Metabolism of Carbohydrates ,Proteins Flashcards
explain the role of glucose
( line to Krebs )
(1)
glucose –> pyruvate –> Acetyl CoA–> Krebs =ATP
what does insulin do?
4
Insulin regulates blood glucose levels :
reduces blood glucose levels via :
1-increases glucokinase which increases glucose 6 phosphate & glucose uptake into cell
2-Glycogen synthetase = increases glycogen storage
3-Gluconeogenesis decreases
4-Glycogenolysis decreases
what does glucagon do?
(3)
where is it produced and what can stop the secretion
produced by Alpha cells in the islet of Langerhan cells
stimulated by increased circulating AA as well
1- Less storage of glucose Stimulated by low blood glucose levels
2-Glucogneogensis
3-Glycogenolysis increases
(glucagon receptor signalling causes an increase in cAMP, PKA to stimulate glycogen phosphorylase promoting glycogen break down)
Somatostatin = stops glucagon secretion
what do glucocorticoids and adrenaline and other hormones do?
GANGC
(5)
Growth hormone= decreases glucose uptake by muscle, lipolysis increases, gluconeogenesis increases
Adrenaline=increases glycogenolysis and lipolysis
Noradrenaline=increases lipolysis, glycogenolysis
Glucagon=decreases glucose uptake into cells
Cortisol= increases lipolysis, gluconeogenesis, decreases glucose uptake
They all increase glucose in Blood
they are protective of Hypoglycaemia ( low blood sugar )
what osmotic changes does hyperglycaemia cause
4
1-increased blood glucose causes an increase in OSMOLARITY of ECF so water moves out from cells to ECF
2-high blood glucose also causes an increase in OSMOLALITY of renal tubular fluid=more urine loss
3-increase in blood osmolarity causes ADH to be secreted
4-we become more thirsty and try to increase body water.
ketoacidosis
what causes the smell?
(3)
Decreased amounts of insulin –>fat metabolism –>beta oxidation of fatty acids –>ketone ( fruity smell like acetone )
NOTE :
Normally the acetyl CoA goes to Krebs and combines with oxaloacetate, but when it doesn’t = KETONE BODIES
predict the effects of hypoglycemia
5
1-Glycosuria ( glucose in urine) 2-Dehydration =polyuria , Polydipsia 3-Tired= brain is starved 4-dizzy 5-hungry
distinguish between type 1 and type 2 diabetes
2
Type 1 =not enough insulin due to beta-cell dysfunciton
Type 2 =insulin resistance ( receptors don’t recognise body insult anymore) most common =90%
outline carbohydrate metabolism
2
dietary carbs :
1-fructose, galactose converted in the liver to glucose 6 phosphates –>glucose via Glucose 6 phosphatase
2- glucose can also be made via B oxidation + amino acids in gluconeogenesis
what are the 4 receptors for glucose and where are they found?
(4)
1- GLUT 1= most tissues, it takes up glucose
2-GLUT2 = less efficient, found in liver, pancreatic B cells ( removes excess glucose only when glucose is HIGH )
3-GLUT3= CNS = very sensitive to Glucose uptake
4-GLUT4=takes glucose into Skeletal muscle, adipose tissue= insulin causes these receptors to increase in number
what is the islet of Langerhans?
(2)
what do they secrete?
endocrine cells which secrete hormones in liver
Beta-cell =insulin
Alpha cell = glucagon
how is glucose filtered in the kidney
1-SGLT1/2 Co transporter and then GLUT2
- Na+ and glucose into the tubule
- Glucose –>GLUT2 = blood
- Na+ taken out via pump back out into blood
what is the islet of Langerhans?
(2)
what do they secrete?
endocrine cells which secrete hormones in the liver
Beta-cell =insulin
Alpha cell = glucagon
how is glucose filtered in the kidney
4
1-SGLT1/2 Co transporter and then GLUT2
2-Na+ and glucose into the tubule
3-Glucose –>GLUT2 = blood
4-Na+ taken out via pump back out into blood
How does diabetes cause a switch to fat metabolism?
4
1- increases hormone sensative lipase wihc is normally inhibited by insulin
2-lipolysis = glycerol + fatty acids
3-Fatty acids = beta oxidation =ketone bodies =ketoacidosis
4-acid= increased H+ in blood so more K+ moves into blood causng hyperkalemia
