Lecture 12 Flashcards
Define the term “electrolyte.” Give several examples of electrolytes in the body. Give two examples of why maintaining balance of electrolytes is important.
Electrolytes are inorganic compounds, aka salts, that dissociate into ions. Important for maintaining homeostasis and fluid balance
What is the average osmolarity of extracellular fluid and intracellular fluid?
The average osmolarity of extracellular fluid and intracellular fluid are both 300. They are equal because most plasma membranes are permeable to water.
What electrolytes have higher concentration in intracellular fluid?
Potassium and phosphate
What electrolytes have higher concentration in extracellular fluid?
Sodium, Calcium and Chloride
Which fluid compartments are most similar in their concentrations of individual electrolytes? Which are most dissimilar?
Concentrations of electrolytes are very similar in IF and plasma.
Concentrations of individual electrolytes are dissimilar in Extracellular Fluid and Intracellular Fluid.
What is the most common electrolyte imbalance?
Sodium. Often due to dehydration.
It is the main solute in Extracellular Fluid consisting of 90% of the osmolarity.
List three reasons why maintaining sodium balance in the body is important.
osmoregulation
electrical activity of neurons and muscle cells
cotransport of K+/Ca2+/glucose/AAs
How is it that ions are typically gained and lost in the body?
Gained through eating and lost through urine, feces, and sweat.
Hypernatremia
To much extracellular sodium.
Causes: Diabetes insipidus, dehydration, hyper secretion of Aldosterone.
Effects: Increased blood plasma, pressure, volume, and thirst. Edema
Hyponatremia
Not enough sodium in extracellular fluid.
Causes: not enough dietary sodium, to much water intake, and hyperglycemia
Effects: same as hypotonic hydration
What is the most dangerous electrolyte imbalance?
Potassium because it can effect the electrical activity of heart.
Hypokalemia
Not enough potassium in the extracellular fluid. K
Describe the mechanism that results in hyperpolarization of excitable cells due to hypokalemia.
More potassium has to leak out to maintain action potential. Has to pull positive charged ions from cell making it more negative thus lowering its action potential
fast hyperkalemia
Fast increases in ECF K+ causes resting membrane potentials to be closer to threshold, and excitable cells to be hyper excitable.
Causes: Crushing injury, transfusions with old blood, hemolytic anemia, and lethal injection.
Effects: Cardiac arrhythmias and hyper excitable cells.
Slow Hyperkalemia
Opposite effect of fast.
Causes: aldosterone hyposecretion, renal failure, and chronic acidosis.
Affects: H+ displaces K+ in cells and Principal cells can secrete H+ instead of K+ while reabsorbing Na+
Muscles become inactive because voltage gated Na+ channels close.
Three reasons that calcium balance in the body is important.
Bone formation, muscle contractions, blood clotting, exocytosis of neural transmitters, second messenger systems.
Why is it that extracellular levels of calcium are high, while intracellular levels of calcium are low, and at the same time extracellular levels of phosphate are low, and intracellular levels are high?
Because if they were both high in the same compartment calcification would occur.
Hypercalcemia
To much calcium in the extracellular fluid.
Causes: Hyperparathyroidism, Hypothyroidism, immobilization, or boneless due to cancer.
Effects: decreased permeability of excitable cell’s plasma membranes to sodium, cardiac arrhythmia, classification of soft tissue, fatigue, constipation, confusion.
Hypocalcemia
Not enough calcium in extracellular fluid.
Causes: Hypoparathyroidism, Hyperthyroidism, Vitamin D deficiency, and pregnancy.
Effects: Increased permeability of sodium in excitable cells. spasms of larynx and osteoporosis.
pH of intracellular and extracellular fluid
Extracellular fluid 7.35-7.45
Intracellular fluid 7
Why is acid-base balance important?
Enzyms activity by maintaining the proper shape of proteins
Electrical gradients because H+ can displace intracellular K+
Acids in our body
Carbonic Acid, Lactic Acid, Fatty Acid, Sulfuric Acid, Phosphoric Acid, Amino Acid, HCL, and Ketone Bodies
Factors that can affect Acid-Base balance
Acidic = high protein or wheat diet. Diarrhea Basic = Vegetarian diet. Chronic vomiting or antacids.
What buffer systems regulate pH balance?
Chemical buffers - Fast acting but will run out. least effective. only good for short term.
Physiological Buffers- Reparatory and Urinary.
