Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ANAT 1111 > FLUID BALANCE > Flashcards

FLUID BALANCE Flashcards

1
Q

state the percentage of body mass which is made up of water, and describe the factors which effect this?

A

*approximately 60% of total body mass (TBM) is water, but varies with:
—age: newborns have 75% water, declined to 60% by 1 y/o
—amount of adipose tissue: woman have more adipose tissue to 55% of TBM water
—obesity reduces water percentage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

explain how fluid is compartmentalised?

A

-an average 70kg has approximately 40L of fluid (60% TBM)
*fluid is compartmentalised by:
—intracellular
—extracellular (intestinal, vascular [plasma])

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

explain the significance of compartmentalisation?

A

*interstitial and intracellular compartments act as fluid reservoir for the vascular compartment
—this facilitates homeostasis of BP and ensures perfusion of vital organs
*there is constant fluid and electrolyte movement between compartments to ensure cells constantly supplied m with requirements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe the signs of dehydration?

A

*only occur when reverse of interstitial is already depleted
—patient in negative balance if several litres
*altered vital signs and blood chemistry are Kate signs of dehydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe the importance of fluid balance in health?

A

-fluid intake is balanced with fluid output during normal health
—kidneys are the main regulator of fluid stability
-homeostasis is key as water loss of as little as 1-2% impairs cognition and physical performance
—loss of 7% body water can lead to circulatory collapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

list examples of micro control of homeostasis of fluid balance between compartments?

A
  • osmotic pressure
  • hydrostatic pressure
  • capillary permeability
  • lymphatic drainage
  • tissue expansion potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

list examples of macro control of homeostasis of fluid balance between compartments?

A
  • hormonal regulation (RAAS, ADH)

- homeostasis: constant flux but net equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

explain how body fluids remain electrically neutral?

A
  • negative electrons follow a positive charge which is moving (Na+, Cl-) or a different positive electron will go in the other direction (K+)
  • water likes equilibrium so does this by osmosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

define osmosis?

A

-type of diffusion from a less concentrated solution to a more concentrated solution, aiming to equalise both solutions
-electrolytes and plasma proteins are the main solutes which affect concentration
—electrolyte movement alters concentrations- influencing water movement by osmosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

define the word electrolyte?

A
  • dissolved chemicals with a balance of positive and negatively charged atoms that separate into ions when dissolved in water
  • table salt (NaCl) becomes Na+ and Cl- when dissolved in water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

explain the relationship between electrolytes and membrane potential?

A

-is essential we have balanced electrolytes to facilitate membrane potential for functioning of muscles and nerves
—key for vital body functions such as contraction of heart muscles and respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

name some important electrolytes needed in the body?

A

-sodium (Na+)
-chloride (Cl-)
-potassium (K+)
-bicarbonate (HCO3-)
-calcium (Ca2+)
-magnesium (Mg2+)
*capillaries are permeable to these ions so concentrations equal in interstitial fluid (ISF) + plasma
—but cell membrane controls movement of ions between cells and ISF so ion conc very different

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe the differences in electrolytes between extra cellular and intracellular fluid?

A

extracellular: sodium, chloride, bicarbonate
intracellular: potassium, phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the movement of water between different compartments?

A

-water and electrolytes move freely across capillary membrane
—allows movement between the vascular and interstitial compartments
-water and electrolytes can move across the cell wall, but much more tightly controlled
—allows movement between interstitial and intracellular compartments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe the forces which influence osmosis between capillaries and interstitial fluid?

A

-hydrostatic pressure
-osmotic pressure
—caused by proteins (colloid oncotic pressure)
—caused by electrolytes (crystalloid oncotic pressure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe fluid balance between capillary and interstitial fluid in health?

A

-colloid oncotic pressure generated by protein level in the blood, draws water out tissue into blood
—prevents oedema
-in hypertension (think): is the opposite, draws water out of blood into tissue
-in severe liver disease: fluid build up in abdominal cavity
-hormonal regulation of water movement also occurs (RAAS, ADH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

define the term electrical gradient?

A

opposites attract to try and achieve a neutral charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

define the term concentration gradient?

A

Ions flow from an area of high concentration to an area of low concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe the active pump mechanism of the cell membrane?

A

work via ion channels in the cell membrane

—sodium potassium pump (2K in, 3Na out)

20
Q

discuss the role of sodium in fluid balance?

A

-water always follows sodium (codependent)
-the overall sodium content determined overall water volume
-sodium balance and BP are codependent
—any alteration in electrolyte levels will alter BP
-diuretics increase renal sodium exertion

21
Q

discuss the role of the kidneys in fluid balance?

A

-if the body loses 1% or more fluids, the kidneys start to conserve water
—reabsorbing more water from renal tubules, resulting in concentrated urine
-the kidneys must excrete min 20mls per hour to eliminate body waste
-hormones control this response:
—ADH (anti diuretic hormone)
—RAAS (renin angiotensin aldosterone system)
—ANP (atrial natriuretic peptide)

22
Q

describe how the kidneys control blood volume by RAAS?

A

RAAS = renin angiotensin aldosterone system
-kidneys detect a low BP
—secrete renin
—changes to angiotensinogen (liver) to angiotensin I
—goes to the lungs and converted to angiotensinogen II which:
—constricts blood vessels
—stimulates thirst
—promotes aldosterone release from adrenal glands (kidneys reabsorb more sodium and therefore more water)
—triggers release of ADH

23
Q

describe how the kidneys control blood volume by ADH?

A
  • released by the pituitary gland

- directly causes kidneys to absorb more water

24
Q

describe how the kidneys control blood volume by ANP?

A

ANP = atrial natriuretic peptide
-released by muscle cells in the heart
—when heart muscles overstretched because of circularity overload
-blocks reabsorption of sodium
—indirectly stops water reabsorption by reducing renin and aldosterone in the blood

25
Q

describe the kidney conditions needed for optimal function?

A
  • fluid intake: 1.5-2.0L per day
  • BP: systolic 80-180mmHg
  • blood flow: cardiac output 1.2L per min
  • healthily functioning nephrons
26
Q

discuss dehydration?

A

causes blood compartment to become more concentrated
-water drawn into blood from interstitial fluid and kidneys conserve water
—not much change it vital signs since compensating
-when interstitial fluid depleted, decompensation starts (vital signs alter)
—negative balance of several litres
-fluid moved out of cells to interstitial space

27
Q

list the causes of dehydration?

A
  • gastrointestinal lost (diarrhoea)
  • fever
  • blood loss
  • burns
  • peritonitis (inflammation in peritoneum)
  • fluid shifts
  • diuretics
  • inhalation of dry gases
28
Q

what is oedema?

A

excess interstitial fluid
-fluid moved into interstitial spaces faster than can be reabsorbed at venous end/ drained drained by lymphatic system
—detectable after 10% increase
-excess accumulation of fluid in interstitial space
—detectable after 10% increase

29
Q

describe the 2 mechanisms of oedema?

A
  • local oedema: occur secondary to trauma and/or inflammation (vasodilation)
  • generalised oedema: occur secondary to cardiac or renal failure
30
Q

describe the causes of oedema?

A
  • inflammatory: increased capillary permeability = loss plasma protein = increased interstitial space pressure
  • hypoproteinaema: decreased albumin conc = decreased plasma colloid oncotic pressure
  • congestive (venous congestion): increased venous hydrostatic pressure = build up of metabolites and anoxia = increased permeability = protein loss etc
  • lymphatic blockage: mechanical flow obstruction e.g. tumour
  • sodium retention: various triggers including kidney disease
31
Q

what is third space loss?

A

-fluid gets trapped and accumulated in spaces normally not occupied by extracellular fluid
—due to injury or disease e.g. inflammatory response
-not available for normal physiological processes
—e.g. fluid in abdomen, pleura and joints
-although this fluid is in the body, it is lost from the balance equation so needs replacing
—loss is isotonic so can be replaced with isotonic fluid
-the fluid trapped in the third space represents a volume loss (hypovolaemia)
—clinically difficult to quantify since may not be reflected in weight changes/ fluid input or output
—may not be apparent until organ malfunction

32
Q

explain intravenous (IV) fluids?

A

-consist of sterile water with solutes
—can contain electrolytes such as proteins and starches (colloids)
-number of solutes in the fluid will influence osmotic pressure that the solution can exert
-this can be described as osmolality and osmolarity

33
Q

compare osmolality and osmolarity?

A
  • osmolaLity: mg per ml of fluid - weight per volume

* osmolaRity: millimoles per ml of fluid - number of particles

34
Q

crystal loss are described in terms of tonicity (osmolality), define tonicity?

A

the concentration of solutes dissolved in the solution compared with body plasma or inside the cells

35
Q

what is meant by the term hypotonic solution?

A

has a lower osmolality than plasma
-may exert osmotic pressure, shifting fluid from vascular compartment to interstitial and intracellular compartments
—will address cellular dehydration but may result in hypotension

36
Q

what is meant by the term hypertonic solution?

A

higher osmolality than plasma
-pulls water back into vascular circulation from the interstitial and cellular compartments
—usually used to correct electrolyte imbalance

37
Q

what is meant by the term isotonic solution?

A

same osmolality as plasma so no osmotic pressure exerted
-expand the intravascular compartment but have no effect on cells
—some fluid move into interstitial space by hydrostatic pressure depending on volume given *general fluid replacement

38
Q

describe how IV fluids work and when they are used?

A

work by manipulating hydrostatic and osmotic pressure

  • as replacement fluids e.g. replacing electrolytes lost
  • maintenance fluids when when patients nil by mouth or can’t drink from other reasons
  • provide a medium for medication administered
  • intraoperative fluids which may be maintenance or replacement for blood loss/ third space loss
39
Q

name 3 crystalloids along with their use and any considerations?

A

*hypotonic: use = shifts fluids out of vascular compartment into the cells
considerations = may worsen hypotension, increase oedema, cause hyponatraemia
*isotonic: use = no fluid shift, expansion of vascular fluid and electrolyte replacement
considerations = trigger fluid overload/ generalised oedema, dilutes haemoglobin
*hypertonic: use = shift fluid back into circulation with vascular expansion
considerations = irritates veins and trigger fluid overload and hypernatraemia

40
Q

name 4 colloids along with their use and any care considerations?

A

*albumin: use = keeps fluid in vascular compart, maintains volume, replace proteins/ treat shock
considerations = cause anaphylaxis, fluid overload and pulmonary oedema
*dextran: use = shift fluid into vascular compartment for vascular expansion
considerations = overload and hypersensitivity, increased risk bleeding
*hetastarch: use = shift fluid into vascular compartment for vascular expansion
considerations = overload and hypersensitivity, increased risk bleeding
*mannitol: promotes diuresis, refuse cerebral oedema, eliminates toxins
considerations = fluid overload, electrolyte imbalance, cellular dehydration

41
Q

describe hypovolaemia as a volume imbalance?

A
  • decreased extracellular fluid or blood volume only
  • causes: actual fluid loss or fluid shift
  • signs: dropping BP, decreased urine (concentrated) output, increased HR
42
Q

describe hypervolaemia as a volume imbalance?

A
  • excess fluid intake
  • causes: excess IV fluid, heart failure, renal failure
  • signs: dropping BP, decreased urine (dilate) output, oedema, dyspnoea
43
Q

describe hyponatraemia as an electrolyte imbalance?

A
  • low serum sodium levels
  • causes: renal/ cardiac failure, parenteral feeding and hyperglycaemia
  • signs: headache, nausea and vomiting, muscle cramps, confusion to coma
  • treatment: focused on treating the cause
44
Q

describe hypernatraemia as an electrolyte imbalance?

A
  • elevated serum sodium levels
  • causes: diarrhoea, decreased water intake
  • signs: lethargy, irritability, ataxia (loss muscle control in limbs), seizures
  • treatment: restore fluid volume with oral water or IV
45
Q

describe hypokalaemia as an electrolyte imbalance?

A
  • low potassium levels
  • causes: parenteral nutrition, diuretics, severe GI upset
  • signs: ECG changes, muscle weakness
46
Q

describe hyperkalaemia as an electrolyte imbalance?

A
  • excess potassium levels
  • causes: acute renal failure, stored blood transfusions, certain drugs e.g. ACE inhibitors
  • signs: ECG changes, major dysrhythmias and sudden death
47
Q

summarise the 3 compartments of fluid balance?

A
  • vascular: macro-control by kidneys, micro-control but colloid oncotic pressure and hydrostatic pressure, electrical and concentration gradients
  • interstitial: fluid space between blood vessels and cells
  • cellular: micro-control by osmosis (tonicity of interstitial fluid) and active pump mechanisms

ANAT 1111 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions