Salt and Water-Fluid Homeostasis at the Cellular and System Level

Question 1

there are many places in the animal body that contains a selectively permeable membrane for water. If water moves from side A to side B, which side has the lowest osmotic pressure?

Answer 1

side A

Question 2

which body compartment contains the highest proportion of total body water?

Answer 2

intracellular fluid

Question 3

What are the percentages of body weight that is contained within each fluid compartment?

Answer 3

Intracellular fluid = 40%
Interstitial fluid = 15%
Intravascular fluid = 5%

Question 4

edema is an abnormal increase in the volume of which type of fluid?

Answer 4

interstitial fluid

Question 5

what electrolytes are in which body fluid compartment?

Answer 5

sodium: intravascular fluid
potassium: intracellular fluid

Question 6

the desert-dwelling kangaroo rat can derive up to 100% of its water needs from metabolic water. What is metabolic water?

Answer 6

water obtained from the krebs cycle and electron transfer chain

Question 7

What happens once a dairy cow begins lactation

Answer 7

increased water loss as a result of milk production and increased fecal output

Question 8

A feline patient presents to the emergency room in Tucson after having been stuck outside for a whole day. The cat is now dehydrated. From which body compartment is water lost in the early stages of dehydration?

Answer 8

extracellular fluid

Question 9

Coming back to the dehydrated feline patient. What would you expect to see on blood tests for this cat?

Answer 9

electrolyte levels should be normal is the kidneys are working

Question 10

Due to it being the most common extracellular ion, which would be the most important electrolyte to supplement in your fluid replacement plan for this cat?

Answer 10

sodium

Question 11

If you were to provide this cat with intravenous fluids, which type of fluid would be most likley to cause the cat’s red blood cells to fill with water and burst?

Answer 11

hypotonic saline

Question 12

body fluid takes up more volumes than body water because

Answer 12

it has solutes in it

Question 13

what body compartment contains a higher percentage of total body water

Answer 13

intracellular

Question 14

what molecule would exert greater osmotic pressure when in water, glucose or NaCl?

Answer 14

NaCl

Question 15

what odes isotonic mean in relation to red blood cells?

Answer 15

fluid has the same osmotic pressure as the RBC

Question 16

if the RBC was placed in hypertonic solution, which way would water want to go?

Answer 16

water would move from the RBC to the extracellular fluid

Question 17

if the RBC was placed in a hypotonic solution, which way would water move?

Answer 17

water would move from the extracellular fluid into the RBC

Question 18

when an animal is mildly dehydrated, the electrolyte levels will typically be

Answer 18

normal because electrolytes are excreted through the kidneys in proportion to water loss in an attempt to keep things in balance

Question 19

in early dehydration, where is fluid lost from?

Answer 19

extracellular fluid

Question 20

If a 11lb (5 kg) cat is 10% dehydrated, about how much fluid needs to be replaced?

Answer 20

0.5 L

Question 21

A racing horse weighs 500 kg. During a race, horses lose fluid through sweating and other insensible losses. After the race, you are asked to replace fluid losses. Therefore, you must calculate the estimated body fluid compartment volumes. The horse is estimated to have a total body water percent of 60%. Calculate what the volume of these body fluid compartments would be: ICF, ECF, ISF, and P (plasma).

Answer 21

ICF: 200L, ECF: 100L, ISF: 75L, P: 25L

Question 22

If a 500 kg horse was 5% dehydrates, how much fluid would roughly have to be replaced if you were to rehydrate the horse?

Answer 22

25L

Question 23

Imagine you are treating an 18-week old puppy with parvovirus. Parvovirus is a viral infection that attacks white blood cells and gastrointestinal cells to cause severe vomiting and diarrhea, particularly in puppies. The puppy has severely decreased skin turgor (a skin tent), has low blood pressure and his eyes are sunken. You suspect he is severely dehydrated (10% dehydrated). The best way to rehydrate a severely dehydrated animal is to give fluids directly into the bloodstream (intravenously). Intravenous fluids come in several different formulations. Most of them have saline in them (NaCl) and are isotonic. They can also be hypertonic or hypotonic. Which type of fluid would be the best choice to ensure that the puppy’s RBCs do not swell up or shrink when the fluid is given IV?

Answer 23

Isotonic

Question 24

Some fluids that can be used IV contain NaCl and some also contain glucose. When added to a fluid, which molecule would most increase the osmotic pressure of that fluid?

Answer 24

NaCl