Lecture 2 - Function of Circulation

Question 1

What are the functions of circulation?

Answer 1

Transport oxygen and nutrients TO cells and CO2 and other waste products AWAY from cells.

Transport hormones (chemical signals) around the body.

Immune response - white blood cells, platelets, fibrinogen

Regulate temperature via vasodilation and vasoconstriction

Fluid balance - Control blood volume and electrolyte conc.

Question 2

What are the two divisions of circulation?

Answer 2

Systemic - supplies oxygenated blood to the body

Pulmonary - absorbs o2 and discharges co2 at the lungs

Question 3

Describe the functional parts of the circulatory system.

Answer 3

Arteries - Transport oxygenated blood under high pressure, with thick, elastic walls

Arterioles - Smaller branches off of arteries. Act as ‘control conduits’ and can alter flow

Capillaries - Small, thin walled vessels. Exchange nutrients, oxygen, hormones from blood to interstitial fluid.

Venules - Collect deoxygenated blood from capillaries

Veins - transports deoxygenated blood back to the heart. Thinner walls than arteries as lower pressure. Act as reservoir of blood

Question 4

What is flow through a blood vessel determined by?

Answer 4

Pressure difference between the two ends of the vessel (pressure gradient);
Impediment to blood flow through the vessel (vascular resistance).

Question 5

Ohm’s Law Equation

Answer 5

Q=deltaP/R

Question 6

Reynolds number thresholds for laminar, transition, turbulent

Answer 6

Laminar Re<2000
Transition 2000<Re<4000
Turbulent Re>4000