Lecture Notes: Human Body Composition and Metabolism

Body Composition Breakdown

• Water (64%): Major component, not visible externally.
• Protein (16%): Present in muscles, enzymes, hemoglobin, sodium-potassium pumps in neurons.
• Fat (16%): Stored in adipose tissue, used for energy storage, organ cushioning.
• Minerals (4%): Includes calcium, phosphorus (bones), iron (blood).
• Carbohydrates (1%): Used for immediate energy or stored as glycogen.

Metabolic Processes

• Continuous Acquisition and Loss: The body constantly takes in, utilizes, and discards substances.
• Protein Synthesis: Over a lifetime, the body synthesizes 225-450 kg of protein.
• Energy and Raw Materials from Food: Necessary for maintaining body functions.

Metabolic Reactions

• Catabolic Reactions: Break down complex molecules into simpler ones, releasing energy.
• Anabolic Reactions: Build complex molecules from simpler ones, consuming energy.
• Metabolism: All biochemical reactions in the body, balancing catabolic and anabolic processes.

Nutrients

• Six Major Groups of Nutrients:
  • Water: Vital for most bodily functions.
  • Vitamins: Fat-soluble and water-soluble. Assist in utilizing other nutrients (e.g., Vitamin C for iron absorption).
  • Minerals: Important for various bodily functions (e.g., calcium for bones, iron for hemoglobin).
  • Carbohydrates: Mainly from plants, provide glucose for ATP production.
  • Lipids: Store energy, form cell membranes, and produce hormones.
  • Proteins: Build muscle, connective tissue, enzymes, ion channels, etc.

Carbohydrates

• Sources: Fruits, honey, sugar beets, sugar cane, veggies, grains.
• Function: Glucose is crucial for ATP production.
• Storage: Energy from carbs stored as glycogen or converted to fats.

Lipids

• Sources: Meat, plant-based fats (fruits, nuts, seeds).
• Function: Energy storage, vitamin storage, organ cushioning, myelin formation, and cell membrane composition.
• Essential Fatty Acids: Omega-6 and Omega-3 must be ingested.

Proteins

• Sources: Meat, dairy, eggs, legumes, nuts, cereals.
• Function: Muscle formation, enzyme production, ion channels, cellular reactions.
• Essential Amino Acids: Nine amino acids must be ingested.
• Protein Synthesis: Amino acids from food are reassembled based on DNA instructions.

Metabolism Summary

• Anabolic vs. Catabolic Reactions: Anabolism builds and consumes energy; catabolism breaks down and releases energy.
• Conflict and Balance: These reactions create a dynamic balance within the body's metabolism.

Additional Information

• Crash Course Acknowledgements: Contributors and team involved in production.

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• Next topic: Detailed exploration of how carbohydrates create energy.