Chapter 3 Fluids & Electrolytes Flashcards
Total body fluid of an infant
70-80%
Total body fluid of a one year old
64%
Total body fluid from puberty to 39 years old
M:60%
F: 54%
Total body fluid from 40-60 years old
M: 55%
F: 47%
Total body fluid over 60 years old
M: 52%
F: 46%
Intracellular fluid compartment
Fluid within the cell
Amounts to 2/3 of body fluid or 40% of body weight
Extracellular fluid compartment
Fluid outside the cell
Amounts to 1/3 of body fluid or 20% of body weight
Located in two spaces (5% plasma & 15% interstitial)
Transcellular fluid compartment
All secretions / cerebral spinal fluid
No % given
Total of approximately 1 liter
Composition of body fluid
Water
Non-electrolytes
Electrolytes
Calcium & magnesium
Non-electrolytes
Urea
Dextrose
Creatinine
Albumin
Electrolytes
Intracellular (2 p’s in a pod) - potassium and phosphate
Extracellular - sodium and chloride (like a saline flush)
What are chemotherapy pt’s and crush injury pt’s at risk of
Hyperkalemia and hyperphosphatemia due to damaged cells leaking K+ and phos
Percentage breakdown of calcium and magnesium in the body
Calcium = 99% bone and 1% Extracellular
Magnesium = 60% bone, 39% Intracellular, 1% Extracellular
Osmotic pressure
Drawing power of water
Dependent on number of molecules in a solution
Water is mobilized from an area of lesser concentration to an area of higher concentration
Oncotic pressure
Drawing power of colloids (albumin)
Water mobilized from the interstitial area to the venous system
Diffusion
Random movement of molecules from regions where concentration is high to regions where concentration is low
Ex: change of CO2 and O2 in the lungs
Active transport
Ions move from areas of lesser concentration to areas of higher concentration via release of ATP (energy)
Ex: pushing your way from the back of a crowded concert to the front towards the stage requires a lot of energy
Filtration
Transfer of H2O and a dissolved substance from regions of high pressure (arterials) to low pressure (interstitial)
What are the regulators of homeostasis
Kidneys
Circulatory system
Lungs
Pituitary gland
Adrenal gland
Thyroid/parathyroid
How do the kidneys regulate homeostasis
Filter 170L of plasma per day
Regulate blood pH via excretion or retention of hydrogen ions
Regulate the Extracellular fluid (ECF) volume and osmolality by retention or exertion of H2O
Regulate ECF electrolytes
Renal output
Normal: 1000-1500ml/24hr or 40-80ml/hr on average
Oliguria: below 400ml/24hr
Anuria: below 50-100ml/24hr
Total anuria: no urine
Polyuria: above 1500-2000ml/24hr
Urine output of 200ml/hr or more is too much
How does the circulatory system regulate homeostasis
Blood flow to kidneys
Circulate all hormones including: aldosterone, antidiuretic hormone (ADH), parathyroid hormone (PTH) and calcitonin
How do the lungs regulate homeostasis
Effect blood pH by the regulation of hydrogen ions via CO2 retention and exhalation
How does the pituitary gland regulate homeostasis
Releases ADH which stimulates the kidneys to retain H2O
ADH is manufactured in the hypothalamus and released by the pituitary gland
