Chapter 12: Problem 13
(a) What is the \(difference\) between the pressure of the blood in your brain when you stand on your head and the pressure when you stand on your feet? Assume that you are 1.85 m tall. The density of blood is 1060 kg/m\(^3\). (b) What effect does the increased pressure have on the blood vessels in your brain?
Short Answer
Step by step solution
Define the Variables
Understand Pressure Change
Calculate Pressure While Standing on Feet
Calculate Pressure While Standing on Head
Determine the Difference in Pressure
Analyze the Effects on Blood Vessels
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Hydrostatic Pressure
For any fluid at rest, hydrostatic pressure can be calculated using the formula: \[ P = \rho g h \] where
- \( \rho \) is the fluid density
- \( g \) is the acceleration due to gravity
- \( h \) is the height of the fluid column
Blood Pressure
A key point in understanding this exercise is recognizing that blood pressure in the brain changes based on whether you're upright or inverted. This happens because the blood column height from the heart to the brain changes drastically.
When standing upright, the height-related component increases the pressure in the brain. Whereas in an inverted position, the height is minimized, thereby reducing or altering the distribution of that pressure.
Impact on Blood Vessels
When standing on your head, the blood vessels in the brain can experience increased pressure due to the gravitational pull on the entire column of blood. This can lead to serious consequences, such as the dilation or even rupture of vessels if the vessel walls cannot accommodate the increased load.
This phenomenon is a prime example of how bodily orientation and gravity affect physiological functions, particularly affecting sensitive structures like the blood vessels in the brain.
Effect of Gravity on Fluids
In an upright position, blood is under more pressure in the lower body, meaning the heart has to work hard to push it upwards against gravity. In contrast, when inverted, gravity assists in the movement of blood to the head, leading to potential overpressure in cerebral vessels.
As a result, our bodies have mechanisms, like valves in veins, to manage these pressure differences. These allow the maintenance of appropriate blood flow and pressure, although sudden changes in position can sometimes temporarily overwhelm these mechanisms.