Cadrio Vascular System Flashcards
How many litres of blood does an adult have
5 litres
What is the function of blood
To transport nutrients
Regulate body temp
Protection and healing
When at rest what percentage of blood is in your veins
65%
What happens to rate of venous return during exercise
It increases
What are the 4 processes to increase blood flow back to the heart
Skeletal muscle pump
Pocket valves
The respitory pump
Cardiac suction
What is the skeletal muscle pump
When skeletal muscle compress veins during movement they force blood back towards the heart
What is the respiratory pump
When a person inhales the pressure in the thoracic cavity decreases which causes a small amount of blood flow back towards the heart
Ventilation increases during exercise pulling more blood back towards the heart
What is cardiac suction
When ventricles contract the atrio ventricular valves are pulled down increasing the size of the atria
This causes a pressure difference between atria and veins sucking blood back towards the heart
What is stroke volume
Heart rate times stroke volume
What is cardiac output
The volume of the blood pumped out of the heart per minute.
What is cardiac output equation
Heart rate times stroke vomume
What does starlings law state
Cardiac output is dependent on the extensibility of cardiac muscle fibres
Why do fibres stretch more in exercise
Venous return increases
What is ejection fraction
Ejection fraction is the percentage of blood
pumped out of the left ventricle each beat
At rest it’s about 55%
What is ejection fraction during exercise
70%
Why does sweating decrease cardiac output
Blood volume decreases which decreases venous return and stroke volume due to starlings law
Why does heart rate increase before exercise
Anticipotary rise which is caused by release of adrenaline
How is blood pressure measured
Systolic blood pressure/ dystolic blood pressure
What is normal blood pressure
Between 80-120/60-80
What physiological factors affect blood pressure
Blood viscosity
Blood flow
Blood volume
What affect does aerobic exercise have on blood pressure
It increases systolic to around 220 but dyastolic stays the same
