Chapter 4: Flashcards
(33 cards)
Define hydrostatic pressure:
The pressure exerted by a fluid, at a given point in the fluid, due to the force of gravity. This is the pressure created on a blood vessel, from the blood flowing within it.
If the hydrostatic pressure of a blood vessel that supplies an organ is increased, which of the following would occur?
a. The oncotic pressure will increase.
b. The organ will increase in mass and weight.
c. The blood flow to the orgall decreases.
d. The oncotic pressure will decrease.
b. The organ will increase in mass and weight - because as hydrostatic pressure increases, more fluid will leave the blood vessel and enter the organ tissue.
d. The oncotic pressure will decrease -
What does oncotic pressure do physiologically?
Pull water back into the bloodstream, thanks to the concentration of large solutes (albumin) in the plasma.
Pressure in a blood vessel:
P = pgh
p = density of a fluid.
g = acceleration due to gravity.
h = height.
When arterial pressure and venous pressure are equal:
a. The venous return from the supplied tissue will increase.
b. The volume of blood supplied to the tissue will increase.
c. The flow of blood between the blood vessels and tissue will be almost 0.
d. The flow of blood through the vessels will halt, and there will be no oxygenation of tissues.
c - The blood flow between the blood vessels and tissue will be almost 0.
When arterial = venous, there is no net change in blood exchange between a vessel and its target tissue.
An incompressible solid plastic bowling ball with a density of 1.32 g/cm^3 is held at a depth of 10 m in a freshwater lake. When released, the ball will:???????????????
a. Sink with an initial velocity of 3.3 m/s.
b. Sink with an initial acceleration of 2.5 m/s.
c. Sink with an initial acceleration of 9.8 m/s^2.
d. Float upward with with an initial velocity of 3.3 m/s.
Sink with an initial acceleration of 2.5 m/s.
Since the ball is more dense than water, it will sink.
a = (Fg - Fb)/m
Fq = mg = (mvol)(9.8) – Mass and volume of ball.
Fb = mg = (mvol)(9.8) — Mass and volume of water.
What is the density of water?
1 g/cm^3
- Heart to lungs - Blood raises up slightly, causing an increase in gravitational potential energy.
- As blood goes back to the heart it will go back to the initial gravitational potential energy.
- As blood leaves the heart and goes up the aorta, the gravitational potential energy will slightly increase.
- As blood leaves the aorta and goes into peripheral vessels, the gravitational potential energy will drastically decrease.
- As blood returns to the heart via venous return, gravitational potential energy is slowly (venous return is slow) increasing back to the initial gravitational potential energy.
DRAW OUT AS A GRAPH!
In order for an object to float in a fluid, what must be true?
Fb = Fq
Fb = boyant force.
Fg = Gravitational force.
If a 78 kg woman lays with 1/10th of herself submerged in a body of water. At what gravitational force would this woman NOT float?
a. 12.5 N.
b. 0.6 N.
c. 9.8 N.
d. The woman would float at any of these.
Fb = Fg
FB = (density)(volume) (gravitational acceleration) = pVg.
FG = (mass)(gravitational force) = m*g
mg = pV*g Gravitational acceleration will cancel out
m = p*V - Now the woman will always float.
Equation for buoyant force of a fluid:
Fb = p * V * g
p = density of the fluid.
V = volume of the fluid.
g = Gravitational acceleration (9.8 m/s^2)
Which of the following can fluids be:
a. solid.
b. gas.
c. liquid.
B & C.
True or false: Both gasses and liquids can be compressed.
FALSE - only gases can be compressed and have no shape, while liquids can’t be compressed and fill the shape of their container.
Define density and what equation:
Density is the ratio of a substances mass to volume.
P(ro) = m/V
Mass/Volume
When will a substance sink in water? When will it float?
A substance will float in water if it’s density is less than waters (1 g/cm^3 or 1000 kg/m^3), and will sink when its density is greater than water.
What are the 3 ways we may represent the density of water?
- 1 g/cm^3
- 1 g/mL
- 1000 kg/m^3
How may we calculate weight using density of a fluid?
Fg = P(ro)V*g
Define specific gravity:
Specific gravity is the ratio of a substance’s density, as compared to that of water. It is unitless.
SG = p/1 g.cm^3
If the specific gravity of a substance is less than 1:
a. The substance is more dense than water and will float.
b. The substance is less dense than water and will sink.
c. The substance is less dense than water and will float.
d. The substance is more dense than water and will sink.
c - The substance is less dense than water and will float.
SG = p/ ph2o
If the specific gravity of a substance is greater than 1:
a. The substance is more dense than water and will float.
b. The substance is less dense than water and will sink.
c. The substance is less dense than water and will float.
d. The substance is more dense than water and will sink.
d - The substance is more dense than water and will sink.
During inhalation:
a. The pressure in the lungs in negative to the external environment, and air will be drawn into the lungs.
b. The pressure in the lungs remains unchanged, but the area will increase.
c. The pressure in the lungs is positive to the external environment, and air will be drawn into the lungs.
a - The pressure in the lungs is negative to that of the external environment, and air will be drawn into the lungs
During exhalation:
a. The pressure in the lungs is negative to the external environment, and air will be expelled from the lungs.
b. The pressure in the lungs is positive to the external environment, and air will be expelled from the lungs.
c. The pressure in the lungs remains unchanged, as exhalation is a passive process.
b - The pressure in the lungs is positive to the external environment, and air will be expelled from the lungs.
Pressure is a _________, since its force component will be felt equally in all directions (specifically in fluids).
Scalar.
You want to analyze the pressure exerted on a balloon at different sizes. If you start at the maximum inflation, and then release 23% of the original area of the balloon, while holding the force constant:
a. The pressure of the balloon will increase.
b. The pressure of the balloon will decrease.
c. Area of the container does not affect the pressure exerted.
A - the pressure in the balloon will increase. Pressure exerted by a fluid is inversely proportional to area of the container.
Pressure = F/A.
F = Force.
A = area.
