Temperature Regulation And Metabolism Flashcards
Normal Body Temperature
96.5F - 99.5F
Average: 98.6F
Lowest while sleeping
What are the factors that influence cellular respiration?
- Thyroxine (and T3)
- Epinephrine/ Stress response
- Normally active organs/ skeletal muscle
- Food Intake
- Body temperature changes
Thyroxine and Metabolism
Thyroxine Increases -> Cells increases energy production -> Metabolic rate Increases
Thyroxine Decreases -> Cells decreases energy production -> Metabolic rate decreases
How does Thyroxine and T3 affect heat production?
Increases rate of cell respiration (ATP production) and heat production in all tissues
How does epinephrine and sympathetic stimulation affect heat production?
Important in stress situations
Esp. Increase cell respiration in heart, skeletal muscles, and liver (increase heat)
How was skeletal muscles affect heat production?
Normal muscle tone require ATP
Produces ~ 25% of the total body heat at rest
How does the liver affect heat production?
Always metabolically active
Produces up to 20% of total body heat at rest
How does food intake affect heat production?
Increased activity in GI tract; APT and heat production occurs with peristalsis and synthesis of digestive enzymes
How does higher body temperature affect heat production?
Increased metabolic rate, Increases heat production, Increases metabolic rate and heat production
May become detrimental during high fevers
What does the hypothalamus do?
Thermostat
- Balances heat production and heat loss
- Receives information from skin peripherally as well as central receptors that detect temperature of blood flow through the brain
What are the Mechanisms to Increase Heat Loss (cooling mechanism)
- In warm environment or during exercise
-> Increase body temperature causes VASODILATION in dermis and causes heat loss (vasodilation = heat loss) - Environment temp is close to or higher than body temp
-> Vasodilation becomes ineffective
-> Evaporations of sweat is primary mechanism for heat loss
- SWEATING is inefficient if atmospheric humidity is high (evaporation doesn’t readily occur) - Reducing resting muscle tone can also heat production
-> Makes us sluggish on hot, humid days - EXCRETION (poop pee)
- Increase RR
- Decrease Metabolism
- Volitional control
What are the Mechanisms to conserve heat?
- Vasoconstriction
- Sweating decreases
- Increasing muscle tone
-> SHIVERING - Increase metabolism (via thyroxine)
- Epinephrine
- Food Intake
- Volitional Control (putting on layers)
Fever Mechanism
- Pyrogens: set hypothalamus (thermostat) to higher temperature
- Heat production mechanisms are triggered (we feel cold because our thermostat is raised)
- Increase muscle tone (shivering)
- Increase vasoconstriction
- Increase metabolism - Fever break
- Immune cells -> resolution of inflammatory response (medication)
What is metabolism, anabolism, and catabolism?
Metabolism: life sustaining chemical reactions in the body
Anabolism: Synthesis or formation of molecules, Requires (ATP)
Catabolism: breakdown of molecules, Energy released (often to produce ATP)
Anabolic and catabolic reactions are catalyzed by enzymes
What is gluconeogenesis (reverse glycolysis)
- Metabolic process that creates glucose from non carbohydrate sources
- Liver and kidneys breakdown food sources and store in liver
- low blood sugar levels trigger release
-> regulated by insulin, glucagon, and cortisol
What is glycogenolysis?
- Liver converts glycogen to glucose
- stimulated by low blood sugar
What do you need for glycolysis and what do you get as a result?
Needed
- Glucose: ATP needed as energy of ACTIVATION
- Niacin (part of NAD)
Result
- ATP
-> Released into the cell for energy use
- NADH
-> travels to the mitochondria, carrying high energy elections to the Electron transport system
- Pyruvic acid (lactic acid: anaerobic)
-> needed for next step (kreb’s cycle)
What doe you need for the Kreb’s citric acid cycle and what do you get?
Needed
- Pyruvic acid (from glucose or glycerol or excess amino acids
Or
- acetyl CoA ( from fatty acids or excess amino acids)
- Thiamine (to remove CO2)
- Niacin (part of NAD)
- Riboflavin (part of FAD)
- Pantothenic acid (part of coenzyme A)
Result
- CO2 (exhaled)
- ATP
- NADH and FADH (need for next step: electron transport system)
- 4 carbon molecule is regenerated for the next cycle
What do you need for the Cytochrome/Electron transport system and what do you get?
Needed
- NADH2 and FADH2 from glycolysis or the Kreb’s cycle
- Iron and copper (part of cytochromes)
Result
- ATP (A LOT)
-> produces the most ATP out of all the steps
- Metabolic water
How does Thyroxine (thyroid gland) affect metabolism?
- Increases use of glucose, fats, and amino acids for energy
- Increases protein synthesis
How does Growth hormone (anterior pituitary) affect metabolism
- Increases amino acids transport into cells
- increases protein synthesis
- increases use of fats for energy
How does insulin (pancreas) affect metabolism
- increases glucose transport into cells and use for energy
- increases conversion of glycogenesis in liver and muscles
- increases transport of amino acids and fatty acids into cells for synthesis rxns (not for energy production)
How does glucagon (pancreas) affect metabolism
- increases glcogenolysis
- increases use of amino acids and fats for energy
How does cortisol (adrenal cortex) affect metabolism
- increases conversion of glycogenesis in liver
- increases use of amino acids and fats for energy
- DECREASES protein synthesis except in liver and GI tract (ONLY DECREASE)
How does epinephrine affect metabolism
- increases glycogenolysis
- increases use of fats for energy
What is BMR and what factors affect it?
Basal Metabolic rate: energy expenditure at rest (measured in kcal)
MET: metabolic equivalent- caloric consumption (by means of breathing) of an active individual compared to rest
1 MET= 3.5mL/kg
Factors affecting metabolic rate
- Exercise INCREASES metabolic rate
- Age: higher in young children, DECREASES with age
- Body configuration: tall, thin people usually have higher metabolic rates than shorter people of same weight
- Sex hormones: testosterone increases metabolic activity more that estrogen
- Sympathetic stimulation: Metabolic rate increases in stress situations
- Decreased food intake: prolonged decrease in food intake causes metabolic rate to decrease -> body attempts to conserve energy sources that are still available
- Climate: People living in cold climates have higher metabolic rate than those living in tropical regions
