Fluid Balance and Acid Base (MR) Flashcards
Total Body Water is what % of body weight?
60.00%
ICF is what % of Total Body Water? ECF?
66% 33%
What % of ECF is Intravascular? What fluids are Intravascular?
25% Plasma – proteins Blood What % of TBW is Blood Volume? 8% What % of ECF is Interstitial? What is in Interstitial fluid?
What is basically the same between intravascular fluid (Plasma) and interstitial fluid?
Solutes
What % of ECF is Transcellular? What is in transcellular fluid?
25% Synovial Peritoneal CSF Intraocular
Hydration is a physiological balance between?
Interstitial and intravascular fluid
2 organs with big spaces in the vasculature?
Spleen Liver
2 organs where there are there are no spaces in the vasculature?
Brain (BBB) Prostate (BPB)
What are the 4 main forces of Starlings forces?
Interstitial Oncotic (∏i) - pulling fluid out Capillary Oncotic (∏c) - pulling fluid in Interstitial Hydrostatic (Pi) - pushing fluid in Capillary Hydrostatic (Pc) - pushing fluid out P = Hydrostatic Pressure - water thru your garden hose. C = Capillary I - Interstitial ∏ = Oncotic
What is the sum of all the forces?
Net Fluid Movement
When can it be a more influential component? Why is there water in the abdomen?
∏I , Dz State
A 10 yo female spayed Shitzu presents to you with grade 4/6 tricuspid systolic murmur and a belly full of fluid. You stick a needle in it and its a transudate. Why is the water in the belly?
Pc is ↑ due to backup of blood back into body from right side of heart
You have a 6yo Sharpei with chronic dxa and he’s got limb edema and mild ascites. Why is the fluid where it is?
↓ ∏c due to ↓ in TP - shitting it out - PLE
Normal dog, nothing wrong with it. Doing a study on Hetastarch which is an Oncotically (∏) active fluid. If you give him Hetastartch, what is going to happen to his interstitial fluid compartment?
↑ in ∏c - pull fluid from interstitium into capillaries
K factor in the equation is related to? What does it affect?
Leakiness of vasculature Fluid will move more easily in areas that are leakier like the spleen and liver
The role of lymphatics: You have a dog with limb edema and a very enlarged inguinal LN, why is there leg edema?
Pi - backup of lymphatics will cause a backup of interstitial fluid and an ↑ in Pi
What do lymphatics drain?
Interstitium
Effective Osmols: ECF?
Na+ Cl- HCO3-
Effective Osmols: ICF?
K+ PO4- ICF Proteins (too big to get out)
How much Na+ is there in ECF? ICF?
142 mEq/L 10 mEq/L
How similair is plasma to interstitial fluid? They are both ______?
Very Similar Extracellular
How much K+ is there in ECF? ICF?
4 mEq/L 140 mEq/L
How much Ca2+ is there is ECF? ICF? Then, where the hell is all this “oh so important” Ca2+?
5 mEq/L <1 mEq/L Hidden away in lil compartments inside the cell. Like Binladen.
Where can fluid move freely between for the most part? Where can it not?
Interstitium & Plasma ECF & ICF
Tonicity is regulated by? Where/how is it restricted?
Effective Osmols (EOs) ICF by membrane
Isotonic?
same concentration of EOs inside and out of cell
Hypotonic?
Less EOs outside/More Eos inside of cell and fluid enters cell
Hypertonic?
Less Eos inside/More EOs outside of cell and fluid exits cell
What is the Osmosis Cheer?
Water follows solute hey!
What is dehydration? Who bears the brunt of the fluid loss?
Loss of bodywater due to hypertonic ECF ICF
What is the hallmark of dehydration? Why?
Hypernatremia It is the 1º ECF so if it is ↑, you know dehydration! What does body care about more, water in cells or water in vasculature? When ECF becomes hypertonic and water exits cells. Volume in vasculature to stay alive, even to detriment of cells
What behaviors/situations lead to thirst?
Fever Panting lack of water
What are the two types of thirst?
Hypovolemic Osmotic
Ostmotic Thirst: what signals to brain that you need to drink?
Na+
What is the pathway of signaling that leads to water conservation?
Osmosensory neurons to preoptic area = ↑ Vasopressin release to ↑ water conservation and to hypothalmus to ↑ thirst and make you drink
Hypovolemic Thirst: what is the difference and where are the signals involved in correction?
Volume is the concern Cardiac Baroreceptors signal to brainstem Kidney Baroreceptors to trigger Angiotensin II signal to subfornical Then, both brainstem and sf organ signal Preoptic Area
Explain the common portion of the thirst and water conservation mechanism?
Water Conservation: Preoptic Area to Supraoptic nucleas & paraventricular nucleas to release Vasopressin and inact water conservation
What is hypovolemia?
Water & Electrolyte Loss
What is the change in water balance with Isotonic water loss?
None
Which compartment is primarially affected with hypovolemia? Causes?
Intravascular Hemorrhage GI loss Burns Tissue Injury
With hypovolemia, what is the cascase of events?
↓ Blood Volume - ↓ Venus Return - ↓ Stroke Volume - ↓ Cardiac Output ↓ Tissue Perfusion
What can you test to see if you have a ↓ in tissue perfusion?
Lactate
What do baroreceptors respond to?
Blood Pressure and Volume
What 2 mechanisms do Baroreceptors turn on to correct pressure and volume?
Neuro Mechanisms Endocrine Mechanisms
What are the neuro mechanisms turned on by baroreceptors?
Baroreceptors Chemo receptors Cardiovascular centers Sympathetic Activation to release Epi and NE leading to ↑ Cardiac CO
What is the result of the neural mechanism?
↑ CO Peripheral Vasoconstriction ↓ BP ↓ Venous Reserve
What are the Endocrine mechanisms turned on by baroreceptors? What is the combined effect?
ADH Angiotensis II Aldosterone EPO ↑ Blood Volume
What does Angiotensin II do?
↑ Sympathetic System Tubular reabsorption of Na+, Cl-, & Water follows (& K+ excretion) Powerful Vasoconstrictor - ↑ BP
ADH Secretion from Posterior Pituitary - Collecting duct H2O absorption