Cardiovascular System Flashcards
Why are there valves in veins?
To ensure one-way flow to the heart.
Why is a circulatory system needed?
Transport of nutrients and oxygen Removal of waste Transport of hormones Immunity Erection
What is the function of the systemic circuit?
Distribution of blood around the body.
What is the function of the pulmonary circuit?
Oxygenation of blood.
For what type of flow is flow directly proportional to difference in pressure between two points?
Laminar flow.
What is the clinical significance of turbulent flow being noisy?
Can indicate a stenotic (narrowed) valve or an insufficient (leaky) valve.
How do length and width of a vessel effect peripheral resistance?
Increased length and reduced diameter increase resistance.
Resistance is inversely proportional to r^4.
Which of vessel length and vessel width can be physiologically manipulated?
Width.
How does hematocrit effect blood viscosity and therefore resistance and flow?
Increased hematocrit increases blood viscosity, and resistance, decreasing flow.
What is the basic flow equation?
F = delta P/ R
How does smooth muscle control arteriole diameter?
Relaxation of smooth muscle increases the radius. Contraction decreases the radius.
What are the three factors that influence blood flow?
Viscosity, length of tube and radius of tube.
