Ch 1: Nutrient Intake, Digestion, Absorption, & Excretion Flashcards
Which glycoprotein is secreted by the parietal cells of the stomach?
The Intrinsic Factor (IF)
What is produced in the colon by action of bacteria on fermentable dietary fiber?
Short chain fatty acids (SCFA)
Which substances are absorbed in the stomach?
Aspirin and ETOH
How much volume can a relaxed stomach hold?
A volume of 0.8-1.5 Liters.
In which situations does ASPEN suggest EN be withheld?
- hypoperfusion of the gut splanchnic circulation (often occurs in sepsis/trauma or in pt’s being initiated on catecholamines)
- when catecholamine does are increasing
- when patients require a high level of hemodynamic support including high dose catecholamines (norepinephrine, phenylephrine, or epinephrine, dopamine) to maintain cellular perfusion.
Which are the anorexigenic gut hormones? (appetite suppressing)
Glucagon like peptide 1 & Glucagon like peptide 2 (GLP-1, GLP-2) oxyntomodulin (OXM), Peptide tyrosine tyrosine (PYY), pancreatic polypeptide (PP), & cholecystokinin (CCK)
Which form is most dietary iron in?
Ferric form
Which mineral absorption depend on body stores?
Calcium and Iron
Which patients are at risk for ischemic bowel?
Hyporperfused/hemodynamically unstable; usually have a MAP < 50
Which type of fat does not require formation of micelles or action of bile salts?
MCTs (8-10 carbons long). This type of fat is water soluble, and pass through enterocytes directly into portal circulation.
According to ASPEN guidelines, when should EN initiated for critically ill patients?
Within 24-48 hours when oral intake is not possible
What is the principle metabolic fuel for intestinal cells?
Glutamine; its absence may contribute to mucosal atrophy that accompanies bowel rest
In which form is iron absorbed?
Ferrous form
What part of the brain regulates appetite?
Hypothalamus
What type of fiber should be avoided in critically ill patients?
Insoluble
What is the definition of “trickle feeding”
10-20mL/hour or 10-20 kcals/hours
Trickle feeding can prevent mucosal atrophy in low to moderate risk patents, but will not achieve desired clinical outcomes in high risk patients.
Should C Diff patients be supplemented with probiotics?
Use with caution; evidence for this practice is weak
What is an orexigenic (appetite stimulating) gut hormone?
Ghrelin
During extended periods of fasting (starvation), the main source of energy is from what?
Fatty Acid oxidation
During starvation, glucose utilization is reduced in most tissues and organs because of a reduced supply of glucose and decline in circulating insulin concentration. Higher glucagon concentrations promote fatty acid oxidation. Fat tissue becomes the main energy source for nearly all tissue
Why is Phosphofructokinase (a rate-limiting enzyme of glycolysis) inhibited when ATP is abundant?
Allows the cell to divert glucose to be stored as glycogen
What is the half life of albumin?
20 days
What is the half life of pre-albumin?
2-3 days
Oxidation of fatty acids for adenosine triphosphate (ATP) production occurs where?
In the mitochondria
Where does absorption of large polypeptides, oligopeptides and free amino acids takes place?
Small intestine
How do glucose and galactose gain access to enterocytes?
Sodium-glucose transporter 1 (SGLT-1).
The presence of what facilitates the absorption of sodium in the lumen of the small intestine?
Glucose
Symptoms of diarrhea, bloating, and flatulence after ingestion of sugar are caused by what?
Deficiency of brush border oligosaccharidases
The primary fuel source for the brain after a 48 hour fast is what?
Ketone bodies
What is the AMDR?
defined as a range of intake for a particular energy source that is associated with a reduced risk, rather than assisting in the treatment, of chronic disease. The AMDR provides adequate intakes of essential nutrients and has been established for Omega-3 fatty acids, Omega-6 fatty acids and total fat.
What is the Tolerable Upper Intake?
The Tolerable Upper Intake Level is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population.
How is the Estimated Average Requirement (EAR) defined?
The Estimated Average Requirement (EAR) is defined as the average daily nutrient intake level estimated to meet half the needs of healthy individuals in a particular life stage and gender group.
What is the most redominant clinical change seen with essential fatty acid deficiency (EFAD)?
A dry, scaly rash
The energy for glucose transport is provided by active transport of what?
Sodium out of the cell
Glucose and sodium share common co-transporters
Why should antiperistalsis agents be used w/ caution in patients suspected of having infectious diarrhea or AA colitis?
with infectious diarrhea, slowing GI motility may increase risk for bacterial translocation
Carbohydrate digestion begins in the ____
Protein digestion begins in the ____
Fat digestion begins in the ____
Mouth
Stomach
Mouth & stomach
Why does the passage of feces continue during prolonged bowel rest when patients are restricted from eating food?
Because fecal contents include material other than food residue (inorganic material, water, fiber, and bacteria)
How long are SCFA?
2-5 carbons; produced in colon by action of bacteria on fermentable dietary fiber
