NUTR 1020: Science and Application of Human Nutrition - Module 3 Flashcards

Comprehensive vocabulary flashcards covering the digestive system, protein metabolism and structure, dietary fiber, carbohydrate regulation and disorders, cardiovascular disease, and cancer biology from Module 3.

Peristalsis

An automatic muscular wave action caused by smooth-muscle contractions that begins in the esophagus and propels food through the entire GI tract.

Bolus

A softened, chewed mass of food produced in the mouth through mastication and mixing with salivary secretions.

Chyme

A slushy, liquefied mixture of food bolus, hydrochloric acid, and digestive enzymes produced by the stomach's mixing and churning actions.

Bile

A substance synthesized by the liver and stored in the gallbladder that acts as an emulsifier to increase fat surface area for lipase access.

Cholecystokinin (CCK)

A gastrointestinal hormone released by intestinal cells when fat-rich chyme enters the duodenum that stimulates gallbladder contraction to release bile.

Secretin

A hormone triggered by acidic chyme entering the small intestine that signals the liver to produce bile and the pancreas to secrete digestive enzymes and sodium bicarbonate.

Passive Diffusion

The cellular absorption mechanism where nutrients such as water and lipids cross cell membranes freely down a concentration gradient without requiring energy.

Facilitated Diffusion

The passive transport of nutrients (such as water-soluble vitamins) across membranes from high to low concentration using specific carrier proteins or receptors without energy expenditure.

Active Transport

The energy-dependent movement of nutrients (such as glucose and amino acids) across membranes against a concentration gradient utilizing selective carrier proteins and ATP.

Anabolic Reactions

Metabolic reactions that synthesize larger, complex molecules from smaller units, typically occurring via condensation reactions.

Catabolic Reactions

Metabolic reactions that break down complex molecules into smaller units, typically occurring via hydrolysis reactions.

Homeostasis

The maintenance of a stable internal environment achieved through the dynamic equilibrium of catabolic and anabolic physiological reactions.

Deamination

The metabolic process of removing the nitrogen-containing amino group from an amino acid prior to its use for energy, producing urea which is excreted by the kidneys.

Primary Protein Structure

The basic linear sequence of amino acids joined together by peptide bonds in a polypeptide chain.

Secondary Protein Structure

The localized, uniform folding of sections of a polypeptide chain into alpha-helices or beta-pleated sheets.

Tertiary Protein Structure

The complete three-dimensional folding pattern of a single polypeptide chain that determines its specific functional shape.

Quaternary Protein Structure

The spatial arrangement and combination of multiple polypeptide chains into a single functional protein complex, such as hemoglobin.

Fibrous Proteins

Proteins characterized by long, uniform helical or pleated structures that provide strength and physical support to hair, nails, tendons, and connective tissues.

Globular Proteins

Compact, irregularly folded or spherical proteins that perform functional roles including nutrient transport, immunity, and enzymatic catalysis.

Denaturation

The unfolding of a protein's tertiary and secondary structure caused by heat, acid, alkali, or heavy metals, which prepares the protein for digestion without breaking peptide bonds.

Transcription

The initial stage of gene expression where a DNA gene sequence inside the nucleus is copied into messenger RNA (mRNA) by RNA polymerase.

Translation

The stage of protein synthesis where cytoplasmic ribosomes read the genetic code on mRNA and transfer RNA (tRNA) delivers complementary amino acids to assemble a polypeptide chain.

Complete Proteins

High biological value proteins, mainly from animal sources, that contain all nine essential amino acids in quantities sufficient to support human needs.

Incomplete Proteins

Proteins, primarily from plant foods, that lack adequate amounts of one or more of the nine essential amino acids.

Kwashiorkor

A severe form of protein malnutrition caused by inadequate protein intake despite adequate calorie intake, marked by peripheral edema, abdominal swelling, and reduced muscle mass.

Marasmus

A severe form of protein-energy malnutrition caused by an extreme deficiency of both protein and calories, presenting as emaciation and severe muscle and fat wasting.

Dietary Reference Intake (DRI) for Protein

The standard daily intake recommendation for healthy sedentary adults, established at $0.8\text{ g/kg/day}$.

Functional Fiber

Indigestible carbohydrates that are manufactured or isolated from natural sources (such as psyllium, inulin, and cellulose gel) and added to processed foods for physiological benefits.

Soluble Fiber

Non-digestible plant carbohydrates (including pectin, gums, and mucilage) that dissolve or form a viscous gel in water, slowing gastric emptying and binding bile acids.

Insoluble Fiber

Non-digestible plant carbohydrates (including cellulose, hemicellulose, and lignin) that do not dissolve in water, acting to increase fecal bulk and accelerate GI transit time.

Daily Recommended Intake (DRI) for Fiber

An intake target of $14\text{ g}$ per $1,000\text{ Calories}$ consumed, or absolute daily goals of $38\text{ g/day}$ for adult men and $25\text{ g/day}$ for adult women aged 19 to 50.

Enrichment Act of 1942

Federal legislation mandating that refined grains have specific lost micronutrients restored, specifically thiamin, riboflavin, niacin, and iron (with folic acid added in 1998).

Liver Glycogen

A carbohydrate storage reserve in the liver containing roughly $80\text{--}120\text{ grams}$ ($320\text{--}480\text{ Calories}$) used to regulate and maintain blood glucose levels between meals.

Muscle Glycogen

A carbohydrate storage reservoir within skeletal muscle containing roughly $300\text{--}500\text{ grams}$ that is reserved exclusively for fueling muscular activity.

Insulin

A pancreatic hormone secreted by beta cells in response to elevated blood glucose that promotes cellular glucose uptake and stimulates glycogen synthesis.

Glucagon

A pancreatic hormone secreted by alpha cells when blood glucose falls that stimulates liver glycogenolysis and gluconeogenesis to elevate circulating glucose.

Gluconeogenesis

The metabolic process by which the liver synthesizes new glucose molecules from non-carbohydrate precursors, primarily amino acids.

Hypoglycemia

An abnormally low blood glucose concentration, typically defined as falling below $70\text{ mg/dL}$, producing symptoms such as sweating, dizziness, headaches, and confusion.

Type 1 Diabetes Mellitus

An autoimmune disorder accounting for about 5% of diabetes cases where pancreatic beta cells are destroyed, resulting in little to no insulin production and requiring daily insulin therapy.

Type 2 Diabetes Mellitus

A metabolic disease accounting for about 95% of diabetes cases characterized by cellular insulin resistance and progressive beta-cell dysfunction, strongly associated with obesity and inactivity.

Fasting Blood Glucose Diagnostic Criteria

Clinical blood values defining metabolic status: Normal is $70\text{--}99\text{ mg/dL}$, Prediabetes is $100\text{--}125\text{ mg/dL}$, and Diabetes Mellitus is $\ge 126\text{ mg/dL}$.

Lactose Intolerance

A condition caused by insufficient lactase production in the small intestine, leading to bacterial fermentation of undigested lactose in the colon and causing bloating, gas, and diarrhea.

Milk Allergy

An IgE antibody-mediated immune reaction directed against milk proteins (such as casein or whey) that triggers histamine release, hives, rashes, and potentially life-threatening anaphylaxis.

Glycemic Index (GI)

A standardized scale that ranks carbohydrate-containing foods according to how quickly and significantly they raise blood glucose levels compared to a reference food.

Atherosclerosis

The primary cause of heart disease, characterized by the progressive accumulation of fatty streaks, cholesterol, and arterial plaque that narrows lumen diameter and limits blood flow.

Low-Density Lipoprotein (LDL)

A lipoprotein known as 'bad cholesterol' that carries cholesterol from the liver to peripheral tissues; high circulating levels accelerate arterial plaque deposition.

High-Density Lipoprotein (HDL)

A lipoprotein known as 'good cholesterol' that carries cholesterol away from peripheral tissues back to the liver for disposal, conferring cardiovascular protection.

Hypertension Clinical Stages

Blood pressure classifications: Stage 1 is $130\text{--}139\text{ systolic}$ or $80\text{--}89\text{ diastolic mmHg}$; Stage 2 is $\ge 140\text{ systolic}$ or $\ge 90\text{ diastolic mmHg}$; Hypertensive crisis is $> 180\text{ systolic}$ and/or $> 120\text{ diastolic mmHg}$.

Metabolic Syndrome

A clinical cluster of metabolic disorders diagnosed when an individual presents with at least three of five signs: central adiposity, elevated triglycerides, low HDL, elevated blood pressure, or elevated fasting glucose.

Carcinogenesis

The multistep process of cancer development comprising initiation (DNA damage and mutation), promotion (enhanced division of mutated cells), and progression (malignant transformation and metastasis).