Flow (Q) results from a difference in pressure (P₁–P₂) - this can occur from either an upstream rise or a downstream fall in pressure. Resistance (R) represents the barrier to flow created by the conducting pathway (Fig 1).

The most efficient type of flow is laminar, in which fluid layers move smoothly over each other. Under laminar conditions flow can be calculated from Poiseuille’s formula.

Question 1: What equation links pressure, flow and resistance?

Click here for answer.

Flow (Q) results from a difference in pressure (P₁–P₂) - this can occur from either an upstream rise or a downstream fall in pressure. Resistance (R) represents the barrier to flow created by the conducting pathway (Fig 1).

The most efficient type of flow is laminar, in which fluid layers move smoothly over each other. Under laminar conditions flow can be calculated from Poiseuille’s formula.

Question 1: What equation links pressure, flow and resistance?

Answer: Pressure = Flow x Resistance

Question 2: What are the equivalent values for the circulation?

Click here for answer.

Flow (Q) results from a difference in pressure (P₁–P₂) - this can occur from either an upstream rise or a downstream fall in pressure. Resistance (R) represents the barrier to flow created by the conducting pathway (Fig 1).

The most efficient type of flow is laminar, in which fluid layers move smoothly over each other. Under laminar conditions flow can be calculated from Poiseuille’s formula.

Question 1: What equation links pressure, flow and resistance?

Answer: Pressure = Flow x Resistance

Question 2: What are the equivalent values for the circulation?

Answer: BP = CO x SVR

BP = Blood Pressure

CO = Cardiac Output

SVR = Systemic Vascular Resistance