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9. What is always similar about every body fluid compartment in the body?
Each compartment has the same number of particles dissolved in the water
11. If one body fluid compartment is larger than another, will they have different volumes, compositions, and particles dissolved in water?
They will have different volumes
They may or may not have different compositions (how much of each type of particle)
They will have the same number of particles dissolved in water (same osmolality)
12. Does size or composition (of the particles dissolved in the water) affect the number of particles dissolved in the water of each body compartment?
No, size or composition does not affect the number of particles dissolved in water.
13. How many particles per million are dissolved in each liter of water (milliosmoles) are in each compartment?
300 million particles (or 300 milliosmoles, abbreviated 300 mOsm) per liter of water.
What is the osmolarity of body fluid compartments?
That means 300 million particles per liter (300 million osmoles) or described as having an osmolarity of 300 mOsm.
14. If one compartment has more particles than another one next to it, and if those particles cannot reach equal numbers on their own because the cell membrane blocks their passage, how will the water react?
The water will travel in the direction necessary to dilute the compartment with the higher number of particles until they are at the same number of particles per liter.
15. Does water always move across the compartments? Why?
Yes, because cell membranes always allow water to pass.
16. Do body fluid compartments have the same composition (types of particles per liter)?
No, the composition varies. For example, one compartment may have 76% sodium, 12% glucose, and 12% glucose, while another compartment has 76% potassium, 12% glucose, and 12% potassium
18. Do body fluid compartments have the same osmolalities (number of particles per liter)?
Yes, the osmolality is the same, regardless of the volume
19. What is a law of physics that states all particles want to move from an area of high concentration to low concentration?
21. If I have two identical cups of water, and I add 20tsp of lemonade to one cup and 10 tsp. of lemonade to the other cup which one is more concentrated with lemonade?
The one with 20tsp of lemonade is more concentrated because it has the most particles.
22. Which cup is more concentrated with water?
The cup with 10tsp of lemonade is more concentrated with water because it has fewer particles of lemonade.
23. Diffusion: If these two solutions were in body compartments next to each other, and the particles cannot move from their area of high concentration to low concentration, which way will water move?
Water will move from its area of high concentration to low concentration. (From the cup with 10tsp of lemonade to the cup with 20tsp of lemonade).
24. What does the saying "particles suck" mean?
With two given solutions water will diffuse towards the substance containing more particles. Therefore, the compartment with the most particles will suck the water in
25. In the case where the plasma has 260 mOsm (260 particles per liter) and the nearby cells have 300 mOsm, will the cells will draw the water into themselves, or will the plasma draw water into the blood vessel?
The compartment with more particles (the cells) will suck the water in. Therefore, water will move from the plasma to the adjacent cells.
26. When particles cannot diffuse down their concentration gradient because the cell membrane blocks them, what will move, in order to dilute the cells?
Water! This is because cells with more particles will suck the water in to dilute their particle concentration.
29. What was the problem the young mother eventually passed away from during the water drinking contest?
She drank 3L of water/hour and your kidney is only able to filter 1L per hour. The excess water in the plasma moved into her brain cells, rupturing them.
30. When the plasma is too dilute, where will the extra water go?
Water will leave the bloodstream and enter the tissues where there is a higher concentration of solutes.
31. If the particles in cells are at a higher mOsm compared to the particles in the nearby blood vessels, which way do the PARTICLES want to move? Will they be able to move?
The particles will WANT to move from the cells to the blood vessel, but they cannot move
32. If the particles in cells are at a higher mOsm compared to the particles in the nearby blood vessels, which way does WATER want to move? Will it be able to move?
The water wants to move from the blood vessel into the cells, and yes, it can move
33. In a person who is overhydrated, will the person initially have more water in their plasma or in their cells?
The person will initially have more water in their PLASMA than in their cells.
35. In a person who is overhydrated, will their plasma's osmolality now be greater than 300 mOsm (more concentrated) in particles or less than 300 mOsm (more diluted) in particles?
The plasma will have a lower osmolality than 300 mOsm (more diluted) in particles due to the increase of water ingested
36. If the plasma is now below 300 mOsm and the surrounding cell are still at 300 mOsm, in what direction will the water diffuse?
The cells will draw in water from the plasma.
37. What will happen to the cells as they draw in more water?
The cells will enlarge and eventually rupture.
38. In order to counteract the effects of overhydration, should the person be given an IV that is hypertonic (greater than 300 mOsm) or hypotonic (less than 300 mOsm)?
Hypertonic (greater than 300 mOsm)
39. Why should an overhydrated person be given an IV that is hypertonic (greater than 300 mOsm)?
Since the plasma is diluted below 300 mOsm because of the extra water consumed, a hypertonic (greater than 300 mOsm) IV is given in order to raise the number of particles in the plasma so that it will once again balance and match the number of particles in the cells.
40. Patient recovering from bacterial infection has been suffering with diarrhea. He has not been able to eat or drink anything. Low BP=70/40, High Pulse-110bpm.
Do you give an iv solution that is hyper, hypo, or isotonic? Why?
• Give Isotonic solution (ringers solution).
• The person has a high pulse rate and low blood pressure.
• Since the person is severely dehydrated, but the water loss and particle loss are equal (diarrhea or vomiting) you do not want to overhydrate the cells with a hypotonic solution and you don't want to make the dehydration worse by giving him a hypertonic solution, thus you give him an isotonic solution.
41. Patient, age 24, has been suffering from food poisoning with vomiting and diarrhea. He has been drinking a lot of plain water, not Gaitoraid or Pedialite. Skin and mucous membranes are dry, and he's complaining of a headache. Heart rate is normal, but he has high BP=200/120.
Do you give an iv solution that is hyper, hypo, or isotonic? Why?
• The person has hypotonic dehydration, so give a hypertonic solution.
• He has excess solute loss from GI distress, while replacing it with plain water. His plasma fluid has more water than particles, water moves from the plasma to the interstitial space, and then into the cells. This can lead to shock.
• The headache is from the brain cells swelling from the excess water they have absorbed.
• He should have replaced the electrolytes by drinking something like Gaitoraid or Pedialite.
42. A 35 year old patient recovering from food poisoning has been vomiting and eating only Saltine crackers. She has a moderately rapid pulse and moderately low blood pressure
Do you give an iv solution that is hyper, hypo, or isotonic? Why?
• She has a hypertonic fluid deficit, so she needs a hypotonic solution.
The salty crackers replaced the sodium lost from GI distress, but the salt replacement exceeded the water replacement, so her plasma is hypertonic
43. How much of your body weight is from water?
Answer: 60%. Water is the most abundant substance in the body.
44. Calculate the weight of a person weighing 150lbs into kg.
Divide in pounds by 2.2
150/ 2.2 = 68kg
45. Once you know someone's weight in kg, how to you calculate how much of their weight is water?
Formula: #kg x 0.6
Example: 150 lbs divided by 2.2 = 68kg
68kg x 0.6 = 40.8 liters of water
46. What has the highest extracellular fluid to intracellular fluid concentration ratio for most mammalian cells?
47. Outside of cells (in the plasma), there is a high concentration of which particles? What particles are low in concentration?
High in sodium and calcium
Low in potassium and proteins
48. Inside of each cells, there is a high concentration of which particles, and a low concentration of which particles?
High in potassium and proteins, low in sodium and calcium
49. Why don't we want a net gain or loss of fluid across the cell membrane
The cell will shrink or swell and burst
50. What keeps the sodium ions from moving down their concentration gradients towards equilibrium?
The cell membrane, it is designed to be semi- permeable and it prevents sodium and other particles from entering the cell.
51. If you have a cell immersed in pure water, will it shrink or burst?
Particles suck, so pure water will get sucked into the cell until the cell bursts.
53. What particles can cross the cell membrane through simple diffusion, with no channel?
• Gases (O2, CO2)
Lipids and lipid-loving (hydrophobic or lipophilic) substances such as alcohol
54. What are examples of gases that can cross the cell membrane through simple diffusion?
Oxygen, Carbon Dioxide
55. What is an example of a lipid-loving substance that can cross the cell membrane through simple diffusion?
58. What type of molecules can pass through the membrane without help
Only molecules that are small, uncharged, or fat soluble
59. How do they get through
One of (2) ways:
1. Passive transport; means that energy (ATP) is not needed
2. Active transport; means that energy (ATP) is needed
60. What causes positive feedback to be so dangerous?
It is a vicious cycle that can lead to progressive instability and death. It promotes instability and disease. It is rare in the body, and it has to eventually be stopped with a negative feedback mechanism
61. Which type of situation is typically associated with positive feedback and how common are they?
Positive feedback is very rare and typically associated with illnesses.
62. How are positive feedback mechanisms stopped?
Positive feedback mechanisms must eventually be stopped with a negative feedback mechanism.
63. Which direction does positive feedback follow?
It follows the direction of the deviated variable , and eventually both become too high.
64. What are three examples of normal positive feedback in the body?
Clotting of blood, pregnancy, and ovulation
65. What is facilitated diffusion?
• Facilitated diffusion is when an ion wants to travel down its concentration gradient, but they have to use a channel in the cell membrane that opens and closes
66. Does facilitated diffusion require any energy to occur?
No, it is passive transport and does NOT require energy (ATP).
68. What are the three types of passive transport (do not require ATP)?
69. What is Active Transport?
When a substance needs to move against its concentration gradient (it is moved from an area of LOW concentration on one side of the cell membrane to an area of HIGH concentration on the other side of the cell membrane)
70. How is Active Transport accomplished?
A protein embedded in the cell membrane grabs onto the substance and drags it across the cell membrane (this requires ATP)
73. Does negative or positive feedback need to be carefully controlled?
Positive feedback needs to be carefully controlled.
75. What is Osmosis?
The movement of water molecules across a membrane from water's area of high concentration (lots of water but low concentration of particles) to water's area of low concentration (less water but more particles).
78. In a solution, what is the solvent and what is the solute?
In a solution, water is the solvent and the particles are the solute
79. What is Hydrostatic Pressure?
Hydrostatic pressure is the pressure of fluid exerted on the vessel or container
80. What is Hydrostatic Pressure inside a blood vessel
Hydrostatic pressure is the pressure that water in plasma (inside a blood vessel) exerts on the inside of a blood vessel wall. When the pressure is high, plasma leaks out of the vessel and into the interstitial space.
81. What is Hydrostatic Pressure outside a blood vessel?
Hydrostatic pressure is the pressure that water in the interstitial space (fluid between cells) exerts on the outside of a blood vessel wall. This is how you remove swelling by applying an ACE wrap. It makes the pressure on the outside of the vessel higher than the inside, so goes back into the blood vessel.
82. Why is hydrostatic pressure important?
This is how water moves between fluid compartments. It leaves the plasma and becomes interstitial fluid, bathing the cells with nutrients. The cells can also give or take water as needed.
83. What is osmosis?
Osmosis is the movement of water across a cell membrane. It is NOT the proper term to use to describe particles moving across a cell membrane...that is diffusion.
84. When will osmosis occur?
Osmosis will occur when there is a difference in particle concentration on each side of a cell membrane.
85. Since particles cannot always diffuse across a membrane, water does but in what direction will the water move?
Down a concentration gradient to the side with a higher concentration of particles and a lower concentration of water. Particles suck water!
86. When will osmosis stop?
When the particle concentration per liter is the same on both sides of the membrane (equilibrium)
87. Osmosis is affected by what three things?
Solute concentration, Osmotic force, and hydrostatic force
88. Why does water move into dialysis tubing until it reaches a certain column height without climbing higher and higher in the column indefinitely?
Because gravity will be exerting forces on it (hydrostatic pressure).
90. When water enters a solution that contains lots of particles that are impermeable across a membrane, will the solution have a high or low osmotic pressure?
High osmotic pressure
91. In terms of water movement through the GI tract, explain what would happen if you swallowed some aspirin.
There would be no net gain or water loss, because aspirin particles can cross the cell membrane of a person's intestinal tract.
92. What would happen to the water movement through the GI tract if cellulose were to be consumed instead of aspirin?
Cellulose cannot cross the membrane. Therefore, more particles occupy the GI tract lumen, which will cause an influx of water from nearby cells.
93. Explain how laxatives work.
A laxative will cause there to be more particles in the GI tube. Since the osmolality has increased, water from the surrounding cells will enter the GI lumen. Over time, this extraction of fluid will cause dehydration.
94. If a person ingests a non-absorbable solute (like a laxative) into the gastrointestinal tract, then the osmolality of the GI tube compartment will increase or decrease?
95. When a person takes a laxative, there will be a net movement of water from where to where?
From the surrounding cells into the gastrointestinal lumen
96. Will a solution with a smaller number of particles have a higher or lower hydrostatic pressure than a solution with a greater number of particles?
It will have a lower hydrostatic pressure.
101. What is the amount of pressure required to stop osmosis from happening called?
102. Will a solution containing lots of particles that are impermeable across a membrane have a high or low osmotic pressure?
High osmotic pressure
106. What is osmotic pressure?
The amount of hydrostatic pressure you need to apply to stop the water from moving from the top of the tube where there are more particles.
107. What type of hydrostatic pressure you need to apply to stop the water from moving?
108. If the plasma fluid becomes hyperosmotic compared to the intracellular fluid of surrounding cells, would we expect the cells to shrink or swell?
109. What will happen to a cell placed in the ISOSMOTIC (300mOsm) solution?
There is no net gain or loss of water.
110. What will happen to a cell placed in the HYPEROSMOTIC (600 mOsm) solution?
Particles suck so solution will suck the water from the cell. The cell will SHRINK.
111. What will happen to a cell placed in the HYPO-OSMOTIC (100 mOsm) solution?
Particles suck so the cell will suck water from the solution and will BURST.
114. When particles diffuse across a membrane is there a net gain or net loss of water in the compartment?
There is no net gain or loss of water in a compartment when particles are able to diffuse across the membrane.
115. What are 2 characteristics of plasma in a diabetic patient?
Increased glucose in blood plasma and an overall increased solute concentration which leads to more water in the blood
116. A diabetic patient's blood plasma has changed from 300 mOsm to 304 mOsm. Will water move out of the blood plasma into the interstitial space or the other direction?
Water will move from the interstitial space into the blood plasma as the particles in the blood plasma are greater due to the solute being greater from increased glucose in the blood. PARTICLES SUCK!
117. Describe the effects and usage of insulin in a healthy individual vs. a patient with diabetes.
When you eat, sugars are absorbed into plasma. Normally, insulin transports these sugars into the cells, but in a diabetic with no insulin, the sugars stay in high concentration in the plasma.
118. When a person has many particles in the blood (such as glucose), does water flow into the blood vessel or out of the blood vessel?
Flows into the blood vessel (particles suck!)
119. In the above question, where does the water come from that flows into the blood vessel?
120. What does that do to the osmolality of that compartment that lost the water?
Interstitial Space; it becomes dehydrated since it lost the water to the blood vessel, so now it has the same number of particles in less water, so its concentration goes up. That means the osmolality becomes higher.
121. If the interstitial space becomes dehydrated, what happens to water in the nearby cells?
122. What will that do to the cells?
The water leaves the cells and enters the interstitial compartment, so the cells shrink.
123. In a dehydrated compartment, if osmolality is at 300 particles per HALF a liter, instead of 300 particles per liter, (which is the same as saying it has become 600 mOsm), in what direction will water travel?
Water will leave the surrounding compartments and enter the dehydrated compartment
124. After a diabetic patient eats sugar, in what direction will water initially flow? Ultimately, will the person become dehydrated or overhydrated?
Water flows from the interstitial space to the plasma; person will be dehydrated
125. The condition where a person drinks a lot of water because they are thirsty is called (_______________)
What happens to blood pressure in a dehydrated athlete?
Blood pressure drops for the same reason as a person with diabetes
1. What is missing from the diet of a person with Kwashiorkor?
They are missing protein in their diet
130. What is the osmotic effect of the blood vessel in a person who has a diet without protein?
Many of the particles in blood are proteins. With no proteins, the number of particles in the plasma fluid compartment becomes low.
1. When there are too few particles in the plasma, where will water flow?
Too few particles means there is too much water in that compartment, so water will flow out of the blood vessel and into the interstitial space.
132. Why does a person with Kwashiorkor have a distended belly?
Their plasma osmotic pressure is low compared to the transcellular's.
All of the compartments are missing proteins, so all of the particle counts are low, so water leaves all the compartments. It has nowhere to go except the spaces in the abdominal cavity.
134. What substance is needed to make albumin? Where do we get that substance?
Amino acids; they come from eating protein
136. The peritoneal cavity is best described as...
The space outside the digestive organs and under the skin and fat
137. What two conditions are caused by fluid going from the plasma into the peritoneal compartment?
Ascites and Kwashiorkor
139. What other medical conditions are caused by ascites?
Portal hypertension, jaundice, and nerve cell death
141. What groups of people are at higher risk for developing ascites here in the USA?
Elderly and alcoholics
143. When your body is malnourished, how will the body cope?
The body will break down proteins from its own muscles, to get what it needs.
144. What happens to the liver with alcoholism?
The liver becomes scarred and is unable to make new proteins
146. What is "portal hypertension".
Pressure on the bile duct that prevents the release of bilirubin.
149. What causes the color of waste products in the body?
Bilirubin (breakdown product of RBC destruction. It causes the color of the urine and feces
151. What is tonicity?
The number of particles per kg of water in each of two compartments, where the membrane that separates them is impermeable to the particles. Differences in tonicity between the two compartments always lead to water moving from one compartment to the other.
154. Since urea can cross a cell membrane, will water shift from one compartment to another?
No, water might move a little, but it shifts back (that is called a transient shift).
155. Why is it important to understand this about urea?
Because urea is reabsorbed in the early stage of kidney filtration, and then excreted in the later stage. During the early stage, it does not cause water to be reabsorbed with it, so the kidneys are free to excrete the excess water.
158. Is 300 mmol/L of sucrose isosmotic, hyper, or hypo-osmotic compared to our body fluids?
162. Is 600 mmol/L of sucrose isosmotic, hyper, or hypo-osmotic compared to our body fluids?
166. Is 200 mmol/L of sucrose isosmotic, hyper, or hypo-osmotic compared to our body fluids?
168. Is 400 mmol/L of UREA isosmotic, hyper, or hypo-osmotic compared to our body cells?
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