Resistance To Blood Flow

What are the factors that affect blood flow to tissues?

1) blood pressure 2) vascular resistance 3) Venous return 4) Velocity of blood flow

What are the sub-factors of vascular resistance that affect blood flow to tissues by proxy?

1) Turbulence 2) Viscosity of blood 3) Vessel Length 4) Vessel lumen radius

What does viscosity refer to?

resistance of fluid to its flow

The thicker the fluid (i.e. blood), the more viscous it is, and the greater its _________ to flow.

resistance

If a person’s blood has a higher concentration of erythrocytes or is dehydrated, the blood is MORE or LESS viscous? MORE or LESS resistance to flow?

more, more

Blood flow is always __________ by resistance

opposed

Friction brought on by resistance is due to the contact between ______ and the blood vessel ___.

blood, wall

Because longer vessels result in ______ friction increasing vessel length __________ resistance.

greater, increases

Vessel length remains relatively constant in an individual, and as a result, DOES or DOES NOT influence short-term changes in blood pressure?

Does not

If vessel lumen radius __________, there is relatively less blood flow near the edges and overall blood flow __________.

increases, increases

What is the formula expressing proportionality between blood flow and radius?

F ∝ r⁴

If a vessel vasoconstricts and its radius decreases from 2mm to 1mm the overall change in flow is ___ times ______

16, less

If a vessel vasodilates and its radius increases from 1 mm to 2 mm the overall change in flow is ___ times ______.

16, greater

Resistance is __________ proportional to radius of blood vessel lumen.

inversely

What is the FORMULA expressing the relationship between resistance and radius of blood vessel lumen?

R ∝ 1/r⁴

Blood flow is _______ proportional to radius⁴ of blood vessel lumen.

directly

What FORMULA expresses that total blood flow is influenced by blood pressure gradients and resistance?

F ∝ 𝚫P/R

What is the FORMULA that combines factors influencing resistance to flow?

R = 8ηL/πr⁴

What is the FORMULA that describes volume flow rate?

π(pressure difference) (radius)⁴ / 8 (viscosity) (length)

Vascular resistance is the ______ between the vessel wall and blood.

friction

Pressure and flow are ______ related.

directly

Resistance and flow are __________ related.

inversely

Blood pressure is _______ proportional to vessel resistance.

directly