Lecture: #12 (Nutrition and health)

Question 1

Energy

Answer 1

We measure energy in calories

Question 2

What factors influence an organism’s metabolism?

Answer 2

• Body size As you get bigger total energy usage increases
• Body temperature

Endotherms (warm-blooded): 
Extend energy to keep the temperature at some constant

Ectotherms: 
let their body temperature change with the environment. Don't extend energy to regulate body temperature. But it is hard to regulate things inside

• Activity level more activity requires more energy

Surface area to volumes matter a lot, more of your tissue is in contact with the outside world which means you’re losing more heat to the environment

Question 3

Metabolism

Answer 3

the chemical reactions in the body’s cells that change food into energy

Question 4

Endotherms

Answer 4

(warm-blooded): Extend energy to keep the temperature at some constant

Question 5

Ectotherms

Answer 5

let their body temperature change with the environment. Don’t extend energy to regulate body temperature. But it is hard to regulate things inside

Question 6

Basal Metabolic Rate (BMR)

Answer 6

How much energy an organism would need if it were in a state with no activity (no energy; no digestion; no temperature regulation); The energy needed to maintain life, without any activity, stress, growth, thermoregulation, or digestion

Question 7

Ingestion

Answer 7

The digestion process begins in the mouth with food intake:
* Mechanical digestion: The teeth play an important role in physically breaking food into smaller particles → increase surface area exposing more of the enzymes in the food so you can break more chemical bonds
* Chemical: The enzymes present in saliva also begin to chemically break down food.

Food goes down esophagus into the stomach in the form of a bolus

Question 8

Digestion

Answer 8

• Breaks down (carbohydrates → simple sugars, proteins → amino acids) into their component parts so they can be absorbed into the bloodstream
• sphincter closes, prevents regurgitation.
• Stomach churns (the muscles in your stomach) (so that the acid and the various enzymes can get at that material)

step 2

Question 9

Absorption (and more digestion–of lipids)

Answer 9

• There are finger-like projections that increase the surface area for the fluid to flow through; the more surface area the more you can absorb the broken-down macromolecules you have eaten in your food and use it for energy or raw materials
• Pancreas secretes enzymes that break down fats, carbs, and proteins
• Liver secrets bile - a detergent that breaks up clusters of fats and allows enzymes to break them down

Happens in the small intestine (tube in your midsection)

in the stomach during digestion the bolus moves down the esophagus into the stomach, and then we produce chyme (mix of gastric juices and partially digested food)

Question 10

Elimination

Answer 10

All around the small intestine there is smooth muscle that squeezes and pushes this clump of material continents into the colon (same as the large intestine).