Electrolytes and Fluid Flashcards
Fluid Balance at the Capillary Level relies on a balance between what two forces?
(pushing force of) hydrostatic pressure and (pulling force of) oncotic pressure
At the arterial end of the capillary, is hydrostatic pressure is higher or lower the oncotic pressure?
Higher
At the arterial end of the capillary, hydrostatic pressure is higher than oncotic pressure in the capillary, so fluid moves and is pushed IN or OUT?
Out (into the interstitial space)
Current research shows interstitial hydrostatic pressure has a small negative or positive value?
small negative value
Current research shows that interstitial hydrostatic pressure has a small negative value and contributes slightly to the movement of fluid from the ____________ to the __________
capillary and tissue
At the venous end of the capillary, much of the fluid has moved to the interstitial space, leaving what behind?
solutes (in particular, the plasma proteins)
At the venous end of the capillary, this creates a higher or lower capillary osmotic pressure?
Higher
At the venous end of the capillary, much of the fluid has moved to the interstitial space, leaving the solutes (in particular, the plasma proteins) behind
This creates higher capillary osmotic pressure which effectively does what to the fluid?
pulls fluid from the interstitial space back into the vessel
At the venous end of the capillary, much of the fluid has moved to the interstitial space, leaving the solutes (in particular, the plasma proteins) behind
This creates higher capillary osmotic pressure which effectively pulls fluid from the _______________ __________ back into the _______
Some particles (such as glucose and electrolytes) move from the vessel into the interstitial space and creates interstitial colloidal osmotic pressure, pulling a small amount of fluid into the interstitial space
interstitial space and vessel
At the venous end of the capillary, much of the fluid has moved to the interstitial space, leaving the solutes (in particular, the plasma proteins) behind
This creates higher capillary osmotic pressure which effectively pulls fluid from the interstitial space back into the vessel
Some particles (such as _________ and ____________) move from the vessel into the interstitial space and creates interstitial colloidal osmotic pressure, pulling a small amount of fluid into the interstitial space
glucose and electrolytes
Excess interstitial fluid is taken up by what?
the lymphatics (and returned to the central circulation)
To review, fluid balance is determined by the push and pull of fluids across what type of membrane?
Semi-permeable capillary membrane
Normal movements of fluids depends on the integrity of the capillary membrane.
True or False?
True
Increased capillary hydrostatic pressure can cause what to occur?
high amounts of fluid to leave the capillary
If hydrostatic pressure continues to be high at the ends of the capillary, net movement will be IN or OUT of the capillary?
Out (of the capillary)
Increased capillary hydrostatic pressure can result from what two reasons?
Hypertension and from an increase in fluid volume (for example in the case of sodium and water retention)
Hydrostatic pressure also increases if there is any back-up of blood flow.
- For example, a DVT might obstruct venous blood flow, resulting in a higher than normal pressure at the venous end of the capillary.
True or False?
True
A lack of sufficient capillary oncotic pressure could occur. What does oncotic pressure do, push or pull the fluid? At which end of the capillary?
Pull the fluid (back into the intravascular space) and at the venous end
What is the most prevalent colloid (or solid) in the plasma?
albumin
Any clinical situation that results in decreased albumin, can result in a decrease of what type of pressure?
capillary oncotic pressure
What are 4 common medical diagnoses associated with low albumin?
burns, liver disease, malnutrition, and excessive wound drainage
Increased interstitial colloidal osmotic pressure could occur. In this case, what could escape into the interstitial fluids? What do they take with them and where is it held?
solutes (particles) and they will take fluid with them and hold that fluid in the interstitial space
Recall that the capillary should only allow _________ solutes to escape.
some
Capillary permeability increases in response to what of the inflammatory process (leaky capillaries)?
chemical mediators
An increase in tissue hydrostatic pressure could occur. The can happen when what is obstructed?
lymphatics (fluid is not removed)
What can occur if there is an increase in tissue hydrostatic pressure, the lymphatics are obstructed for some reason and do not remove excess fluid.
Lymphedema
The fourth mechanism that results in fluid imbalance is an increase in tissue hydrostatic pressure.
This can happen when the lymphatics are obstructed for some reason and do not remove excess fluid.
They are also complicated by increased tissue oncotic pressure which continues to pull fluid from the vessel.
True or False?
True
An increase in tissue hydrostatic pressure could occur.
Lymphatic obstruction can occur in what two instances?
liver disease or from physical obstruction from surgery
What can represent an increase in fluid in the interstitial space?
Edema
When there is an increased capillary hydrostatic pressure, it causes what?
fluid to move into the tissue (eventually edema)
What does a decrease in plasma proteins result in?
The lack of “pull” factors means that fluid remains in the interstitial space instead of moving back to the vessel.
decreased capillary oncotic pressure (this is edema)
Leaky capillaries or increased capillary permeability results in the loss of what to the interstitial space?
This movement is accompanied by fluid and the solutes keep the fluid in the interstitial space.
intravascular proteins and other solids (this is edema)
Lymphatic obstruction results in decreased absorption of what?
interstitial fluid (therefore is edema)
What is it known as when fluid shifts into the transcellular space and cannot be pushed or pulled out of that space OR if there is an obstruction to lymphatic flow and fluid becomes trapped?
(The transcellular compartment is a small subdivision of the extracellular fluid compartment)
third spacing
What are some examples of transcellular space?
joint spaces, the pericardial and pleural cavities, the peritoneum and ocular fluid
Normally, fluid moves in and out of transcellular spaces using the same mechanisms as usual.
True or False?
True
As with edema (fluid trapped in the interstitial space), the fluid is not readily available for exchange with ECF and therefore is referred to as what?
non-functional
In the brain, edema is associated with what two things?
infectors or trauma (both initiate an inflammatory response)
Although the skull is an enclosed space with little room for extra fluid, cerebral edema is not very life threatening.
True or False?
False
Because the skull is an enclosed space with little room for extra fluid, cerebral edema is life threatening
What are these signs of:
headaches, altered level of consciousness or coma, abnormal pupil size or reflexive response, changes in patterns of respiration, and changes in muscle tone and abnormal posturing
Intracranial Pressure (ICP)
Swelling of airway constitutes what?
an acute, life-threatening condition
Swelling of airway constitutes an acute, life-threatening condition
It is frequently due to an inflammatory response to what two things?
allergens or microorganisms
What may result in difficulty swallowing, anxiety, stridor, possible airway obstructions, and asphyxia?
Airway swelling
When fluid is forced out of the capillaries at the level of the lungs and accumulates around the alveoli, the result is a decrease in what two things?
a decrease in gas exchange and a decrease in the ability of the lungs to inflate
What type of edema may occur with the presentation of these symptoms:
anxiety, restlessness, diminished breath sounds, and/or crackles
lung edema
What type of edema may occur with the presentation of these symptoms:
anxiety, restlessness, diminished breath sounds, and/or crackles
lung edema
What is the term for fluid that collects in the peritoneal cavity? Is this an example of third spacing?
ascites and yes
With abdomen edema, this accumulation of fluid could be due to increased intravascular hydrostatic pressure that results when which vein is affected?
the portal vein (by liver cirrhosis)
With abdomen edema, a significant inflammatory response to something like an abdominal girth and a protruding umbilicus.
True or False?
True
With abdomen edema, the client may complain of abdominal discomfort and if the accumulation of fluid is considerable, shortness of breath when the expansion of the diaphragm is impeded by fluid.
True or False?
True
With intestinal edema, clients may experience a third space loss of fluid inside where?
the lumen and wall of the intestine, if obstructed
What are the two reasons why peripheral edema may occur?
obstruction of venous blood flow (which increases capillary hydrostatic pressure) and due to obstruction in lymphatic drainage
Where does peripheral edema predominately occur in ambulatory patients?
lower extremities
Where does peripheral edema predominately occur in bedridden patients?
sacral area
Peripheral Edema can occur:
Predominantly in the lower extremities in ambulatory patients
Also occurs in the sacral area in bedridden patients;
In both cases, this is referred to as what?
“dependent” edema
Edema that is related to salt retention is usually called what?
(When a finger is pressed into the edematous area, the fluid in the soft tissue shifts and when the finger is removed, a “pit” is evident)
“pitting” edema
What type of edema is only apparent after significant amounts of fluid have collected?
Overt edema
Health care team (doctors, nurses, etc.) need to determine the mechanisms underlying a client’s edema, then treat/correct accordingly to correct or control what?
the cause
Treatment may be simple or complex for edema, depending on the situation?
True or False?
True
If edema is related to malnutrition and the lack of albumin, an obvious solution would be to ensure the client consumes what?
adequate amounts of protein
If the mechanism responsible for edema is a lack of albumin intravascularly, but the problem is that a massive inflammatory response has created capillary permeability so protein is leaking from the vessels.
The treatment of this problem would be more complex.
In this case, the client would require transfusions of albumin or other colloid solutions to increase the capillary oncotic pressure, but unless the problem of increased capillary permeability is resolved, albumin will continue to move to the interstitial space and will take fluid with it, increasing the edema
True or False?
True
The body’s fluid-conserving mechanisms can further complicate the problem of edema
What body part will conserve water and sodium, effectively increasing the capillary hydrostatic pressure and increasing the edema?
the kidneys
When there increased ECF volume, what type of therapy is commonly used?
(For those with hypertension and edema)
Diuretic therapy
For pregnant clients who had swelling of her ankles due to increased hydrostatic pressure, they should do what?
Keep legs elevated and not stand for extended periods of time to decrease swelling in ankles.
Clients who have peripheral edema due to heart disease should wear _______________ _______________ to increase interstitial fluid pressure, thereby providing some resistance to the movement of fluid from the capillary to the interstitial space
supportive stockings
Edema and third-space fluid shifts are examples of what?
loss of intravascular fluid volume
Movement of body fluid between the Intracellular Fluid (ICF) and Extracellular Fluid (ECF) compartments, depends on what?
The ECF levels of water and of sodium
What is the primary solute in the ECF?
Sodium
What is the major regulator of sodium and water balance?
the amount of circulating blood volume
Our bodies strive to maintain __________ ____________ ___________ to effectively perfuse tissues, supplying them with nutrients and removing wastes.
adequate vascular volume
The Fluid Balance Receptors or Sensors pick up messages in the body about the adequacy of our circulating fluid volume.
True or False?
True
What type of receptors are located in the hypothalamus and keep track of the osmolality (concentration of the blood)?
Osmoreceptors
Where are osmoreceptors located?
In the hypothalamus
What are osmoreceptors responsible for?
Keeping track of the osmolality (concentration of the blood)
What type of receptors are located on the blood vessel walls and in the kidneys and measure the stretch in the vessel walls that is produced by blood volume and blood pressure?
Baroreceptors
Where the two places that are baroreceptors located?
on the blood vessel walls and in the kidneys
What are baroreceptors responsible for?
They measure the stretch in the vessel walls that is produced by blood volume and blood pressure
The body uses several mechanisms of fluid balance in response to messages from the osmoreceptors and baroreceptors including what 5 things?
Thirst, ADH, Sympathetic Nervous System, Renin-Angiotensin-Aldosterone System, and Natriuretic Peptides
What is the primary regulator of water intake?
Thirst
Normally, we drink without being “reminded” by the thirst mechanism.
True or False?
True
Sometimes, our bodies can experience unanticipated decreases of blood volume or increases in osmolarity, that alter the body to take what?
corrective action
When eating a lot of salty food, the thirst mechanism will prompt you to do what?
drink more
Thirst develops only with a large change in fluid volume or osmolarity.
True or False?
False
Thirst develops with even a small change in fluid volume or osmolarity
Other than thirst, what is the second mechanism of fluid regulation?
ADH (antidiuretic hormone/vasopressin)
Where is ADH made and then stored?
hypothalamus and posterior pituitary
What can the Hypothalamus can detect?
low blood volume or increased osmolality
What does the hypothalamus do after it detects low blood volume or increased osmolality?
send a signal to the posterior pituitary to release ADH
ADH acts on the kidney tubules to ________ ________ and therefore increases _________ ___________ and reduces serum osmolality
retain water and blood volume
Which nervous system responds to changes in arterial blood pressure and blood volume in several ways?
Sympathetic Nervous System
Sympathetic Nervous System responds to changes in arterial blood pressure and blood volume in several ways
By regulating the constriction or relaxation of the afferent and efferent arterioles in the kidney, what can be controlled?
The amount of glomerular filtrate can be controlled
When the Sympathetic Nervous System is stimulated, the ____________ _____________ will constrict therefore limiting the amount of blood flow to the kidney and ________________ glomerular filtration pressure
afferent arterioles and lowering
What does sympathetic activity regulates?
the reabsorption of sodium
Sympathetic Nervous System stimulation results in the release of what?
release of renin
What is the hormonal regulator of fluid balance?
Renin-Angiotensin-Aldosterone System
If circulating blood volume drops, there is less blood flow to the glomerulus, so less _______ ____________ ____________.
renal perfusion pressure
Juxtaglomerular cells in the kidney sense the reduced stretch of the afferent arteriole because of what?
reduced blood flow
Renin-Angiotensin-Aldosterone System (R-A-A-S) causes an increase in release of _______, which acts as an enzyme to convert _______________________ to _____________________
renin, angiotensinogen, andangiotensin I
Angiotensin I is converted to angiotensin II (the active angiotensin) by which enzyme?
ACE (angiotensin converting enzyme)
Angiotensin II (when activated) acts directly on kidney tubules to increase _____________ ________________ and stimulates the production of ___________________ in the adrenals
sodium reabsorption and aldosterone
Aldosterone works in the what parts of the kidney to promote exchange of sodium and potassium
distal tubule
Aldosterone works in the distal tubule of the kidney to promote exchange of sodium and potassium. Is sodium reabsorbed or lost?
reabsorbed
Aldosterone works in the distal tubule of the kidney to promote exchange of sodium and potassium. Is potassium reabsorbed or lost?
Lost
When sodium is reabsorbed, what does it bring with it that results in an increase in circulating blood volume?
Water
What provides a counterbalance to the activity of baroreceptors, ADH and the Renin-Angiotensin-Aldosterone System (R-A-A-S)?
Natriuretic Peptides
What are examples of Natriuretic Peptides? (What do they respond to?)
ANP and BNP (Respond to increased BP and volume)
Natriuretic Peptides Cells ANP and BNP respond to increased BP and volume and can cause the kidneys to do what?
increase sodium and water exertion
Natriuretic Peptides Cells ANP and BNP respond to increased BP and volume.
These cells can cause the kidneys to increase sodium and water excretion by:
- Suppressing renin levels
- Decreasing aldosterone release
- Causing vasodilation
True or False?
True
Infants have a lower percentage of body water than adults
True or False?
False
Infants have a higher percentage of body water than adults
Where is more than half of infants total body water found?
Extracellular compartment
Infants ingest and excrete a relatively higher daily water than who?
adults
Infants may exchange up to half of this daily extracellular Fluid and have a smaller reserve of body fluid than adults.
True or False?
True
Why is fluid exchange is greater in infants?
Because of their high metabolic rate
Infants are at risk for fluid imbalances because of the inability of infant’s immature kidneys to do what efficiently?
concentrate urine
Why do infants lose a relatively greater fluid loss through the skin than adults?
Because of their proportionally greater body surface area
Both infants and children have immature homeostatic regulating mechanisms therefore they cannot respond as efficiently as adults, to small changes in fluid balance.
True or False?
True
Aging kidneys experience a decrease in _______________ and a decrease in ___________
glomeruli and GFR (Glomerular Filtration Rate)
Who has a decreased ability to concentrate urine?
Infants and elderly
Elderly individuals are slower to respond to sodium and water imbalances, including having a decreased response to ________ and a decrease in secretion of _____________
ADH and aldosterone
The elderly have a reduction in total body water
True or False?
True
Thirst sensation decreases or increases with age.
Decreases
