30. Muscle Work

Question 1

what are the necessities of muscular work for survival and give 5 examples

Answer 1

skeletal muscle is needed to move in various enviornments

1. endotherms - generate heat via metabolism
2. forage/hunt for food
3. avoid predators
4. adapt to changing envirnments
5. reproduce

all require muscular work and food

Question 2

why dont mammals store ATP for energy? how is it generated and used for energy?

Answer 2

because its a large molecule so its not stored. instead we constantly produce it through digestion

Question 3

what is the order of macronutrient energy use in a mammal?

Answer 3

muscle glycogen

liver glycogen

fat

protein

Question 4

what is a mammals main source of energy? why is it this nutrient?

Answer 4

fats!! fat is 9 calories per gram and for every 1 gram of carbs taken in, 3 grams of water is required. this means theres less physical room for energy expenditure

Question 5

what is the most economical speed of muscular work and why?

also what is a negative about the opposite one

Answer 5

aerobic activity because it uses fat as its main source of energy

due to the high amount of fat stores in the body, it can be ongoing.

negative of anaerobic acitivity: heat production which can negativly impact thermoregulation balance

Question 6

what are four examples of economising muscular work?

Answer 6

• hibernation
• long-term torpor (decresing the metabolic rate)
• an adaptation to winter cold and food scarcity
• body temperature is reduce
  *

Question 7

what is the unethical way to measure muscular work? how does it work?

Answer 7

in a metabolic chamber

where water flows around the room and the temperature change of the water is measured through the CO2 emmisions caused by the person/organism inside the room

Question 8

what is the ethical way of measuring muscular work?

Answer 8

indirect caloimetry - less accurate but more ethical

Question 9

what are three modern day issues with energy expenditure?

Answer 9

1. industrialisation - dont need to travel so far
2. domesitcation - agricultrue for easy food (no hunter gatheres)
3. food as a status symbol - obsesity for wealth or slimness (eating distorders
4. low energy expenditure because easy to get food and desk jobs