Salt and Water transport in the GI tract Flashcards
Why is the regulation of water and electrolyte transport important?
The regulation of water and electrolyte transport is important because it provides a medium for digestion and waste elimination in the lumen of the gastrointestinal tract. It also helps replace the daily loss of body fluids through sweat, urine, lungs, and feces.
What regulates water and electrolyte transport?
Water and electrolyte transport are regulated by various factors. These include the gut lumen, the enteric nervous system (part of the nervous system that controls the gastrointestinal tract), autonomic neural mechanisms, and hormonal and immunogenic signals.
What are the functions of hormonal and immunogenic signals in regulating water and electrolyte transport?
Hormonal and immunogenic signals play a role in regulating water and electrolyte transport in the gastrointestinal tract. These signals can initiate an immune response and contribute to the regulation of fluid balance and electrolyte concentrations.
What are the consequences of disruption to absorption in the GI tract?
Disruption to absorption in the GI tract can lead to secretory diarrhea, which can result in dehydration and electrolyte imbalance.
What is the definition of electrolytes?
Electrolytes are substances that carry an electrical charge. For example, when NaCl (sodium chloride) dissolves in solution, it dissociates into Na+ and Cl- ions.
Why are concentrations of electrolytes important?
Concentrations of electrolytes differ between the cytosol (intracellular fluid) and extracellular fluid. These concentrations are important for various metabolic activities in the body
What is an electrochemical gradient?
An electrochemical gradient refers to the difference in both concentration and electrical charge across a membrane. It influences the movement of ions.
How do ions move down an electrochemical gradient?
Ions will diffuse down an electrochemical gradient if there are mechanisms present to facilitate their movement across the membrane.
Which ion is the dominant cation in the extracellular fluid?
Na+ (sodium) is the dominant cation in the extracellular fluid.
Which ion is the dominant cation in the intracellular fluid?
K+ (potassium) is the dominant cation in the intracellular fluid.
Which ion is the dominant anion in the extracellular fluid?
Cl- (chloride) is the dominant anion in the extracellular fluid.
What is the role of electrolytes in creating an osmotic gradient?
Electrolytes create an osmotic gradient across a semi-permeable membrane, which allows for the movement of water by osmosis.
How does water move across a cell membrane?
Water moves into the cell from an extracellular hypotonic (low NaCl) environment to an intracellular hypertonic environment by osmosis.
What is the permeability of cell membranes?
Cell membranes are semi-permeable. They are permeable to non-polar, hydrophobic molecules (such as O2 and CO2), as well as some small, uncharged molecules (such as water, urea, and ethanol).
What molecules are non-permeable to cell membranes?
Cell membranes are non-permeable to the movement of large and charged molecules, such as ions and glucose.
What mechanisms are involved in the movement of large and charged molecules across the cell membrane?
The movement of large and charged molecules across the cell membrane requires protein pumps, carriers, and channels, as well as mechanisms like endocytosis and exocytosis.
: What type of membrane protein is responsible for active transport of ions?
The Na+/K+ ATPase pump is a membrane protein responsible for active transport of ions, specifically sodium (Na+) and potassium (K+), against their concentration gradient.
How does the Na+/glucose symport work?
The Na+/glucose symport is a protein carrier-mediated transport mechanism that uses the energy from the movement of sodium ions down their concentration gradient to transport glucose molecules against their concentration gradient.
