9. Intestinal Transport

<p>It recycles $\text{H}^+$ that enters the cell during peptide transport. (B)</p> Signup and view all the answers

<p>Peptidases (C)</p> Signup and view all the answers

<p>Inhibiting enteric effector neurons to permit increased fluid absorption. (C)</p> Signup and view all the answers

<p>Crypts (B)</p> Signup and view all the answers

<p>Net fluid accumulation. (B)</p> Signup and view all the answers

<p>Inhibit fluid absorption. (D)</p> Signup and view all the answers

<p>Cyclic AMP (A)</p> Signup and view all the answers

<p>Paracrine (C)</p> Signup and view all the answers

<p>Cholera toxin (B)</p> Signup and view all the answers

<p>Secretory diarrhea (C)</p> Signup and view all the answers

<p>It establishes a pH gradient by pumping $H^+$ out of the cell, making the cell surface more acidic. (C)</p> Signup and view all the answers

<p>To enhance the absorption of $Na^+$, which then promotes water absorption. (A)</p> Signup and view all the answers

<p>It depends on the availability of specific cotransporters. (C)</p> Signup and view all the answers

<p>K+ (A)</p> Signup and view all the answers

<p>Increased $H_2O$ absorption due to osmotic gradient (A)</p> Signup and view all the answers

<p>A cell surface pH &lt; 7.0. (C)</p> Signup and view all the answers

<p>Transports digested peptides of 2- or 3- amino acid length. (B)</p> Signup and view all the answers

<p>A $H^+$ gradient (A)</p> Signup and view all the answers

<p>Parasympathetic nervous system mediators (A)</p> Signup and view all the answers

<p>Increased cAMP and cGMP production, resulting in diarrhea (B)</p> Signup and view all the answers

<p>Blockage of digestive neuroendocrine control by the sympathetic nervous system (B)</p> Signup and view all the answers

<p>Na+/H+ exchangers dominate, neutralizing excess HCO3- from the pancreas (B)</p> Signup and view all the answers

<p>By secreting HCO3- to buffer VFAs in the large intestine (A)</p> Signup and view all the answers

<p>To alkalize the ileal effluent by secreting HCO3- (B)</p> Signup and view all the answers

<p>The proximal large intestine employs the same transporters as the small intestine for electroneutral NaCl absorption. (A)</p> Signup and view all the answers

<p>The Cl-/HCO3 exchange is less in the healthy colon compared to the ileum, as the colon receives low [Cl-] from ileal effluent. (B)</p> Signup and view all the answers

<p>It couples with $Cl^−/HCO_3^−$ exchangers to recycle $Cl^−$ and enhance bicarbonate secretion. (C)</p> Signup and view all the answers

<p>Osmotic gradient created by electrolyte secretion (B)</p> Signup and view all the answers

<p>The balance of fluid and electrolyte levels maintained by hormonal and neural regulation. (A)</p> Signup and view all the answers

<p>By increasing cAMP or cGMP, leading to excessive fluid secretion (C)</p> Signup and view all the answers

<p>Compromised composition and volume of secreted luminal fluid, leading to thick mucus (B)</p> Signup and view all the answers

<p>Stimulates fluid secretion at the crypts and inhibits fluid absorption at the villi. (C)</p> Signup and view all the answers

<p>Catalyzes a reaction essential for the production of bicarbonate ($HCO_3^−$). (B)</p> Signup and view all the answers

<p>Ion secretion creates an osmotic gradient, drawing water into the lumen. (D)</p> Signup and view all the answers

<p>$Na^+$ absorption through $Na^+$ channels down its electrochemical gradient, coupled with $K^+$ secretion to maintain membrane potential. (B)</p> Signup and view all the answers

<p>It increases the expression of $ENaC$, increases $Na^+/K^+$ ATPase activity, and increases $K^+$ channels. (C)</p> Signup and view all the answers

<p>The absorption of $Na^+$ against a large concentration gradient via specific $Na^+$ channels. (C)</p> Signup and view all the answers

<p>To maintain membrane potential, counterbalancing the electrogenic $Na^+$ absorption. (B)</p> Signup and view all the answers

<p>They both contain the same processes involving electrogenic $Na^+$. (A)</p> Signup and view all the answers

<p>$Cl^-$ follows the electrical gradient, and water follows the osmotic gradient. (D)</p> Signup and view all the answers

<p>Sodium-potassium ATPase activity. (B)</p> Signup and view all the answers

<p>Decreased fecal $Na^+$ and increased fecal $K^+$. (B)</p> Signup and view all the answers

Transport of nutrients in the small intestine that depends on H+ gradients.

A mechanism in which sodium ions are exchanged for hydrogen ions in the small intestine.

A transporter that facilitates the absorption of dipeptides and tripeptides.

Enzymes that break down peptides into smaller units for absorption.

Process of moving amino acids from the intestinal lumen into the bloodstream.

A process where substances cross cell membranes with the help of carrier proteins.

A transporter responsible for sodium-dependent glucose transport in the intestines.

Solutions containing electrolytes and glucose, used to prevent dehydration.

Glucose enhances sodium absorption through sodium-glucose transporters.

Absorption of nutrients driven by a gradient of protons (H+), such as through Pept1.

Forces that drive the movement of ions and water across membranes.

Absorbs Na+ electrogenically, generating a net charge across its barrier.

The electrogenic Na+ absorption does not occur in rodents.

Na+ channels absorb Na+ against a large concentration gradient.

Epithelial Na+ channels (ENaC) absorb Na+ down to 5mM in the lumen.

Increases ENaC expression and Na+/K+ ATPase activity, enhancing Na+ absorption.

K+ secretion maintains the membrane potential in the distal large intestine.

Cl- follows the electrical gradient during Na+ absorption.

Water follows osmotic gradients related to Na+ and Cl- absorption.

Neurons that inhibit enteric effector neurons to regulate fluid absorption and secretion.

Absorption of more fluid at villi and surface, enhancing NaCl absorption.

Reduction of fluid secretion at crypts, decreasing CFTR activity.

Intracellular messengers that affect fluid secretion and absorption in the gut.

Substances that stimulate fluid secretion at crypts and inhibit absorption at villi.

A bacterial enterotoxin that irreversibly activates adenylate cyclase, causing fluid secretion.

Absorption of sodium and chloride ions without creating electrical gradients.

Diarrhea caused by excessive fluid secretion due to pathogens or toxins.

A healthy state of extracellular fluid (ECF) balance.

NaCl absorption is inhibited while digesting; resumes afterwards to recover sodium and water.

Bacterial enterotoxins increase cAMP and cGMP, leading to diarrhea.

State where salt and water absorption is favored due to sympathetic nervous system activation.

Transporters that adjust luminal pH in specific intestinal regions through ion exchange.

Recovers bicarbonate (HCO3) while secreting H+ to neutralize excess juice from the pancreas.

The ileum uses Cl-/HCO3 exchange to alkalize effluent and buffer volatile fatty acids (VFA).

Salt and water absorbed through the same transporters as the small intestine, especially low Cl-.

An enzyme that helps to catalyze the conversion of carbon dioxide and water to bicarbonate and protons.

Cystic Fibrosis Transmembrane Conductance Regulator; a channel protein that transports chloride ions across epithelial cells.

The release of bicarbonate ions into the pancreatic duct or intestine, aiding in digestion.

A genetic disorder caused by CFTR mutations leading to thick mucus build-up in various organs.

Part of the autonomic nervous system that promotes 'rest and digest' actions including stimulation of fluid secretion.

Part of the autonomic nervous system that inhibits fluid absorption and prepares body for 'fight or flight.'