Human Physiology Digestive System Quiz

Multiple Choice Questions

• Questions cover topics like zymogens, gastrointestinal organs, carbohydrates, intestinal enzymes, lactose intolerance, glucose metabolism, and more.

Zymogen Characteristics

• Zymogens are inactive enzyme forms activated by proteolysis.

Digestive Organ Roles

• The small intestine is the primary site for enzymatic food breakdown.

Monosaccharides

• Glucose is a monosaccharide.

Intestinal Carbohydrate Enzymes

• Isomaltase cleaves (1,6) glucose-glucose branches on amylopectin/glycogen.

Lactose Intolerance

• Lactose intolerance involves an inability to properly digest lactose, a disaccharide of glucose and galactose.

Glucose Uptake Mechanisms

• Facilitated diffusion contributes to glucose uptake by intestinal enterocytes.

Liver Gluconeogenesis

• Conditions like diabetes, fasting, and carbohydrate-free diets elevate liver gluconeogenesis.

Glycogen Breakdown

• Glucagon is a key hormone regulating glycogen breakdown.

Cori Cycle

• The Cori cycle involves muscle-derived lactate as a source for gluconeogenesis.

Glycogen Synthesis

• UDP-glucose is a precursor substrate for glycogen synthesis.

Kidney Glucose Filtration Capacity

• The kidney's ability to filter glucose is overwhelmed at 170 mg/dL.

Gluconeogenesis

• Pyruvate carboxylase converts pyruvate to oxaloacetate, an initial step.

Essential Fatty Acids

• Linoleic acid is an essential fatty acid.

Fatty Acid Synthesis

• Acetyl CoA is transported out of the mitochondria to the cytoplasm to initiate fatty acid synthesis.

Fatty Acid Oxidation

• Carnitine shuttles fatty acids into the mitochondria for oxidation.

Lipid Absorption in Intestine

• Intestinal cells cannot absorb fatty acids.

Triglyceride Digestion

• Pancreatic lipase is key in digesting triglycerides in the small intestine.

Fatty Acid End

• Omega end: methyl end.

Lipoproteins and Cholesterol

• Very Low-density lipoproteins (VLDL) have the highest cholesterol content.

Cholesterol Ester Transfer Protein (CETP)

• CETP targets HDL.

Apolipoproteins

• Apolipoprotein B100 is found on VLDL.

Lipoprotein Lipase

• Lipoprotein lipase acts on triglycerides.

Apolipoprotein C2 (ApoC2)

• ApoC2 activates lipoprotein lipase.

Liver Lipoproteins

• The liver produces HDL and VLDL.

Familial Hypercholesterolemia (FH)

• FH is a genetic mutation in the LDL receptor.

Reverse Cholesterol Transport

• HDL is pivotal in reverse cholesterol transport.

PCSK9 Protein Inhibitors

• New drugs target PCSK9 to lower LDL cholesterol.

Protein Digestion Enzymes

• Pancreatic amylase is not a protein digesting enzyme.

Amino Acid Nitrogen Transport

• Glutamine carries nitrogen to the liver.

Ketogenic Amino Acids

• Leucine is a solely ketogenic amino acid.

Essential Amino Acids

• Valine is an essential amino acid.

Skeletal Muscle Amino Acid Metabolism

• Skeletal muscle primarily metabolizes amino acids with branched side chains.

Hydrochloric Acid (Stomach Acid) Function

• Hydrochloric acid deactivates pepsinogen and creates an acidic environment facilitating protein digestion.

Amino Acid Breakdown Products

• Valine's breakdown yields succinyl-CoA.

Urea Production

• Urea synthesis happens mostly in hepatocytes.

Urea Cycle Intermediates

• Ammonia combines with ATP and carbamoyl-phosphate to form carbamoyl-phosphate.

Urea Nitrogen Levels and Protein Intake

• High 24-hour urea nitrogen levels suggest a high-protein diet.

Post-Absorptive Phase Duration

• The post-absorptive phase lasts roughly 3 to 18 hours.

Brain Energy Source

• Glucose is the primary fuel for the brain (during both fed and fasting states).

Ketone Production Tissue

• The liver is the primary site of ketone production.

Starvation Amino Acid Release

• Alanine and glutamine are the primary amino acids released from muscles during starvation.

Glucose-6-phosphatase Deficiency

• Liver cells lack glucose-6-phosphatase, so they cannot contribute to blood glucose levels between meals.

Ketogenic Diet

• A ketogenic diet contains high amounts of fat with low or moderate protein and low carbohydrate contents.

Insulin Secretion Stimulation

• Stimuli like glucose cause incretins to be released, stimulating insulin secretion.

Insulin Action

• Insulin facilitates glucose transport into muscle and adipose tissue.

Pre-Proinsulin Processing to Insulin

• The C-peptide is cleaved during processing from Pre-Proinsulin to Insulin.

Ketone Production Cause

• During starvation, glucose production in the liver depletes oxaloacetate resulting in incomplete TCA and more Acetyl-Coa build-up to form ketones.

Liver Ketone Utilization

• Liver cells cannot use ketones as an energy source.

Incretins

• Incretins are gastrointestinal hormones that stimulate insulin secretion after a meal.

Hyperglycemia Causes

• The liver continually produces glucose, and the muscles have decreased glucose uptake—a common outcome of insulin resistance.

FTO Genetic Locus

• The FTO gene locus is a significant factor in body mass index (BMI) variation.

Glucose Tolerance Test

• The oral glucose tolerance test is a clinical way to diagnose diabetes.

Nutritional Biochemistry

• Students are asked to identify favorite topics and indicate what more topics they'd like to learn about.

Test your knowledge of the digestive system with this quiz covering zymogens, intestinal enzymes, carbohydrates, and glucose metabolism. Explore key concepts like lactose intolerance and the role of the liver in gluconeogenesis. Perfect for students studying human physiology!