Flashcards in metabolism Deck (51):
what is anabolism
small to large
what is catabolism
large to small
what is fuel metabolism
Reactions involving the degradation, synthesis, and transformation of proteins, carbohydrates, and fats
-Nutrient molecules are broken down through the process of digestion into smaller absorbable molecules
what do proteins turn into?
what do carbohydrates turn into?
what do triglycerides turn into?
monoglyerdies and free fatty acids
what is absorptive state?
-after a meal, food is being digested and absorbed
-nutrients are absorbed from the lumen into the blood
what happens to CHO during absorptive state?
-glycogen synthesis and storage
-excess is converted and stored as triglyceride fat
what happens to fat during absorptive state?
triglyceride and synthesis and storage
what happens to protein during absorptive state?
-excess converted and stored as fat
what is post-absorptive state?
-in between meals, metabolic fuels are mobilized
-glucose comes from storage and is used to provide energy to body cells
-synthesis of proteins and fats is inhibited, since it takes up energy
-glycogenolysis (glycogen-> glucose)
primary role of liver?
maintaining blood glucose levels
how does glycerol act as a lesser energy source?
when triglyceride undergoes hydrolysis it is converted into glycerol, which can be converted to glucose by the liver
how can lactic acid be used as a lesser energy source?
- as it is produced by incomplete catabolism (large to small) of glucose via glycolysis in the muscle, it can also be converted to glucose in the liver
How can ketone bodies be used as a lesser energy source?
-it is produced by the liver during starvation
-produced through citric acid cycle
-because acetyl coenzyme A(produced by liver be using fatty acids) is unable to be further processed through the citric acid cycle for further energy extraction, the liver converts Coenzymes A to ketone bodies which are released into blood
-uses during long term starvation in replacement of glucose
what are the endocrine cells of the pancreas called and what does it produce?
Islets of Langerhans
-produces Beta cells and Alphas cells
What are B cells the site of?
the site of insulin synthesis and secretion
what do A cells do?
what is the role of insulin and glucagon?
regulate fuel metabolism
- can shift the metabolic pathway from anabolism to catabolism in feasting and fasting states
what is the flow of nutrients along metabolic pathway influenced by?
what does insulin promote?
lowers glucose, fatty acid, amino acid in blood
-promotes storage of glucose, amino acids, and fatty acids (absorptive state)
-promotes cellular uptake and conversion into glycogen, triglycerides, and proteins.
How does insulin exert its effect?
-alters transport of specific blood borne nutrients into cell.
-alters the activity of enzymes involves in metabolic pathways
what is glycogenesis?
glucose to glycogen
what is glycogenoLYSIS
glycogen to glucose
what is glucoNEOgenesis?
amino acids into glucose
what is lipolysis?
triglycerides into fatty acids and monoglycerides
what does insulin regulate with CHO?
1) glucose absorption from GI tract
2) transport of glucose into cells
3)production of glucose
4) urinary excretion of glucose
-it stimulates glycogenesis (glucose to glycogen)
what does insulin inhibit?
-glycigenolysis (glycogen to glucose
-inhibits enzymes that convert amino acids into glucose
what does GLUT do?
transports glucose between blood and cells
What does GLUT -1 do?
crosses glucose across BBB
what does GLUT-2 do?
transfers glucose into the blood from kidneys and intestinal cells
what does GLUT -3 do?
transfers glucose into neurons
what does GLUT 1 and 3 do?
transfers glucose into brain
how do the GLUTS transport glucose?
what different about GLUT 4?
-its the only type of glucose transporter that responds to insulin,
-it present in the plasma membrane of tissue of skeletal and fat tissue
what organ does not depend on insulin for glucose uptake?
what transports does the brain get its supply of glucose from?
GLUT 1 and 3
what are the actions of insulin on fat?
lowers blood fatty acids and promotes storage of triglycerides into the adipose tissue
-insilin increases glucose transport into adipose tissue through GLUT4
-inhibits break down of fats
-activates enzymes that catalyze production of fatty acids to glucose
action of insulin on proteins
-lowers amino acid levels and enhances synthesis
-promotes active transport of amino acids from the blood into muscles
-inhibits protein degeneration
What happens when blood glucose is high?
-increase secretion of insulin
-lowers blood glucose, fatty acids, and amino acid levels
-blood glucose increases following meal ingestion
-stimulates B-cells to synthesis insulin
what happens when blood glucose is low?
inhibits insulin secretion
-this shift metabolism to post absorptive state
negitive feedback of insulin and glucose?
- meal stimulates pancreas to activate B cells
B cells synthesis insilin
insulin is released into blood - an decrease in blood glucose feedsback on b cells to stop it
what does an elevated amount of amino acids in the blood trigger?
triggers beta cells to secrete insulin to bring the amino acids into cells, lowering blood amino acids
-promotes protein synthesis
what secretes glucagon?
alpha cells of the pancreas
what act does glucagon do?
increases blood glucose, by turning glycogen to glucose
during starvation, glucagon antagonizes insulins actions by doing what?
-promoting breakdown of fat
-inhibit triglyceride synthesis
-enhances ketone production
what is the action of glucagon on proteins?
-inhibits protein synthesis
-stimulate gluconeogenesis (amino acids into glucose)
-stimulates protein catabolism in liver
what is epinephrine's and cortisol's role in metabolism?
-increases blood glucose levels
-cortisol mobilizes amino acids through protein catabolism (large to small)
-long term starvation- cortisol helps maintain glucose concentration
what is GH's role in metabolism?
-exerts growth promoting effects- GH elevates blood glucose and fatty acids but have limited effects on overall fuel metabolism
-helps maintain blood glucose concentration during starvation
what is TH role in metabolism?
-increases metabolic rates
- however, onset of TH is too slow to have any significant effects on rapid adjustments to maintain normal nutrient levels