Infant Total Body Water (TBW) %
70%
Male Total Body Water (TBW) %
60%
Female Total Body Water (TBW) %
50%
T/F: Older adults and obese persons have higher proportion of water.
False
ICF
Intracellular fluid (within cells) 2/3 of TBW
ECF
Extracellular fluid (outside cell) 1/3 of TBW
Electrolytes
inorganic salts, acids & bases, and some proteins that conduct electricity in solution
non-electrolytes
covalent bonds that don't dissociate in water, don't conduct electricity, and can cause fluid shifts
E.g. Electrolytes
Sodium, potassium, chloride, magnesium, bicarbonate, phosphate, sulfate, and calcium
E.g. Non-electrolytes
Lipids, glucose, creatinine, and urea
intravascular (IVF) and interstitial (ISF) are part of the...
extracellular fluid
Thirst Mechanism
Osmoreceptors in the hypothalamus promote intake when needed
Antidiuretic hormone (ADH)
Promotes normal reabsorption of water into the blood from the kidneys
Atrial Natriaretic peptide - ANP
Regulates fluid, sodium, and potassium levels to reduce workload of heart by lowering blood pressure
Renin Angiotensin Aldosterone System (RAAS)
Renin- kidney releases to blood. Angiotensinogen- liver secretes to blood. Renin breaks down AGT to inactivate AGT 1. Angiotensin Converting Enzyme (ACE)- lung secretes to blood. Inactive AGT 1 and ACE meet in blood. AGT 1 --> AGT 2. AGT 2 acts on cells of the adrenal cortex to cause the secretion of Aldosterone.
Salts
Responsible for regulation of fluid movement, maintenance of cell excitability, membrane permeability, and secretory activity.
Sodium
Most abundant in ECF. Important in the control of fluid volume and water distribution in the body.
Sodium Balance
RAAS, ANP, estrogen (increase cause fluid retention), Progesterone, and Glucocorticoids.
Progesterone
Blocks Aldosterone effects
Aldosterone
secreted by the adrenal cortex; increases salt reabsorption; ECF increase. causes NA-K pump action
Potassium Balance
Most abundant cation in ICF, necessary for electrical conductivity in muscles and nerves
Calcium Balance
Important in blood coagulation, membrane permeability, cellular secretion, muscle contraction. Is regulated by the Parathyroid Hormone (PTH) & calcitonin
Phosphate & Anion Balance
most phosphate ions are reabsorbed in Proximal Convoluted Tubule (PCT) --> Important in pH regulation. Cl- is major anion in ECF --> reabsorbed in PCT
Greater in H+ ion concentration
more acidic/low pH 1-6
Lower in H+ ion concentration
more basic/high pH 8-14
Blood pH: 6-7 & 7.8-9
results in death
Blood pH: 7-7.35
results in acidosis
Blood pH: 7.35-7.45
normal blood pH level
Blood pH: 7.45-7.8
results in alkalosis
Optimal pH
Lungs, kidneys, and major organs involved in regulation acid-base balance
Buffer Systems
help maintain constancy of pH, changes stronger acids/bases to substances that don't greatly affect pH
H2CO3 / HCO3- system
one of the most important plasma buffer systems
carbonic acid-bicarbonate buffer system
major extracellular buffer, WB - bicarbonate, WA - carbonic acid
phospate buffer system
important in ICF, WB - monohydrogen phosphate, WA - dihydrogen phosphate
protein buffer system
most important buffer in body cells and blood, WB - the amine group (e.g. -NH2) , WA - the carboxyl group (e.g. -COOH)
Decompensation
Occurs when -causative problem becomes more severe -additional problems occur -compensation mechanisms are exceeded or fail (requires intervention to maintain homeostasis life threatening)
Edema
Accumulation of fluid in the interstitial spaces, swelling
Dehydration
sodium levels rise, increased osmolaty
Hyponatremia
low sodium in the blood
Hypernatremia
high sodium in the blood
hypokalemia
low potassium in the blood
Hyperkalemia
high potassium in the blood
Hyperchloremia
an excess of chloride in the blood plasma
Hypochloremia
deficiency of chloride in the blood plasma
Sodium importance outside the cell
helps w/ nerve and muscle cell interaction (recommended daily does 1.5 g)
Chloride importance outside the cell
helps maintain osmotic pressure
Calcium importance outside the cell
stabilize the cell membrane and reduce its permeability to sodium, transmit nerve impulses, contract muscles
Potassium importance inside the cell
role in regulation of cell excitability, nerve impulse conduction, muscle contraction, myocardial membrane responsiveness
Phosphate importance inside the cell
essentially for energy metabolism. key role in mineralization of bones and teeth
Studied by 38 People