Fluid Balance 2 Flashcards
Factors contributing to water distribution
Age
Gender
Body fat
Intravascular water distribution
plasma
Transcellular
Lymph system, joints and eyes
Sodium (solute) concept
Where sodium goes, water flows
Concept of fluid movement between compartments
Higher osmolality
Water goes from an area of lower solute to concentration to area of higher solute concentration
- increase particles= increase osmolatity
Osmolality
Measure of osmoles in a weight kg (solvent)
Osmolarity
measure of the number of osmoles in a volume L solvent
Hydrostatic pressure
pressure of the blood that builds up coming from the capillaries
Oncotic pressure
Osmotic pull from the proteins that remain in the capillary
Albumin
Key plasma protein creating osmotic pull
Key 3 fluid balance regulators
Central Nervous System
Kidneys (renal system)
Heart
Thirst
Hypothalamis osmoreceptors
activated by increase in blood osmolality stimulates thirst centre in hypothalamus- feels thirsty
Kidneys
Controls excretion of water and solutes
Anti- diuretic hormone
Lets bring the urine home
Key first 4 steps in ADH
- Blood osmotic pressure increases
- Sensed by osmoreceptors in hypothalamus
- Stimulates thirst centre
- Sends message to pituitary gland
Key last 3 steps in ADH
- Increase amount of H20 reabsorbed in colleting duct of kidney
- Urine output reduced
- Blood volume increased, Osmolality reduced
What is RAAS
Renin- Angiotensin- Aldosterone System
RAAS concept
Just call me RAAS ill keep the volume pumping
RAAS steps 1-3
- WHen blood volume is low. Juxtaglomerular cells in the kidneys secrete renin directly into circulation
- Renin coverts antgiotensinogen (made in the liver) to angiotensin 1
- Angiotensin enzyme ACE (from the lungs) then concerts angiotensin 1 to angiotens 2
RAAS steps 4-6
Angiotensin 2 is potent vascocontrictor. Stimulates adrenal cortex to release aldosteron (causes sodium and water retention by kidneys)
- Thirst an ADH are stimulated
- Blood volume is increased
ANP- Atrial Natriurectic peptide concept
ANP-ill work with the kidney to make you wee
ANP function
secreted from atrial muscle cells in the heart are stretched indicating high fluid volumes and BP
Inhibits ADH and aldosterone and renin excretion of water and sodium increases urine output increases fluid volume decrease
WHAT is Hypervolaemia
Excess amounts of Fluid
Causes of Hypervolemia
renal impairment
heart failure
liver failure
Syndrome of inappropriate ADH
H20 intake high
increased IVF
Oedema
abnormal collection of excess fluid in the interstitial compartment
Hypovolaemia
Fluid volume deficit
Causes of hypovolemia
Too much out/ not enough in
diarrhea, burns, vomiting. Not able to swallow
Symptoms of Fluid volume deficit ( Hypovolemia)
Poor skin
decreased uring output
decreased BP
Heat rate increase
Oedema causes
Dysfucntional lymphatic system
Increases hydrostatic pressure
decreased plasma proteins
Crystalloids
Molecules small enough to freely cross capillary walls
Colloid
Molecule too large to cross capillary wall
Outline Aldosterone
Released in the adrenal gland
Stimulates Na+ & H20 absorption in kidneys
What are the 4 main distribution of fluid within the cells
Intecellular- in the cell
Intravascular: within the capillary (plasma)
interstitial- space outside of the capillaries
Extracellular: includes: intravascular & interstitial fluid
sensible fluid loss
sweat, faeces, urination, vommiting
Insensible fluid loss
Skin and respiration
effect of Hypervalemia
increase urination
confusion, pulmonary/periperpheral odema
Therapies of Hypervolemia
diurectic
monitor fluid intake
hypovolemia risk factors
age
illness
medical condition
inability to drink/eat
Therapies for Hypovolemia
Rehydration
Replace blood
correct electrolyte balance
