energy metabolism

nutrient

substance in food needed for growth, maintenance, repair

nutrients include

carbohydrates, proteins, lipids, vitamins, minerals

nutrient pools

the total body content of nutrients, both stored and circulating forms

what nutrients circulate in plasma

amino acids, glucose, fatty acids

what nutrients are stored

protein (amino acids, skeletal muscle), glycogen (glucose, skeletal muscle/liver), triglycerides (fatty acids, adipose)

protein nutrient function

structural materials, enzymes, fuel

lipids nutrient function

• cell membrane

• cholesterol

• hormones

• in adipose tissue

• inflammation

• fuel

metabolism

sum of all biochemical reactions inside a cell involving nutrients

anabolism

synthesis of large molecules from small ones

catabolism

hydrolysis of complex structures to simpler ones (ex digestion)

In general metabolic terms, food digestion is a form of _______, while building new protein molecules is a form of _______.

catabolism; anabolism

glycogen

stored carbohydrate (polysaccharide) in animals; chain of glucose molecules connected by covalent bonds

main sites fo glycogen storage

liver and skeletal muscle

Glycogenolysis

breakdown of glycogen into glucose; plasma glucose levels increase; catabolism

Glycogenesis

formation of glycogen from glucose molecules; plasma glucose levels decrease; anabolism

Gluconeogenesis

synthesis of glucose from non-carbohydrates, e.g. amino acids; plasma glucose levels increase; anabolism

Glycogenolysis process

breakdown of glycogen into glucose → plasma glucose levels increase

Glycogenesis process

formation of glycogen from glucose molecules → plasma glucose levels decrease

the process whereby excess glucose is stored in cells is called

glycogenesis

lipolysis

break down of lipids to fatty acids and glycerol; increased plasma fatty acid levels; catabolism

lipogenesis

formation of triglycerides (lipids); decreased plasma fatty acid levels; anabolism

• increases triglycerides (fats), but decreases free fatty acid levels

ketosis

• burning of fat instead of glucose energy

when is ketosis common

in starvation or diabetes mellitus

break down of lipids, what is present in body & urine

• ketone bodies in body and urine

  • breath smells sweet and like alcohol

build up of ketones (acidic)

metabolic acidosis (ketoacidosis) → decreased pH

• breathing becomes rapids because → it is a survival response where the body tries to correct the acid-base imbalance

metabolic states of the body

• fed → absorptive state

• fasted → post-absorptive state

fed (adsorptive state) happens

during and shortly after eating because nutrients are being absorbed into blood

• anabolic processes preside over catabolic

• we are using nutrients we need, putting excess nutrients into storage

  • excess circulating forms → storage

hormonal control of the absorptive state

• insulin → hypoglycemic hormone (lowers blood glucose)

insulin is secreted by

• secreted by beta cells of pancreas due to:

  • elevated blood levels of glucose and amino acids

  • parasympathetic stimulation

hormonal control of the absorptive state → insulin effects

• allows for glucose to diffuse into muscle and adipose cells

  • brain and liver do not need insulin

• stimulates glycogenesis

• inhibits glycogenolysis and gluconeogenesis

• promotes uptake of amino acids and protein synthesis

• stimulates lipogenesis

insulin allows

for glucose to diffuse into muscle and adipose cells

insulin stimulates

• stimulates glucose oxidation (b/d for energy), glycogenesis, lipogenesis

insulin inhibits

glycogenolysis and gluconeogenesis

insulin promtes

uptake of amino acids and protein syntesis

insulin results in

decreased blood glucose, fatty acids, amino acids

postabsorptive state

• catabolic processes preside

• GI tract empty

• energy obtained by breaking down storage form of nutrients

• storage → circulating

Hormonal control of the postabsorptive state

• glucagon - hyperglycemic hormone → raises blood glucose

glucagon is secreted by

alpha cells of pancreas

• declining blood glucose levels

• declining blood fatty acids

glucagon effects

• increases blood glucose

• increases blood fatty acids

glucagon primary target

liver

glucagon promotes

• Glycogenolysis in liver

• Gluconeogenesis in liver

• Lipolysis in adipose tissue

glucagon decreases

• glycogenesis

glucagon results

increased blood glucose & fatty acids

What is the primary objective during the postabsorptive state?

to make glucose