14 Questions
What is the primary function of sodium in maintaining cellular homeostasis?
Maintaining fluid and electrolyte balance
What happens to cells when there is too low sodium in the serum?
Cells swell due to water entry
What is the term for having too low sodium levels in the serum?
Hyponatremia
Where is sodium mostly found in the body?
Blood and extracellular fluid
What is the primary way that sodium is excreted from the body?
Through urine
What is the role of sodium in nerve cells?
Stimulating nerve cell excitability
What is the primary cause of Hypernatremia?
Limited access to water or impaired thirst mechanism
What is the relationship between sodium and potassium in the body?
Potassium has a strong inverse relationship with sodium
What is the primary function of potassium in the body?
All of the above
What is the consequence of low potassium levels in the blood?
Irregular heartbeat and muscle weakness
What is the primary source of magnesium in the body?
Bones
What is the role of magnesium in the body?
Cofactor in various enzyme reactions
What is the consequence of high potassium levels in the blood?
Weakness, paralysis, and heart muscle activity reduction
What is the relationship between potassium and sodium in urine excretion?
Most potassium is excreted in urine, with a small amount in sweat and stool
Study Notes
Sodium
- Found mostly in blood and extracellular fluid (ECF)
- Excreted mostly in urine
- Physiological functions:
- Maintains normal cellular homeostasis
- Regulates fluid and electrolyte balance and blood pressure
- Transports nutrients and substrates through plasma membranes
- Essential for the excitability of muscle and nerve cells
- Diseases associated with sodium:
- Hyponatremia (low Na in serum): water enters cells, causing them to swell
- Hypernatremia (high Na in serum): water leaves cells and enters blood, causing dehydration
- Excessive sodium intake: facial puffiness, high blood pressure, heart disease, and stroke
Potassium
- Found mostly inside cells, present in all body tissues
- Excreted mostly in urine, with some in sweat and stool
- Strong relationship with sodium
- Physiological functions:
- Essential for normal cell function
- Maintains intracellular fluid volume and transmembrane electrochemical gradients
- Helps preserve acid-base balance and maintain isotonicity and electrodynamic cellular function
- Activates many enzymes, such as pyruvate kinase
- Essential for transmission of nerve impulses, contraction of cardiac muscles, skeletal and smooth muscles, and tissue synthesis
- Relaxes walls of blood vessels, lowers blood pressure
- Diseases associated with potassium:
- Hypokalemia (low K in blood): excessive K loss in urine, low K intake, associated with increased blood pressure and higher risk of stroke
- Hyperkalemia (high K in blood): life-threatening, can cause reduced heart muscle activity, weakness, and paralysis
Magnesium
- 50% of body's magnesium is in bone, very little in blood
- Physiological functions:
- Cofactor in various structures/enzymes that regulate reactions
- Essential for protein synthesis, muscle and nerve function, and blood pressure regulation
- Required for energy production, oxidative phosphorylation, and glycolysis
- Regulates insulin secretion in pancreatic beta cells
- Critical for phosphorylation of insulin receptor
- Contributes to formation of bone and teeth
- Diseases associated with magnesium:
- Hypomagnesemia (low Mg levels)
Learn about the physiological functions of essential metals like sodium, potassium, magnesium, and calcium, and their associated diseases. Understand the role of metals in human health and disease.
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