Flashcards in fluid and electrolytes Deck (107):
How much of body mass is water?
How many mls are required per day for life?
How much water do we typically consume a day?
what is a healthy daily water consumption?
What does out water balance affect?
cardiovascular function (blood pressure)
What are some factors that affect water balance?
What makes up total body water (TBW)?
what is extracellular fluid composed of?
lymoh, synovial, intestinal, biliary, hepatic, pancreatic, CSF, sweat, urine, pleural, peritoneal, pericardial, and intraocular fluids
Where does ADH (vasopressin) come from?
where does ADH act?
collecting Duct of Nephron
what does ADH do?
causes insertion of aquaporins into collecting duct which leads to water reabsorption by kidneys.
What does ADH do?
regulates urine flow by increasing the permeability of the renal collecting duct to water.
more water is removed from the urine when ADH is present.
How do baroreceptors in the aortic arch and carotid sinus regulate ADH?
It sensing the decrease in blood pressure
How does the hypothalamic osmoreceptor regulate ADH?
it detects increased plasma osmolarity which then reduces blood volume.
right arterial stretch as well as a alcohol and caffeine _____ ADH release
as blood pressure ______, urine flow _____.
as blood pressure increase, urine flow increases.
where is aldosterone released from?
what does aldosterone regulate?
sodium and potassium balance.
how does aldosterone increase sodium?
Sodium reabsorption from the urine and sweat
uptake from the gut
how does aldosterone decrease potassium?
by increasing secretion into the urine
Atrial natriuretic peptide or factor
the signal to increase or decrease blood volume
When is ANP released from the right atrium?
when the atrium is stretched as a cause of high venous blood volume and congestive heart failure.
what are pressures that determine the movement of water between vessels and tissues (capillary shift)?
the physical pressure that the fluid is excerting on walls
a function os heart beat, water volume, gravity and vessel size
its kinda of a pulling pressure. Is there is a compartment with more "stuff" it will have a higher oncotic pressure. The more proteins the more it will pull water in.
it's a function of plasma proteins
Capillary hydrostatic pressure
out of the capillary
plasma oncotic pressure
into the capillary
interstitial hydrostatic pressure
out of the interstitial fluid (into the capillary)
interstitial oncotic pressure
into the interstitial fluid (from the capillary)
How much water comes out the Arterial end of capillaries?
How much water comes out of the venous end of the capillary?
the hydrostatic pressure is _____ as the blood goes through blood vessels
Where is the high pressure zone in a capillary?
the arterial end
where is the low pressure zone in a capillary?
the venous end
Why is interstitial fluid hydrostatic pressure (IFP) negative compared to atmospheric pressure?
It is because of draining of fluid from the tissue by the lymphatic vessels.
the IFP is pushing toward the capillary but it's not strong enough to counter the hydrostatic pressure pushing out so the net pressure is going out.
What is the value for interstitial hydrostatic pressure?
neg bc its coming out then going in like it wants
Plasma oncotic pressure (POP)
The blood contains large amounts of protein and this exerts an osmotic pressure.
What is the value of the POP?
28 mHg going into the blood (capillary)
Interstitial fluid oncotic pressure (IFOP)
the interstitial fluid has small amounts of protein that pulls fluid into the tissues (out of the blood).
What is the value for IFOP?
8 mmHg out of the blood (capillary)
which pressures occur through the length of the vessel?
plasma oncotic pressure
interstitial fluid oncotic pressure
interstitial hydrostatic pressure
Where does water and dissolved solutes move out of the capillary and why?
at the arterial end because of the pressure which is 13 mmHg out.
Where does water and dissolved solutes move into the capillary?why?
At the venous end because of the pressure which is 7mmHg in.
Where does lymphatic fluid come from?
the 2 ml/min of water that leaves the arterial end of the capillary does not return at the venous end of the capillary
the accumulation of fluid within the interstitial spaces.
what does edema cause?
increase in capillary hydrostatic pressure
diminished plasma albumin
increases in capillary permeability
unilateral limb edema
affects one limb on one side
caused by venous or lymph obstruction
caused by congestive heart failure because it increases hydrostatic pressure which makes it so that your heart can't bring fluid from veins back into heart.
Edema in the face
caused by hyprproteinemia and as conditions worsen it causes edema of the abdomen.
What is the purpose of edema?
maintain function of organs
prevent tissue damage
what are treatments of edema?
elevation of affected area
Blockers of angiotensin II receptors.
blockers tell body to reabsorb water.
Active Learning Exercise
A person with chronic heart failure has edema in the lower legs and sacral area. This is due to a(n):
Increase in capillary hydrostatic pressure
increased total body water
decreased total body water
What is an important indicator of water amount in the blood?
the % of the blood that is cells
what is a normal hematocrit for males and females?
males : 42-45
What might changes in hematocrit indicate?
changes in plasma volume
increase in hematocrit suggests plasma volume may be ______
decrease in hematocrit suggests plasma volume may be ____
what causes hypvolemia ?
losing water through:
uncontrolled diabetes mellitus
Why should isotonic hypovolemia be treated with 0.9% saline?
because .9% is isotonic saline.
Why should pure water not be used to treat isotonic hypovolemia?
it will cause osmolarity to go down (water will goto higher concentration)
Why is pedialyte used to treat a child with fluid loss due to vomiting or diarrhea?
because it gives them back some of the things other than water that they are losing.
What causes hypervolemia?
excess administration of isotonic fluids
chronic renal failure
congestive heart failure
increase aldosterone when normal deefback inhibited (aldosterone or renin-secreting tumor)
what are some clinical manifestations of hypervolemia?
sudden weight gain (water weight)
if BP is high then severe headache
dyspnea (shortness of breath)
cough (fluid in lungs)
What are some treatments of hypercolemia?
what is normal plasma sodium concentrations?
what is normal plasma potassium concentration?
sodium is less than 135 mEq/L
potassium less than 3.5 mEq/L
sodium is greater than 150
plasma potassium conc is greater than 5.0
what is normal osmolarity?
what causes hyponatremia?
excess addition of fluid whose osmolarity is less than that of body fluid
decrease in Na intake
adrenal failure (dec aldosterone)
water replacements after excess diaphoresis, vomiting, diarrhea, or gastrointestinal tract aspiration
Psychogenic polydipsia (compulsion to drink lots of water)
decreased fluid excretion due to renal disease
fluid therapy in patients with high ADH levels.
what are some clinical manifestations of hyponatremia?
reduced action potential which leads to:
-lethargy, confusion, apprehension, seizure, coma
how do you treat hyponatremia?
treat cause of condition
how do you treat hyponatremia if total body water is low (hematocrit high)?
replace fluid with a solution rich in sodium (ez .9% saline) and a diet rich in sodium
how do you treat hyponatremia if total body water is near normal?
provide a diet rich in sodium
how do you treat hyponatremia is total body water is high?
restrict water intake and provide diet rich in sodium.
what do you do in emergency cases of hyponatremia?
give small amounts of hypertonic saline via IV
this is rare.
what causes hypernatremia?
decrease in water intake
increased output of water
excess sodium intake (rare)
what can cause hypernatremia?
dysphagia (difficulty swallowing)
profuse dilute sweating
polyuria of diabetes (insipidus or mellitus)
what are clinical manifestations of hypernatremia?
calls shrink and water moves from the ICF to ECF because of high osmolarity of ECF
pulmonary edema (cough, dyspnea)
dry mucous membrane
what should you do to treat hypernatremia?
how should you treat hypernatremia if total body water is high (low hematocrit)?
you can use diuretics
how should you treat hypernatremia if totaly body water is low (high hematocrit)?
provide fluid low in sodium (5% dextrose in water)
what happens if you have chronic hypernatremia or hyponatremia?
the CNS has a protective mechanism that permits it to adjust to long term (several days) changed in ECF osmolarity by altering the intracellular content of specific molecules names neuronal osmolites.
the imbalance needs to be changed slowly to prevent damage to the CNS.
Laboratory test of the man in the previous slide revealed a hematocrit of 40% and plasma sodium concentration of 120 mEq/L (120 mM). What would be the ideal treatment of this patient?
he has enough water so we wouldn't want to treat with saline so we would just treat with a diet rich in sodium.
how do we regulate potassium when it if in excess or deficient?
the source of potassium is diet so control your intake.
kidneys reabsorb K+ in proximal tubule. the distal tubule and collecting duct can either reabsorb or secrete potassium.
potassium has direct effects on kidneys. therefore, when K+ is ____ secretion is ____ and vice versa
when K+ is high secretion is high
tissue damage ____ plasma potassium. Why?
increases because potassium moves out of cells upon cell death.
ex. burn wounds
Plasma K+ _____ during healing. Why?
decreases, because K+ moves into cells during new cell growth.
insulin _____ plasma K+
diurectics ____ K+ loss in the urine
increase. So you lose more K+ in urine?
aldosterone ____ K+ excretion
what can lower activity of the Na/K pump?
What happens to the Na+/K+ pump when insulin is very high?
It speeds up and pushes Na out which then causes hyperkalemia because the cells will get bigger and will then need more K+
What are some causes of Hypokalemia?
decreased potassium intake
Healing stage of trauma/burns
insulin therapy (injections)
corrected long term acidosis
what are some clinical manifestations of hypokalemia?
hyperpolarization so cells are further away from threshold so its harder to get an action so potion. which then causes:
how can we treat hypokalemia?
oral K+ supplements
slow infusion of small amounts of K+ IV.
In emergency: IV push of K+
Should be monitored with ECG through procedure.
what are some causes of hyperkalemia?
large increase in K+ uptake
tissue trauma (early)
extremely low Na diet (too little aldosterone)
correction of long term alkalosis
what are clinical manifestations of hyperkalemia?
muscle weakness (in relative or refractory period)
flaccid, dilated heart (heart in relative or absolute refractory period)
nausea, vomiting, diarrhea
digital numbness and tingling
what are some ways to treat hyperkalemia?
correct condition that caused problem
oral or rectal cation exchange resins (bind potassium)
insulin and glucose injections
total body water change with proportional electrolyte and water change.
-isotonic volume depletion
-isotonic volume excess