On the earth, the pressure generated by the heart is...

On the earth, the pressure generated by the heart is sufficient to pump blood to a height of 1.3 $\mathrm{m} .$ The density of blood is 1.04 $\mathrm{g} / \mathrm{cm}^{3} . )$ If the top of your head were 0.5 $\mathrm{m}$ above your heart, what would be the strongest gravitational acceleration that you could endure on another planet before your heart would be unable to pump blood to your brain? $$\begin{array}{l}{\text { A. } 2 g} \\ {\text { B. } 3 g} \\ {\text { C. } 5 g} \\ {\text { D. } 10 g}\end{array}$$

On the earth, the pressure generated by the heart is sufficient to pump blood to a height of 1.3 $\mathrm{m} .$ The density of blood is 1.04 $\mathrm{g} / \mathrm{cm}^{3} . )$ If the top of your head were 0.5 $\mathrm{m}$ above your heart, what would be the strongest gravitational acceleration that you could endure on another planet before your heart would be unable to pump blood to your brain?
$$\begin{array}{l}{\text { A. } 2 g} \\ {\text { B. } 3 g} \\ {\text { C. } 5 g} \\ {\text { D. } 10 g}\end{array}$$

Key Concepts

Hydrostatic Pressure

Hydrostatic pressure is the pressure exerted by a fluid at equilibrium due to the force of gravity. It depends on the density of the fluid, the gravitational acceleration, and the height of the fluid column. This concept is critical in understanding how pressure differences are established in fluids, such as when the heart generates enough pressure to push blood upward against gravity.

Fluid Density

Fluid density is a measure of how much mass is contained in a given volume of a fluid. It plays a crucial role in determining how fluids respond to gravitational forces. In the context of blood circulation, knowing the density of blood allows us to calculate the pressure required to move it through the body against gravitational forces.

Gravitational Acceleration

Gravitational acceleration is the acceleration due to the force of gravity acting on objects. It influences the hydrostatic pressure in fluids, as the pressure exerted by a column of fluid increases with greater gravitational pull. Understanding this concept helps in analyzing how different gravitational conditions, such as those on other planets, could affect blood circulation.

Blood Circulation Physiology

Blood circulation physiology focuses on how the heart pumps blood through the body's network of vessels. It involves the understanding of how pressure generated by the heart is used to overcome both resistance and the effects of gravity, ensuring that blood is delivered to all parts of the body, including regions elevated relative to the heart.

Transcript

00:02 For this problem, we're being told that a human heart can pump blood to a height of 1 .3 meters on earth, and we're given the density of blood 1 .04 grams per cubic centimeter.

00:13 We are then told that if our head is half a meter above our heart, generally, we're asked to figure out the maximum acceleration due to gravity that we could experience on another planet where our brain would still be receiving blood.

00:25 So if we were to travel to a different planet with a higher acceleration due to gravity, our heart wouldn't be able to pump as high because it would be fight.

00:32 More acceleration downward toward the surface of that planet.

00:35 So we're figuring out what is that maximum acceleration due to gravity, where our brain could still be receiving blood.

00:43 In order to do this, we need to know that our relative pressure, our gauge pressure, is going to be equal to density times the acceleration due to gravity, times the height that our fluid is traveling.

00:58 Down here on earth, we can calculate that by substituting in the values we were given.

01:04 We could say the density of blood is 1 .04 grams per cubic centimeter.

01:08 The acceleration due to gravity is 9 .8 meters per second squared.

01:13 And our height is 1 .3 meters.

01:15 Now i want to point out the units in this calculation do not work together.

01:19 We have centimeters.

01:20 We have grams.

01:21 We have meters.

01:22 We have meters per second squared.

01:25 But our goal is just to get a coefficient here.

01:27 We're looking for a multiple of g.

01:29 So the units themselves do not matter.