Anatomy 1352: Metabolism and Nutrition

Metabolic States

Absorptive State

• Occurs while nutrients are being absorbed into bloodstream during digestion.
• Glucose is plentiful.
• Insulin is dominant hormone, facilitating glucose and amino acid uptake into cells for energy and protein synthesis.
• Excess glucose stored as glycogen in liver/muscles, or converted into fats.

Postabsorptive State

• Follows the absorption of nutrients; nutrients are no longer entering bloodstream.
• Aim is to maintain blood glucose levels.
• Red blood cells and nervous system heavily reliant on glucose.
• Glucagon becomes dominant hormone, promoting glycogen breakdown and gluconeogenesis.

Basal Metabolic Rate (BMR)

• Dependent on hormone levels (insulin, glucagon, thyroid hormones) and nutritional supply.
• Average adult needs 1,200-1,800 calories/day, influenced by activity level and body size.
• Affects body temperature; maintained through homeostasis by hypothalamus.

Thermoregulation

• Core body temperature is maintained at ~37°C.
• Hypothalamus regulates body temperature through vasoconstriction, muscle activity, and hormone release.
• Shivering generates heat through muscle contractions.

Essential Nutrients

Categories

1. Carbohydrates
   • Primary energy source found in grains, fruits.
   • Fiber is crucial for gut health; often removed in processed foods.
2. Lipids
   • Found in meats, nuts, seeds, and some vegetables (e.g., avocados).
   • Unsaturated fats preferred over saturated fats; avoid trans fats.
3. Proteins
   • Sourced from meats, nuts, seeds, and beans.

Vitamins

• Fat-soluble: A, D, K (important for vision, calcium absorption, and blood clotting, respectively).
• Water-soluble: B, C (important for connective tissue and nerve function).

Minerals

• Essential for various bodily functions.
• Includes calcium, phosphorus, sodium, potassium, iodine.

Vitamin and Mineral Deficiencies

• Vitamin A: Night blindness, immune deficiencies.
• Vitamin D: Rickets, osteomalacia.
• Vitamin K: Blood clotting issues.
• Vitamin C: Scurvy, connective tissue problems.
• B Vitamins: Essential for energy metabolism and nerve function.
  • Thiamine (B1) deficiency: Beriberi.
  • Niacin (B3) deficiency: Pellagra.
  • Folate (B9) deficiency: Megaloblastic anemia.
  • Cobalamin (B12) deficiency: Pernicious anemia.

Dietary Sources

• Carbohydrates: Majorly from grains and fruits.
• Proteins: Primarily from meats and secondary from beans, nuts.
• Lipids: Sourced from meats, seeds, nuts, and healthy vegetables like avocados.
• Vitamins and Minerals: Balanced diet necessary; supplements only in specific cases.

Conclusion

• Understanding the metabolic states and nutritional needs is crucial for maintaining health.
• Proper intake of macro- and micronutrients supports body functions, growth, and repair.