
Isolated systolic hypertension
Systolic = increases
Diastolic = decreases
Pulse pressure therefore = increases
It occurs due to atherosclerosis of the vessels
