"Control of Energy, Metabolic Rate, and Body Temperature"

What are the two metabolic states?

Absorptive (fed) and postabsorptive (fasting).

When does the absorptive state occur?

During and right after eating.

What is the goal of the absorptive state?

Store energy and use incoming nutrients.

What hormone is high in the absorptive state?

Insulin.

What happens to glucose in the absorptive state?

Used for ATP or stored as glycogen.

What happens to fatty acids in the absorptive state?

Stored as triglycerides in adipose tissue.

What happens to amino acids in the absorptive state?

Used for protein synthesis; excess converted to energy or fat.

When does the postabsorptive state occur?

Between meals, when no food is being absorbed.

What is the goal of the postabsorptive state?

Maintain blood glucose levels.

What hormonal shift occurs in the postabsorptive state?

Lower Insulin, Higher Glucagon.

What is glycogenolysis?

Breakdown of glycogen into glucose (in liver).

What is gluconeogenesis?

Formation of glucose from non‑carbohydrates (amino acids).

What is glucose sparing?

Cells switch to fatty acids so glucose is saved for the brain.

What hormone lowers blood glucose?

Insulin.

What hormone raises blood glucose?

Glucagon.

When is insulin released?

When blood glucose is high.

What are insulin's main effects?

Higher Glucose uptake, Higher glycogen formation, Higher fat storage.

When is glucagon released?

When blood glucose is low.

What are glucagon's main effects?

Higher Glycogen breakdown, Higher gluconeogenesis, Higher blood glucose.

What happens to insulin after a meal?

It increases.

What happens to insulin during fasting?

It decreases.

What organ is the central regulator of glucose?

Liver.

How do muscles use glucose?

Locally for their own energy needs.

What does adipose tissue do with nutrients?

Stores fat.

What increases during exercise?

ATP demand and oxygen consumption.

What hormonal changes occur during exercise?

Lower Insulin, Higher Glucagon, Higher Epinephrine.

What is metabolic rate?

Total energy used over time.

What is basal metabolic rate (BMR)?

Energy use at rest, fasting, neutral temperature.

What organs contribute most to BMR?

Brain, heart, liver, kidneys; ion gradient maintenance.

What regulates appetite?

Hypothalamus.

What signals influence appetite?

Blood glucose, leptin, ghrelin.

Why is body temperature regulation important?

Enzyme function and membrane stability.

What happens to cells at high temperature?

Protein denaturation; membranes become too fluid.

What happens to cells at low temperature?

Slow reactions; membranes become rigid.

What are ectotherms?

Animals relying on external heat sources.

What are endotherms?

Animals generating internal heat.

What are homeotherms?

Maintain constant body temperature.

What are heterotherms?

Body temperature varies.

What is radiation?

Heat transfer via electromagnetic waves.

What is conduction?

Direct heat transfer between surfaces.

What is convection?

Heat transfer by moving air or water.

What is evaporation?

Heat loss via water vapor (sweating/panting).

What is vasodilation?

Widening of blood vessels → heat loss.

What is vasoconstriction?

Narrowing of blood vessels → heat retention.

What causes obesity?

Energy intake > expenditure, sedentary lifestyle, genetics, hormones, medications.

What are health risks of obesity?

Heart disease, type 2 diabetes, hypertension, cancers, joint damage, social