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26 Cards in this Set
- Front
- Back
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What is the absorptive state?
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period during which ingested nutrients enter the blood from the gastrointestinal tract.
The nutrients are either used to supply the body's energy needs, or put into energy stores. |
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What is the postabsorptive state?
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period during which the gastrointestinal tract is empty of nutrients and the body's own store must supply energy
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What is glycogenolysis?
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the hydrolysis of glycogen stores to monomers of glucose-6-phosphate, occurs in the liver and in skeletal muscle
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What is anabolism?
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cellular synthesis of organic molecules
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What is catabolism?
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cellular breakdown of organic molecules
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What is glucose sparing?
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A metabolic adjustment during transition from absorptive to postabsorptive state.
Most organs and tissues reduce their glucose catabolism and increase their fat utilization for energy. The glucose produced by the liver is then "spared" for the nervous system's use. |
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What is glucagon?
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the peptide hormone produced by alpha cells of the pancreatic islets
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What are the functions of glucagon?
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1) increases glycogen breakdown
2) increases gluco |
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What stimulates glucagon secretion?
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epinephrine and sympathetic nerves
decreased plasma glucose levels |
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How does glucagon oppose insulin?
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by increasing plasma glucose and ketones
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What stimulates glycogenesis in the liver?
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epinephrine and glucagon
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Insulin favors glycogen formation in muscle cells by increasing _______________, stimulating the enzyme ____________, and inhibiting the enzyme ____________.
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Increases glucose transport into the cell
STIMULATES: GLYCOGEN SYNTHASE Inhibits: glycogen phosphorylase (which breaks down glycogen) |
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Insulin favors protein synthesis in muscle cells by increasing ____________________, stimulating ______________, and inhibiting _____________________.
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Increases amino acid transport into the cell
Stimulates: ribosomal enzymes that increase synthesis of proteins Inhibits: Enzymes that decrease synthesis of proteins |
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hypoglycemia
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low plasma glucose
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Islets of Langerhan-
Three types of cells and what they produce |
B (beta)- insulin
A (alpha)- glucagon D (delta)- somaostatin all peptide hormones! |
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the major physiologic effects of glucagon __________ those of insulin
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oppose
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lipolysis
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the catabolism of triglycerides in adipose tissue--> glycerol and fatty acids enter the blood stream --> glycerol that reasches the liver is converted to glucose= increase in blood glucose!
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gluconeogensis
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synthesis of glucose from pyruvate, glycerol, or amino acids
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What opposes insulin secretion?
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Sympathetic stimulation
Glucagon Epinephrine Cortisol Growth Hormone |
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What stimulates insulin secretion?
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Increased plasma glucose concentration
Increased amino acid concentration GIP hormone (secreted in GI tract in response to food intake) Autonomic neurons to the islets of langerhan |
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What are the physiologic effects of glucagon?
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1. increases glycogen breakdown
2. increases gluconeogenesis 3. increases the synthesis of ketones Overall: Increases plasma conc. of glucose and ketones (postabsorptive period) |
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What stimulates glucagon secretion?
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Hypoglycemia
Sympathetic nerves to the islets of langerhan epinephrine |
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What inhibits glucagon secretion?
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increased plasma glucose
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What does epinephrine do?
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stimulates HSL enzyme (hormone-sensitive lipase)
which causes the breakdown of triglycerides to free fatty acids and glycerol |
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what does the krebs cycle do?
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converts ketones into an energy source for the nervous system
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fatty acids + & glycerol phosphate=
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triglycerides
(in adipose tissue and liver) |
