CGIER 6 - Static Fluids and Fluid Pressure Flashcards
What is the formula for density?
Mass (kg) / volume (m3)
What is the formula for pressure?
P = F (N) / A (m2)
How does a fluid in a container act?
A fluid always exerts a force perpendicular to the walls of its container.
What is Pascal’s Principle?
Any pressure applied to the surface of an enclosed fluid is transmitted undiminished to all points within the fluid.
What is the formula for Pascal’s Principle?
P = F1/A1/ = F2/A2
List clinical examples of Pascal’s Principle (SHOPPF).
There are 7 clinical examples of Pascal’s Principle:
- Screening for Brain Tumors
- Hydraulic Lifts
- Onset of Glaucoma
- Penile Prosthesis
- Prevention of Decubitus Ulcers
- Foetal Protection in the Womb
- Bladder
Explain how Screening for Brain Tumors is related to Pascal’s Principle?
The presence of a brain tumor decreases the volume in which cerebrospinal fluid is contained, therefore increases the pressure cerebrospinal fluid exerts on the brain. The pressure can be determined by inserting a spinal tap connected to a water manometer between the 3rd and 4th lumbar. If the pressure is higher than customarily accepted values, this may indicate a brain tumor.
Explain how Hydraulic Lift relates to Pascal’s Principle?
With a hydraulic lift, a force is applied to a cylinder with a small cross-sectional area, which then transmits to a much greater force to the connected cylinder with a larger cross-sectional area.
Explain how Glaucoma relates to Pascal’s Principle.
In a normal eye, excess fluid is allowed to escape through the trabecular meshwork, however, in glaucoma, this is prevented and causes an increase in the intraocular pressure. This can result in permanent damage to the optic nerve and blindness.
Explain how Decubitus Ulcers relate to Pascal’s Principle.
Decubitus Ulcers are pressure ulcers caused by patients spending prolonged periods in the same position. They tend to occur around bony regions that are in direct contact with the mattress.
Explain how foetal protection of the womb relates to Pascal’s Principle.
An unborn baby is surrounded by amniotic fluid in the womb. This is excellent because the amniotic fluid distributes any force applied to a pregnant woman’s abdomen.
Explain how fluid pressure in the bladder relates to Pascal’s Principle.
The bladder is a sac which collects urine as it is produced. As urine fills the bladder, the fluid pressure increases until pressure detector cells on the walls of the bladder send signals to the brain that the bladder is full and initiates the contraction of the bladder for urination.
