Human Nutrition (Chapters 4–7) – Key Vocabulary

39 vocabulary flashcards covering essential terms and definitions from Chapters 4–7 on nutrient absorption, digestive disorders, energy metabolism, and metabolic integration.

Crypts of Lieberkühn

Intestinal regions where new enterocytes are formed.

Micelle

Tiny bile-coated fat droplet that helps lipids cross enterocytes.

Chylomicron

Lipoprotein that transports dietary fats from the intestine into the lymphatic system.

Lipoproteins

Complexes of lipids and proteins that carry fats in the blood (e.g., LDL, HDL).

Lacteal

Lymph vessel inside an intestinal villus that absorbs chylomicrons.

PepT1 transporter

Major transporter that brings di- and tripeptides into enterocytes.

Portal vein

Blood vessel that carries absorbed nutrients like glucose and amino acids to the liver.

Glycemic Index

Measure of how quickly a food raises blood glucose levels.

Insulin

Hormone that lowers blood sugar by moving glucose into cells; dominant in the fed state.

Glucagon

Hormone that raises blood sugar by promoting glucose release from the liver; dominant in fasting.

Peptic Ulcer

Sore in the stomach or small intestine caused by acid erosion.

Helicobacter pylori (H. pylori)

Bacterium that can infect the stomach and cause ulcers.

Gallstones

Hardened deposits in the gallbladder that can obstruct bile flow.

IBS (Irritable Bowel Syndrome)

Functional gut disorder causing cramping, bloating, diarrhea, or constipation.

IBD (Inflammatory Bowel Disease)

Chronic intestinal inflammation, includes Crohn’s disease and ulcerative colitis.

Celiac Disease

Autoimmune disorder in which gluten damages the small intestine.

Diverticulosis

Formation of small pouches (diverticula) in the colon wall.

Diverticulitis

Inflammation or infection of diverticula.

Hemorrhoids

Swollen veins in the rectum or anus, often caused by straining.

Metabolism

All chemical reactions in the body that produce or use energy.

Glycolysis

Pathway that breaks glucose into pyruvate to generate energy.

Gluconeogenesis

Synthesis of glucose from non-carbohydrate sources such as amino acids.

Glycogenesis

Formation of glycogen from glucose for storage.

Glycogenolysis

Breakdown of glycogen into glucose.

Citric Acid Cycle (TCA or Krebs Cycle)

Central energy-producing cycle of aerobic metabolism.

Electron Transport Chain

Final stage of aerobic respiration that produces most cellular ATP.

Beta-oxidation

Catabolic process that converts fatty acids to acetyl-CoA for energy.

Ketone Bodies

Energy molecules produced from fat when carbohydrate is scarce.

Alcohol Dehydrogenase (ADH)

Liver enzyme that oxidizes ethanol to acetaldehyde.

Acetaldehyde

Toxic intermediate produced during alcohol metabolism.

Acetyl-CoA

Central metabolic molecule used to generate energy or synthesize fatty acids.

Liver metabolism

Processing of all macronutrients and detoxification (e.g., alcohol) in the liver.

Extrahepatic metabolism

Metabolic activities occurring outside the liver, such as in muscle or adipose tissue.

Fed state (Anabolic)

Post-meal period when the body stores nutrients and builds tissues.

Fasting state (Catabolic)

Period between meals when the body mobilizes stored fuels for energy.

Ketogenesis

Production of ketone bodies in the liver during fasting or low-carb intake.

Lactate

Product formed from pyruvate during anaerobic metabolism.