Digestion of nutrients, fluids, electrolytes physio , Liver & pancreas physio Flashcards
How much water is absorbed daily?
8.8 L/day
Which organ absorbs the most water?
Small Intestine
Where is the major source of water and electrolytes in a diarrheic stool from?
The small intestines
True or False? The volume of fluid moving from blood to lumen (secretion) is LESS than that moving from the lumen to the blood (absorption), thus resulting in net absorption.
TRUE!!!
True or False? Luminal fluid remains Isotonic with plasma while Stool water is Hypotonic.
FALSE!! Luminal fluid remains Isotonic with plasma while Stool water is HYPERTONIC
Fill in the blanks. “ In the luminal fluid , Water is absorbed from _______ solutions and enters _________solutions.”
Water is absorbed from HYPOTONIC solutions and enters HYPERTONIC solutions
True or False? the Na+ and Cl− concentrations in the lumen progressively become LOWER than the plasma concentrations.
TRUE!!
What is the major anion found in the duodenum?
Chloride (Cl-)
What are the major anions found in the Ileum?
Chloride (Cl- )and Bicarbonate (HCO3-)
What are the major anions in the Colon?
Chloride (Cl- )and Bicarbonate (HCO3-)
By what pathways do ions move between the gut lumen and the blood ?
Transcellular and paracellular pathways
Fill in the blanks. “ Passive movement of Na+ into or out the lumen is regulated by ________.”
Tight junctions OR zonnulae occludens
The rate of the passive movement of Na+ into or out the lumen is affected by?
Electrochemical gradients and Starling forces .
True or False? The tight junctions ( zonulae occludens) are more permeable to Na+ and Cl- than K+.
FALSE!! The tight junction is about twice as permeable to Na+ and K+ as it is to Cl−
Na + & K+ »_space;» Cl-
What is the Potential difference in the colon ?
20 mV
What is the Transmural Potential difference in the small intestine?
2 to 5 millivolts due to the relatively leaky epithelium.
True or False? The driving force for Cl− absorption is greater in the colon.
TRUE!!
What is the primary mechanism for colonic Na+ absorption?
Restricted diffusion
Which hormone increases the number of Na+ channels and enhances Na+ absorption?
Aldosterone
Restricted diffusion in the colon (electrogenic process) is dependent on channels that are under regulation by ?
Mineralocorticoids
True or False? All areas of the colon absorb Na+ & Cl-.
TRUE!!
What are the transport mechanisms for the absorption of Sodium and chloride in the small intestines?
- Movement of Na+ by restricted diffusion through water-filled channels.
- The co-transport of Na+ with organic solutes (e.g., glucose and amino acids)
- The co-transport of Na+ with Cl.
- The counter- transport of Na+ in exchange for H+
What is the main mechanism for absorption of Potassium(K+) in the small intestines ?
Diffusion through paracellular pathways
What is the main mechanism for absorption of Potassium(K+) in the colon?
The presence of K+ channels on the apical & basolateral membrane.