Question

In hemodynamics, blood flow through the cardiovascular system can be modeled as an electric circuit in which the blood serves as electricity, the blood vessels as resistive wires, and the heart as a battery (see Figure 1).

Figure 1 Cardiovascular circuit model

Ohm’s law states that the voltage drop ΔV across each element, the current I flowing through it, and its electrical resistance R are related by ΔV = IR. In a blood vessel, pressure difference between one vessel and the next ΔP relaxes ΔV, volumetric blood flow Q replaces I, and vascular resistance R replaces electrical resistance. Therefore, Ohm’s law for blood flow in a vessel is

Vascular resistance is due to the blood’s viscosity Ƞ and the dimensions of the vessel through which it flows. Assuming blood vessels are cylinders, R can be approximated as

Where L is the length of the vessel, an r is its inner radius. If Equation 2 is combined with Equation 1, the resulting equation is Poiseuille law.

In a study of the circulatory system in rats, researchers measured the intravascular blood pressure of the mesenteric blood vessels. The mesentery is the set of tissues that holds the intestines in place. Blood flows in the following order: aorta, superior mesenteric artery (SMA), arterial arcade, venous arcade, superior mesenteric vein (SMV).

For the procedure catheters with pressure transducers were inserted into each vessel via laparotomy. Laparotomy is an invasive procedure that involves a surgical incision into the abdominal cavity. Blood pressure measurements were taken simultaneously at the proximal end (beginning) of each blood vessel.

Question 6 In the image shown, a simplified cardiovascular system is modeled as an electrical circuit. Which of the following would occur if the blood flow to the brain is blocked? (Assume that the blood pressure supplied by the heart remains unchanged.) Muscle Gut Brain Battery heart A. Total vascular flow resistance will increase 0 B. Pressure drop across the muscle will increase C.Blood flow through the gut will always increase D. Blood flow throughout the cardiovascular system will stop Submit

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Answer 1

The answer is option (A) which says that the vascular resistance will increase. Thank you ,please like the answer.

Here, given blood pressure is compared with the current in relation to the ohm's law when blood to brain stops i.e. it is disconnected blood from heart is constant I then the blood will flow from heart to the Gut remains same = v_volts the pressure drop also remains same across muscle so the total vascular flow resistance will increase