When muscles contract and relax, they press on veins squeezing blood back to the heart
What is the respiratory pump?
When muscles contract and relax during breathing, pressure changes occur in the chest cavity which compress nearby veins squeezing blood back to the heart
What are pocket valves?
Valves in veins keep the blood flowing in one direction and close to prevent backflow
What does the smooth muscles in veins do?
Squeeze the blood back to the heart
How does the heart help to maintain venous return?
The heart acts as a suction pump when it contracts and relaxes
What is the impact of blood pressure on venous return?
When the systolic blood pressure increases, there is an increase in venous return and vice versa
What is the equation for blood pressure?
Blood flow x resistance
What is blood pressure?
The force exerted against the vessel wall
What is systolic pressure?
The pressure in the arteries when the ventricles contract
What is diastolic pressure?
The pressure in the arteries when the ventricles relax
Where is blood pressure measured?
At the brachial artery in the upper arm
What is a typical blood pressure reading at rest?
120/80 mmHg
What is blood pressure dependent on?
The type of blood vessel and the distance from the heart
What is the blood pressure in arteries?
High
What is the blood pressure in arterioles?
Medium
What is the blood pressure in capillaries?
Low
What is the blood pressure in the venules?
Low
What is the blood pressure in the veins?
Low
What is the total area of arteries?
Low
What is the total area of arterioles?
Medium
What is the total area of capillaries?
High
What is the total area of venules?
Medium
What is the total area of veins?
Low
What are the two types of circulation?
Pulmonary and systemic
What is pulmonary circulation?
Deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart
What is systemic circulation?
Oxygenated blood to the body from the heart and then the return of the deoxygenated blood from the body to the heart