NRS 312 Lecture Notes - Lecture 1: Action Potential, Liver Disease, Xerostomia
Fluid and Electrolyte Balance- Lecture Part 1
• 1st space:
o Intracellular: where fluid in our cells should be (70%)
• 2nd space
o Interstitial (22%) + intravascular (6%): where we see edema. Commonly see this in the
lower extremities, arms, face. We are concerned about fluid in the lungs.
o We want to first assess the lungs. This is our primary concern.
• 3rd space
o Fluid trapped in an abnormal space
o Common in the peritoneal cavity that results in the ascities
• Important electrolytes
o Sodium (Na+): (ECF) primarily an extracellular cation, plays a role in cell action
potentials and water balance. 135-145 mEq/L
o Potassium (K+): (ICF) primarily intracellular cation. Important role in cell actions
potentials for transmission of nerve impulses, cardiac myocyte contractility, and skeletal
muscle function. 3.5-5.0 mEq/L
o Calcium (Ca++): 90% in bones, 10% ECF. Healthy bones and teeth, promotes
coagulation factors, plays a role in cell action potentials for nerve conduction,
cardiomyoctye contractility, and skeletal muscle. Total calcium 8.4 – 10.5 mg/dL
o Magnesium (Mg2+): Provides the energy source for the sodium – potassium pump
(necessary for nerve impulse conduction) 1.5-2.5 mEq/L
o Bicarbonate (HCO3-): Both ECF and ICF. Major base buffer, essential for acid-base
balance to maintain pH 7.35 to 7.45.
o Chloride (Cl-): Major ECF anion. Nerve conduction role again, also important in
digestion. 95-105 mEq/L
• First spacing
o Patho repeat
• Different organs involved and hormones for volume regulation
o Pituitary
▪ Body knows when to secrete ADH when you have a low MAP but more
specifically a high concentration (high HCT and high Specific gravity). Reabsorb
more water and do not secrete urine. Blood serum concentration tell kidneys to
hold on to water
o Thyroid hormone
▪ Helps to regulate cardiac output (fluid being sent throughout the body)
▪ If we have a problem: hypothyroid= low cardiac output.
o Adrenal glands
▪ Regulation of electrolytes. Enhance sodium retention and K+ excretion.
o Kidneys
▪ Responds to low MAP. Secrete Renin and start the RAAS system.
o Atrial natriuretic peptides
▪ Found in heart in response to increased aerial pressure. Overstretched atrium
wants less volume.
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Document Summary
Fluid and electrolyte balance- lecture part 1: 1st space: Intracellular: where fluid in our cells should be (70%: 2nd space. Interstitial (22%) + intravascular (6%): where we see edema. Commonly see this in the lower extremities, arms, face. We are concerned about fluid in the lungs: we want to first assess the lungs. This is our primary concern: 3rd space, fluid trapped in an abnormal space, common in the peritoneal cavity that results in the ascities. Important electrolytes: sodium (na+): (ecf) primarily an extracellular cation, plays a role in cell action potentials and water balance. 135-145 meq/l: potassium (k+): (icf) primarily intracellular cation. Important role in cell actions potentials for transmission of nerve impulses, cardiac myocyte contractility, and skeletal muscle function. 3. 5-5. 0 meq/l: calcium (ca++): 90% in bones, 10% ecf. Healthy bones and teeth, promotes coagulation factors, plays a role in cell action potentials for nerve conduction, cardiomyoctye contractility, and skeletal muscle.
