# OPTIMIZATION OF BLOOD VESSEL BRANCHING WITH A MATHEMATICAL APPROACH

This is for my International Baccalaureate Math Internal Assessment using High School Calculus. Please ensure the math is not too complex or too simple.

“The optimization of blood vessel branching can be modeled mathematically using Poiseuille’s Law, which describes the flow of fluids through cylindrical tubes. Poiseuille’s Law states that the flow rate (Q) of a fluid through a cylindrical tube is proportional to the fourth power of the radius (r) of the tube and the pressure difference (P) between the two ends of the tube, and inversely proportional to the viscosity () of the fluid and the length (L) of the tube.

Q rP/L

In the case of blood vessels, we can assume that the pressure difference between the arterial and venous systems is constant, and the viscosity of blood is also constant. Therefore, we can simplify Poiseuille’s Law to:

Q r/L

This equation implies that, for a given pressure difference and blood viscosity, the flow rate through a cylindrical blood vessel is directly proportional to the fourth power of its radius and inversely proportional to its length.

Now, let’s consider the branching of blood vessels. Suppose we have a single parent vessel that branches into two daughter vessels of different radii, r1 and r2, with lengths L1 and L2, respectively. We can calculate the total flow rate through the parent vessel as:

Q = Q1 + Q2

where Q1 and Q2 are the flow rates through the daughter vessels. According to Poiseuille’s Law, we can write:

Q1 r1/L1

Q2 r2/L2

To optimize the branching of blood vessels, we want to find the radii of the daughter vessels that maximize the total flow rate Q. We can use basic calculus to solve for the optimal radii.

First, we need to express Q in terms of r1 and r2:

Q = Q1 + Q2 r1/L1 + r2/L2

To find the maximum of Q, we need to take the partial derivatives of Q with respect to r1 and r2 and set them equal to zero:

Q/r1 = 4r1/L1 – 0 = 0

Q/r2 = 0 – 4r2/L2 = 0

Solving these equations for r1 and r2, we get:

r1 = (L1/L2)^(1/4) * r2

r2 = (L2/L1)^(1/4) * r1

These equations show that the optimal radii of the daughter vessels depend on the ratio of their lengths. If L1 is greater than L2, then r1 should be smaller than r2, and vice versa.

In summary, the optimization of blood vessel branching can be approached mathematically using Poiseuille’s Law and basic calculus. The optimal radii of the daughter vessels can be found by taking partial derivatives of the total flow rate with respect to the radii and setting them equal to zero. The solution depends on the ratio of the lengths of the daughter vessels.”

The above text is a starting point.

Please reword it but this math is the basics. Feel free to add more but no complex trig.