Podcast
Questions and Answers
What is the primary function of the sodium-potassium pump?
What is the primary function of the sodium-potassium pump?
How many sodium ions are pumped out of the cell for every two potassium ions pumped in?
How many sodium ions are pumped out of the cell for every two potassium ions pumped in?
What provides the energy necessary for the sodium-potassium pump to function?
What provides the energy necessary for the sodium-potassium pump to function?
What does the term 'electrogenic' mean in the context of the sodium-potassium pump?
What does the term 'electrogenic' mean in the context of the sodium-potassium pump?
Signup and view all the answers
What happens to the membrane potential if the sodium-potassium pump fails?
What happens to the membrane potential if the sodium-potassium pump fails?
Signup and view all the answers
In the Nernst equation, what does the variable 'Em' represent?
In the Nernst equation, what does the variable 'Em' represent?
Signup and view all the answers
What is the universal gas constant (R) value in Joules per mole per Kelvin?
What is the universal gas constant (R) value in Joules per mole per Kelvin?
Signup and view all the answers
What represents the valency of sodium in the context of the Nernst equation?
What represents the valency of sodium in the context of the Nernst equation?
Signup and view all the answers
What proportion of the adult body is approximately made up of water?
What proportion of the adult body is approximately made up of water?
Signup and view all the answers
What does the term homeostasis refer to?
What does the term homeostasis refer to?
Signup and view all the answers
Which component primarily makes up the lipid bilayer in biological membranes?
Which component primarily makes up the lipid bilayer in biological membranes?
Signup and view all the answers
What effect do unsaturated lipids have on the lipid bilayer?
What effect do unsaturated lipids have on the lipid bilayer?
Signup and view all the answers
What is the approximate thickness of the lipid bilayer?
What is the approximate thickness of the lipid bilayer?
Signup and view all the answers
What is typically found embedded within the lipid bilayer?
What is typically found embedded within the lipid bilayer?
Signup and view all the answers
Which of the following is NOT a concept related to fluid compartments?
Which of the following is NOT a concept related to fluid compartments?
Signup and view all the answers
Which of these terms best describes the salt concentration in a solution?
Which of these terms best describes the salt concentration in a solution?
Signup and view all the answers
What accounts for the high concentration of sodium in plasma compared to inside muscle cells?
What accounts for the high concentration of sodium in plasma compared to inside muscle cells?
Signup and view all the answers
Which component significantly contributes to the negative charges in plasma?
Which component significantly contributes to the negative charges in plasma?
Signup and view all the answers
Why do proteins in plasma have multiple negative charges at pH 7.4?
Why do proteins in plasma have multiple negative charges at pH 7.4?
Signup and view all the answers
What is the primary reason for the lower concentration of sodium in muscle cells?
What is the primary reason for the lower concentration of sodium in muscle cells?
Signup and view all the answers
Which ions help in establishing the electrical gradient across the cell membrane?
Which ions help in establishing the electrical gradient across the cell membrane?
Signup and view all the answers
What dictates the osmolarity in a fluid compartment?
What dictates the osmolarity in a fluid compartment?
Signup and view all the answers
What contributes primarily to the negative charge in muscle cells?
What contributes primarily to the negative charge in muscle cells?
Signup and view all the answers
What is the effect of tonicity on cell membranes?
What is the effect of tonicity on cell membranes?
Signup and view all the answers
What is osmolarity primarily dependent on?
What is osmolarity primarily dependent on?
Signup and view all the answers
How is clinical osmolarity calculated?
How is clinical osmolarity calculated?
Signup and view all the answers
What is tonicity a measure of?
What is tonicity a measure of?
Signup and view all the answers
What happens to red blood cells in hypotonic plasma?
What happens to red blood cells in hypotonic plasma?
Signup and view all the answers
Which of the following statements about extracellular compartments is true?
Which of the following statements about extracellular compartments is true?
Signup and view all the answers
Why are the values 18 and 2.8 used in osmolarity calculations?
Why are the values 18 and 2.8 used in osmolarity calculations?
Signup and view all the answers
Which ion has a higher concentration in intracellular fluid compared to extracellular fluid?
Which ion has a higher concentration in intracellular fluid compared to extracellular fluid?
Signup and view all the answers
What characteristic defines hypertonic plasma?
What characteristic defines hypertonic plasma?
Signup and view all the answers
What is the concentration of sodium inside the cell?
What is the concentration of sodium inside the cell?
Signup and view all the answers
What is the calculated membrane potential based on the information provided?
What is the calculated membrane potential based on the information provided?
Signup and view all the answers
Which fluid compartment contains the majority of the body's water in a 70 kilo man?
Which fluid compartment contains the majority of the body's water in a 70 kilo man?
Signup and view all the answers
What percentage of the total body water is represented by interstitial fluid in a 70 kilo man?
What percentage of the total body water is represented by interstitial fluid in a 70 kilo man?
Signup and view all the answers
Which of the following is not categorized under transcellular fluids?
Which of the following is not categorized under transcellular fluids?
Signup and view all the answers
How much total fluid is there in a 70 kilo man?
How much total fluid is there in a 70 kilo man?
Signup and view all the answers
What factor contributes to women having slightly less body water compared to men?
What factor contributes to women having slightly less body water compared to men?
Signup and view all the answers
What happens to the water content of the body as one ages?
What happens to the water content of the body as one ages?
Signup and view all the answers
Study Notes
Sodium-Potassium Pump
- Primary Function: Maintains the concentration gradients of sodium and potassium ions across the cell membrane.
- Ion Ratio: Pumps 3 sodium ions out of the cell for every 2 potassium ions pumped in.
- Energy Source: Powered by ATP (adenosine triphosphate).
- Electrogenic: The pump creates an electrical potential across the membrane due to unequal ion movement.
- Pump Failure: Leads to a disruption of membrane potential and cell function.
Nernst Equation
- Em: Represents the equilibrium potential for a specific ion across the membrane.
- R: Universal gas constant, value is 8.314 J/mol K.
- Valency of Sodium: Represents the charge of the sodium ion (+1).
Body Composition and Water
- Water Proportion: Water makes up approximately 60% of an adult's body weight.
- Homeostasis: Refers to the body's ability to maintain a stable internal environment.
Biological Membranes
- Lipid Bilayer: Primarily composed of phospholipids.
- Unsaturated Lipids: Increase membrane fluidity.
- Lipid Bilayer Thickness: Approximately 5-8 nanometers.
- Embedded Components: Proteins and other molecules are embedded within the lipid bilayer.
Fluid Compartments
- Not a Fluid Compartment Concept: Diffusion.
- Solute Concentration: Described as osmolarity.
- High Sodium in Plasma: Due to the active transport of sodium out of cells by the sodium-potassium pump.
- Plasma Negative Charges: Primarily from proteins with multiple negative charges.
- Protein Charges: Proteins in plasma have multiple negative charges at pH 7.4 due to the dissociation of their acidic amino acid side chains.
- Low Sodium in Muscle Cells: Result of active transport by the sodium-potassium pump.
Electrical and Osmotic Gradients
- Electrical Gradient Established by: Sodium and potassium ions.
- Osmolarity Dictated by: The concentration of dissolved solutes.
- Muscle Cell Negative Charge: Primarily due to proteins.
- Tonicity Effect on Cell Membranes: Determines the movement of water across the membrane.
- Osmolarity Dependence: Primarily dependent on the number of solute particles.
- Clinical Osmolarity Calculation: Calculated using the formula: 2 x [Na] + [Glucose]/18 + [BUN]/2.8
- Tonicity Definition: Measure of the effective osmotic pressure of a solution.
- Hypotonic Plasma Effect on Red Blood Cells: Causes red blood cells to swell and potentially burst (hemolysis).
Extracellular and Intracellular Fluids
- Extracellular Compartments: Fluids outside the cells, comprising interstitial fluid and plasma.
- 18 and 2.8 Values in Osmolarity Calculations: Represent the molecular weights of glucose and urea, respectively.
- Higher Intracellular Ion Concentration: Potassium has a higher concentration in intracellular fluid compared to extracellular fluid.
- Hypertonic Plasma Definition: Characterized by a higher solute concentration compared to intracellular fluid.
Intracellular Sodium Concentration and Membrane Potential
- Sodium Concentration Inside the Cell: Approximately 10-15 mM.
- Calculated Membrane Potential: Based on the Nernst equation, taking into account the ionic concentrations and permeability of the membrane.
Total Body Water
- Majority Water in 70kg Man: Located in the intracellular fluid compartment.
- Interstitial Fluid Percentage: Approximately 15% of total body water in a 70kg man.
- Transcellular Fluid Examples: Cerebrospinal fluid, synovial fluid, and intraocular fluid.
Fluid Content and Factors
- Total Fluid in 70kg Man: Approximately 42 liters.
- Lower Body Water in Women: Due to a higher proportion of body fat.
- Aging Effect on Water Content: Water content in the body decreases with age.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
